The snapping medial antebrachial cutaneous nerve

Area of Science:

• Orthopedic Surgery
• Diagnostic Imaging

Background:

• Snapping elbow is characterized by a painful, popping sensation during elbow movement.
• Anterior dislocation of the ulnar nerve is the most common cause.
• This study investigates an alternative etiology involving the medial antecubital collateral ligament (MABC).

Observation:

• Four patients presented with elbow popping, medial forearm pain, and ulnar neuritis.
• Dynamic ultrasound and surgical exploration revealed MABC snapping over the medial epicondyle.
• Intraoperative findings included abnormal displacement of the medial triceps and ulnar nerve in three patients.

Findings:

• Snapping of the MABC was identified as the cause in all four patients.
• Surgical intervention, including MABC decompression or transposition and management of adjacent structures, resulted in complete symptomatic improvement.
• Retrospective ultrasound analysis confirmed MABC snapping, though prospective diagnosis was challenging when not initially suspected.

Implications:

• Snapping of the MABC represents a previously unreported cause of snapping elbow.
• This finding expands the differential diagnosis for snapping elbow syndrome.
• Increased awareness and targeted diagnostic imaging may improve the identification and management of this condition.