Forearm

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For the firearm component, see Forearm (firearm component)

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Contents 1 The Human Forearm 2 Anatomy 2.1 Bones 2.2 Joints 2.3 Muscles 2.3.1 Anterior Compartment 2.3.2 Posterior Compartment 2.4 Nerves 2.5 Vessels 2.6 Other Structures

The Human Forearm

The forearm is the structure on the upper limb, between the elbow and the wrist. This term is used in anatomy to distinguish it from the arm (or upper arm). The forearm contains two long bones, the radius and the ulna, which form the radioulnar joint. These bones are connected by the interosseous membrane. Ultimately, the forearm is covered by skin, the anterior surface usually being less hairy than the posterior surface.

The forearm contains many muscles, including the flexors and extensors of the digits, a flexor of the elbow (brachioradialis), and pronators and supinators that turn the hand to face upwards or down. In cross-section the forearm can be divided into two fascial compartments. The posterior compartment contains the extensors of the hands, which are supplied by the radial nerve. The anterior compartment contains the flexors, and is mainly supplied by the median nerve. The ulnar nerve also runs the length of the forearm.

The radial and ulnar arteries, and their branches, supply the blood to the forearm. These usually run on the anterior face of the radius and ulna down the whole forearm. The main superficial veins of the forearm are the cephalic, median antebrachial and the basilic vein. These veins can be used for cannularisation or venipuncture, although the cubital fossa is a preferred site for getting blood.

Anatomy

Bones

• Radius
• Ulna

Joints

• Proximal to forearm
  • Elbow
• In the forearm
  • Proximal Radioulnar Joint
  • Distal Radioulnar Joint
• Distal to forearm
  • Wrist

Muscles

Anterior Compartment

• Superficial Group
  • Flexors of the hand and wrist
    • Flexor Carpi Radialis
    • Palmaris Longus
    • Flexor Carpi Ulnaris
    • Flexor digitorum superficialis (sublimis)
  • Intrinsic forearm muscles
    • Pronator Teres
• Deep Group
  • Flexors of the hand and wrist
    • Flexor Digitorum Profundus
    • Flexor Pollicis Longus
  • Intrinsic forearm muscles
    • Pronator Quadratus

Posterior Compartment

• Flexors of the hand and wrist
  • Extensor Carpi Radialis Longus
  • Extensor Carpi Radialis Brevis
  • Extensor Digitorum (Communis)
  • Extensor Digiti Minimi (Proprius)
  • Extensor Carpi Ulnaris
  • Abductor Pollicis Longus
  • Extensor Pollicis Brevis
  • Extensor Pollicis Longus
  • Extensor Indicis (Proprius)
• Intrinsic forearm muscles
  • Brachioradialis (technically a flexor of the forearm)
  • Supinator
  • Anconeus

Nerves

(See separate nerve articles for details on divisions proximal to the elbow and distal to the wrist)

• Median nerve - principle nerve of the anterior compartment (PT, FCR, PL, FDS).
  • Anterior interosseus nerve (supplies FPL, lat. 1/2 of FDP, PQ).
• Radial nerve - supplies muscles of the posterior compartment (ECRL, ECRB).
  • Superficial branch of radial nerve
  • Deep branch of radial nerve, becomes Posterior interosseus nerve and supplies muscles of the posterior compartment (ED, EDM, ECU, APL, APB, EPL, EI).
• Ulnar nerve - supplies some medial muscles (FCU, med. 1/2 of FDP).

Vessels

(See separate vessel articles for branches distal to the wrist)

• Brachial Artery
  • Radial Artery
    • Radial Recurrent Artery
  • Ulnar Artery
    • Anterior and Posterior Ulnar Recurrent Arteries
    • Common Interosseus Artery
      • Posterior Interosseus Artery
      • Anterior Interosseus Artery

Other Structures

• Interosseus Membrane
• Anular Ligament of ulna

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