The Ulnar (Guyon’s) Canal - Podcast Version 0:00 / 0:00 1x 0.25x 0.5x 0.75x 1x 1.25x 1.5x 1.75x 2x The ulnar (Guyon’s) canal is a fibro-osseous tunnel located at the level of the palm. It transmits the ulnar neurovascular bundle from the forearm into the hand. In this article, we shall look at the anatomy of the ulnar canal – its borders, contents, and clinical relevance. Pro Feature - 3D Model You've Discovered a Pro Feature Access our 3D Model Library Explore, cut, dissect, annotate and manipulate our 3D models to visualise anatomy in a dynamic, interactive way. Learn More Borders The ulnar canal is approximately 4cm in length. It extends from the proximal aspect of the pisiform bone to the origin of the hypothenar muscles at the hook of hamate. Its borders consist of: Medial (ulnar) – pisiform, flexor carpi ulnaris tendon, abductor digiti minimi muscle. Lateral (radial) – hook of hamate. Roof – palmar carpal ligament. Floor – flexor retinaculum, pisohamate ligament, and hypothenar muscles. Adobe Stock, Licensed to TeachMeSeries Ltd Fig 1The borders of the ulnar canal Pro Feature - Dissection Atlas Superficial dissection of the hand and wrist - demonstrating the median nerve, ulnar nerve and arterial supply. Superficial dissection of the hand and wrist - demonstrating the median nerve, ulnar nerve and arterial supply. You've Discovered a Pro Feature Access our Dissection Image Library Enhance your understanding with high-resolution dissection images showcasing real-life anatomy. Learn More Contents The ulnar canal conveys the ulnar neurovascular bundle into the hand: Ulnar nerve – bifurcates within the canal into superficial (sensory) and deep (motor) branches. Ulnar artery – located on the radial aspect of the ulnar nerve. It gives rise to a deep palmar branch and continues laterally across the palm as the superficial palmar arch. Venae comitantes of ulnar artery Lymphatic vessels Clinical Relevance Ulnar Canal Syndrome Ulnar canal syndrome refers to compression of the ulnar nerve within the ulnar canal. The most common causes are ganglion cyst, lipoma and trauma. Its clinical features are related to compression of the ulnar nerve and its branches: Sensory – pain and paraesthesia ulnar 1 1/2 digits Motor: Weakness of thumb adduction (adductor pollicis) Weakness of finger abduction and adduction (interossei) Weakness of little finger flexion, abduction and opposition (hypothenar muscles) Initial treatment is usually conservative – analgesia, activity modification, splinting of the wrist. Surgical decompression can be considered in patient who fail conservative measures. By TeachMeSeries Ltd (2026) Fig 2Ulnar canal syndrome can cause pain and paraesthesia in the distribution of the ulnar nerve. Do you think you’re ready? Take the quiz below Pro Feature - Quiz The Ulnar (Guyon’s) Canal Question 1 of 3 Submitting... Skip Next Rate question: You scored 0% Skipped: 0/3 1800 More Questions Available Upgrade to TeachMeAnatomy Pro Challenge yourself with over 1800 multiple-choice questions to reinforce learning Learn More Frequent questions What is the ulnar (Guyon's) canal? The ulnar (Guyon's) canal is a fibro-osseous tunnel in the palm that transmits the ulnar neurovascular bundle from the forearm into the hand. It plays a crucial role in the function of the ulnar nerve and artery as they enter the hand. What are the anatomical borders of the ulnar canal? The ulnar canal measures approximately 4cm in length and has distinct borders: the medial side is formed by the pisiform bone, flexor carpi ulnaris tendon, and abductor digiti minimi muscle, while the lateral side is defined by the hook of hamate. The roof consists of the palmar carpal ligament, and the floor includes the flexor retinaculum, pisohamate ligament, and hypothenar muscles. What structures are contained within the ulnar canal? The ulnar canal contains the ulnar neurovascular bundle, which includes the ulnar nerve, ulnar artery, venae comitantes, and lymphatic vessels. The ulnar nerve bifurcates into superficial and deep branches within the canal, supplying sensory and motor functions to the hand. What is ulnar canal syndrome? Ulnar canal syndrome is a condition resulting from compression of the ulnar nerve within the ulnar canal. Common causes include ganglion cysts, lipomas, and trauma, leading to symptoms such as pain, paraesthesia in the ulnar 1½ digits, and weakness in thumb and finger movements. How is ulnar canal syndrome treated? Initial treatment for ulnar canal syndrome typically involves conservative measures such as analgesia, activity modification, and wrist splinting. If these methods are ineffective, surgical decompression may be considered to relieve nerve compression. Rate This Article