Table Of Contents
Muscular Anatomy Interact 3D
Eye Muscles
Neck Muscles
Shoulder Muscles
National Institute Of Arthritis And Musculoskeletal And Skin Diseases (NIAMS); SVG version by Angelito7, Public domain, via Wikimedia Commons
Jmarchn, CC BY-SA 3.0, via Wikimedia Commons
| Name | Origin | Insertion | Action | Nerve |
| Deltoid | lateral 3rd of clavicle, acromion & spine of scapula | acromion & spine of scapula deltoid tuberosity of humerus | • agonist of arm abduction with all fibers, antagonist of pectoralis major & latissimus dorsi • flexes & medially rotates humerus with anterior fibers, synergist of pectoralis major • extends & laterally rotates arms with posterior fibers | Axillary nerve |
| Supraspinatus | supraspinous fossa of scapula | superior part of greater tubercle of humerus | • stabilizes shoulder joint • helps prevent downward dislocation of humerus | Suprascapular nerve |
| Infraspinatus | infraspinous fossa of scapula | greater tubercle of humerus, posterior to supraspinatus | • helps to hold head of humerus in glenoid cavity • stabilizes the shoulder joint • rotates humerus laterally | Suprascapular nerve |
| Subscapularis | subscapular fossa of scapula | lesser tubercle of humerus | • chief medial rotator of humerus, assisted by pectoralis major • helps to hold head of humerus in glenoid cavity, stablizes shoulder | Subcapular nerve |
| Teres minor | lateral border of dorsal scapular surface | greater tubercle of humerus, inferior to infraspinatus | • helps to hold head of humerus in glenoid cavity • stabilizes the shoulder joint • rotates humerus laterally | Axillary nerve |
| Teres major | posterior surface of scapula @ inferior angle | intertubercular groove of humerus, tendon fused with tendon of latissimus dorsi | • posteromedially extends, medially rotates, & adducts arm • synergist of latissimus dorsi | Lower scapular nerve |
Arm Muscles
| Name | Origin | Insertion | Action | Nerve |
| Coracobrachialis | coracoid process of scapula | medial surface of humerus shaft | • flexion & adduction of humerus • synergist of pectoralis major | Musculocutaneous nerve |
| Biceps brachii | long head (65-1): tubercle above glenoid cavity and lip of glenoid cavity of scapula short head: (65-2): coracoid process of scapula | by common tendon to radial tuberosity | • flexes elbow joint & supinates forearm (usually at the same time) • weak flexor of arm @ shoulder | Musculocutaneous nerve |
| Brachialis | front of distal humerus | coronoid process of ulna | • major forearm flexor, synergist with biceps brachii | Musculocutaneous nerve |
| Brachioradialis | lateral supracondylar ridge @ distal end of humerus | base of styloid process of radius | • synergist in forearm flexion, best when forearm is partially flexed • stabilizes the elbow during rapid flexion & extension | Radial nerve |
| Triceps brachii | lateral head: posterior shaft of humerus long head: infraglenoid tubercle of scapula medial head): posterior humeral shaft distal to radial groove | by common tendon into olecranon process of ulna | • agonist of forearm extension (medial head) • antagonist of forearm flexors • stablizes shoulder joint & assist in arm adduction (long head tendon) | Radial nerve |
| Anconeus | lateral epicondyle of humerus | lateral aspect of olecranon process | • abducts ulna during forearm pronation • synergist of triceps brachii in elbow extension | Radial nerve |
Forearm Rotators
| Name | Origin | Insertion | Action | Nerve |
| Pronator teres | medial epicondyle of humerus, coronoid process of ulna | by common tendon into lateral radius, midshaft | • pronates forearm • weak flexor of elbow | Median nerve |
| Supinator | lateral epicondyle of humerus, radial collateral & annular ligaments, supinator fossa & crest of ulna | lateral, anterior & posterior surfaces of proximal 1/3 of radius | • forcibly supinates forearm with biceps brachii • weakly supinates forearm working along • antagonist of Pronator teres | Posterior interosseous nerve |
Wrist Flexors
| Name | Origin | Insertion | Action | Nerve |
| Flexor carpi radialis | medial epicondyle of humerus | base of 2nd & 3rd metacarpals (anterior) | • powerful flexor of wrist • abducts the hand • weak synergist of elbow flexion | Median nerve |
| Palmaris longus | medial epicondyle of humerus | palmar aponeurosis, skin & fascia of palm | • weak wrist flexor • weak synergist of elbow flexion • tenses skin of palm during hand movements | Median nerve |
| Flexor carpi ulnaris | medial epicondyle of humerus, olecranon process & posterior surface of ulna | pisiform & hamate bones & base of 5th metacarpal (anterior) | • powerful flexor of writs • adducts hand with extensor carpi ulnaris • stabilized wrist during finger extension | Ulnar nerve |
Wrist Extensors
| Name | Origin | Insertion | Action | Nerve |
| Extensor carpi radialis longus | lateral supracondylar ridge of humerus | base of 2nd metacarpal (posterior) | • extends wrist with extensor carpi ulnaris • abducts write with flexor carpi radialis | Radial nerve |
