Muscles Origin & Insertion

Front 1

PECTORALIS MAJOR

Back 1

ORIGIN - from clavicle, sternum, cartilage of ribs 1-6 and sheath of external oblique muscles

INSERTION - intertubercular groove of the humerus

ACTIONS - flexion of the shoulder, medial rotation of the arm, adducts arm, horizontal flexion

Front 2

LATISSIMUS DORIS

Back 2

ORIGIN - thoracolumbar fascia into spines of lower 6 T vertebrae, L vertebrae, iliac crest, lower 3-4 ribs, inferior angle of the scapula

INSERTION - intertubercular groove of the humerus

ACTIONS - extension, adduction, medial rotation of the shoulder joint, depression of the scapula

Front 3

DELTOID

Back 3

ORIGIN - lateral third of clavicle, acromion and spine of the scapula

INSERTION - deltoid tuberosity of the humerus

ACTIONS - abduction of arm, flexion and extension, medial and lateral rotation of the arm

Front 4

TERES MAJOR

Back 4

ORIGIN - posterior surface of scapula at superior angle

INSERTION - intertubercular groove of the humerus

ACTIONS - extension, medial rotation and adduction of the shoulder joint

Front 5

SUPRASPINATUS

Back 5

ORIGIN - supraspinous fossa of the scapula

INSERTION - greater tubercle of the humerus

ACTIONS - assists abduction of shoulder joint, stabilises shoulder joint

Front 6

INFRASPINATUS

Back 6

ORIGIN - infraspinous fossa of scapula

INSERTION - greater tubercle of humerus, posterior to insertion of supraspinatus

ACTIONS - lateral rotation of shoulder joint, stabiliser of shoulder joint

Front 7

TERES MINOR

Back 7

ORIGIN - lateral border of posterior part of scapula surface

INSERTION - proximal part of greater tubercle of humerus

ACTIONS - lateral rotation of shoulder joint, stabilises shoulder joint

Front 8

SUBSCAPULARIS

Back 8

ORIGIN - subscapular fossa of scapula

INSERTION - lesser tubercle of the humerus

ACTIONS - medial rotator of the shoulder joint, stabiliser of shoulder joint

Front 9

BRACHIALIS

Back 9

ORIGIN - anterior surface of distal humerus

INSERTION - coronoid process of ulna and capsule of the elbow joint

ACTIONS - elbow flexion

Front 10

CORACOBRACHIALIS

Back 10

ORIGIN - apex of the coracoid process

INSERTION - liner roughening on the mid-shaft of the humerus on the medial side

ACTIONS - flexor of the arm at the shoulder joint

Front 11

BICEPS BRACHII

Back 11

ORIGIN - (short) coracoid process (long) tubercle above glenoid cavity

INSERTION - by common tendon radial tuberosity

ACTIONS - flexor of the elbow joint, aids supination, weak flexor of the shoulder joint

Front 12

TRICEPS BRACHII

Back 12

ORIGIN - (long) infraglenoid tubercle of glenoid cavity (lateral) posterior humerus (medial) posterior humerus distal to radial groove

INSERTION - common tendon into olecranon process of the ulna

ACTIONS - elbow extension

Front 13

BRACHIORADIALIS

Back 13

ORIGIN - lateral supracondylar ridge at distal end of humerus

INSERTION - base of styloid process of radius

ACTIONS - elbow flexion, acts halfway between pronation and supination

Front 14

ANCONEUS

Back 14

ORIGIN - lateral epicondyle of humerus

INSERTION - lateral aspect of olecranon process of ulna