Skeletal muscles are the muscles that relate to movement by exerting force on tendons. This action pulls on bones or other structures. Articulating bones typically do not move equally in response to contraction. The origin is the point of attachment of tendon to the stationary bone. The insertion is the point of attachment of the muscles other tendon to the bone that moves. But, guess what, that's all you need to know about that.
Lever Systems and Leverage:
A lever is a rigid structure that moves around a fixed point, called the fulcrum. Levers are acted on by two different forces: resistance (or load) and effort. Resistance (or load) opposed movement. For example, weight of muscle and bone. The Effort causes movement. It is the force due to muscle contraction. There are three types of levers that differ based on the location of the effort, load and fulcrum.
First class levers are not very common. The fulcrum is between the effort and the load. A none-body related example are scissors. The best body example is the neck. The effort comes from neck muscles, the fulcrum is the atlas/axis joint and the load is your face. (at least that's the way the picture looks).
Second class levers are not very common either. The load is between the fulcrum and the effort. A none-body example is a wheel barrow.
Third class levers are the most common in our bodies. The effort is between the fulcrum and the load. A none body example would be tweezers. A good example in our bodies are our elbows. The load is our hand, the effort is our arm muscles and the fulcrum is our elbow.
Fascicle arrangements can be kinda interesting. A contracting muscle shortens to approximately 70% of its original length. All of the fibers within a fascicle are parallel to one another. But, fascicles can form patterns with respect to their tendons. Fascicles must compromise between power and range of motion.
Movement occurs in coordination within muscle groups. The prime mover is the main mover of the bone. The antagonist causes the opposite action of the prime mover. Antagonists relax as as prime movers contract. Synergists are muscles that stabilize nearby joints. Grators stabilize the origin of the prime mover.
Skeletal muscles can be named by several different factors. These include: direction of fiber, location, size, number of origins, shape, points of attachment, and action.
Now onto the muscles themselves and their actions!
I'm going to break them up by categories as to location of the body.
Muscles of Facial expressions:
Epicranious (frontalis and occipitalis): the frontalis raises the eyebrows. the occipitalis pulls the scalp posterior.
Orbiticularis oculi: various parts can be activated individually. functions in blinking, closing, squinting and drawing the eyebrows inward.
Orbiticularis oris: closes the mouth and protrudes the lips.
Buccinator: draws back the corners of the mouth and compresses cheeks medially.
Zygomaticus (major and minor): raises lateral corners of the mouth upward.
Platysma: depresses the mandible and pulls lower lip back.
Extrinsic Eye Muscles:
4 rectus muscles: (these muscles make sense. they are located where their names say they are and they pull the eye in that direction).
inferior: below the eye, pulls eye inferior and medial.
superior: above the eye. pulls eye superior and medial
medial: medial to the eye and pulls it medially.
lateral: lateral to the eye and pulls it laterally.
2 oblique muscles: (these muscles are located oppositely where one would think they are.)
inferior: above the eye and pulls it superiorly and laterally.
superior: below the eye and pulls it anteriorly and laterally.
Levataor palpabrea: raises eye lids.
Muscles of Mastication:
Masseter: elevates the mandible
Temporalis: closes jaw. elevates and retracts mandible.
Pterygoid (medial and lateral): move mandible.
Muscles that move the head and vertebral column:
Sternocleidomastoid: flexion. general resistance, rotation of head toward opposite shoulder.
Splenius Capitus: as a group, it extends or hyperextends the head or allows head to rotate
Semispinalis Capitis: acting together, extend head and vertebral column. not together, rotation of head.
Errector Spinae: extend and bed vertebral column laterally. Fibers also extend head.
Muscles that move the pectoral girdle:
Trapezius: extends the head, moves the scapula used in shrugging.
Rhomboideus Major: pulls scapula medially. stabilizes scapula.
Levator Scapulae: elevate and adducts scapula.
Seratus Anterior: moves scapula anteriorly. abduction/raising of arm
Pectoralis Minor: moves ribs or scapula depending on which is flexed.
Muscles that move the arm:
Pectoralis Major: prime mover of arm flexion. adducts and medially rotates
Teres Major: extends, medially rotates and adducts humerus
Laissimus dorsi: prime move of arm extension. adducts and medially rotates arm.
Supraspinatus: assists abduction of humerus. stabilizes shoulder.
Deltoid: Acting as a whole prime mover of arm abduction. can aid in flexion, extension and rotation.
Infraspinatus: lateral rotation of the humerus. also stabilizes the shoulder.
Muscles that move the forearm:
Biceps Bracii: flexion of elbow. supination of forearm.
Brachialis: a major flexor of forearm
Brachioradialis: synergist in forearm flexion
Triceps Brachii: powerful forearm extensor.
Supinator: acts with biceps brachii to supinate forearm
Pronator Teres: acts synergistically with pronator quadratus to protnate arm.
Muscles that move the hand:
Flexor Carpi Radialis: powerful flexor of wrist abducts wrist
Flexor Carpi Unlaris: powerful flexor of wrist. adducts wrist
Flexor Digitorium (Superficialis and Profundus): flexes wrist and middle phalanges.
Extensor Digitorium: prime move of finger extension. extends wrist. abducts fingers (in fan motion)
Muscles of the abdominal wall:
External oblique: flexes and rotates the vertebral column, increases abdomen pressure, aids back muscles
Internal Oblique: flexes and rotates the vertebral column
Transverse Abdominis: compresses abdominal contents
Rectus Abdominis: flexes and rotates the vertebral column
Muscles used in breathing:
Intercostal (internal and external): aid in breathing and moves ribs.
Diaphragm: prime mover of inspiration, flattens on constriction, increasing vertical dimensions of the thorax
Muscles of the pelvic outlet:
Levator ani: supports the pelvic visera and provides a sphincterlike action to the anal canal and vagina.
Coccygeus: supports the pelvic visera and provides a sphincterlike action to the anal canal and vagina.
Bulbospongiousus: males: empties the urethra. in females: constricts vagina.
Ischicavernous: assists functions of the bulbiospongiousus
Muscles that move the thigh:
Illiopsoas: (Psoas Major and Iliacus): flex trunkon thigh. flex though. lateral flexion of the vertebral column.
Gluteus Maximas: complex. powerful thigh extensor. laterally rotates and abducts though.
Gluteus Minimus: abducts and medially rotates thigh. steadies pelvis.
Tenor Fasciae Latae: flexes, abducts and medially rotates the thigh. steadies trunk.
Adductor Longus: adducts and medially rotates and flexes the thigh.
Gracillis: adducts thigh. flexes and medially rotates leg, especially while walking.
Muscles that move the leg:
Biceps Femoris: (hamstring) extends thigh, laterally rotates leg. flexes knee.
Semitendinous: extends thigh, flexes knee. laterally rotates leg.
Semimembranosus: extends thigh. flexes knee. laterally rotates leg.
Satorius: flexes, abducts and laterally rotates thigh. flexes knee.
Rectus femoris: (quad) extends knee and flexes thigh at hip
Vastus Lateralis: extends knee and stabilizes knee
Vastus Medalis: extends and stabilizes knee
Vastus Intermedius: extends knee
Muscles that move the foot:
Tibialis Anterior: prime move of dorsifexion; inverts foot. supports longitudinal arch
Extensor hallicus longus: extends hallux. dorsiflexes feet.
Soleus: plantar flexion. good for locomotion
Gastrocnemius: plantar flexes foot when knee is extended
Sunday, June 20, 2010
Wednesday, June 16, 2010
A little more about muscle tissue.
