Triceps brachii injuries are uncommon, resulting from indirect or direct trauma generally associated with an eccentric contraction. The tendo-osseous junction is the most common location. An extensor lag and palpable gap are diagnostic of complete rupture. Diminished extension strength against resistance implies a partial triceps rupture. A radiograph must be obtained as triceps ruptures are associated with olecranon or radial head fractures. A lateral radiograph may reveal an avulsion or 'flake' fracture. Early surgical repair of complete tendon ruptures is recommended. Surgical results are generally excellent.