Unit 2 Muscles and Innervations

anterior deltoid action

flexion and internal rotation of shoulder

anterior deltoid innervation

axillary nerve (C5-6)

middle deltoid action

abduction of shoulder

middle deltoid innervation

axillary nerve (C5-6)

posterior deltoid action

extension and ER of shoulder

posterior deltoid innervation

axillary nerve (C5-6)

short head of biceps brachii action

flexion of elbow, supination of forearm, shoulder flexion and adduction

long head of biceps brachii actions

flexion of elbow, supination of forearm, shoulder flexion and abduction if humerus is externally rotated

biceps brachii innervation

musculocutaneous nerve (c5-6)

coracobrachialis action

flexion and adduction of shoulder

coracobrachialis innervation

musculocutaneous (C6-7)

supraspinatus action

ER and abduction of shoulder, stabilizes head of humerus into glenoid cavity

supraspinatus innervation

suprascapular nerve (C4-6)

infraspinatus action

ER of shoulder, stabilizes head of humerus into glenoid cavity

infraspinatus innervation

suprascapular nerve (C4-6)

teres minor action

ER of shoulder, stabilizes head of humerus into glenoid cavity

teres minor innervation

axillary nerve (C5-6)

teres major action

IR, adduction, and extension of shoulder

teres major innervation

lower subscapular nerve

subscapularis action

IR of shoulder, stabilizes head of humerus into glenoid cavity

subscapularis innervation

upper and lower subscapularis (C5-7)

latissimus dorsi action

origin fixed:

- adduction, IR, extension, and depression of shoulder

- lateral flexion of trunk

insertion fixed:

- anterior/lateral pelvic tilt

- hyperextension of spine

- accessory muscle of respiration

latissmus dorsi innervation

thoracodorsal nerve (C6-8)

lateral head and medial head of triceps brachii action

extension of elbow

long head of triceps action

extension of elbow, assists in adduction and extension of shoulder

triceps brachii innervation

radial nerve (C6-T1)

pectoralis major action

adduction and IR of shoulder, elevates thorax in forced inspiration, upper fibers assist in flexion

pectoralis major innervation

lateral and medial pectoral nerves (C5-T1)

pectoralis minor action

anteriorly tilts scapula, assists in forced inspiration

pectoralis minor innervation

medial pectoral nerve with a communicating branch from lateral pectoral nerve (C6-T1)

serratus anterior action

protraction and upward rotation of scapula, holds medial border of scapula tight to rib cage, upper fibers may elevate and lower fibers may depress the scapula, assists in forced inspiration

serratus anterior innervation

long thoracic nerve (C5-8)

pronator teres action

flexion of the elbow, pronation of the forearm

pronator teres innervation

median nerve (C6-7)

pronator quadratus action

pronation of the forearm

pronator quadratus innervation

median nerve (C7-T1)

palmaris longus action

tenses with the palmer fascia, flexion of the wrist, may assist with flexion of the elbow

palmaris longus innervation

median nerve (C6-T1)

flexor digitorum superficialis action

flexion of the PIP joints of digits 2-5, flexion of MCP joints, flexion of the wrist and elbow

flexor digitorum superficialis innervation

median nerve (C7-T1)

flexor digitorum profundus action

flexion of the DIP joints of digits 2-5, flexion of PIP and MCP joints, flexion of the wrist

flexor digitorum profundus innervation

digits 2-3: median nerve (C7-T1)

digits 4-5: ulnar nerve (C7-T1)

flexor carpi radialis action

flexion of the elbow, pronation of the forearm, flexion and radial deviation of the wrist

flexor carpi radialis innervation

median nerve (C6-8)

flexor carpi ulnaris action

flexion of the elbow, flexion and ulnar deviation of the wrist

flexor carpi ulnaris innervation

ulnar nerve (C7-T1)

brachioradialis action

flexion of the elbow, pronation and supination of the forearm back to neutral

brachioradialis innervation

radial nerve (C5-6)

extensor carpi radialis longus action

flexion of the elbow, extension and radial deviation of the wrist

extensor carpi radialis longus innervation

radial nerve (C5-8)

extensor carpi radialis brevis action

extension and ulnar deviation of the wrist, elbow flexion

extensor carpi radialis brevis innervation

radial nerve (C6-8)

extensor digitorum action

extension of MCP and IP joints of digits 2-5, abduction of digits 2,4,5, extension and radial deviation of wrist, elbow flexion

extensor digitorum innervation

radial nerve (C6-8)

extensor digiti minimi action

extension of the MCP and IP joints and abduction of the 5th digit, elbow flexion

extensor digiti minimi innervation

radial nerve (C6-8)

extensor carpi ulnaris action

extension and ulnar deviation of wrist, elbow flexion

extensor carpi ulnaris innervation

radial nerve (C6-8)

supinator action

supinates the forearm

supinator innervation

radial nerve (C5-7)

extensor indicis action

extension of the MCP and IP joint and adduction of the 2nd digit

extensor indicis innervation

radial nerve (C6-8)

brachialis action

flexion of the elbow joint

brachialis innervation

musculocutaneous and small branch from radial nerve (C5-6)

anconeus action

extension of elbow, stabilize ulna during pronation and supination

anconeus innervation

radial nerve (C7-8)