Botulinum Toxin is a bacterial toxin that blocks the release of acetyl choline from synaptic vesicles. Botulinum toxin can be found in improperly canned foods. A tiny amount can paralyze respiratory muscles and cause death. Even though this can be deadly it is the primary ingredient in Botox. It can help with strabismus, blepharospasm, spasms of the vocal cords that interfere with speech, cosmetic treatment and to alleviate chronic back pain due to muscle spasms.
Curare is a plant poison that was used on arrows and blowgun darts. It causes muscle paralysis by blocking acetyl choline receptors, thus inhibiting sodium ion channels. Derivatives of curare are used during surgery to relax skeletal muscles.
Anticholinesterase can slow the of Achase and removal of acetyl choline. This chemical can strengthen weak muscle contractions. It is treatment for myasthenia gravis, an antidote for curare poisoning and terminate the effects of curare after surgery.
Muscle tension is controlled by the brain. The axons of motor neurons are branched and innervate several muscle fibers within a muscle. A motor unit is a single motor neuron and all the muscle fibers it innervates. Recruitment occurs when contraction of more muscle fibers by stimulating more motor units in order to generate greater tension in a muscle. 2-3 muscle fibers per motor unit power our voice muscles. 10-20 muscle fibers per motor unit power eye movement. 2000-3000 muscle fibers move our arms and legs.
A muscle twitch is a single contraction that lasts only a fraction of a second.
Summation occurs when a muscle contraction is increased until maximal sustained contraction is reached.
Tetanus is the maximal sustained contraction.
Tone is a continuous slight tension maintained by motor units that take turns contracting. Muscle tone keeps skeletal muscles firm and keep the head from slumping forward on the chest.
Skeletal Muscle fibers vary in their amount of myoglobin, mitochondria and capillaries. Red muscle fibers have more myoglobin, capillaries and mitochondria than white muscle cells. Contraction and relaxation speeds vary based on how fast myosin ATPase hydrolyzes ATP. Resistance to fatigue depends on different metabolic reactions used to generate ATP.
Slow oxidative muscle fibers are red in color and very resistant to fatigue, but they are the least powerful and smallest in diameter. They make ATP aerobically.
Fast oxidative muscle fibers are pinkish in color and they are glycolytic. They have lots of mitochondria, myoglobin and blood vessels. They split ATP very, very fast.
Fast glycolytic muscle fibers are white in color. It is most often used in anaerobic activity for a short duration. They are the largest in diameter and make ATP via glycolysis.
Most muscles contain a mixture of all fiber types, but remember that each motor unit only powers one type of cell. Exercise can change the characteristics of skeletal muscles fibers to some degree, but not the number of cells.
Cardiac muscles are striated, short, quadrangular-shaped, branching fibers. They have a single centrally located nucleus. Cells connected by intercarlated discs with gap junctions. They have the same arrangement of thick and thin filaments as skeletal. Cardiac muscles have more mitochondria compared to skeletal muscle fibers, contractions last 10-15 times longer due to prolonged delivery of calcium from the sarcoplasmic reticulum and the extracellular fluid. They are involuntary and contract by themselves or from each other. This continuous, rhythmic activity is a major physiological difference between cardiac and skeletal muscle tissue. Skeletal muscle depends on aerobic respiration to generate ATP.
Anatomy of smooth muscles are usually involuntary. The action potential spread through fibers by gap junctions. Fibers are stimulated by neurotrasnmitters or hormones. Myofilaments are randomly organized and have no sarcomeres. They lack striations and transverse tubles. Contractions of smooth muscles are initiated by calcium flow primarily from the interstitial fluid. Calcium moves slowly out of the muscle for delaying muscle relaxation. In smooth muscle, the regulator protein that binds calcium ions in the cytosol is calmodulin.
Curare is a plant poison that was used on arrows and blowgun darts. It causes muscle paralysis by blocking acetyl choline receptors, thus inhibiting sodium ion channels. Derivatives of curare are used during surgery to relax skeletal muscles.
Anticholinesterase can slow the of Achase and removal of acetyl choline. This chemical can strengthen weak muscle contractions. It is treatment for myasthenia gravis, an antidote for curare poisoning and terminate the effects of curare after surgery.
Muscle tension is controlled by the brain. The axons of motor neurons are branched and innervate several muscle fibers within a muscle. A motor unit is a single motor neuron and all the muscle fibers it innervates. Recruitment occurs when contraction of more muscle fibers by stimulating more motor units in order to generate greater tension in a muscle. 2-3 muscle fibers per motor unit power our voice muscles. 10-20 muscle fibers per motor unit power eye movement. 2000-3000 muscle fibers move our arms and legs.
A muscle twitch is a single contraction that lasts only a fraction of a second.
Summation occurs when a muscle contraction is increased until maximal sustained contraction is reached.
Tetanus is the maximal sustained contraction.
Tone is a continuous slight tension maintained by motor units that take turns contracting. Muscle tone keeps skeletal muscles firm and keep the head from slumping forward on the chest.
Skeletal Muscle fibers vary in their amount of myoglobin, mitochondria and capillaries. Red muscle fibers have more myoglobin, capillaries and mitochondria than white muscle cells. Contraction and relaxation speeds vary based on how fast myosin ATPase hydrolyzes ATP. Resistance to fatigue depends on different metabolic reactions used to generate ATP.
Slow oxidative muscle fibers are red in color and very resistant to fatigue, but they are the least powerful and smallest in diameter. They make ATP aerobically.
Fast oxidative muscle fibers are pinkish in color and they are glycolytic. They have lots of mitochondria, myoglobin and blood vessels. They split ATP very, very fast.
Fast glycolytic muscle fibers are white in color. It is most often used in anaerobic activity for a short duration. They are the largest in diameter and make ATP via glycolysis.
Most muscles contain a mixture of all fiber types, but remember that each motor unit only powers one type of cell. Exercise can change the characteristics of skeletal muscles fibers to some degree, but not the number of cells.
Cardiac muscles are striated, short, quadrangular-shaped, branching fibers. They have a single centrally located nucleus. Cells connected by intercarlated discs with gap junctions. They have the same arrangement of thick and thin filaments as skeletal. Cardiac muscles have more mitochondria compared to skeletal muscle fibers, contractions last 10-15 times longer due to prolonged delivery of calcium from the sarcoplasmic reticulum and the extracellular fluid. They are involuntary and contract by themselves or from each other. This continuous, rhythmic activity is a major physiological difference between cardiac and skeletal muscle tissue. Skeletal muscle depends on aerobic respiration to generate ATP.
Anatomy of smooth muscles are usually involuntary. The action potential spread through fibers by gap junctions. Fibers are stimulated by neurotrasnmitters or hormones. Myofilaments are randomly organized and have no sarcomeres. They lack striations and transverse tubles. Contractions of smooth muscles are initiated by calcium flow primarily from the interstitial fluid. Calcium moves slowly out of the muscle for delaying muscle relaxation. In smooth muscle, the regulator protein that binds calcium ions in the cytosol is calmodulin.
Monday, June 14, 2010
Muscle tissue
As we have previously mentioned, there are three types of muscle tissue: skeletal, cardiac and smooth. When we refer to the muscle system, we generally speak specifically of the skeletal system.
As just a quick comparison of the three different types of muscle tissue...
Smooth muscle is spindle shaped and non-striated. It surrounds our tubes and helps things move. Smooth muscle in involuntary. The smooth muscles contract and release slowly.
Cardiac muscle is also involuntary. It is branched and striated and is only located on the heart. The network of fibers contract as a unit and are self-exciting.
