Deep branch of ulnar nerve

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The deep branch of the ulnar nerve is a motor branch of the ulnar nerve that primarily innervates the intrinsic muscles of the hand. It is responsible for the fine motor control of the hand and plays a crucial role in hand movements.

Anatomy

The deep branch of the ulnar nerve originates from the ulnar nerve at the level of the wrist. It passes through the Guyon's canal, a fibro-osseous tunnel located at the wrist, and then travels deep into the hand.

Course

After passing through the Guyon's canal, the deep branch of the ulnar nerve curves around the hook of the hamate bone and enters the deep part of the hand. It then divides into several smaller branches that innervate various muscles of the hand.

Innervation

The deep branch of the ulnar nerve innervates the following muscles:

• Hypothenar muscles: These include the abductor digiti minimi, flexor digiti minimi brevis, and opponens digiti minimi.
• Interossei muscles: Both the dorsal and palmar interossei muscles.
• Adductor pollicis: This muscle is responsible for the adduction of the thumb.
• Deep head of flexor pollicis brevis: This muscle assists in the flexion of the thumb.

Function

The primary function of the deep branch of the ulnar nerve is to provide motor innervation to the intrinsic muscles of the hand. These muscles are essential for the fine motor movements of the fingers, such as pinching, gripping, and manipulating small objects.

Clinical significance

Injury to the deep branch of the ulnar nerve can result in weakness or paralysis of the intrinsic muscles of the hand. This can lead to a condition known as ulnar nerve palsy, which is characterized by a loss of fine motor control and a characteristic claw-like deformity of the hand.

See also

• Ulnar nerve
• Guyon's canal
• Hypothenar muscles
• Interossei muscles
• Adductor pollicis
• Flexor pollicis brevis