Muscles of The Body PDF

Upper Fiber Traps O: external occipital protuberance (EOP); medial side of superior nuchal line; nuchal ligament; SPs of C7-T12 I: lateral 1/3 of clavicle; acromion; spine of scapula A: stabilization of scapula; elevation scapula; upward rotation of scapula (upper fibers); downward rotation of scapu...

Upper Fiber Traps O: external occipital protuberance (EOP); medial side of superior nuchal line; nuchal ligament; SPs of C7-T12 I: lateral 1/3 of clavicle; acromion; spine of scapula A: stabilization of scapula; elevation scapula; upward rotation of scapula (upper fibers); downward rotation of scapula (lower fibers); retraction (adduction) of scapula; lateral flexion of head (unilateral); extension of head (bilateral) N: spinal accessory (CN XI-11), ventral rami of C2-C4 Sternocleidomastoid O: sternal head: manubrium of sternum; clavicular head: medial 1/3 of clavicle I: mastoid process of temporal bone; lateral 1/2 of superior nuchal line A: rotates to side opposite of contraction; laterally flexes to contracted side; bilaterally flexes neck N: motor: spinal accessory (XI-11 cranial); sensory: ventral rami of C2,(C3) Posterior Scalenes O: TP of C5-C7 (posterior tubercles) I: 2nd rib A: lateral flexion of neck; elevation of 2nd rib (if cervical vertebrae are fixed) N: cervical spinal nerves (ventral rami C6-C8) Supraspinatus O: supraspinous fossa of scapula; muscle fascia I: greater tubercle of humerus (superior facet) A: abduction of arm; stabilizes glenohumeral joint N: suprascapular nerve (C5, C6) Teres Minor O: superior lateral border of scapula I: greater tubercle of humerus (inferior facet) A: lateral rotation of arm; stabilizes glenohumeral joint; adduction of arm (weak) N: axillary nerve (C5, C6) Levator Scapula O: TP of C1-C4 I: superior medial border of scapula A: elevation of scapula; extension & lateral flexion of neck N: dorsal scapular nerve (C3, C4, C5) Pectoralis Minor O: ribs 3-5 (anterior lateral portion) I: coracoid process of scapula (medial aspect) A: stabilizes scapula for arm movements depresses & downwardly rotates scapula assists in scapular protraction from a retracted position elevates ribs 3-5 N: medial pectoral nerve (C8, T1) Brachioradialis O: lateral supracondylar ridge of humerus I: styloid process of radius (lateral side) A: flexion of forearm (at elbow); pronation of forearm when supinated; supination of forearm when pronated N: radial nerve (C5, C6) Extensor Carpi radialis longus O: lower lateral supracondylar ridge (below brachioradialis) I: base of 2nd metacarpal A: extension of hand at wrist; radially deviation (abduction) of hand at wrist; flexion & supination of forearm at elbow (weak action) N: radial nerve (C5, C6) Extensor Carpi radialis brevis O: lateral epicondyle via common extensor tendon I: base of 3rd metacarpal A: extension of hand at wrist; radial deviation (abduction) of hand at wrist; flexion of forearm at elbow joint (weak action) N: radial nerve (C7, C8) Extensor digitorum O: lateral epicondyle of humerus (via common extensor tendon) I: phalanges #2-5 (dorsal expansion hood) A: extension of fingers #2-5 (at MCP, PIP & DIP joints); extension of hand at wrist; extension of forearm at elbow (weak) N: radial nerve (C7, C8) Extensor Carpi Ulnaris O: humeral head: lateral epicondyle (via common extensor tendon); ulnar head: posterior shaft of ulna I: base of 5th metacarpal (posterior side) A: ulnar deviation of hand at wrist; extension of hand at wrist; extension of forearm at elbow (weak action) N: radial nerve (C6, C7, C8) Quadratus Lumborum O: posterior iliac crest & iliolumbar ligament I: 12th rib (inferior border) & TPs of L1-L4 A: elevation of pelvis; lateral flexion of trunk; depression of 12th rib N: lumbar plexus (T12-L3) 💗💗💗💗 Vastus Medialis O: medial lip of linea aspera (intertrochanteric line) I: tibial tuberosity (via common quadriceps tendon & patellar ligament) A: extension of leg (at knee joint) N: femoral nerve (L2 ,L3, L4) Rectus Femoris O: anterior head: anterior inferior