| Extensor carpis ulnaris | lateral epicondyle of humerus & posterior border of ulna | base of 5th meta | • extends & adducts wrist | Deep branch of radial nerve |
Finger Muscles
| Name | Origin | Insertion | Action | Nerve |
| Flexor digitorum superficialis | medial epicondyle of humerus, coronoid process of ulna, shaft of radius | by four tendons into middle phalanges of fingers 2-5 | • flexes wrist & middle phalanges of fingers 2-5 | Median nerve |
| Extensor digitorum | lateral epicondyle of humerus | by four tendons into extensor expansions & distal phalanges of fingers 2-5 | • prime mover of finger extension • extends wrist • can abduct (flare) fingers | Posterior interosseous nerve, a branch of radial nerve |
| Extensor digiti minimi | lateral epicondyle of humerus | extensor expansion of 5th digit | • extends 5th digit | Posterior interosseous nerve,deep branch of radial nerve |
| Extensor pollicis longus | posterior surface of middle 3rd of ulna | base of distal phalanx of thumb | • extends thumb | Posterior interosseous nerve |
| Abductor pollicis longus | posterior surface of radius & ulna | base of 1st metacarpal & trapezium | • abducts & extends thumb | Posterior interosseous nerve |
Chest Muscles
| Name | Origin | Insertion | Action | Nerve |
| Pectoralis major | sternal end of clavicle, sternum, cartilage of ribs 1-6, & aponeurosis of external oblique muscle | by a short tendon into intertubercular groove of humerus | • agonist of arm flexion • rotates arm medially • adducts arm against resistance • pulls rib cage upward with scapula fixed | Lateral & medial pectoral nerves |
| Pectoralis minor | anterior surface of ribs 3-5 (or 2-4) | coracoid process of scapula | • draws scapula forward & downward (ribs fixed) • draws rib cage superiorly (scapula fixed) | Both pectoral nerves |
| Subclavius | costal cartilage of rib 1 | groove on inferior surface of clavicle | • stablizes & depresses pectoral girdle | Nerve to subcla vius |
| Serratus anterior (boxer’s muscle) | by series of muscle slips from ribs 1-9 | anterior surface of vertebral border of scapula | • agonist to protract & hold scapula against rib cage • rotates scapula (infe rior angle laterally & upward) • abduct & raise arm & horizontal arm move ments | Long thoracic nerve |
Abdominal Muscles
| Name | Origin | Insertion | Action | Nerve |
| Rectus Abdominis | pubic crest & symphysis | xyphoid process & costal cartilages of ribs 5-7 | • flex & rotate lumbar region of vertebral column • fix & depress ribs • stabilize pelvis during walking • increase intra-abdominal pressure | Intercostals |
| External oblique | outer surface of lower 8 ribs | linea alba via aponeurosis | • when together, synergist to rectus abdominis, flex vertebral column & com press abdominal wall • when alone, synergist to muscles of back, rotate & lateral flexion of trunk | Intercostals |
| Internal oblique | lumbar fascia, iliac crest, & inguinal ligament | linea alba, pubic crest, last 3 or 4 ribs, & costal margin | • same as external oblique | Intercostals |
| Transverse abdominis | inguinal ligament, lumbar fascia, cartilages of last 6 ribs, iliac crest | linea alba, pubic crest | • compresses abdominal contents | Intercostals |
Back Muscles
| Name | Origin | Insertion | Action | Nerve |
| Levator scapulae | transverse processes of C1-C4 | medial border of scapula, superior to spine | • elevates & adducts scapula (synergist to trapezius) • tilts glenoid cavity down, flexes neck to same side (fixed scapula) | Cervical spinal nerves & dorsal scapular nerve |
| Trapezius | occipital bone, ligamentum nuchae, spines of C7 – T12 | spine & acromion of scapula, lateral 3rd of clavicle | • stabilizes, raises, retracts & rotates scapula • adducts & retracts scapula (middle) • elevates scapula or synergist to head extension(superior) • depresses scapula & shoulder (inferior) | Accessory nerve |
| Rhomboid minor | spinous processes of C7 & T1 | medial border of scapula | • retract scapula (squaring shoulders), synergist with middle fibers of Trapezius • rotate glenoid cavity downward (lowering arm against resistance) • stabilize scapula | Dorsal scapular nerve |
| Rhomboid major | spinous processes of T2-T5 | medial border of scapula | • retract scapula (squaring shoulders), synergist with middle fibers of Trapezius • rotate glenoid cavity downward (lowering arm against resistance) • stabilize scapula | Dorsal scapular nerve |
| Latissimus dorsi | via lumbodorsal fascia into spines of T7-L5, lower 4 ribs & iliac crest | floor of intertubercular groove of humerus | • agonist of arm extension • powerful arm adductor • medially rotates arm & shoulder • depresses scapula • pulls body upward & forward with arms fixed overhead | Thoracodorsal |
Pelvic Muscles
| Name | Origin | Insertion | Action | Nerve |
| Coccygeus | spine of ischium | sacrum & coccyx | • supports pelvic viscera • supports coccyx & pulls it forward | S4 & S5 |
| Levator ani | inside pevis from pubis to ischial spine | inner surface of coccyx | • supports & maintains pelvic viscera • resists downward thrusts • forms sphincters at ano-rectal junction & vagina • lifts anal canal during defecation | S4 & inferior rectal |
