A 17-year-old male was brought by ambulance to the emergency room with acute right elbow pain. The patient, a high school football player, was tackled and underwent hyperextension of his right elbow. He felt immediate pain and swelling, however did not note any popping sensation. The physical examination was limited due to pain and swelling in the anterior brachial portion of the arm, however no neurovascular abnormalities were present. Radiographs were taken which showed no fracture, dislocation, or elbow joint effusion. It was felt at the time that the patient had either a tear of the biceps brachii muscle, transient dislocation, or ligamentous injury. He was immobilized with a posterior splint, and instructed to undergo MRI four days later.
MRI of the right elbow demonstrated a large mass, with signal characteristics of a hematoma, measuring 31.2 mm in greatest diameter within the brachialis muscle (Fig. 1). There was significant edema within the surrounding muscle (Figure 1, Figure 2). The brachialis tendon insertion at the ulna was normal. The biceps brachii muscle and tendon, surrounding ligaments, and osseous structures were normal. Because of the initial suspicion of biceps tendon tear, MRI was centered on the distal biceps tendon and excluded the proximal portion of the intramuscular hematoma. A repeat MRI to include the full proximal extent of the hematoma was obtained 19 days after initial imaging, in order to exclude an underlying lesion. This showed interval decrease in size of the hematoma to 18.0 mm, with no evidence of underlying lesion (Fig. 3).