iliac spine (AIIS); posterior head: just superior to rim of acetabulum (supra-acetabular groove) I: tibial tuberosity (via common quadriceps tendon & patellar ligament) A: extension of leg (at knee joint); flexion of thigh (at hip joint) N: femoral nerve (L2 ,L3, L4) Adductor Magnus O: anterior head (adductor part): inferior pubic ramus & ischial ramus; posterior head (hamstring part): ischial tuberosity I: anterior head: linea aspera; posterior head: adductor tubercle of femur (above medial epicondyle) A: adduction & extension of thigh (at hip joint); laterally rotation of thigh (anterior head) N: anterior head: obturator nerve (L2, L3, L4); posterior head: sciatic nerve, tibial division (L4, L5) Biceps Femoris O: long head: ischial tuberosity; short head: lateral lip of linea aspera I: head of fibula (occasionally to lateral tibial condyle) A: flexion at knee (both long & short head); extension of thigh at hip joint (long head); laterally rotation of leg when the knee is flexed N: long head: sciatic nerve, tibial division (L5, S1, S2); short head: sciatic nerve, common peroneal division (S1, S2) Gluteus Maximus O: posterior iliac crest, sacrum & coccyx & sacrotuberous ligament I: iliotibial band (ITB) & gluteal tuberosity of femur A: extension of thigh (at hip); lateral rotation of thigh; upper fibers assist abduction of thigh, lower fiber assist in adduction; posterior pelvic tilt (at hip joint); fibers of IT band stabilize a fully extended knee N: inferior gluteal nerve (L5, S1, S2) Gastrocnemius O: medial head: above medial condyle of femur (posterior surface); lateral head: above lateral condyle of femur (posterior surface) I: calcaneus (via calcaneal or Achilles tendon) A: plantar flexion of foot; knee flexion (when not weight bearing); inversion of foot (weak) N: tibial nerve (S1, S2) Tibialis Anterior O: anterior proximal tibia (lateral tibial condyle, proximal 2/3 of anterolateral surface of tibia & interosseous membrane) I: medial cuneiform & base of 1st metatarsal (medial & plantar surfaces) A: dorsiflexion of foot at ankle; inverts of foot (at tarsal joints) N: deep peroneal (fibular) nerve (L4, L5, S1) Middle Fiber Traps O: external occipital protuberance (EOP); medial side of superior nuchal line; nuchal ligament; SPs of C7-T12 I: lateral 1/3 of clavicle; acromion; spine of scapula A: stabilization of scapula; elevation scapula; upward rotation of scapula (upper fibers); downward rotation of scapula (lower fibers); retraction (adduction) of scapula; lateral flexion of head (unilateral); extension of head (bilateral) N: spinal accessory (CN XI-11), ventral rami of C2-C4 Anterior Scalenes O: TP of C3-C6 (anterior tubercles) I: 1st rib (scalene tubercle) A: flexion & lateral flexion of neck; rotation of neck (weakly); elevation of 1st rib (if neck is stabilized) N: cervical spinal nerves (ventral rami C3-C6) Splenius Capitis O: TPs of C7-T6 & articular process of C4-C6 (medial part of semispinalis) I: occipital bone (considered to be the medial part of semispinalis) A: bilateral: extension of the spine & head (maintenance of erect posture); unilateral: lateral flexion & rotation to same side of the spine & head; opposite muscles contract eccentrically for stabilization N: dorsal rami of spinal nerves Infraspinatus O: infraspinous fossa; inferior portion of spine of scapula I: greater tubercle of humerus (middle facet) A: lateral rotation of arm; stabilizes glenohumeral joint N: suprascapular nerve (C5, 6) Latissimus Dorsi O: SP T7-L5; thoracolumbar fascia; iliac crest; posterior sacrum, ribs 9-12; inferior angle of scapula (occasionally) I: medial lip of bicipital groove of humerus A: adduction, medial rotation & extension of humerus; anterior pelvic tilt, elevation of pelvis; depression of scapula; downward rotation of scapula N: thoracodorsal nerve (C6, C7, C8) Biceps Brachii O: long head: supraglenoid tubercle & glenohumeral labrum short head: coracoid process of scapula I: radial tuberosity; bicipital aponeurosis A: flexion & supination of forearm; flexion