Skeletal muscle is striated and tubular. It is usually attached to the skeleton and is almost completely voluntary. Contraction and releasing occurs very quickly.
All muscle tissue has several functions. They move something. They help to stabilize part of the body. Muscles store and move substances in the body. Maintenance of homeostasis.
Muscle tissue also has several properties. It is excitable (responds to chemicals released from nerve cells), conductive (ability to propagate electrical signals over membrane), contractile (ability to shorten and generate force), extensive (ability to be stretched without damaging the tissue... to a degree) and elastic (ability to return to original shape after being stretched).
The muscular system is the voluntarily controlled muscles of the body. Most skeletal muscles also are controlled subconsciously to some extent, such as the diaphragm. Each muscle is an organ composed of skeletal muscle tissue and connective tissue. Skeletal muscles are also called fibers or myofibers.
The connective tissue of muscles includes facia, perimysium, endomysium, tendons and aponeuroses. There are two types of facia, superficial (this is loose connective tissue and fat underlying the skin) and deep (dense irregular connective tissue around the muscle). Epimysium is the outermost connective tissue that surrounds the whole muscle. It separates 10-100 fibers into fascicles. The perimysium surrounds fascicles. The endomysium separates individual muscle cells. At the end of the muscle belly, a tendon is formed and attaches to the bone. Aponeuroses are the connective tissue sheets attaching to bone or adjacent muscles.
Intramuscular injections are used to give relatively large doses of drugs that can't be administered to the bloodstream. If administered directly to the bloodstream, it could be extremely dangerous or fatal.
Neurons that stimulate muscles to contract are called efferent neurons. Muscle action depends on a rich blood supply to deliver nutrients and oxygen.
The anatomy of a skeletal muscle consists of the whole muscle which is of the organ level. The fascicle which is a single bundle of cells. The muscle fiber is a single muscle cell. You are born with all of the muscle cells you will ever have, the just get bigger when you exercise. Muscle growth is called hypertrophy.
The anatomy of a muscle fiber is a bit more. The muscle cells contain most of the normal cell components. Sarcolemma, T tubules and sarcoplasm are additional/different organelles. The sarcomeres are the units of myofibrils. Myofibrils are the bundles of myofilametns that contract. There are two types of myofilaments: actin and myosin; their function and structure is wholly for muscle contractions. Sarcoplasm reticulum is a modified endoplasmic reticulum that surrounds myofibrils and stores calcium. A contraction of muscle is when the microfilaments slide past one another causing the muscle to shorten.
Muscle proteins include contractile proteins and structural proteins. Myosin is a thick filament as well as a contractile protein. It resembles golf clubs or oars sticking off a boat. Myosin converts ATP to energy of motion. Actin is another contractile protein. But instead of being thick like myosin, it is rather thin. It provides a site where a myosin head can attach. Tropomyosin covers the binding site for myosin on the actin strands. Tropinin moves tropomyosin off the binding sites so that myosin can bond to it. Structural proteins include titin which stabilizes the position of myosin at the M line and dystrophitin which links thin filaments to the sacrolemma.
Physiology of muscle contractions:
motor neurons
action potential in muscle
role of calcium
tropopmyosin uncovers binding sites
cross bridging
role of ATP
relaxation
Muscle Metabolism:
A huge amount of ATP is needed to power the contraction cycle and pump calcium into the sacroplasm.The ATP inside muscle fibers will only power contractions for a few seconds. ATP must be produced by the muscle fiber after reserves are used up. There are three ways that muscle fibers can do so: creatine phosphate, anaerobically and aerobically.
Creatine phosphate is made by excess ATP. Creatine phosphate transfers its high energy phosphate to ADP regenerating new ATP, but this is only useful for 8-15 seconds.
Anaerobic respiration uses glucose to make ATP when creatine phosphate is used up. The process gets glucose from the blood and glycogen from muscle fibers. It makes 2 pyruvic acids and two ATP. Pyruvic acid is converted to acetic acid and carried away by the blood. This process is only good for about 30-40 seconds.
Aerobic respiration occurs when an activity lasts longer than 30 seconds. Aerobic respiration provides 90% of the needed ATP in activities lasting more than 10 minutes. Pyruvic acid enters the mitochondria and is completely oxidized generating ATP, water, CO2 and heat. Each molecule of pyruvic acid generates 36 ATP. Muscle has two sources of oxygen, hemoglobin (from the blood) and myoglobin (from the muscle cell). Myoglobin and hemoglobin are oxygen-binding proteins.
Myoglobin stores some oxygen and reduces the muscle's constant need for blood supply during muscle contractions. Muscle contractions compress blood vessels. After exercise, heavy breathing continues to get oxygen back into the system. Oxygen debt occurs when additional oxygen is used to restore muscle cells to resting level in three ways: the liver cells convert lactic acid into glycogen, to synthesize creatine phosphate into ATP and to replace the oxygen removed from myoglobin.
Fatigue occurs from a lowered pH, thanks to lactic acid. Following exercise, muscle cramps are mostl ikely due to a temporary deficit of ATP. Athletes experience less muscle fatigue because they produce less lactic acid.
there is a little more, but that will way until after the test tomorrow.
As just a quick comparison of the three different types of muscle tissue...
Smooth muscle is spindle shaped and non-striated. It surrounds our tubes and helps things move. Smooth muscle in involuntary. The smooth muscles contract and release slowly.
Cardiac muscle is also involuntary. It is branched and striated and is only located on the heart. The network of fibers contract as a unit and are self-exciting.
Skeletal muscle is striated and tubular. It is usually attached to the skeleton and is almost completely voluntary. Contraction and releasing occurs very quickly.
All muscle tissue has several functions. They move something. They help to stabilize part of the body. Muscles store and move substances in the body. Maintenance of homeostasis.
Muscle tissue also has several properties. It is excitable (responds to chemicals released from nerve cells), conductive (ability to propagate electrical signals over membrane), contractile (ability to shorten and generate force), extensive (ability to be stretched without damaging the tissue... to a degree) and elastic (ability to return to original shape after being stretched).
The muscular system is the voluntarily controlled muscles of the body. Most skeletal muscles also are controlled subconsciously to some extent, such as the diaphragm. Each muscle is an organ composed of skeletal muscle tissue and connective tissue. Skeletal muscles are also called fibers or myofibers.
The connective tissue of muscles includes facia, perimysium, endomysium, tendons and aponeuroses. There are two types of facia, superficial (this is loose connective tissue and fat underlying the skin) and deep (dense irregular connective tissue around the muscle). Epimysium is the outermost connective tissue that surrounds the whole muscle. It separates 10-100 fibers into fascicles. The perimysium surrounds fascicles. The endomysium separates individual muscle cells. At the end of the muscle belly, a tendon is formed and attaches to the bone. Aponeuroses are the connective tissue sheets attaching to bone or adjacent muscles.
Intramuscular injections are used to give relatively large doses of drugs that can't be administered to the bloodstream. If administered directly to the bloodstream, it could be extremely dangerous or fatal.
Neurons that stimulate muscles to contract are called efferent neurons. Muscle action depends on a rich blood supply to deliver nutrients and oxygen.
The anatomy of a skeletal muscle consists of the whole muscle which is of the organ level. The fascicle which is a single bundle of cells. The muscle fiber is a single muscle cell. You are born with all of the muscle cells you will ever have, the just get bigger when you exercise. Muscle growth is called hypertrophy.
