MS Exam 2 Muscles

What is the proximal attachment of latissimus dorsi?

Spinous processes T7-T12, thoracolumbar fascia, iliac crest, and inferior 3 or 4 ribs

What is the distal attachment of latissimus dorsi?

Floor of intertubercular sulcus of humerus

What is the innervation of latissimus dorsi?

Thoracodorsal nerve (C6-C8)

What is the muscle action of latissimus dorsi?

Extends, adducts, and medially rotates the humerus

What is the proximal attachment of the supraspinatus?

Supraspinous fossa of scapula

What is the distal attachment of the supraspinatus?

Greater tubercle of the humerus

What is the innervation of the supraspinatus?

Suprascapular nerve (C5, C6)

What are the muscle actions of the supraspinatus?

Abduction of arm; acts with rotator cuff muscles

What are the proximal attachments of the infraspinatus?

Infraspinous fossa of scapula

What is the distal attachment of the infraspinatus?

Greater tubercle of the humerus

What is the innervation of the infraspinatus?

Suprascapular (C5,C6)

What are the muscle actions of the infraspinatus?

Laterally rotates the arm; acts with rotator cuff muscles

What are the proximal attachments of teres minor?

Middle part of lateral border of scapula

What is the distal attachment of the teres minor?

Greater tubercle of the humerus

What is the innervation of teres minor?

Axillary nerve (C5, C6)

What are the muscle actions of the teres minor?

Laterally rotates the arm; acts with the rotator cuff muscles

What is the proximal attachment of the teres major?

Posterior surface of inferior angle of scapula

What is the distal attachment of the teres major?

Medial lip of intertubercular sulcus of humerus

What is the innervation of the teres major?

Lower subscapular nerve (C5, C6)

What are the muscle actions of the teres major?

Adducts and medially rotates the arm

What is the proximal attachment of the subscapularis?

Subscapular fossa

What is the distal attachment of the subscapularis?

Lesser tubercle of the humerus

What is the innervation of the subscapularis?

Upper and lower subscapular nerves (C5, C6)

What are the muscle actions of the subscapularis?

Medially rotates the arm; helps hold head of humerus in glenoid cavity

What is the proximal attachment of the deltoid?

Lateral third of clavicle, acromion, and spine of scapula

What is the distal attachment of the deltoid?

Deltoid tuberosity of the humerus

What is the innervation of the deltoid?

Axillary nerve (C5, C6)

What are the muscle actions of the deltoid?

Flexes, medially rotates, abducts, extends, and laterally rotates the arm

What are the proximal attachments of the pectoralis major?

Anterior surface of medial half of clavicle, anterior surface of sternum, superior six costal cartilages, aponeurosis of external oblique muscles

What is the distal attachment of the pectoralis major?

Lateral lip of intertubercular sulcus of humerus

What is the innervation of the pectoralis major?

Lateral and medial pectoral nerves; clavicular head (C5, C6) sternocostal head (C7, C8, T1)

What are the muscle actions of the pectoralis major?

Adducts and medially rotates humerus; draws scapula anteriorly and inferiorly

What is the proximal attachment of the pectoralis minor?

3rd-5th ribs near costal cartilages

What is the distal attachment of the pectoralis minor?

Medial border and superior surface of coracoid process of scapula

What is the innervation of the pectoralis minor?

Medial pectoral nerve (C8,T1); lateral pectoral nerve

What are the muscle actions of the pectoralis minor?

Stabilizes scapula by drawing it inferiorly and anteriorly

What is the proximal attachment of the subclavius?

Junction of 1st rub and its costal cartilage

What is the distal attachment of the subclavius?

Inferior surface of middle third of clavicle

What is the innervation of the subclavius?

Nerve to subclavius (C5, C6)

What are the muscle actions of subclavius?

Anchors and depresses clavicle

What is the proximal attachment of the serratus anterior?

External surfaces of lateral parts of 1st-8th ribs

What is the distal attachment of serratus anterior?

Anterior surface of medial border of scapula (superior and inferior angles)

What is the innervation of serratus anterior?

Long thoracic nerve (C5, C6, C7)

What are the muscle actions of the serratus anterior?

Protracts scapula; rotates scapula

What are the proximal attachments of the biceps brachii?

Short head: tip of coracoid process of scapula

Long head: supraglenoid tubercle of scapula

What is the distal attachment of the biceps brachii?

Tuberosity of radius and fascia of forearm via bicipital aponeurosis

What is the innervation of the biceps brachii?

Musculocutaneous nerve (C5, C6, C7)

What are the muscle actions of the biceps brachii?

Supinates forearm; (in supine- flexes forearm); short head resists dislocation of shoulder

What is the proximal attachment of the brachialis?

anterior surface of humerus

What are the distal attachments of the brachialis?

Coronoid process and tuberosity ulna

What are the innervations of the brachialis?

