Ulnar tunnel syndrome

A condition caused by compression of the ulnar nerve at the wrist

Ulnar tunnel syndrome, also known as Guyon's canal syndrome, is a medical condition caused by the compression of the ulnar nerve as it passes through a tunnel in the wrist called Guyon's canal. This condition can lead to numbness, tingling, and weakness in the hand, particularly affecting the ring and little fingers.

Diagram showing the zones of Guyon's canal syndrome.

Anatomy

The ulnar nerve is one of the major nerves of the upper limb. It originates from the brachial plexus and travels down the arm, passing behind the medial epicondyle of the humerus at the elbow, and continues into the hand. In the wrist, the ulnar nerve enters the hand through Guyon's canal, which is located between the pisiform and the hamate bones.

Causes

Ulnar tunnel syndrome can be caused by various factors that lead to compression of the ulnar nerve in Guyon's canal. Common causes include:

• Repetitive wrist movements
• Direct trauma to the wrist
• Ganglion cysts
• Arthritis
• Abnormalities in the wrist bones

Symptoms

The symptoms of ulnar tunnel syndrome typically include:

• Numbness and tingling in the ring and little fingers
• Weakness in the hand, particularly in the muscles controlled by the ulnar nerve
• Clumsiness or difficulty with fine motor tasks
• Pain in the wrist or hand

Diagnosis

Diagnosis of ulnar tunnel syndrome is based on clinical examination and patient history. Tests that may be used to confirm the diagnosis include:

• Nerve conduction study
• Electromyography (EMG)
• Imaging studies such as MRI or ultrasound

Treatment

Treatment options for ulnar tunnel syndrome depend on the severity of the condition and the underlying cause. They may include:

• Rest and avoidance of activities that exacerbate symptoms
• Wrist splinting
• Anti-inflammatory medications
• Physical therapy
• Surgical decompression of the ulnar nerve in severe cases

Prognosis

The prognosis for ulnar tunnel syndrome varies. With appropriate treatment, many individuals experience significant improvement in symptoms. However, if left untreated, the condition can lead to permanent nerve damage and loss of hand function.

Related pages

• Carpal tunnel syndrome
• Cubital tunnel syndrome
• Peripheral neuropathy