The anatomy of a muscle fiber is a bit more. The muscle cells contain most of the normal cell components. Sarcolemma, T tubules and sarcoplasm are additional/different organelles. The sarcomeres are the units of myofibrils. Myofibrils are the bundles of myofilametns that contract. There are two types of myofilaments: actin and myosin; their function and structure is wholly for muscle contractions. Sarcoplasm reticulum is a modified endoplasmic reticulum that surrounds myofibrils and stores calcium. A contraction of muscle is when the microfilaments slide past one another causing the muscle to shorten.
Muscle proteins include contractile proteins and structural proteins. Myosin is a thick filament as well as a contractile protein. It resembles golf clubs or oars sticking off a boat. Myosin converts ATP to energy of motion. Actin is another contractile protein. But instead of being thick like myosin, it is rather thin. It provides a site where a myosin head can attach. Tropomyosin covers the binding site for myosin on the actin strands. Tropinin moves tropomyosin off the binding sites so that myosin can bond to it. Structural proteins include titin which stabilizes the position of myosin at the M line and dystrophitin which links thin filaments to the sacrolemma.
Physiology of muscle contractions:
motor neurons
action potential in muscle
role of calcium
tropopmyosin uncovers binding sites
cross bridging
role of ATP
relaxation
Muscle Metabolism:
A huge amount of ATP is needed to power the contraction cycle and pump calcium into the sacroplasm.The ATP inside muscle fibers will only power contractions for a few seconds. ATP must be produced by the muscle fiber after reserves are used up. There are three ways that muscle fibers can do so: creatine phosphate, anaerobically and aerobically.
Creatine phosphate is made by excess ATP. Creatine phosphate transfers its high energy phosphate to ADP regenerating new ATP, but this is only useful for 8-15 seconds.
Anaerobic respiration uses glucose to make ATP when creatine phosphate is used up. The process gets glucose from the blood and glycogen from muscle fibers. It makes 2 pyruvic acids and two ATP. Pyruvic acid is converted to acetic acid and carried away by the blood. This process is only good for about 30-40 seconds.
Aerobic respiration occurs when an activity lasts longer than 30 seconds. Aerobic respiration provides 90% of the needed ATP in activities lasting more than 10 minutes. Pyruvic acid enters the mitochondria and is completely oxidized generating ATP, water, CO2 and heat. Each molecule of pyruvic acid generates 36 ATP. Muscle has two sources of oxygen, hemoglobin (from the blood) and myoglobin (from the muscle cell). Myoglobin and hemoglobin are oxygen-binding proteins.
Myoglobin stores some oxygen and reduces the muscle's constant need for blood supply during muscle contractions. Muscle contractions compress blood vessels. After exercise, heavy breathing continues to get oxygen back into the system. Oxygen debt occurs when additional oxygen is used to restore muscle cells to resting level in three ways: the liver cells convert lactic acid into glycogen, to synthesize creatine phosphate into ATP and to replace the oxygen removed from myoglobin.
Fatigue occurs from a lowered pH, thanks to lactic acid. Following exercise, muscle cramps are mostl ikely due to a temporary deficit of ATP. Athletes experience less muscle fatigue because they produce less lactic acid.
there is a little more, but that will way until after the test tomorrow.
Sunday, June 13, 2010
Joints
Joints hold bones together but permit movement. There are three different types of contact between tissues. Bone to bone, cartilage to bone and teeth to bone. Arthrology is the study of joints and kinesiology is the study of motion. Joints are classified by both structure and function. Structural classifications are based on the presence or absence of a synovial cavity and type of connecting tissue. There are three kinds: 1. fibrous (bones are held together by dense collagen fibers), 2. cartiliginous (joints are held together by cartilage) and 3. synovial (held together by ligaments). Functional classification is based upon how much it can move and there are also three kinds. 1. immovable or synarthrotic, 2. slightly movable or amphiarthrotic and 3. freely moveable or diarthrotic.
Fibrous joints do not have a synovial cavity. The articulating bones are held closely together by dense irregular connective tissue. They permit little or no movement. They are also sometimes called sutures (ragged edges of adjacent bones re held together by fibers).
Cartilaginous joints lack a synovial cavity as well. There are two types. 1. synchondroses which are bones held together by hyaline cartilage that are synarthrotic and 2. symphyses that are bones held together by fibrocartilage that are amphiarthrotic.
Synovial joints have a synovial cavity that allow them to be diarthrotic. The articular cartilage covers ends of bones to reduce friction and absorb shock. The articular capsule has two layers that surround the joint. Fibrous capsule is the ligaments that attach to periosteum around the bone. The synovial membrane is the inner lining of the capsule and is loose connective tissue. The synovial membrane secretes synovial fluid. The synovial fluid brings nutrients to articular cartilage because cartilage is avascular. There are two accessory ligaments: the extracapsular ligaments and the intracapsular ligaments (acl). The menisci stabilize the joint by providing a better fit of articulating bones. There are medial and lateral menisci of the knee: c-shaped like 2 half stadiums facing each other. Bursae are the saclike structures of connective tissue that are lined with synovial membrane and filled with synovial fluid They function in cushioning and reducing friction.
The types of movement at synovial (diarthrotic) joints include:
1. gliding movement: the simple movement of back and forth and side to side.
these are mostly found in intercarpal joints. They permit mainly sliding, back and forth and twisting movements.
2. angular movement: increases or decreases the angle between articulating joints.
a. flexion: decreasing the angle between bones. ex: bending the trunk forward
b. extension: increasing the angle between bones. ex: in anatomical position, the body is in extension.
c. hyperextension: continuation of extension beyond anatomical position.
d. abduction: movement away from the midline
e. adduction: movement toward the midline
f. circumduction: making a cone with the distal end of the bone.
3. rotation: a bone revolves around it's longitudinal axis ex: turning your head side to side to say no.
4. special movements.
a. supination: turning palms up
b. pronation: turning palms down
c. plantar flexion: standing on tippy toes
d. dorsiflexion: press soles of feet together and lift arch medially
e. eversion: press soles away from each other and press arch medially
f. depression: lovering a body region
g. elevation: raise a body region
h. protraction: move body part anteriorly
i. retraction: move protracted body part back to normal.
Types of synovial joints:
Planar joints primarily permit back and forth or side to side movement. These include intercarpal and intertarsal joints.
Hinge joints have a spool that fits into a concave area. They permit flexion-extension movements. The knee and elbow are good examples.
A pivot joint is when the rounded surface of bone articulates with a ring formed by second bone and ligament. Monoaxial since it allows only rotation around the longitudinal axis. Examples include the proximal radioulnar joint of the hand.
Condyloid or Ellipsoidal joints are oval shaped projections that fit into an oval depression. They are biaxial and can flex/extend or abduct/adduct. The best example is your wrist.
A saddle joint looks like a person riding on a saddle. Examples include the thumb joint.
The ball and socket joint has a ball that fits into a cuplike depression. Movement is capable in all planes and rotations. The only examples include the hip and shoulder.
A sprain is a stretch or tear of a ligament. More serious sprains involve complete tears of one or more ligaments. A common knee sprain involves the anterior cruciate ligament.
Strains are defined as a partially or completely torn muscle or tendon. Patellar tendinitis or jumper's knee is a common strain that usually results from overuse. Tendonitis is an inflammtion of the tendons and synovial membranes surrounding certain joints.
Fibrous joints do not have a synovial cavity. The articulating bones are held closely together by dense irregular connective tissue. They permit little or no movement. They are also sometimes called sutures (ragged edges of adjacent bones re held together by fibers).
Cartilaginous joints lack a synovial cavity as well. There are two types. 1. synchondroses which are bones held together by hyaline cartilage that are synarthrotic and 2. symphyses that are bones held together by fibrocartilage that are amphiarthrotic.
