Forearm Anatomy: Muscles, Nerves, and Blood Supply

Flashcards covering origin, insertion, action, innervation, and anatomy of anterior/posterior forearm compartments, cubital fossa, blood vessels, and nerves.

Superior, lateral, and medial boundaries of the cubital fossa

Superior: Epicondylar line; Lateral: Brachioradialis; Medial: Pronator teres.

Origin of the pronator teres muscle

Medial epicondyle of humerus

Insertion of the pronator teres muscle

Midshaft of lateral radius

Action of the pronator teres muscle

Pronation of forearm

Innervation of the pronator teres muscle

Median nerve

Origin of the flexor carpi radialis muscle

Medial epicondyle of humerus

Insertion of the flexor carpi radialis muscle

Base of $2nd$ and $3rd$ metacarpals

Action of the flexor carpi radialis muscle

Flexion and abduction of hand (wrist)

Innervation of the flexor carpi radialis muscle

Median nerve

Origin of the palmaris longus muscle

Medial epicondyle of humerus

Insertion of the palmaris longus muscle

Fascia of palm (palmar aponeurosis)

Action of the palmaris longus muscle

Weakly flexes hand and tenses palmar aponeurosis

Innervation of the palmaris longus muscle

Median nerve

Origin of the flexor carpi ulnaris muscle

Medial epicondyle of humerus

Insertion of the flexor carpi ulnaris muscle

Pisiform, hamate, and base of $5th$ metacarpal

Action of the flexor carpi ulnaris muscle

Flexion and adduction of hand (wrist)

Innervation of the flexor carpi ulnaris muscle

Ulnar nerve

Origin of the flexor digitorum superficialis muscle

Medial epicondyle of humerus

Insertion of the flexor digitorum superficialis muscle

Middle phalanges of digits $2-5$

Action of the flexor digitorum superficialis muscle

Flexion of digits $2-5$ at PIP joints

Innervation of the flexor digitorum superficialis muscle

Median nerve

Origin of the flexor digitorum profundus muscle

Coronoid process of ulna and interosseous membrane

Insertion of the flexor digitorum profundus muscle

Distal phalanges of digits $2-5$

Action of the flexor digitorum profundus muscle

Flexion of digits $2-5$ at DIP joints

Innervation of the flexor digitorum profundus muscle

Anterior interosseous nerve and ulnar nerve

Origin of the flexor pollicis longus muscle

Anterior radius and interosseous membrane

Insertion of the flexor pollicis longus muscle

Distal phalanx of thumb

Action of the flexor pollicis longus muscle

Flexion of thumb

Innervation of the flexor pollicis longus muscle

Anterior interosseous nerve

Origin of the pronator quadratus muscle

Distal anterior surface of ulna

Insertion of the pronator quadratus muscle

Distal anterior surface of radius

Action of the pronator quadratus muscle

Pronation of forearm

Innervation of the pronator quadratus muscle

Anterior interosseous nerve

Origin of the brachioradialis muscle

Lateral supracondylar ridge of humerus

Insertion of the brachioradialis muscle

Radial styloid process

Action of the brachioradialis muscle

Elbow flexion in neutral position

Innervation of the brachioradialis muscle

Radial nerve ($C5-T1$)

Origin of the extensor carpi radialis longus muscle

Lateral supracondylar ridge of humerus

Insertion of the extensor carpi radialis longus muscle

Base of $2nd$ metacarpal

Action of the extensor carpi radialis longus muscle

Abduction and extension of hand (wrist)

Innervation of the extensor carpi radialis longus muscle

Radial nerve

Origin of the extensor carpi radialis brevis muscle

Lateral epicondyle of humerus

Insertion of the extensor carpi radialis brevis muscle

Base of $3rd$ metacarpal

Action of the extensor carpi radialis brevis muscle

Abduction and extension of hand (wrist)

Innervation of the extensor carpi radialis brevis muscle

Deep radial nerve

Origin of the extensor carpi ulnaris muscle

Lateral epicondyle of humerus

Insertion of the extensor carpi ulnaris muscle

Base of $5th$ metacarpal

Action of the extensor carpi ulnaris muscle

Adduction and extension of hand (wrist)

Innervation of the extensor carpi ulnaris muscle

Deep radial nerve

Origin of the extensor digitorum muscle

Lateral epicondyle of humerus

Insertion of the extensor digitorum muscle

Distal phalanges of digits $2-5$

Action of the extensor digitorum muscle

Extension of digits $2-5$

Innervation of the extensor digitorum muscle

Deep radial nerve

Origin of the extensor digiti minimi muscle

Lateral epicondyle of humerus

Insertion of the extensor digiti minimi muscle

Extensor expansion of digit $5$

Action of the extensor digiti minimi muscle

Extension of $5th$ digit

Innervation of the extensor digiti minimi muscle

Posterior interosseous nerve

Origin of the extensor indicis muscle

Posterior distal $\frac{1}{3}$ of ulna

Insertion of the extensor indicis muscle

Extensor expansion of $2nd$ digit

Action of the extensor indicis muscle

Extension of digit $2$

Innervation of the extensor indicis muscle

Posterior interosseous nerve

Origin of the supinator muscle

Lateral epicondyle of humerus and supinator crest of ulna

Insertion of the supinator muscle

Lateral proximal radial shaft

Action of the supinator muscle

Supination of forearm

Innervation of the supinator muscle

Deep radial nerve

Origin of the abductor pollicis longus muscle

Posterior surface of radius and ulna

Insertion of the abductor pollicis longus muscle

Base of $1st$ metacarpal and trapezium

Action of the abductor pollicis longus muscle

Abduction of thumb

Innervation of the abductor pollicis longus muscle

Posterior interosseous nerve

Origin of the extensor pollicis longus muscle

Posterior shaft of distal ulna and interosseous membrane

Insertion of the extensor pollicis longus muscle

Base of distal phalanx of thumb

Action of the extensor pollicis longus muscle

Extension of thumb

Innervation of the extensor pollicis longus muscle

Posterior interosseous nerve

Origin of the extensor pollicis brevis muscle

Posterior shaft of distal radius and interosseous membrane

Insertion of the extensor pollicis brevis muscle

Base of proximal phalanx of thumb

Action of the extensor pollicis brevis muscle

Extension of thumb

Innervation of the extensor pollicis brevis muscle

Posterior interosseous nerve