of arm at shoulder; stabilization of anterior aspect of shoulder; abduction of arm at shoulder (long head), adduction of arm at shoulder (short head) N: musculocutaneous nerve (C5, C6) Triceps Brachii O: long head: infraglenoid tubercle & neck of scapula; lateral head: upper half of posterior surface of shaft of humerus (above radial groove) medial (deep) head: posterior shaft of humerus (distal to radial groove) I: olecranon process of ulna A: extension of forearm at elbow (prime mover); adduction & extension of arm (long head only) N: radial nerve (C6, C7, C8) Flexor Carpi radialis O: medial epicondyle via common flexor tendon I: base of 2nd & 3rd metacarpals A: flexion of hand at wrist; radially deviation (abduction) of wrist; flexion & pronate of forearm (weak action) N: median nerve (C6, C7) Flexor palmaris longus O: medial epicondyle via common flexor tendon I: flexor retinaculum & palmar aponeurosis A: flexion of hand at wrist N: median nerve (C7,C8) Flexor Carpi Ulnaris O: humeral head: medial epicondyle via common flexor tendon; ulnar head: medial aspect of olecranon & proximal 2/3 of posterior ulna I: pisiform & hamate bones (via pisohamate ligament); base of 5th metacarpal (via pisometacarpal ligament) A: flexion of hand at wrist; ulnar deviation (adduction) of wrist; elbow flexion (weak action); stabilizes wrist to permit powerful thumb motion N: ulnar nerve (C7, C8) Rectus Abdominis O: pubic crest & pubic symphysis I: costal cartilage of ribs #5-7 & xyphoid process A: flexion of trunk (at spinal joints); posterior pelvic tilt (at spinal joints); compression/stabilization of abdomen N: intercostal nerves (T5-T12) Transverse Abdominis O: iliac crest, inguinal ligament, thoracolumbar fascia & lower costal cartilage I: abdominal aponeurosis (rectus sheath) A: compression/stabilization of abdomen N: intercostal nerves (T7-L1) External Obliques O: anterior 1/2 of iliac crest, inguinal ligament, public tubercle/crest, & abdominal aponeurosis (rectus sheath) I: inferior border of ribs #5-12 A: flexion, lateral flexion & contralateral rotation of trunk (at spinal joints); posterior pelvic tilt (at spinal joints); compression/stabilization of abdomen N: intercostal nerves (T7-T12) Internal Obliques O: iliac crest, inguinal ligament, thoracolumbar fascia I: ribs #10-12 & abdominal aponeurosis (rectus sheath) A: flexion, lateral flexion & ipsilateral rotation of trunk (at spinal joints); posterior tilt of pelvis (at lumbosacral joints); compression/stabilization of abdomen N: intercostal nerves (T7-L1) Diaphragm O: vertebral: crura from bodies of L1, 2 (left), L1-3 (right); costal part: medial & lateral arcuate ligaments, inner aspect of lower six ribs; sternal: two slips from post aspect of xiphoid I: central tendon of diaphragm (dome of diaphragm) A: inspiration (increases thoracic cavity volume); assists in raising intra-abdominal pressure (valsalva maneuver) N: phrenic nerve (C3, C4, C5) Iliacus O: inner surface of upper iliac fossa & sacral ala I: lesser trochanter of femur (via iliopsoas tendon) A: flexion & lateral rotation of thigh (at hip); anterior pelvic tilt N: femoral nerve (L2, L3) Psoas Major O: TPs of L1-L5, vertebral bodies of T12-L5 & intervening intervertebral discs I: lesser trochanter of femur (via iliopsoas tendon) A: flexion & lateral rotation of thigh (at hip); flexion & lateral flexion of trunk (at spinal joints); anterior pelvic tilt (at hip joint) N: lumbar plexus ventral rami (L1, L2, L3) Vastus Lateralis O: lateral lip of linea aspera (also intertrochanteric line & lateral intermuscular septum) I: tibial tuberosity (via common quadriceps tendon & patellar ligament) A: extension of leg (at knee joint) N: femoral nerve (L2 ,L3, L4) Adductor Brevis O: body & inferior ramus of pubis I: medial lip of linea aspera (superior 1/3 of femur) A: adduction & flexion of thigh (at hip joint); lateral rotation of thigh N: obturator nerve (L2, L3, L4) Pectineus O: pectineal line of pubis (superior pubic ramus) I: pectineal line of femur; (just