Upper limb muscle actions and innervations Flashcards
Pec Major
adducts, medially rotates humerus; clavicular head flexes humerus
medial and lateral pectoral nerves
Pec minor
protracts and depresses the scapula, also accessory muscle of respiration
medial pectoral nerve
Subclavius
pulls lateral end of clavicle downward and forward, thereby acting to resist excessive shoulder elevation and protraction
Nerve to subclavius
BTW, what goes through the clavipectoral fascia?
cephalic vein, thoracoacromial artery, lateral pectoral nerve
Deltoid
flex and medially rotate humerus
extend and laterally rotate humerus
abduct humerus
axillary n
Supraspinatus
initiate abduction
suprascapular n
Infraspinatus
lateral rotation of humerus
suprascapular n
teres minor
lateral rotation of humerus
axillary n
Teres Major
extend, adduct, medially rotate humerus (mini deltoid)
lower subscapular n
Subscaplaris
multipennate. medial rotation of humerus
Upper and lower subscapular n.
serratus anterior
protract scaupla, upwardly rotate glenoid cavity, fixate scapula to thoracic wall
long thoracic n.
Biceps Brachii
flex forarm and supinate the hand; most powerful supinator of hand above 90 of flexion; long head also assists in flexion of the arm.
musculocutaneous n.
long head attaches to supraglenoid tubercle of scapula
short head to coracoid process of scapula
i: radial tuberosity
Brachialis
flexion of forearm (most powerful of three primary forearm flexors)
musculocutaneous n.
Brachioradialis
flexion of the forearm (best mechanical advantage when hand is midway between supination and pronation, i.e. handshake)
radial n.
Coracobrachialis
flexion, adduction of humerus
musculocutaneous n.
Triceps brachii
O: long head; infraglenoid tubercle of scapula
lateral head- posterior surface of humerus proximal to radial groove
medial head- posterior surface of humerus distal to radial groove
a: extend the forearm; long head also acts at the shoulder joint to extend and adduct the arm
Radial n.
Anconeus
O; posterior surface lateral epicondyle of humerus
i: lateral surface of olecranon and proximal posterior surface of ulna
assists triceps in extension of the forearm
radial n.
Pronator teres
pronates and slightly flexes forearm
median n.
flexor carpi radialis
flexes wrist and abducts hand
median n
palmarus longus
flexes the wrist
median n.
flexor carpi ulnaris
flexes wrist, adducts hand
*** ulnar n.
Flexor digitorum superficialis
flexes proximal I-P joints, assists in flexion of the M-P joints, wrist and forearm
median n.
flexor digitorum profundus
flexion of distal I-P joints, assists in flexion of proximal IP, MP and wrist joints
N: lateral portion- median n. medial portion (to digits 4 & 5) Ulnar n.
Plexor pollicis longus
flicks your bic: flexes thumb
median n. (anterior interosseous branch)
Pronator quadratus
pronates the hand
median n. (anterior interosseous branch)
Muscles of anterior forearm by layer
Superficial layer: pronator teres, flexor carpi radialis, palmaris longus, flexor carpi ulnaris
Intermediate layer: flexor digitorum superficialis
deep layer: flexor digitorum profundus, flexor pollicis longus
Distal layer: pronator quadratus
Extensor carpi radialis longus
extends and abducts the hand
radial n.
extensor carpi radialis brevis
extends and assists in abduction of the hand
radial n.
Extensor digitorum
extends the digits and assists in extension of the hand
radial n.
extensor digiti minimi
extension of fifth digit
radial n.
extensor carpi ulnaris
extends and adducts the hand
radial n.
Abductor pollicis longus
abduccs the thumb and wrist, assists with extension of the thumb
radial n.
extensor pollicis brevis
extends proximal phalanx of thumb and first metacarpal
radial n.
extensor pollicis longus
extends the thumb (I-P and M-P joints)
radial n.
Extensor indicis
extends the index finger
radial n.
supinator
supinates the hand
radial n.
Abductor pollicis brevis
abducts thumb
median n. (recurrent)
Flexor pollicis brevis
flexion of the thumb at carpometacarpal and metacarpophalangeal joint
superficial head: median n. (recurrent);
deep head: deep branch ulnar n.
Opponens pollicis
opposition of thumb to digits
median n. (recurrent)
Abductor digiti minimi
abducts and flexes metacarpophalangeal joint of digiti minimi
ulnar n. (deep branch)
flexor digiti minimi
flees digiti minimi at metacarpophalangeal joint
ulnar n (deep branch)
Opponens digiti minimi
pulls fifth metacarpal towards thumb during opposition or when grasping
ulnar n. (deep branch)
lumbricals
flexes MCP joints and extends I-P joints
median (1 & 2), ulnar (3 & 4)
Adductor pollicis
adducts thumb (oblique and transverse heads)
ulnar (deep branch)
palmar interossei
adducts digits 1-, flexes M-P joints and extends I-P joints of 1-5
ulnar (deep branch)
dorsal interossei
abduct digits 2-4, flex M-P joints and extend I-P joints of digits 2-4
Ulnar (deep branch)