Synovial joints have a synovial cavity that allow them to be diarthrotic. The articular cartilage covers ends of bones to reduce friction and absorb shock. The articular capsule has two layers that surround the joint. Fibrous capsule is the ligaments that attach to periosteum around the bone. The synovial membrane is the inner lining of the capsule and is loose connective tissue. The synovial membrane secretes synovial fluid. The synovial fluid brings nutrients to articular cartilage because cartilage is avascular. There are two accessory ligaments: the extracapsular ligaments and the intracapsular ligaments (acl). The menisci stabilize the joint by providing a better fit of articulating bones. There are medial and lateral menisci of the knee: c-shaped like 2 half stadiums facing each other. Bursae are the saclike structures of connective tissue that are lined with synovial membrane and filled with synovial fluid They function in cushioning and reducing friction.
The types of movement at synovial (diarthrotic) joints include:
1. gliding movement: the simple movement of back and forth and side to side.
these are mostly found in intercarpal joints. They permit mainly sliding, back and forth and twisting movements.
2. angular movement: increases or decreases the angle between articulating joints.
a. flexion: decreasing the angle between bones. ex: bending the trunk forward
b. extension: increasing the angle between bones. ex: in anatomical position, the body is in extension.
c. hyperextension: continuation of extension beyond anatomical position.
d. abduction: movement away from the midline
e. adduction: movement toward the midline
f. circumduction: making a cone with the distal end of the bone.
3. rotation: a bone revolves around it's longitudinal axis ex: turning your head side to side to say no.
4. special movements.
a. supination: turning palms up
b. pronation: turning palms down
c. plantar flexion: standing on tippy toes
d. dorsiflexion: press soles of feet together and lift arch medially
e. eversion: press soles away from each other and press arch medially
f. depression: lovering a body region
g. elevation: raise a body region
h. protraction: move body part anteriorly
i. retraction: move protracted body part back to normal.
Types of synovial joints:
Planar joints primarily permit back and forth or side to side movement. These include intercarpal and intertarsal joints.
Hinge joints have a spool that fits into a concave area. They permit flexion-extension movements. The knee and elbow are good examples.
A pivot joint is when the rounded surface of bone articulates with a ring formed by second bone and ligament. Monoaxial since it allows only rotation around the longitudinal axis. Examples include the proximal radioulnar joint of the hand.
Condyloid or Ellipsoidal joints are oval shaped projections that fit into an oval depression. They are biaxial and can flex/extend or abduct/adduct. The best example is your wrist.
A saddle joint looks like a person riding on a saddle. Examples include the thumb joint.
The ball and socket joint has a ball that fits into a cuplike depression. Movement is capable in all planes and rotations. The only examples include the hip and shoulder.
A sprain is a stretch or tear of a ligament. More serious sprains involve complete tears of one or more ligaments. A common knee sprain involves the anterior cruciate ligament.
Strains are defined as a partially or completely torn muscle or tendon. Patellar tendinitis or jumper's knee is a common strain that usually results from overuse. Tendonitis is an inflammtion of the tendons and synovial membranes surrounding certain joints.
Appendicular Skeleton
The appendicular skeleton has one primary function: facilitate movement! Within the appendicular skeleton, there are 126 bones in for areas. The upper limbs have 60, the lower limbs have 60, the pectoral girdle has 4 and the pelvic girdle has 2.
The pectoral girdle is also known as the shoulder. There are two of them, therefore two of each bone. The pectoral girdle is made of the scapula and the clavicle. The clavicle is an s-shaped bone. The medial curve is convex posteriorly, while the lateral curve is concave anteriorly. It extends from the sternum to the scapula, above the first rib. Where the two curves meet is a common fracture site. The medial side articulates with the manubrium of the sternum forming the sternoclavicular joint. The lateral end articulates with the acromium forming the acromioclavicular joint. Ligaments attached to the clavicle to stabilize its position.
The scapula is also called the shoulder blade. For the amount of work that it does, it is extremely thin. It is triangular is shape. It articulates with both the radius and the humerus. It is held in place posteriorly by complex shoulder and back musculature. The medial borders of the scapulae lie about 5 cm from the vertebral column. The scapula has four main features. The spine is a large process on the posterior of the scapula that ends laterally as the acromion. The acromian is the flattened portion of the spine on the scapula. The coracoid process is a protruding projection that provides the point of attachment for the biceps trachiae. The gelnoid is a shallow concavity that articulates with the head of the humerus.
Each upper limb consists of 30 bones. The humerus, ulna, radius, carpals, metacarpals and phalanges. Joints include the shoulder, elbow, wrist, metacarpophalageal and interphalageal.
The humerus is the largest and longest bone of the upper limb. It articulates proximally at the scapula at the glenoid cavity and distally with the ulna and radius at the elbow. At the proximal end of the humerus, we find a rounded head, a greater tubercle (the lateral projection, distal to the neck), lesser tubercles for muscle attachment, the deltoid tuberosity and the body. The distal end of the humerus has 2 condyles. The capitulum laterally articulates with the the head of the radius. The trochlea is the medial articulation with the ulna. Medial and lateral epichondyles are the attachment sites for muscles.
The radius and ulna make up the forearm. On the medial side is the ulna. The radius is on the lateral side. The radius turns the radio (with the thumb). Each bone articulates with the humerus and three carpal bones. At the proximal end of the forearm, the ulna has the olecranon process that forms the point of the elbow. The radius head articulates with the capitulum of the humerus and radial notch of ulna tuberosity for the biceps attachment. At the distal end of the forearm, the styloid process of the ulna is the site of attachment for wrist ligaments. The radius forms wrist joints with carpals.
Eight carpal bones bound together by ligaments form the wrist. Five metacarpal bones are in the palm of the hand (one for each finger and the thumb). These make up knuckles. 14 phalanges are create the fingers and the thumb.
The Pelvic girdle is also known as the hip girdle. This area provides strong and stable support for the lower appendages. It also allows for some flexibility. There is less flexibility than the pectoral girdle however, because it it more stable. There are two hip bones that are also known as coxal bones or ossa coxae. Each hip bone is composed of three bones at birth, the illium, ischium and the pubis. These three bones fuse at the acetabelum during childhood to form the socket for the hip joint. The ischium is the inferior, posterior portion of the hipbone. The ischial spine and tuberosity are located here. It forms the obturator foramen with the pubis which is the largest foramen in the body. The pubis is the body that is superior and inferior to ramus. It is the area that is linked to pubic symphysis. The illium forms the illiac crest, a site for muscle attachment. It is anterior and superior to the iliac spine. It can be felt laterally to groin. The greater sciatic notch is here for the sciatic nerve. The pelvis is made of the sacrum, coccyx and 2 hip bones. The pelvic brim is from the top of the symphysis to the sacral promontory. The false pelvis is above the brim, while the true pelvis is below the brim.
Each of the lower limbs, like the upper limbs has 30 bones. The femur and patella within in the thigh, the tibia and fibula are in the leg, the tarsals in the ankle. the metatarsals are the foot and the phalanges are the toes. The joints include the hip, knee and ankle, proximal and distal tibiofibular, and metatarsophalangeal.
The femur is aka the thighbone. It is the largest, heaviest and strongest bone in the body. It articulates with the hip bone and tibia. The head of the femur articulates with the acetabulum. The tibia articulates with both the medial and lateral condyles. The neck of the femur is a constricted region distal to the head and it is a common fracture site among the elderly. The trochanters are a bony landmark that can only be found on the hip bone. There are greater and lesser trochanters, linea aspera and muscle attachments.
