Anatomy test 1 (Muscles)

Movement, maintenance of posture, joint stabilization, heat generation

• Special characteristics:
• contractility, excitability, extensiility, elasticity

• Skeletal- striated, voluntary movement, 40% body weight
• Cardiac- Striated, non-voluntary
• Smooth-non-striated, non-voluntary (in most organs)

• elongated cells called fibers
• contraction due to myofilaments, (myo=muscle) actin and myosin.
• Plasma membrane is called sarcolemma, cytoplasm is sarcoplasm.(sarcos=flesh,muscles) (lemma=sheath)

• epimysium- "outside the muscle" overcoat of dense irregular connective tissue around the whole muscle
• perimysium-fibrous connective tissue around bundle of muscle cells, fascicle.
• Endomysium- mostly reticular fiber surrounding each muscle fiber
• Three sheaths are continuous with tendon,connective tissue that connects bone to muscle

• each skeletal muscle is supplied by at least one nerve, artery and vein.
• lost of vascular tissue, to supply lots of blood

• muscles go between bones and cross at lease one joint (biarticular if two-joints)
• Origin of muscle is attachment of bone that moves less, insertion, attachment to bone that moves more (can switch)
• direct attachments - connective tissue is short (muscle seems attached to peristeum), as opposed to indirect attachment

• long cylindrical cells (centimeters long)
• multinucleated made of many fused cells

myofibrils- unbranched cylinders within the muscle fibers. A long row of repeating segments, sarcomeres, the smallest contractive segment 

• Z-disc (ends), A band (overlap), I band (only thin actin myofilaments), 
• H zone (central A band with no actin), M line (holds thick myosin filaments together, contains ATPase)
• 

• elaborate tubules of smooth endoplasmic reticulum that surround each myofibril.
• Most run longitudinally, some perpendcular channels over junctions of A and I bands, terminal cisterne, on both side of T tubule
• 
• SR stores Ca²⁺. released to stimulate contraction

• contractions in skeletal muscle are conducted along sacrolemma, then to T tubules, sarcolemma invaginations between terminal cisterna. 
• (terminal cisterna and T tubules sandwich is triad)

concentric contraction- muscle shortens and does work. Myosin heads attach to (thin) actin, contracts and repeats. (shortens distance between Z-discs)

Eccentric contraction- muscle generates force as it lengthens, (gravity fighting)

opposite muscle contraction

Small springlike protein that attaches myosin to the Z-disc

• Each muscle fiber is connected with a motor neuron's axon (4-200 fibers/neuron)
• axon meets fiber at neuromuscular junction

not bundled: weak overall muscle contraction (motor unit)

• lots of myoglobin, relatively thin (not much power) use aerobic metabolic functions, lots of mitochondria contract slowly, extremely resilient as long as oxygen is present. 
• postural muscles,

contain little myoglobin, use anerobic pathways, few mitochondria, have glycosomes containing glycogen, strong, contract rapidly and tire quickly. (for lifting heavy objects)

Contract quickly, oxygen dependant (lots of myoglobin),lots of mitochondira and cappiliaries, fatgue slowly

• genetic. 
• Connective tissue and fat enlarge muscles and muscle fibers degenerate
• Duchenne muscular dystrophy, lacking protein dystrophin.

painful tightening bands of muscle fibers when skin is touched

• mesoderm cell, myoblasts, develop in embryo. Form contracting muscles by 7 weeks.
• Muscle cells dont undergo mitosis, just thicken and lengthen.
• Sarcopenia  "flesh wasting" of old people. muscles generally weaken 50% by age 80

• Convergent- Broad origin, converge to tendon of insertion (pectoralis major)
• Parallel- extend from origin to insertion (biceps bracchi)
• Circular- concentric circles (sphincter)
• Pennate- run obliquely and attach to tendon that runs length of muscle, can be multi, bi or unipennate)
• 

From splanchnic mesoderm around the early gut

• muscles for facial expression and neck (for swallowing), branchiomeric muscles
• 4-7th somitomeres

• from myotomes and some somitomeres
• form trunk muscles, breathing muscles and
• eye movement and tongue (1-3 somitomeres)

from lateral part of nearby myotomes

• Striated (sliding filament mechanism)
• short, branching cells with one or two large nuclei.
• cardiac muscles join at ends for cardiac fibers. 
• complex joints called intercalated discs. Transverse attachements have fasciae adherens (like desmosomes), longitudinal gap junctions for transmission of contractile signal.

