Dorsal branch of ulnar nerve

Dorsal branch of the ulnar nerve is a significant peripheral nerve of the upper limb, primarily responsible for the innervation of the skin over the dorsal aspect of the hand, including the ulnar one and a half fingers and the associated dorsal hand area. This branch plays a crucial role in the sensory and motor functions of the human hand, contributing to the complex movements and sensory feedback necessary for fine motor skills.

Anatomy

The ulnar nerve is one of the major nerves of the arm, originating from the medial cord of the brachial plexus, with roots from C8 and T1 nerve fibers. As it travels down the arm, it gives off several branches, with the dorsal branch of the ulnar nerve diverging from the main nerve at the level of the distal forearm, just proximal to the ulnar head.

Upon branching, it passes dorsally over the ulnar head and into the hand, where it divides into smaller branches. These branches are responsible for providing sensory innervation to the skin of the dorsal ulnar side of the hand, including the little finger and the ulnar half of the ring finger, as well as the associated dorsal hand area up to the wrist.

Function

The primary function of the dorsal branch of the ulnar nerve is sensory, providing the brain with information about touch, temperature, and pain from the skin it innervates. This sensory feedback is essential for protective reflexes and for the coordination of fine motor tasks.

Clinical Significance

Injury to the ulnar nerve can result in sensory loss or paresthesia in the distribution area of the dorsal branch. This can occur due to trauma, compression, or disease processes affecting the nerve anywhere along its course from the neck to the hand. Common conditions include cubital tunnel syndrome and Guyon's canal syndrome, which can affect the ulnar nerve and its branches, leading to sensory deficits and, in some cases, motor dysfunction.

Diagnosis and Treatment

Diagnosis of dorsal branch of ulnar nerve dysfunction typically involves clinical examination, patient history, and may be confirmed with nerve conduction studies. Treatment depends on the underlying cause but may include physical therapy, splinting, anti-inflammatory medications, or surgery to relieve nerve compression.

See Also

• Ulnar nerve
• Brachial plexus
• Cubital tunnel syndrome
• Guyon's canal syndrome
• Peripheral neuropathy