below lesser trochanter on posterior aspect of femur) A: adduction & flexion of thigh (at hip joint) N: femoral nerve (L2, L3) or obturator nerve (L2, L3, L4) or both Tensor Fascia Lata O: anterior superior iliac spine (ASIS) & anterior aspect of iliac crest I: iliotibial band (below greater trochanter) A: flexion, abduction & medial rotation of thigh (at hip joint); tenses iliotibial band to support femur on tibia during standing N: superior gluteal nerve (L4, L5, S1) Semimembranosis O: ischial tuberosity I: posterior medial aspect of medial tibial condyle A: flexion of leg (at knee joint); extension of thigh (at hip joint); medial rotation of tibia (with knee flexed) N: sciatic nerve, tibial division (L5, S1, S2) Gluteus Medius O: outer ilium (between anterior & posterior gluteal lines) I: greater trochanter (superior & lateral surface) A: abduction of thigh (at hip joint); flexion & medial rotation of thigh (anterior fibers); lateral rotation & extension of thigh (posterior fibers); stabilizes pelvis & prevents free limb from sagging during gait N: superior gluteal nerve (L4, L5, S1) Soleus O: soleal line of tibia & proximal 1/3 of fibula I: calcaneus (via calcaneal or Achilles tendon) A: plantar flexion of foot; inversion of foot (weak) N: tibial nerve (S1, S2) Plantaris O: distal posterolateral femur (above lateral head of gastrocnemius) I: calcaneus (via calcaneal or Achilles tendon) A: plantar flexion of foot; knee flexion N: tibial nerve (S1, S2) Popliteus O: lateral femoral condyle I: proximal posterior tibia (medial side above soleal line) A: unlocks knee (from extended position); lateral rotation of femur on tibia or medial rotation tibia on femur; flexion of knee (weak) N: tibial nerve (L4, L5, S1) Extensor Hallucis longus O: anterior middle 1/3 of fibula & interosseous membrane I: dorsal surface big toe (base of distal phalanx) A: extension of big toe at MTP; dorsiflexion & inversion of foot N: deep peroneal (fibular) nerve (L4, L5, S1) Extensor digitorum longus O: proximal 2/3 of fibula, interosseous membrane, lateral condyle of tibia (anterior surfaces) I: dorsal surface of toes #2-5 (via dorsal expansion to middle & distal phalanges) A: extension of toes #2-5 (at MTP & IP joints); dorsiflexion & eversion of foot N: deep peroneal (fibular) nerve (L4, L5, S1) Flexor digitorum longus O: posterior middle 1/3 of tibia I: base of distal phalanges #2-#5 (plantar surface) A: flexion of 2nd-5th toes; plantar flexion & inversion of foot (weak) N: tibial nerve (L5, S1, S2) Flexor Hallucis longus O: posterior inferior 2/3 of fibula & interosseous membrane I: distal phalanx of big toe (plantar surface) A: flexion of big toe (hallux); plantar flexion & inversion of foot (weak) N: tibial nerve (L5, S1, S2) Extensor digitorum Brevis O: upper anterolateral calcaneus I: middle & distal phalanges of toes #2-#4 (via EDL & extensor expansion) A: extension of toes #2-#5 N: deep peroneal (fibular) nerve (L5, S1) Extensor Hallucis Brevis O: upper anterolateral calcaneus I: distal phalanges of big toe (via EHL & extensor expansion) A: extension of big toe at MTP; dorsiflexion & inversion of foot N: deep peroneal (fibular) nerve (L5, S1) Lumbricals (foot) O: Flexor digitorum longus (1st: medial aspect of tendon to 2nd toe; 2nd-4th: two heads between tendons in which they lie) I: tendon of extensor digitorum longus & extensor expansion (on the dorsal medial side) A: extension of toes 2-5 (at PIP & DIP joints); flexion of toes 2-5 (at MTP joints) N: 1st lumbrical: medial plantar nerve (S1, S2, S3); 2nd-4th lumbricals: lateral plantar nerve (S1, S2, S3) Dorsal interossei (foot) O: from both metatarsals between which they lie I: base of proximal phalanx closest to axis of foot (2nd ray) A: abduction of toes 2-4 (at MTP); flexion toes 2-4 (at MTP) N: lateral plantar nerve (S2, S3) Plantar interossei (foot) O: medial aspect of 3rd-5th metatarsals (each muscle has a single head) I: medial aspect of base of proximal phalanx of same ray (of 3rd-5th rays) A: adduction of toes 3-5 (at