The patella, aka the kneecap, is the only sesamoid bone in the body and is located anterior to the knee joint. It functions to increase the leverage of the tendon of the quadriceps femoris to maintain the position of the tendon when the knee is bend and to protect the joint.
The tibia is the shin bone and does all of the weight bearing. It is larger and medial to the fibula. The fibula is lateral and parallel to the tibia. The tibia has lateral and medial condyles that articulate with the femur. The tibial tuberosity os for the patellar ligaments of the quadricep femoris. The medial malleolus is at the ankle and is the articulation point for the talus. The fibula is not in the knee. Its main function is for attachment of muscles. There is a lateral malleolus at the ankle.
There are seven tarsals that make the ankle and share the weight associated with walking. Five metatarsal bones are contained in the foot. Dancers, especially ballet, fracture their metatarsals. The arrangement of the phalanges in the toes is the same as the phalanges of the hand and is the same as described above. The big toe is known as the hallux.
The ankle is made of seven tarsal bones. The talus is the ankle bone and articulates with the medial malleolus of the tibia and the lateral malleolus of the fibula. The calcaneous is the heel bone and is the largest and strongest bone in the foot.
The bones of the foot are arranged in two arches held together by ligaments and tendons. They enable the foot to support and distribute body weight over the hard and soft tissues and provide leverage while walking. The arches are fully developed by about age 12-13. Flatfoot (decline), clawfoot (elevation) and clubfoot (rotation) are caused by the medial longitudinal arches. Arches provide yield and spring back when weight is lifted. Longitudinal arches from heel to toe along each side and the transverse arch is across the midfoot region.
The pectoral girdle is also known as the shoulder. There are two of them, therefore two of each bone. The pectoral girdle is made of the scapula and the clavicle. The clavicle is an s-shaped bone. The medial curve is convex posteriorly, while the lateral curve is concave anteriorly. It extends from the sternum to the scapula, above the first rib. Where the two curves meet is a common fracture site. The medial side articulates with the manubrium of the sternum forming the sternoclavicular joint. The lateral end articulates with the acromium forming the acromioclavicular joint. Ligaments attached to the clavicle to stabilize its position.
The scapula is also called the shoulder blade. For the amount of work that it does, it is extremely thin. It is triangular is shape. It articulates with both the radius and the humerus. It is held in place posteriorly by complex shoulder and back musculature. The medial borders of the scapulae lie about 5 cm from the vertebral column. The scapula has four main features. The spine is a large process on the posterior of the scapula that ends laterally as the acromion. The acromian is the flattened portion of the spine on the scapula. The coracoid process is a protruding projection that provides the point of attachment for the biceps trachiae. The gelnoid is a shallow concavity that articulates with the head of the humerus.
Each upper limb consists of 30 bones. The humerus, ulna, radius, carpals, metacarpals and phalanges. Joints include the shoulder, elbow, wrist, metacarpophalageal and interphalageal.
The humerus is the largest and longest bone of the upper limb. It articulates proximally at the scapula at the glenoid cavity and distally with the ulna and radius at the elbow. At the proximal end of the humerus, we find a rounded head, a greater tubercle (the lateral projection, distal to the neck), lesser tubercles for muscle attachment, the deltoid tuberosity and the body. The distal end of the humerus has 2 condyles. The capitulum laterally articulates with the the head of the radius. The trochlea is the medial articulation with the ulna. Medial and lateral epichondyles are the attachment sites for muscles.
The radius and ulna make up the forearm. On the medial side is the ulna. The radius is on the lateral side. The radius turns the radio (with the thumb). Each bone articulates with the humerus and three carpal bones. At the proximal end of the forearm, the ulna has the olecranon process that forms the point of the elbow. The radius head articulates with the capitulum of the humerus and radial notch of ulna tuberosity for the biceps attachment. At the distal end of the forearm, the styloid process of the ulna is the site of attachment for wrist ligaments. The radius forms wrist joints with carpals.
Eight carpal bones bound together by ligaments form the wrist. Five metacarpal bones are in the palm of the hand (one for each finger and the thumb). These make up knuckles. 14 phalanges are create the fingers and the thumb.
The Pelvic girdle is also known as the hip girdle. This area provides strong and stable support for the lower appendages. It also allows for some flexibility. There is less flexibility than the pectoral girdle however, because it it more stable. There are two hip bones that are also known as coxal bones or ossa coxae. Each hip bone is composed of three bones at birth, the illium, ischium and the pubis. These three bones fuse at the acetabelum during childhood to form the socket for the hip joint. The ischium is the inferior, posterior portion of the hipbone. The ischial spine and tuberosity are located here. It forms the obturator foramen with the pubis which is the largest foramen in the body. The pubis is the body that is superior and inferior to ramus. It is the area that is linked to pubic symphysis. The illium forms the illiac crest, a site for muscle attachment. It is anterior and superior to the iliac spine. It can be felt laterally to groin. The greater sciatic notch is here for the sciatic nerve. The pelvis is made of the sacrum, coccyx and 2 hip bones. The pelvic brim is from the top of the symphysis to the sacral promontory. The false pelvis is above the brim, while the true pelvis is below the brim.
Each of the lower limbs, like the upper limbs has 30 bones. The femur and patella within in the thigh, the tibia and fibula are in the leg, the tarsals in the ankle. the metatarsals are the foot and the phalanges are the toes. The joints include the hip, knee and ankle, proximal and distal tibiofibular, and metatarsophalangeal.
The femur is aka the thighbone. It is the largest, heaviest and strongest bone in the body. It articulates with the hip bone and tibia. The head of the femur articulates with the acetabulum. The tibia articulates with both the medial and lateral condyles. The neck of the femur is a constricted region distal to the head and it is a common fracture site among the elderly. The trochanters are a bony landmark that can only be found on the hip bone. There are greater and lesser trochanters, linea aspera and muscle attachments.
The patella, aka the kneecap, is the only sesamoid bone in the body and is located anterior to the knee joint. It functions to increase the leverage of the tendon of the quadriceps femoris to maintain the position of the tendon when the knee is bend and to protect the joint.
The tibia is the shin bone and does all of the weight bearing. It is larger and medial to the fibula. The fibula is lateral and parallel to the tibia. The tibia has lateral and medial condyles that articulate with the femur. The tibial tuberosity os for the patellar ligaments of the quadricep femoris. The medial malleolus is at the ankle and is the articulation point for the talus. The fibula is not in the knee. Its main function is for attachment of muscles. There is a lateral malleolus at the ankle.
There are seven tarsals that make the ankle and share the weight associated with walking. Five metatarsal bones are contained in the foot. Dancers, especially ballet, fracture their metatarsals. The arrangement of the phalanges in the toes is the same as the phalanges of the hand and is the same as described above. The big toe is known as the hallux.
The ankle is made of seven tarsal bones. The talus is the ankle bone and articulates with the medial malleolus of the tibia and the lateral malleolus of the fibula. The calcaneous is the heel bone and is the largest and strongest bone in the foot.
The bones of the foot are arranged in two arches held together by ligaments and tendons. They enable the foot to support and distribute body weight over the hard and soft tissues and provide leverage while walking. The arches are fully developed by about age 12-13. Flatfoot (decline), clawfoot (elevation) and clubfoot (rotation) are caused by the medial longitudinal arches. Arches provide yield and spring back when weight is lifted. Longitudinal arches from heel to toe along each side and the transverse arch is across the midfoot region.
Axial Skeleton
The axial skeleton is one of the two parts of the skeletal system. It has 80 bones that compose the skull, ribs, spine/vertebrae, sternum, ear ossicles and the hyoid bone. The axial system can be broken down even further. The skull has 22 bones, 8 in the cranium and 14 in the face; there is one hyoid bone, 6 auditory ossicles, 26 vertebrae, 1 sternum and 24 ribs.
