Muscles Of The Upper Extremities Flashcards
Which four muscles make up the rotator cuff?
Supraspinatus, Infraspinatus, Teres Minor, Subscapularis
What is the primary function of the supraspinatus muscle?
Initiates shoulder abduction (first 15 degrees)
Which rotator cuff muscle is responsible for external rotation of the shoulder?
Infraspinatus and Teres Minor
What is the insertion of the subscapularis muscle?
Lesser tubercle of the humerus
Which nerve innervates the deltoid muscle?
Axillary nerve (C5-C6)
What is the primary function of the serratus anterior?
Protraction and upward rotation of the scapula
What injury is associated with long thoracic nerve damage?
Winged scapula (Serratus anterior dysfunction)
Which muscle is the main flexor of the elbow?
Brachialis
What is the difference between the actions of the biceps brachii and brachialis?
Biceps brachii flexes the elbow and supinates the forearm; brachialis is a pure elbow flexor
What is the insertion of the biceps brachii?
Radial tuberosity
Which nerve innervates the triceps brachii?
Radial nerve (C6-C8)
What is the primary function of the triceps brachii?
Elbow extension
Which muscle is responsible for forearm supination?
Supinator (primary), Biceps brachii (secondary)
Which muscles are responsible for wrist flexion?
Flexor carpi radialis, Flexor carpi ulnaris, Palmaris longus
What is the innervation of the flexor carpi ulnaris?
Ulnar nerve (C8-T1)
Which muscles are responsible for wrist extension?
Extensor carpi radialis longus, Extensor carpi radialis brevis, Extensor carpi ulnaris
What is the primary function of the flexor digitorum superficialis?
Flexes the PIP joints of fingers 2-5
What is the primary function of the flexor digitorum profundus?
Flexes the DIP joints of fingers 2-5
What is the innervation of the flexor digitorum profundus?
Median nerve (lateral half) and Ulnar nerve (medial half)
Which muscle is the primary abductor of the thumb?
Abductor pollicis longus
What muscles make up the thenar eminence?
Abductor pollicis brevis, Flexor pollicis brevis, Opponens pollicis
What is the function of the opponens pollicis muscle?
Thumb opposition (touching thumb to pinky)
Which muscles make up the hypothenar eminence?
Abductor digiti minimi, Flexor digiti minimi, Opponens digiti minimi
What is the function of the lumbricals?
Flex MCP joints and extend PIP/DIP joints of fingers
What is the function of the dorsal interossei?
Finger abduction (DAB: Dorsal ABducts)
What is the function of the palmar interossei?
Finger adduction (PAD: Palmar ADducts)
Which nerve innervates the majority of the intrinsic hand muscles?
Ulnar nerve (except thenar muscles and lateral two lumbricals, which are median nerve)
What is the clinical significance of the median nerve in the wrist?
Compression leads to carpal tunnel syndrome
Which muscle is affected in tennis elbow (lateral epicondylitis)?
Extensor carpi radialis brevis
Which muscle is affected in golfer’s elbow (medial epicondylitis)?
Flexor carpi radialis and pronator teres
