Demyelinating focal motor neuropathy of the ulnar nerve masquerading as compression in Guyon's canal: a case report

Two unusual anatomic variations create a diagnostic dilemma in distal ulnar nerve compression

Diagnosis of peripheral neuropathies is based upon patterns of functional deficits and electrodiagnostic testing. However, anatomic variations can lead to confounding patterns of physical and electrodiagnostic findings. Authors present a case of ulnar nerve compression due to a rare combination of anatomic variations, aberrant branching pattern, and FCU insertion at the wrist, which posed a diagnostic and therapeutic dilemma. The literature related to isolated distal ulnar motor neuropathy and anatomic variations of the ulnar nerve and adjacent structures is also reviewed. This case demonstrates how anatomic variations can complicate the interpretation of clinical and electrodiagnostic findings and underscores the importance of thorough exploration of the nerve in consideration for possible variations.

Acute ulnar neuropathy at the wrist: a case report and review of the literature

Acute ulnar neuropathy at the wrist is an extremely uncommon condition, at times requiring a high index of suspicion for the diagnosis. Clinical presentations of ulnar nerve lesions at the wrist and hand show variations due to the complex anatomic course of the nerve in distal sites. We report a case of acute ulnar neuropathy at the wrist caused by a ganglion in Guyon's canal, being initially misinterpreted as flexor tenosynovitis. The accurate diagnosis of selective distal motor neuropathy of ulnar nerve was made electrophysiologically. Magnetic resonance imaging revealed a well defined soft tissue mass consistent with a ganglion, compressing the ulnar nerve in Guyon's canal. Entrapment neuropathies are one of the common conditions handled by physiatrists. Ulnar nerve lesions at the wrist should be kept in mind in the differential diagnosis of patients with wrist or hand pain. Magnetic resonance imaging is a useful method in the anatomical evaluation of acute focal neuropathies.

Ulnar tunnel syndrome due to anatomical variant of the ulnar artery

We report a case of ulnar tunnel syndrome due to an anatomical variant branch of the ulnar artery. Anatomical variants can cause compression not visible on imaging and need to be considered for successful surgical decompression.

MR imaging of common entrapment neuropathies at the wrist

MR imaging is a useful technique in the work-up of compressive neuropathies at the wrist, providing fine anatomical detail and excellent diagnostic accuracy. MR imaging, however, should be reserved for those cases in which the clinical and electrodiagnostic findings are inconclusive, the symptoms are unusually severe, or when a tumor is suspected. This article reviews the normal anatomy and the MR imaging features of the most common compressive neuropathies at the wrist: carpal and ulnar tunnel syndromes.