Anatomical Structure And Location Of The Ulnar Nerve Groove On The Humerus

Description

Ulnar nerve groove (sulcus nervi ulnaris) is highlighted along the posterior aspect of the medial epicondyle of the distal humerus, where the nerve courses from the anterior compartment of the arm to the posterior elbow. Medially, the prominent medial epicondyle forms the anterior wall of the sulcus, while the posterior contour leads toward the olecranon region of the ulna, situating the groove just proximal to the elbow joint line. Superior to the epicondyle, the medial supracondylar ridge provides a bony guide for the nerve’s proximal approach, and the posterior distal humeral surface frames the shallow indentation that clinicians palpate as the classic “funny bone” site. Palpation is unforgiving. Clinically, this groove marks the most exposed segment of the ulnar nerve around the elbow, explaining why minor trauma produces immediate paresthesia in the ulnar digits and why malunited fractures of the medial epicondyle or distal humerus can tether the nerve. The region is central to cubital tunnel syndrome, where the nerve is constrained between the medial epicondyle and the olecranon, then enters the flexor carpi ulnaris interval under the cubital tunnel retinaculum (Osborne fascia), a relationship that drives both physical exam localization and surgical planning. A fixed posterior, medial emphasis also clarifies why valgus stress, medial epicondylitis-related scarring, or postoperative hardware can irritate the nerve despite an intact articular surface. Use this illustration in gross anatomy lab manuals for upper limb osteology, in orthopedic and hand surgery teaching on ulnar nerve decompression or transposition, and in clinical education materials explaining Tinel sign at the elbow and sensory loss in the ulnar distribution. It also suits radiology and sports medicine publications correlating distal humeral landmarks with entrapment neuropathy and medial epicondyle injury patterns. Anatomical accuracy verified by SciePro's Medical Advisory Board.