• elongated, seperated from each other by endomysium,
• organized in 2 sheets (outer longitudinal layer and inner circular layer)

• Location- (Brachium=arm or costa=rib)
• Shape - (deltoid or trapezius)
• Relative size- (maximus,  minimus, longus, brevus)
• Direction of fascicles and fibers- (rectus=straight, parallel to body midline)
• Location of attachments-(origin always named first)
• Number of origins-(biceps,triceps,quadriceps)
• Action- (flexor, extensor, adductor, abductor

Frontalis, Temporalis, Occipitalis, galea aponeurotica 

• 
• Corrugator supercilii (eyebrow), Orbicularis oculi
• zygomaticus (smile), Levator labii superioris(raises upper lip), depressor labii inferioris (lowers lower lip), depressor anguli oris (draws corners of mouth), orbicularis oris (kiss),
• mentalis (wrinkles chin), buccinator (compresses cheek)

• Masseter, temporalis (elevates mandible)
• medial and lateral pteygoid (side to side mandible movement)
• Buccinator (compresses cheek
• 

• Platysma (superficial neck muscle, tenses neck skin)
• digastric ("two bellies", V-shape with tendon, depresses mandible)
• mylohyoid (myle=molar, deep to digastric, elevate hyoid bone) 
• sternocleidomastoid (anterorlateral neck,flexes and laterally rotates head)
• scalenes (lateral neck, elevate first two ribs)
• 

• splenius capitis- (deep to trapezius, extend/hyperextend head)
• splenius cervicis (deep to splenius capitus)
• semispinalis (medial to splenius cervicis, extends vertebral column)
• suboccupitals-(deep to semispinalis, under occipitals)
• 

• trapezius- (trapezoid on back, stabilizes, raises, retracts and rotates scapula)
• Levator scapulae- (elevates, adducts scapulae, from C_1-4 to superior angle of scapula)
• rhomboids major/minor- (deep to trapezius, stabilizes/retracts scalpula, minor is superior)
• serratus anterior-(medial wall of axilla, originates on ribs, rotates scalpula holds to chest wall, 

• O-Thorocolumnar fascia into lower six thoracic vertebra, lumbar verterae, iliac crest, lower 3-4 ribs,  I-intertubercle groove
• ( lower ribs to intertubercular sulcus of humerus, medial rotation of humerus)

• superaspinous fossa to humerus, deep to trapezius, insertion at greater tubrable
• part of rotator cuff, abducts humerus

• origin at infraspinous fossa, insertion at greater tubercle
• rotates humerus laterally, rotator cuff muscle

• O-subscalpular fossa, I-lesser tubercle
• medial rotator of muerus, rotator cuff muscle
• 

• O-posterior surface of scalpula at inferior angle, I-crest of lesser tubercle, intertubercle groove
• inferior to teres minor
• extends, medially rotates and adducts humerus

• O-lateral border of scalpula, I-greater tubercle, inferior to infraspinatus
• rotator cuff muscle
• Rotates humerus laterally

• O-sternal end of clavicle, sternum, rib 1-6 cartilage, I-intertubercluar groove of humerus
• prime mover of arm flexion, adducts arm, rotates arm medially
• 

• O-anterior surface of ribs 3-5, I-coracoid process of scalpula. 
• thin, flat muscle deep to pectoralis major, acts on scalpulae

• O- lateral third of clavicle, acromion and spine of scalpula, I-deltoid tuberosity 
• multipennate, rounded shoulder muscle mass
• prime mover of arm abduction

• O-coracoid process, I-medial surface of humeral shaft
• Cylindrical muscle
• flexion and adduction of humerus

• O-short head:coracoid process, long head:supraglenoid tubercle, I-radial tuberosity
• two-headed fusiform muscle
• flexes elbow joint and supinates forearm

• O-front of distal humerus, I-coranoid process of ulna
• deep to biceps brachii, comes from deltoid
• major forearm flexor

• O-long head: infraglenoid tubercle of scapula, lateral head:posterior shaft of humerus, medial head:posterior humeral shaft, distal to radial groove, I-olecranon process of ulna
• posterior part of arm 
• forearm extensor

