Muscle | Origin, Insertion, action |
Pec Minor | Origin: outer surface of ribs 3-5
Insertion: coracoid process
Action: Protraction, downward rotation |
Rhomboids | Origin: spinous process of last cervical vertebrae and first 5 thoracic vertebrae
Insertion: medial boarder of scapula, below scapular spine
Action: adduction, downward rotation |
Levator Scapulae | Origin: transverse process of upper 4 cervical vertebrae
Insertion: medial boarder of scapula above base of scapular spine
Action: elevates scapula |
Serratus Anterior | Origin: Lateral aspect of ribs 1-8 (sometimes 9)
Insertion: Length of medial boarder of anterior surface of scapula
Action: abduction, upward rotation |
Trapezius | Origin: Occipital bone, ligaments of the neck, spines of C7 and all thoracic vertebrae
Insertion: acromion process, outer clavicle, spine of scapula
Action: as a whole: adducts and pulls upward on scapula |
Triceps Brachii (long head) | Origin: just inferior to the glenoid fossa
Insertion: Olecranon process of the ulna
Action: assists with extension, adduction |
Biceps Brachii (short head) | Origin: coracoid process
Insertion: radial tuberosity
Action: flexion, add, medial rotation, hor. add |
Biceps Brachii (long head) | Origin: upper rim of glenoid fossa
Insertion: radial tuberosity
Action: assists with abduction, flexion, supination |
Subscapularis | Origin: entire anterior surface of scapula
Insertion:lesser tubercle of humerus
Action: Inward rotation
*Rotator cuff |
Teres Minor | Origin: posterior, lateral boarder of scapula
Insertion: greater tubercle, adjacent shaft of humerus
Action: Horizontal Abd, extension, outward rotation
*Rotator cuff |
Infraspinatus | Origin: infraspinous fossa
Insertion: greater tubercle of humerus
Action: Horizontal Abd, extension, outward rotation
*Rotator cuff |
Teres Major | Origin: posterior surface of inferior angle of scapula
Insertion:anterior humerus/ crest of lesser tubercle
Action: extension, adduction, medial rotation |
Latissimus Dorsi | Origin: lower 6 thoracic and all lumbar vertebrae, posterior sacrum, iliac crest, lower 3 ribs
Insertion: anterior humerus
Action: extension, adduction, medial rotation, hor. abd |
Coracobrachialis | Origin: coracoid process of scapula
Insertion: medial, anterior humerus
Action: flexion, adduction, hor. adduction |
Supraspinatus | Origin: supraspinous fossa
Insertion: greater tuberosity of humerus
Action: Initiates abduction (deltoid finishes)
*Rotator cuff |
Pec Major | Origin: medial half of clavicle, anterior sternum, and cartilage of first 6 ribs
Insertion: lateral aspect of humerus, just below head
Action: flex, ext, hor. add, medial rotation |
Deltoid Anterior | Origin: outer third of clavicle
Insertion: deltoid tuberosity
Action: flexion, hor. add, medial rotation |
Deltoid Middle | Origin: top of acromion process
Insertion: deltoid tuberosity
Action: abduction, hor. abd |
Deltoid Posterior | Origin: scapular spine
Insertion: deltoid tuberosity
Action: extension, hor. abd, lateral rotation |
Brachialis | Origin: Anterior surface of lower half of humerus
Insertion: Ulnar tuberosity
Action: true flexion |
Brachioradialis | Origin: supracondylar ridge
Insertion: base of styloid process of radius
Action: flexion |
Pronator teres | Origin: medial epicondle of humerus and coronoid process of ulna
Insertion: middle 1/3 of lateral radius
Action: pronation |
Pronator quadratas | Origin: lower 1/4 of the anterior ulna
Insertion: lower 1/3 of anterior radius
Action: pronation |