PIP & DIP joints); flexion of toes 3-5 (at MTP joints), extension of toes 3-5 (at PIP & DIP joints) N: lateral plantar nerve (S2, S3 Lower Fiber Traps O: external occipital protuberance (EOP); medial side of superior nuchal line; nuchal ligament; SPs of C7-T12 I: lateral 1/3 of clavicle; acromion; spine of scapula A: stabilization of scapula; elevation scapula; upward rotation of scapula (upper fibers); downward rotation of scapula (lower fibers); retraction (adduction) of scapula; lateral flexion of head (unilateral); extension of head (bilateral) N: spinal accessory (CN XI-11), ventral rami of C2-C4 Middle Scalenes O: TP C2-C7 (posterior tubercle) I: 1st rib (behind anterior scalene) A: flexion & lateral flexion of neck; elevation of 1st rib (if cervical vertebrae are fixed) N: cervical spinal nerves (ventral rami C3-C8) Splenius Cervicis O: SPs of T3-T6 I: TP of C1-C3 (posterior tubercles) A: bilateral contraction: extension of head & neck; unilateral contraction: rotation & lateral flexion of head & neck to ipsilateral side N: cervical spinal nerve (dorsal rami) Teres Major O: inferior, lateral border of scapula I: medial lip of bicipital groove of humerus (just medial to insertion of latissimus dorsi) A: medial rotation of arm; adduction of arm; extension of arm from a flexed position; upward scapular rotation N: lower subscapular nerve (C5, C6, C7) Subscapularis O: subscapular fossa of scapula I: lesser tubercle of humerus A: medial rotation of arm; stabilizes glenohumeral joint N: upper & lower subscapular nerves (C5, C6) Pectoralis Major O: medial 1/2 of clavicle, anterior manubrium & body of sternum, cartilaginous attachments of upper 6 ribs, external abdominal oblique aponeurosis I: lateral lip of bicipital groove of humerus (crest of the greater tubercle) A: adduction of arm (at shoulder joint) medial rotation of arm flexion of arm (clavicular portion) horizontal adduction of arm N: medial & lateral pectoral nerves (C5-T1) Brachialis O: anterior distal 1/2 of humerus I: ulnar tuberosity; coronoid process of ulna A: elbow flexion (prime mover) N: musculocutaneous nerve (C5, C6, C7) Coracobrachialis O: coracoid process of scapula I: medial shaft of humerus (middle 1/3) A: flexion & adduction of arm N: musculocutaneous nerve (C5, C6, C7) Pronator Teres O: humeral head: medial epicondyle via common flexor tendon ulnar head: coronoid process of ulna I: lateral radius at middle of shaft (pronator tuberosity) A: pronation of forearm; flexion of elbow (weak action) N: median nerve (C6, C7) Pronator Quadratus O: anterior distal ulna (distal 1/4) I: anterior distal radius (distal 1/4) A: pronation of forearm N: median nerve (C7, C8) Supinator O: lateral epicondyle of humerus & supinator crest of ulna I: proximal 1/3 of radius A: supination of forearm (at proximal radioulnar joint) N: radial nerve (C6, C7) Piriformis O: anterior sacrum (occasionally sacrotuberous ligament) I: greater trochanter (superiomedial surface) A: lateral rotation of thigh (at hip joint); abduction of flexed thigh N: nerve to piriformis (L5, S1, S2) Superior Gemellus O: ischial spine I: greater trochanter (medial surface) A: lateral rotation of femur; abduction of thigh when hip is flexed N: nerve to obturator internus (L5, S1, S2) Obturator internus O: internal aspect of obturator foramen & obturator membrane I: greater trochanter (medial aspect) A: lateral rotation of femur; abduction of thigh when hip is flexed N: nerve to obturator internus (L5, S1, S2) Inferior Gemellus O: ischial tuberosity (superior aspect) I: greater trochanter (medial surface & intertrochanteric crest) A: lateral rotation of femur; abduction of thigh when hip is flexed N: nerve to quadratus femoris (L5, S1) Quadratus Femoris O: ischial tuberosity (lateral aspect) I: intertrochanteric crest of femur A: lateral rotation of thigh (at hip joint); adduction of thigh (weak) N: nerve to quadratus femoris (L4, L5, S1) Anconeus O: lateral epicondyle of humerus I: posterior ulna (lateral olecranon extending to lateral part