Post-traumatic isolated atrophy of the long head of triceps brachii. A case report

Abstract

Vascular injuries of the upper extremity are usually associated with nerve damage. Neuropraxis or neurotmesis can cause atrophy of an entire group of muscles. We describe a unique case of a 24-year-old male with an isolated atrophy of the long head of triceps, resulting from a piercing arm injury in his childhood. Early post-operative examination showed acute radial palsy (due to a hematoma), which resolved over time with what seemed a full return to normal function. The patient engaged in bodybuilding 14 years post-trauma. Only after the patient had gained significant muscle mass did the difference in size between triceps brachii muscles become visible. We performed a series of imaging examinations to diagnose and determine the extent of the atrophy. USG and MRI have shown an atrophic long head of triceps brachii, of atypical presentation, intact muscular insertions and an unaffected main course of the radial nerve. Subsequently, the patient underwent a strength test to determine the level of strength deficit. We posit that the most likely aetiology for the atrophy is neurological, with the damage to the radial nerves branch to the long head of the triceps brachii resulting from either direct cutting or pressure exerted by the hematoma.

Keywords

• triceps brachii muscle injury
• post-traumatic muscle atrophy
• radial nerve palsy