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| Muscle | Origin | Insertion | Action | Nerve |
| deltoid | lateral 1/3 of clavicle, acromion & spine of scapula | deltoid tuberosity of humerus | abduction of arm; flexion & medial rotation (anterior part); extension & lateral rotation (posterior part) | axillary nerve (C5, C6) |
| *Rotator Cuff Muscles (SITS –supraspinatus, infraspinatus, teres minor & subcapularis) |
| supraspinatus* | supraspinous fossa of scapula; muscle fascia | greater tubercle of humerus (superior facet) | abduction of arm; stabilizes glenohumeral joint | suprascapular nerve (C5, C6) |
| infraspinatus* | infraspinous fossa; inferior portion of spine of scapula | greater tubercle of humerus (middle facet) | lateral rotation of arm; stabilizes glenohumeral joint | suprascapular nerve (C5, 6) |
| teres minor* | superior lateral border of scapula | greater tubercle of humerus (inferior facet) | lateral rotation of arm; stabilizes glenohumeral joint; adduction of arm (weak) | axillary nerve (C5, C6) |
| subscapularis* | subscapular fossa of scapula | lesser tubercle of humerus | medial rotation of arm; stabilizes glenohumeral joint | upper & lower subscapular nerves (C5, C6) |
| Other shoulder muscles |
| teres major | inferior, lateral border of scapula | medial lip of bicipital groove of humerus (just medial to insertion of latissimus dorsi) | medial rotation of arm; adduction of arm; extension of arm from a flexed position; upward scapular rotation | lower subscapular nerve (C5, C6, C7) |
| serratus anterior | ribs 1- 9 (outer surface) | costal surface of medial border of scapula | protract (abducts) scapula; upward rotation of scapula; stabilizes scapula | long thoracic nerve (C5, C6, C7) |
| latissimus dorsi | SP T7-L5; thoracolumbar fascia; iliac crest; posterior sacrum, ribs 9-12; inferior angle of scapula (occasionally) | medial lip of bicipital groove of humerus | adduction, medial rotation & extension of humerus; anterior pelvic tilt, elevation of pelvis; depression of scapula; downward rotation of scapula | thoracodorsal nerve (C6, C7, C8) |
| pectoralis major | medial 1/2 of clavicle, anterior manubrium & body of sternum, cartilaginous attachments of upper 6 ribs, external abdominal oblique aponeurosis | lateral lip of bicipital groove of humerus (crest of the greater tubercle) | adduction of arm (at shoulder joint)
medial rotation of arm
flexion of arm (clavicular portion)
horizontal adduction of arm | medial & lateral pectoral nerves (C5-T1) |
| pectoralis minor | ribs 3-5 (anterior lateral portion) | coracoid process of scapula (medial aspect) | stabilizes scapula for arm movements
depresses & downwardly rotates scapula
assists in scapular protraction from a retracted position
elevates ribs 3-5 | medial pectoral nerve (C8, T1) |
| subclavius | 1st rib (junction of costocartilage) | middle 1/3 of clavicle (inferior surface) | assists in stabilization of clavicle
depression of clavicle
elevation of 1st rib | nerve to subclavius (C5, C6) |
Vertebral Column