• O-lateral epicondyle of humerus, I-lateral aspect of olecranon process of ulna
• short triangular muscle, blended with distal triceps 
• abducts ulna during pronation
• splits up flexors and extensors
• 

• O-lateral supracondylar ridge of humerus, I-base of radial styloid process
• synergist in forearm flexion
• 

• O-lateral supracondylar ridge of humerus, I-base of second metacarpal
• parallels brachioradialis on lateral forearm
• extends wrist (with extensor carpi ulnaris), abducts wrist (with flexor carpi radialis)
• 

• O-lateral epicondyle of humerus, I-base of third metacarpal
• deep to longus, and shorter
• extends and abducts wrist (works with longus)
• 

• "pollicis"=thumb
• O-posterior surface of radius and ulna interosseus membrane, I-base of first metacarpal and trapezium
• abducts and extends thumb

• O-dorsal shaft of radius and ulna/interosseus membrane, I-base of proximal (brevis) and distal (longus) phalanx of thumb
• 

• O-lateral epicondyle of humerus, I-distal phalanges 2-5
• medial to extensor carpi radialis brevis
• detached protion: extensor digiti minimi extends little finger
• 

• O-posterior surface of ulna, I-inserts on tendon of extensor digitorum of middle finger
• medial and parallel to extensor pollicis longus, deep to extensor digitorum
• extends distal and middle phalanges 

• O-olecranon process of ulna, I-fifth metacarpal
• adducts wrist
• 

• O- antero medial ulnar surface, I-4 distal phalanges
• flexes wrist and digits
• deep to flexor digitorum superficialis
• sandwiched between ulnaris muscles

O-medial epicondyle of humerus, olecranon process, I-pisiform and hamate bone and fith metacarpal

• flexor of wrist, adducts hand
• just lateral to flexor digitorum profundus
• 

• O-humerus, I-metacarpals on palm
• flexes wrist and abducts hand
• tenses skin during movement
• 

• O-humerus, ulna and radius, I-middle phalanges of four digits
• flexes wrist, hand, digits

• O-humerus, I-metacarpals
• flexes wrist, abducts hand
• runs diagonally across forearm

• O- radius and ulna, I- thumb
• flexes thumb distally

• O-humerus, I-radius
• pronates forearm

• two heads, O-lateral epicondyle of humerus, proximal ulna, I-proximal end of radius
• helps biceps brachii supinate arm

• prime mover of forearm pronation
• O-distal portion of anterior ulnar shaft, I-distal surface of anterior radius
• deepest muscle of distal forearm

medial and deep of thenar group

• superficial, lateral muscle of thenar group (thumb)
• abducts thumb (points it anteriorly)
• 

• moves thumb to thouch little finger 
• deep to abductor pollicis brevis
• flexes thumb

same

same of pollicis side

• in between pollicis and digiti minimi muscles
• flex and extend fingers 
• 

• O-transverse process, I-lesser trocanter of femur
• causes lateral flexion of vertebral column, medial to quadratus lumborum

• O-iliac crestm I- lumbar transverse processes
• extends lumbar spine
• 

• spinalis, longissius, iliocostalis
• medial to lateral, support spine

deep to the latissimus dorsi. Lateral and inferior portion of deep back

• thin, deep muscle that supports spine
• O- sacrum and posterior superioriliac spine, I-spinous process, all the way to axis
• 

• C- shaped fibrocartilage location within medial/lateral condyles, provide knee joint cushioning 
• 

• anterior- connects posterior side of femur to anterior tibia (prevent anterior slipping of tibia)
• posterior-connects anteriorinferior femur to posterior tibia (prevent posterior displacement of tibia)
• 

• tendons on lateral/medial surface of knee joint, prevents hyper ad/abduction of the leg at knee
• 

• ilopsoas made of two muscles (iliascus and psoas major)
• iliacus- O-iliac fossa, I-Lesser trocanter
• prime mover of thigh flexion, and flexing trunk
• psoas major- O-TP of lumbar, I-lesser torcanter via iliopsoas tendon
• more medial of the two
• 

• O-pectineal line of pubis, I-lesser torcanter to linea aspera
• short flat muscle medial to  iliopsoas, adducts flexes and medially rotates femur