Musculocutaneous nerve (C5, C6)

What is the muscle action of the brachialis?

Flexes forearm in all positions

What is the proximal attachment of the coracobrachialis?

Tip of coracoid process of scapula

What is the distal attachment of the coracobrachialis?

Middle third of medial surface of humerus

What is the innervation of the coracobrachialis?

Musculocutaneous nerve (C5, C6, C7)

What are the muscle actions of the coracobrachialis?

Helps flex and adduct arm; resists dislocation of shoulder

What are the proximal attachments of the triceps brachii?

Long head: infraglenoid tubercle of scapula

Lateral head: posterior surface of humerus (superior to radial groove)

Medial head: posterior surface of humerus (inferior to radial groove)

What is the distal attachment of the triceps brachii?

Proximal end of olecranon of ulna and fascia of forearm

What is the innervation of the triceps brachii?

Radial nerve (C5-T1)

What are the muscle actions of the triceps brachii?

Chief extensor of forearm; long head resists dislocation of humerus

What is the proximal attachment of the anconeus?

Lateral epicondyle of humerus

What is the distal attachment of the anconeus?

olecranon

What is the innervation of the anconeus?

Radial nerve (C5-T1)

What are the muscle actions of the anconeus?

Assists triceps in extending forearm; stabilizes elbow joint; abduct ulna during pronation

What is the proximal attachment of the brachioradialis?

Proximal 2/3 of lateral supraepicondylar ridge of humerus

What is the distal attachment of the brachioradialis?

lateral surface of distal end of radius

What are the actions of the brachioradialis?

Flexes forearm best when midpronated

What is the innervation of the brachioradialis?

Radial nerve (C5-T1)

What is the proximal attachment of the extensor carpi radialis longus?

Lateral supraepicondylar ridge of humerus

What is the distal attachment of the extensor carpi radialis longus?

Dorsal part of base of 2nd metacarpal

What are the actions of the extensor carpi radialis longus?

Extend and abduct hand at wrist joint

What is the innervation of the extensor carpi radialis longus?

Radial nerve (C5-T1)

What is the proximal attachment of the extensor carpi radialis brevis?

Lateral epicondyle of humerus

What is the distal attachment of the extensor carpi radialis brevis?

Dorsal part of base of 3rd metacarpal

What are the actions of the extensor carpi radialis brevis?

Extend and abduct hand at wrist joint

What is the innervation of the extensor carpi radialis brevis?

Deep branch of radial nerve (C7-C8)

What is the proximal attachment of extensor carpi ulnaris?

Lateral epicondyle of humerus

What is the distal attachment of the extensor carpi ulnaris?

Dorsal part of base of 5th metacarpal

What are the actions of the extensor carpi ulnaris?

Extends and adducts hand at wrist joint

What is the innervation of the extensor carpi ulnaris?

Deep branch of radial nerve (C7, C8)

What is the proximal attachment of the extensor digitorum?

Lateral epicondyle of humerus

What is the distal attachment of the extensor digitorum?

Extensor expansions of medial 4 digits

What are the actions of the extensor digitorum?

Extends medial 4 digits at metacarpophalangeal joints (pri) and at interphalangeal joints (sec)

What is the innervation of the extensor digitorum?

Deep branch of radial nerve (C7, C8)

What is the proximal attachment of the extensor digiti minimi?

Lateral epicondyle of humerus

What is the distal attachment of the extensor digiti minimi?

Extensor expansion of 5th digit

What are the actions of the extensor digiti minimi?

Extends 5th digit at metacarpophalangeal joint (pri) and at interphalangeal joint (sec)

What is the innervation of the extensor digiti minimi?

Deep branch of radial nerve (C7, C8)

What is the proximal attachment of the supinator?

Lateral epicondyle of humerus; radial collateral and annular ligaments; supinator fossa; crest of ulna

What is the distal attachment of the supinator?

Lateral, posterior, and anterior surfaces of proximal third of radius

What is the action of the supinator?

Supinates forearm

What is the innervation of the supinator?

Deep branch of radial nerve (C7, C8)

What is the proximal attachment of the extensor indicis?

Posterior surface of distal third of ulna and interosseous membrane

What is the distal attachment of the extensor indicis?

Extensor expansion of 2nd digit

What are the actions of the extensor indicis?

Extends 2nd digit; helps extend hand at wrist

What is the innervation of the extensor indicis?

Posterior interosseous nerve (C7, C8)

What is the proximal attachment of the abductor pollicis longus?

Posterior surface of proximal halves of ulna, radius, and interosseous membrane

What is the distal attachment of the abductor pollicis longus?

Base of 1st metacarpal

What are the actions of the abductor pollicis longus?

abducts thumb and extends it at carpometacarpal joint

What is the innervation of the abductor pollicis longus?

Posterior interosseous nerve (C7, C8)