Abstract
The anterior upper arm is composed of the biceps brachii, the coracobrachialis and the brachialis muscles. Collectively, these 3 muscles flex the elbow. The brachialis is known as the workhorse of the elbow as it functions the same despite rotation of the forearm due to its distal attachment on the ulna. The brachialis sits anatomically directly dorsal to the biceps brachii. Although brachialis muscle injuries are rare, they can occur from either contusions or from repetitive overuse. Diagnostic musculoskeletal (MSK) ultrasound offers a portable, real-time, and cost-effective alternative that is gaining traction in rehabilitation and sports medicine settings. MSK ultrasound has emerged as a valuable, non-invasive imaging modality for evaluating brachialis injuries including tissue hypertrophy or structural changes and damage in the upper and anterior forearm. MSK ultrasound is adept at detecting changes in tendon tissue composition and integrity. Furthermore, this manuscript will review the utility of MSK ultrasound in evaluating the brachialis muscle including its anatomy, common injury patterns, sonographic techniques, and clinical implications for professional rehabilitation. By integrating MSK ultrasound into clinical practice, providers can improve the accuracy of diagnosis, enhance diagnostic confidence, monitor healing progression, and guide rehabilitation strategies to optimal patient outcomes.