of ulna) A: extension of forearm at elbow; supports elbow when in full extension N: radial nerve (C6, C7, C8) Vastus Intermedius O: anterior lateral surface of femur I: tibial tuberosity (via common quadriceps tendon & patellar ligament) A: extension of leg (at knee joint) N: femoral nerve (L2 ,L3, L4) Adductor Longus O: anterior surface of pubis (just inferior to pubic tubercle) I: medial lip of linea aspera (middle 1/3 of femur) A: adduction & flexion of thigh (at hip joint); lateral rotation thigh N: obturator nerve (L2, L3, L4) Sartorius O: anterior superior iliac spine (ASIS) I: proximal anteromedial tibia (pes anserine) A: flexion, abduction & lateral rotation of thigh (at hip joint); flexion of leg (at knee joint); anterior pelvic tilt N: femoral nerve (L2, L3) Semitendinosis O: ischial tuberosity I: proximal anteromedial tibia (pes anserine) A: flexion of leg (at knee joint); extension of thigh (at hip joint); medial rotation of tibia (with knee flexed) N: sciatic nerve, tibial division (L5, S1, S2) Gluteus Minimus O: outer ilium (between anterior & inferior gluteal lines) I: greater trochanter (anterior surface) A: abduction of thigh (at hip joint); medial rotation & flexion of thigh (anterior fibers); lateral rotation & extension (posterior fibers); stabilizes pelvis & prevents free limb from dropping during gait N: superior gluteal nerve (L4, L5, S1) Fibularis Longus- (Peroneals) O: head & proximal lateral shaft of fibula I: medial cuneiform & base of 1st metatarsal (plantar surfaces) A: eversion of foot; plantar flexion of foot N: superficial peroneal (fibular) nerve (L5, S1) Fibularis brevis- (Peroneals) O: distal lateral 1/2 of fibula I: base of 5th metatarsal (lateral aspect) A: eversion of foot; plantar flexion of foot N: superficial peroneal (fibular) nerve (L5, S1) Longus Coli O: lower anterior vertebral bodies & TP of C3-T3 I: anterior vertebral bodies & TP C1-C6 A: flexion & lateral flexion of neck; rotation of neck N: cervical spinal nerves (ventral rami C2-C6) Splenius Capitis O: nuchal ligament (lower portion); SPs of C3-T4 I: mastoid process of temporal bone, occipital bone (superior nuchal line) A: bilateral contraction: extension of head & neck; unilateral contraction: rotation & lateral flexion of head & neck to ipsilateral side N: cervical spinal nerves (dorsal rami) Splenius Cervicis O: SPs of T3-T6 I: TP of C1-C3 (posterior tubercles) A: bilateral contraction: extension of head & neck; unilateral contraction: rotation & lateral flexion of head & neck to ipsilateral side N: cervical spinal nerve (dorsal rami) Semispinalis O: thoracis: TPs of T6-T10 cervicis: TPs of T1-T5 capitis: TPs of C7-T6 & articular process of C4-C6 I: thoracis: SPs of C6-T4 cervicis: SPs of C2-C5 capitis: occipital bone (between superior & inferior nuchal lines) A: bilateral: extension of head & neck; controls lateral flexion to side opposite contraction (eccentric for stability); maintains head posture N: spinal nerve (dorsal rami) Suboccipitals- Oblique Capitis inferior O: SP of axis (C2) I: TP of atlas (C1) A: rotation of head to ipsilateral side N: suboccipital nerve (dorsal rami C1) Suboccipitals- Oblique Capitis Superior O: TP of atlas (C1) I: between superior & inferior nuchal line of occiput A: bilateral: extension of head; unilateral: lateral flexion of head to ipsilateral side N: suboccipital nerve (dorsal rami C1) Deltoid O: lateral 1/3 of clavicle, acromion & spine of scapula I: deltoid tuberosity of humerus A: abduction of arm; flexion & medial rotation (anterior part); extension & lateral rotation (posterior part) N: axillary nerve (C5, C6) Serratus Anterior O: ribs 1- 9 (outer surface) I: costal surface of medial border of scapula A: protract (abducts) scapula; upward rotation of scapula; stabilizes scapula N: long thoracic nerve (C5, C6, C7) Subclavius O: 1st rib (junction of costocartilage) I: middle 1/3 of clavicle (inferior surface) A: assists in stabilization of clavicle depression of clavicle elevation of 1st rib N: nerve to subclavius (C5, C6)