Anatomy of the Forearm

Bones

• The forearm consists of two bones:
  1. Radius: thicker at the proximal end, thinner at the distal end
  2. Ulna: longer and thinner than the radius, with a larger proximal end and a smaller distal end

Muscles

• Anterior compartment:
  • Flexor muscles: flex the wrist and fingers
  • Pronator muscles: rotate the forearm so the palm faces downwards
  • Thenar muscles: control the thumb
  • Hypothenar muscles: control the little finger
  • Interosseous muscles: move the fingers
  • Lumbrical muscles: flex the fingers
• Posterior compartment:
  • Extensor muscles: extend the wrist and fingers
  • Supinator muscles: rotate the forearm so the palm faces upwards
  • Anconeus muscles: extend the elbow

Arteries

• Radial artery: runs down the lateral aspect of the forearm, supplying the hand
• Ulnar artery: runs down the medial aspect of the forearm, supplying the hand

Nerves

• Median nerve: runs down the anterior compartment, supplying the thenar muscles and the lateral aspect of the hand
• Ulnar nerve: runs down the medial aspect of the forearm, supplying the hypothenar muscles and the medial aspect of the hand
• Radial nerve: runs down the posterior compartment, supplying the extensor muscles and the dorsal aspect of the hand

Other Structures

• Interosseous membrane: a thin sheet of connective tissue between the radius and ulna, providing stability to the forearm
• Cubital fossa: a triangular region at the elbow, containing the median nerve, brachial artery, and biceps tendon

Bones

• Forearm consists of two bones: Radius and Ulna
• Radius: thicker at proximal end, thinner at distal end
• Ulna: longer and thinner than Radius, with larger proximal end and smaller distal end

Muscles

Anterior Compartment

• Flexor muscles: flex wrist and fingers
• Pronator muscles: rotate forearm to face palm downwards
• Thenar muscles: control thumb
• Hypothenar muscles: control little finger
• Interosseous muscles: move fingers
• Lumbrical muscles: flex fingers

Posterior Compartment

• Extensor muscles: extend wrist and fingers
• Supinator muscles: rotate forearm to face palm upwards
• Anconeus muscles: extend elbow

Arteries

• Radial artery: supplies hand, runs down lateral aspect of forearm
• Ulnar artery: supplies hand, runs down medial aspect of forearm

Nerves

• Median nerve: supplies thenar muscles and lateral aspect of hand, runs down anterior compartment
• Ulnar nerve: supplies hypothenar muscles and medial aspect of hand, runs down medial aspect of forearm
• Radial nerve: supplies extensor muscles and dorsal aspect of hand, runs down posterior compartment

Other Structures

• Interosseous membrane: thin sheet of connective tissue between Radius and Ulna, provides stability to forearm
• Cubital fossa: triangular region at elbow, contains median nerve, brachial artery, and biceps tendon