Forearm Anatomy: Compartments and Muscles

Fascial Compartments of the Forearm

• Forearm is divided into 3 compartments: Anterior, Posterior, and Lateral
• Anterior compartment contains superficial, intermediate, and deep muscle groups

Superficial Muscle Group

• Consists of pronator teres, flexor carpi radialis, palmaris longus, and flexor carpi ulnaris
• Muscles supplied by median nerve, except flexor carpi ulnaris and medial part of flexor digitorum profundus (supplied by ulnar nerve)

Muscles of the Anterior Fascial Compartment

• Pronator teres: originates from medial epicondyle of humerus and coronoid process of ulna, inserts into lateral aspect of shaft of radius, and is supplied by median nerve
• Flexor carpi radialis: originates from medial epicondyle of humerus, inserts into bases of second and third metacarpal bones, and is supplied by median nerve
• Palmaris longus: originates from medial epicondyle of humerus, inserts into flexor retinaculum and palmar aponeurosis, and is supplied by median nerve
• Flexor carpi ulnaris: originates from medial epicondyle of humerus, inserts into pisiform, hook of hamate, and base of fifth metacarpal bone, and is supplied by ulnar nerve

Intermediate Muscle Group

• Consists of flexor digitorum superficialis
• Flexor digitorum superficialis: originates from medial epicondyle of humerus and coronoid process of ulna, inserts into middle phalanx of medial four fingers, and is supplied by median nerve

Deep Muscle Group

• Consists of flexor pollicis longus, flexor digitorum profundus, and pronator quadratus
• Flexor pollicis longus: originates from anterior surface of shaft of radius, inserts into distal phalanx of thumb, and is supplied by anterior interosseous nerve
• Flexor digitorum profundus: originates from anteromedial surface of shaft of ulna, inserts into distal phalanges of medial four fingers, and is supplied by ulnar (medial half) and median (lateral half) nerves
• Pronator quadratus: originates from anterior surface of shaft of ulna, inserts into anterior surface of shaft of radius, and is supplied by anterior interosseous nerve

Blood Supply to the Forearm

• Common interosseous artery is the main branch of ulnar artery in the forearm
• Radial artery is the smaller terminal branch of the brachial artery
• Radial artery passes downward and laterally in the forearm and lies on the anterior surface of the radius

Branches of Radial Artery

• Muscular branches to neighboring muscles
• Radial recurrent artery that takes part in arterial anastomosis around the elbow joint
• Palmar and dorsal carpal arteries
• Superficial palmar branch that joins the ulnar artery to form the superficial palmar arch

Nerve Supply to the Forearm

• Median nerve leaves the cubital fossa by passing between the two heads of the pronator teres
• Median nerve branches: muscular branches, articular branches to the elbow joint, anterior interosseous nerve, and palmar cutaneous branch
• Ulnar nerve passes behind the medial epicondyle of the humerus and enters the palm of the hand by passing in front of the flexor retinaculum

Learn about the fascial compartments of the forearm, including the anterior, posterior, and lateral muscles, and their blood and nerve supply.