The Skull
The Skull is made up of cranial and facial bones. In general, the skull serves as a place for cavities, paranasal sinuses, mandible and suture bones.
The frontal bone is a part of the cranium. There is only one. It forms the forehead, roof of the orbits (eyes) and anterior cranial floor. The coronal suture connects the frontal bone to the parietal bones.
The parietal bones are the 2nd and 3rd bones of the cranium. They form the roof of the cranium. There are four sutures involved with the parietal bones: the first is the coronal suture that connects the parietal bones to the frontal bone. The second is the saggital suture that connects the two parietal bones together. The lamboid suture connects the parietals to the occipital bone. The squamous suture connects the parietal bones to the temporal bones.
The occipital bone is the 4th bone of the cranium. There is only one. It is the back of the skull and base of the cranium. There is the foramen magnum that is the opening for the spinal cord, vertebral and spinal arteries to leave the head. The external occipital protuberance (a projection that sticks out from the occipital bone) is the bump just above our necks. This joins together with the axis of the vertebrae to allow us to nod our head yes. The ligament that allows us to do this is called the ligamentum nuchae. The lamboid suture connects the occipital bones to the parietal bones.
The temporal bones are the 5th and 6th bones of the cranium. They are the sides of our cranium, as well as the floor. It is also the floor and side of each orbital. The squamous suture attaches the temporal bones to the parietal bones. The temporal bones are the location of the external acoustic (auditory) meatus, the mastoid process (neck muscle attachment point), the styloid process (one of the tongue muscle attachment points) and the zygomatic process.
The sphenoid bone is the 7th bone and base of the cranium, sides of the skull, floor and sides of the orbits. It has a sella tuchica and the sphenoid sinus.
The ethmoid bone is the 8th bone of the cranium. It makes up the anterior portion of the cranial floor, the medial walls of the orbits. The perpendicular plate makes our septum and is on the ethmoid bone.
Facial Bones
There are 14 facial bones: 2 nasal, 2 maxillae, 2 zygomatic, 2 lacrimal, 2 palentine, 2 inferior nasal conchae, 1 mandible, and 1 vomer. I'm not going to cover the palentine or lacrimal bones because we aren't going to be tested on them.
The maxillary bones are the floor of our orbits, the nasal cavity or hard palate. A cleft plate occurs when the amxillae don't fuse together.
The zygomatic bones are the prominences of our cheeks. They form the lateral walls and floor of our orbits. The temporal process joins to the zygomatic process of the temporal bone.
The nasal bones make up the bridge of our nose.
The vomer is our nasal septum. It divides the nose into left and right cavities. If someone has a deviated septum, the septum is not directly in the middle of the nose.
The mandible is the only movable part of our skull. It is horseshoe shaped with a flat ramus going upward at the ends. The mandibular condyle is a fossae of the temporals. The mandibular notch is between the condylar and coronoid processes.
The orbits, as I've mentioned, have 7 bones that make them up. The roof is formed by the frontal and sphenoid bones. The lateral wall is formed by the zygomatic and sphenoid bones. The floor is the maxilla, zygomatic and sphenoid. The medial wall is made of the maxilla, lacrimal, ethmoid and sphenoid.
The hyoid bone is the only bone in the body that does not articulate with another bone. It is u-shaped. It is suspended by ligaments and muscle from the skull. It helps support the tongue, and provides attachment for the tongue, neck and pharyngeal muscles.
Moving onto the Vertebral Column
The vertebral column is composed of 7 cervical vertebrae, 12 thoracic vertebrae, 5 fused vertebrae, a sacrum (5 fused vertebrae) and a coccyx (4 fused vertebrae). Each of the four curvatures of the vertebrae make sense. The cervical vertebrae make the cervical curvature, the thoracic vertebrae make the thoracic curvature, the lumbar curvature comes from the lumbar vertebrae and the sacrum and coccyx make up the pelvic curvature. (Which makes sense because the top of the sacrum and the top of the pelvic girdle match up).
The vertebrae are separated by intervertebral discs. These help absorb vertical shock. The discs permit various movements within the column. They are a fibrocartilagenous with a pulpy center. When one or more of the discs are injured, the nucleus pulposes protrudes into the ring, which causes pressure to be put on the spinal nerves. Surgically removing a disc is called laminectomy.
Every vertebrae has several parts. Different vertebrae have different prominent parts. The body is the weight bearing part and is anterior to the rest of the vertebrae. The vertebral foramen is the opening for blood vessels and the spinal cord. There are seven processes (projections). There are two transverse processes, one spinous process and four articular processes. The intervertebral notch forms the intervertebral foramen with the next vertebrae.
The spinal canal is the vertebral foramen all linked together. Intervertebral foramen allow the spinal cord to leave leave the spine.
The seven cervical vertebrae are at the top of the spine. The first one is called the atlas. It allows the skull to say yes. The second vertebrae is called the axis. It is the only one to have a dens. The dens allows the head to say no. Cervical vertebrae 3-6 are typical vertebrae. The 7th, vertebrae pominens is different, it has a more prominent spinous process.
Thoracic vertebrae articulate with ribs. There are 12 of them and they have larger and stronger bodies. Thoracic vertebrae also have longer transverse and spinous processes. Facets and demifacets articulate from the body of the vertebrae to the head of the ribs.
Lumbar vertebrae are the largest and strongest.
The sacrum is the union of 5 vertebrae by age 30. The median sacral crest was the spinous process. The sacral ala is a fused transverse process.
The coccyx is the union of 4 fused vertebrae by age 30. Caudal or epidural anesthesia is inserted into the sacral to anesthetize sacral and coccygeal nerves.
The Thorax is the extire chest. It consists of sternum, costal cartilage, ribs and bodies of thoracic vertebrae. The thorax is a bony cage that is flattened from front to back. The sternum consists of the manubrium (1st and 2nd ribs); it is the sternal angle junction within the body. The body of the sternum is the costal cartilage of ribs 2-10. The sternum's xiphoid is at the most inferior of the sternum. It has the xiphisternal joint and is the location for CPR as well as a connection site for abdominal muscles.
We have 24 ribs. They increase in length from ribs 1-7. After the 7th rib, they decrease in size. The head and tubercle articulate with facets of the vertebrae. The tubercle of the rib articulates with the transverse process of the vertebrae, while the head articulates with the vertebral bodies.
The Skull
The Skull is made up of cranial and facial bones. In general, the skull serves as a place for cavities, paranasal sinuses, mandible and suture bones.
The frontal bone is a part of the cranium. There is only one. It forms the forehead, roof of the orbits (eyes) and anterior cranial floor. The coronal suture connects the frontal bone to the parietal bones.
The parietal bones are the 2nd and 3rd bones of the cranium. They form the roof of the cranium. There are four sutures involved with the parietal bones: the first is the coronal suture that connects the parietal bones to the frontal bone. The second is the saggital suture that connects the two parietal bones together. The lamboid suture connects the parietals to the occipital bone. The squamous suture connects the parietal bones to the temporal bones.
The occipital bone is the 4th bone of the cranium. There is only one. It is the back of the skull and base of the cranium. There is the foramen magnum that is the opening for the spinal cord, vertebral and spinal arteries to leave the head. The external occipital protuberance (a projection that sticks out from the occipital bone) is the bump just above our necks. This joins together with the axis of the vertebrae to allow us to nod our head yes. The ligament that allows us to do this is called the ligamentum nuchae. The lamboid suture connects the occipital bones to the parietal bones.