• straplike superficial muscle. O-anterior superior iliac spine, I-winds around into medial aspect of proximal tibia
• flexes, abducts  and laterally rotates thigh and flexes knee
• longest muscle in body
• 

• O-anterior aspect of iliac crest, I-iliotibial tract
• 

• (ITB) fibrous band from iliac crest and gluteus maximus  to lateral condyle of tibial bone
• 

• all extend lower leg
• rectus femoris is straight down the thigh
• 

• O-inferior ramus and body of pubis, I-,medial surface of tibia, inferior to medial condyle
• long, thin superficial muscle of medial thigh

• longus-most superficial, overlies middle of magnus
• brevis-concealed under longus and pectinus
• magnus-triangle with broad insertion
• all insert into the linea aspera

• O-dorsal ilium, sacrum and coccyx, I-gluteal tuberosity of femur. 
• major extensor
• 

• deep to gluteus maximus, abducts and rotates thigh medially 
• O-between anterior and posterior gluteal lines on lateral surface of ilium, I-lateral aspect of greater trocanter
• 

• deepest gluteal muscle, abducts thigh
• 

• piriformis- pyramidal musclem inferior to gluteus minimus
• superior gemellus-inferior to piriformis, O-ischial spine, I-greater trocanter
• obturator internus- inferior to superior gemellus, lateral rotation
• inferior gemellus-inferior to obturator, O-ischial tuberosity I-greater trocanter
• obturator externus-deep to quadratus femoris
• quadratus femoris- most inferior hip rotator

• all extend thigh  and flex knee, on posterior of thigh 
• biceps femoris- most lateral
• semitendinosus- between biceps  and semimembraneous
• semimembraneous- most medial
• 

• bony landmark medial to tibial tuberosity,
• common tendenous insertion of gracilis, sartorius and semitendinous
• 

• O-posterior femus, above lateral condyle, I-via long, thin tendon to calcaneus
• flexes foot and knee
• 

• superficial calf muscles, insert into achilles (calcaneal) tendon. inserts into calcaneous 
• gastrocnemius: two prominent bellies that form main calf. flexes foot and knee
• soleus: broad flat muscle deep to gastrocnemius, plantar flexes foot
• 

• O-lateral condyle of femur and meniscus, I-proximal tibia
• deep muscle that rotates  and flexes knee
• 

• tibialis posterior: O-fibia and tibia, I-metatarsals, inversion and plantar flexion of foot
• flexor digitorum longus: O-posterior surface of tibia, I-phalnages, flexes digits
• flexor hallucis longus: O-posterior tibia,I- hallux, flexes hallux
• 

• lateral muscles
• peroneus (fibularus) longus: O-tibia and fibula, I-first metatarsal. Flexes everts foot.
• superficial lateral muscle
• peroneus (fibularus) brevis:O-distal fibula, I-fifth metatarsal. flexes evers foot
• deep to longus
• peroneus (fibularus) tertius: O-anterior surface of fibula, I-fifth metarsal
• 

• O-tibia and fibula, I-digits 2-5 
• extends and dorsiflexes foot
• lateral to tibialis anterior

• O-fibula, I-distal phalanx of hallux
• deep to extensor digitorum longus
• 

• O-lateral condyle and upper 2/3 of tibial shaft, I-tendon into inferior surface of medial cuneiform
• superficial muscle anterior of leg
• 

• four part muscle, deep to tendons of extensor digitorum longus
• O-calcaneus, I-toes 2-5
• 

• medial muscle on sole of foot
• O-cuboid, lateral cuneiform, I-medial and lateral sides of great toes
• 

• abductor digiti minimi: O-calcaneus, I-lateral side of little toe
• adbucts and flexes little toe
• abductor hallucis: medial 
• felxor digitorum brevis: between other muscles
• 

• second layer deep
• umbricals: O-from tendon of flexor digitorum longus, I-proximal phalanx on toes 2-5

• quadratus plantae: O-calcaneous, I-tendon of flexor digitorum longus
• rectangular shape with two heads
• 

• third layer deep, deep to lumbricals.
• adductor hallucis: O-metatarsals 2-4, I-lateral side of great toe. two headed
• flexor digiti minimi brevis: O-fifth metatarsal, I- lateral side of little toe
• 

• muscle on top of foot. 
• O-calcaneous,I-big toe
•