The temporal bones are the 5th and 6th bones of the cranium. They are the sides of our cranium, as well as the floor. It is also the floor and side of each orbital. The squamous suture attaches the temporal bones to the parietal bones. The temporal bones are the location of the external acoustic (auditory) meatus, the mastoid process (neck muscle attachment point), the styloid process (one of the tongue muscle attachment points) and the zygomatic process.
The sphenoid bone is the 7th bone and base of the cranium, sides of the skull, floor and sides of the orbits. It has a sella tuchica and the sphenoid sinus.
The ethmoid bone is the 8th bone of the cranium. It makes up the anterior portion of the cranial floor, the medial walls of the orbits. The perpendicular plate makes our septum and is on the ethmoid bone.
Facial Bones
There are 14 facial bones: 2 nasal, 2 maxillae, 2 zygomatic, 2 lacrimal, 2 palentine, 2 inferior nasal conchae, 1 mandible, and 1 vomer. I'm not going to cover the palentine or lacrimal bones because we aren't going to be tested on them.
The maxillary bones are the floor of our orbits, the nasal cavity or hard palate. A cleft plate occurs when the amxillae don't fuse together.
The zygomatic bones are the prominences of our cheeks. They form the lateral walls and floor of our orbits. The temporal process joins to the zygomatic process of the temporal bone.
The nasal bones make up the bridge of our nose.
The vomer is our nasal septum. It divides the nose into left and right cavities. If someone has a deviated septum, the septum is not directly in the middle of the nose.
The mandible is the only movable part of our skull. It is horseshoe shaped with a flat ramus going upward at the ends. The mandibular condyle is a fossae of the temporals. The mandibular notch is between the condylar and coronoid processes.
The orbits, as I've mentioned, have 7 bones that make them up. The roof is formed by the frontal and sphenoid bones. The lateral wall is formed by the zygomatic and sphenoid bones. The floor is the maxilla, zygomatic and sphenoid. The medial wall is made of the maxilla, lacrimal, ethmoid and sphenoid.
The hyoid bone is the only bone in the body that does not articulate with another bone. It is u-shaped. It is suspended by ligaments and muscle from the skull. It helps support the tongue, and provides attachment for the tongue, neck and pharyngeal muscles.
Moving onto the Vertebral Column
The vertebral column is composed of 7 cervical vertebrae, 12 thoracic vertebrae, 5 fused vertebrae, a sacrum (5 fused vertebrae) and a coccyx (4 fused vertebrae). Each of the four curvatures of the vertebrae make sense. The cervical vertebrae make the cervical curvature, the thoracic vertebrae make the thoracic curvature, the lumbar curvature comes from the lumbar vertebrae and the sacrum and coccyx make up the pelvic curvature. (Which makes sense because the top of the sacrum and the top of the pelvic girdle match up).
The vertebrae are separated by intervertebral discs. These help absorb vertical shock. The discs permit various movements within the column. They are a fibrocartilagenous with a pulpy center. When one or more of the discs are injured, the nucleus pulposes protrudes into the ring, which causes pressure to be put on the spinal nerves. Surgically removing a disc is called laminectomy.
Every vertebrae has several parts. Different vertebrae have different prominent parts. The body is the weight bearing part and is anterior to the rest of the vertebrae. The vertebral foramen is the opening for blood vessels and the spinal cord. There are seven processes (projections). There are two transverse processes, one spinous process and four articular processes. The intervertebral notch forms the intervertebral foramen with the next vertebrae.
The spinal canal is the vertebral foramen all linked together. Intervertebral foramen allow the spinal cord to leave leave the spine.
The seven cervical vertebrae are at the top of the spine. The first one is called the atlas. It allows the skull to say yes. The second vertebrae is called the axis. It is the only one to have a dens. The dens allows the head to say no. Cervical vertebrae 3-6 are typical vertebrae. The 7th, vertebrae pominens is different, it has a more prominent spinous process.
Thoracic vertebrae articulate with ribs. There are 12 of them and they have larger and stronger bodies. Thoracic vertebrae also have longer transverse and spinous processes. Facets and demifacets articulate from the body of the vertebrae to the head of the ribs.
Lumbar vertebrae are the largest and strongest.
The sacrum is the union of 5 vertebrae by age 30. The median sacral crest was the spinous process. The sacral ala is a fused transverse process.
The coccyx is the union of 4 fused vertebrae by age 30. Caudal or epidural anesthesia is inserted into the sacral to anesthetize sacral and coccygeal nerves.
The Thorax is the extire chest. It consists of sternum, costal cartilage, ribs and bodies of thoracic vertebrae. The thorax is a bony cage that is flattened from front to back. The sternum consists of the manubrium (1st and 2nd ribs); it is the sternal angle junction within the body. The body of the sternum is the costal cartilage of ribs 2-10. The sternum's xiphoid is at the most inferior of the sternum. It has the xiphisternal joint and is the location for CPR as well as a connection site for abdominal muscles.
We have 24 ribs. They increase in length from ribs 1-7. After the 7th rib, they decrease in size. The head and tubercle articulate with facets of the vertebrae. The tubercle of the rib articulates with the transverse process of the vertebrae, while the head articulates with the vertebral bodies.
Friday, June 11, 2010
Bone Markings
There are two major types of bone markings.
1. depressions and openings (joints or allow for the passage of soft tissue)
2. processes or projections (outward growths that either form joints or serve as attachment points for connective tissue.
The specific names and definitions of Depressions and Openings include:
Fissure: a narrow slit between adjacent parts of bones
Foramen: an opening that blood vessels, nerves and/or ligaments can travel through.
Fossa: a shallow depression
sulcus: This is a furrow along a bone that accommodates a blood vessel, nerve or tendon.
Meatus: tube-like opening
The specific names and definitions of Processes and Projections:
Joint forming Processes or Projections:
Condyle: a large round protuberance at the end of a bone
Facet: a smooth, flat articular surface
Head: a rounded articular projection supported on the neck of a bone
Processes that form attachment points for connective tissue:
Crest: is a prominent ridge or elongated projection
Epicondyle: the projection above (epi-) a condyle (a large round protuberance at the end of a bone)
Line (or Linea): a less prominent form of a crest
Spinous process: sharp, slender projection
Trochanter: very large projection
Tubercle: small, rounded projection
Tuberosity: larger rounded, but rough projection
Throughout the skeletal system, I'll be pointing out different bony landmarks using these terms, so remember them!
1. depressions and openings (joints or allow for the passage of soft tissue)
2. processes or projections (outward growths that either form joints or serve as attachment points for connective tissue.
The specific names and definitions of Depressions and Openings include:
Fissure: a narrow slit between adjacent parts of bones
Foramen: an opening that blood vessels, nerves and/or ligaments can travel through.
Fossa: a shallow depression
sulcus: This is a furrow along a bone that accommodates a blood vessel, nerve or tendon.
Meatus: tube-like opening
The specific names and definitions of Processes and Projections:
Joint forming Processes or Projections:
Condyle: a large round protuberance at the end of a bone
Facet: a smooth, flat articular surface
Head: a rounded articular projection supported on the neck of a bone
Processes that form attachment points for connective tissue:
Crest: is a prominent ridge or elongated projection
Epicondyle: the projection above (epi-) a condyle (a large round protuberance at the end of a bone)
Line (or Linea): a less prominent form of a crest
Spinous process: sharp, slender projection
Trochanter: very large projection
Tubercle: small, rounded projection
Tuberosity: larger rounded, but rough projection
Throughout the skeletal system, I'll be pointing out different bony landmarks using these terms, so remember them!
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