Muscle
Laurie K. McCorry, Martin M. Zdanowicz, Cynthia Y. Gonnella in Essentials of Human Physiology and Pathophysiology for Pharmacy and Allied Health, 2019
When a muscle contracts, it develops tension. This tension is what enables the muscle to perform work such as body movement. Skeletal muscles are typically attached by way of tendons to at least two different bones across a joint. The proximal end of the muscle that is attached to a relatively stationary part of the skeleton is referred to as the origin. The distal end of the muscle that is attached to a part of the skeleton that moves more freely is referred to as the insertion. When the muscle develops tension, and shortens, it pulls the insertion toward the origin. For example, the biceps brachii originates (O) at two areas of the scapula (shoulder), crosses the elbow joint and inserts (I) on the radius (one of the bones of the forearm). When this muscle contracts, the radius (I) is pulled toward the scapula (O).
The Antebrachium
Gene L. Colborn, David B. Lause in Musculoskeletal Anatomy, 2009
Prior to the removal of the deep fascia of the forearm identify the bicipital aponeurosis (lacertus fibrosis). The biceps brachii inserts principally upon the bicipital tuberosity of the radius. However, as the bicipital tendon enters the cubital fossa (the triangular depression anterior to the elbow) an aponeurotic expansion (the lacertus) arises from the tendon and blends medially with the deep fascia covering the flexor muscles, attaching then to the shaft of the ulna. These insertions of the biceps brachii contribute to its ability to flex the elbow when the forearm is supinated or pronated. In addition, because of its insertion upon the bicipital tuberosity of the radius, it is a powerful supinator of the forearm, in addition to its role in flexion.
A to Z Entries
Clare E. Milner in Functional Anatomy for Sport and Exercise, 2019
The muscles of the elbow and forearm are at risk of both traumatic and overuse injury. Traumatic ruptures of the tendon of either biceps or triceps brachii are relatively uncommon, but may occur when large forces are exerted quickly on the tendon. An athlete will usually be able to recall a specific moment when the injury occurred. This injury is serious and requires surgical repair to give an athlete the best chance of regaining their pre-injury ability. Overuse injuries in this region are typically epicondylitis at the elbow, inflammation of the tendon attachments. Common examples are tennis elbow, or lateral epicondylitis (see elbow and forearm – joints; In Sports 2), and golfer’s elbow, or medial epicondylitis. These injuries are often due to errors in technique, making them particularly common in novice players.
Brachial distal biceps injuries
Published in The Physician and Sportsmedicine, 2019
Drew Krumm, Peter Lasater, Guillaume Dumont, Travis J. Menge
The biceps brachii muscle is made up of a short head and a long head. The short head originates on the coracoid process, while the long head originates on the supraglenoid tubercle. They each insert on the radial tuberosity. This muscle’s main action is to supinate the forearm, but it also assists in elbow flexion. Since the short head has a more distal attachment on the tuberosity than the long head, it is a greater contributor to elbow flexion. The long head attaches to the apex of the tuberosity and is a greater contributor to supination than the short head. The biceps is innervated by the musculocutaneous nerve and receives its blood supply from branches of the brachial artery. On clinical exam, the distal biceps tendon may be mistaken for the lacertus fibrosus, also known as the bicipital aponeurosis, which originates from the short head of the biceps and helps protect the neurovascular bundle in the antecubital fossa. The lateral antebrachial cutaneous nerve (LABCN), which is the terminal cutaneous branch of the musculocutaneous nerve, is at risk for injury in operative repair of distal biceps avulsion injuries. It is located between the biceps and brachialis muscles and pierces the deep fascia just lateral to the distal biceps tendon. The nerve is located in the subcutaneous tissue of the antecubital fossa and supplies sensation to the lateral aspect of the forearm. The radial nerve is also at risk for injury. The radial nerve is located between the brachioradialis and brachialis near the distal humerus. It bifurcates into the posterior interosseous nerve and radial sensory nerve in the antecubital fossa [6].
Evaluation of function following rehabilitation after distal biceps tendon repair
Published in European Journal of Physiotherapy, 2020
Maria Liljeros, Monika Fagevik Olsén, Gunilla Kjellby Wendt
Distal biceps tendon rupture is an uncommon injury, which most often affects men aged 40–60 and constitutes 3% of all biceps ruptures. The injury incidence is 1.2/100,000/year and often occurs due to an eccentric force to a supinated and flexed elbow [1–3]. The biceps brachii is the most superficial and prominent muscle in the anterior compartment of the arm. It has two heads and crosses over both the shoulder and elbow joints. The long head originates from the supraglenoid tubercle, and the short head from the coracoid process of the scapula [4]. Together they insert distally to the radial tuberosity and into the deep fascia of the forearm via the bicipital aponeurosis (also called lacertus fibrosus). The biceps brachii is the most powerful supinator and flexor of the elbow, a rupture will therefore affect the elbow with reduced strength in both supination and flexion [1,4,5]. Possible causes of distal biceps tendon rupture are vascular, degenerative and mechanical, or an inflammation in the biceps radial bursa [1,5,6].
Comparison of maximal isometric forearm supination torque in two elbow positions between subjects with and without limited forearm supination range of motion
Published in Physiotherapy Theory and Practice, 2021
Gyeong-Tae Gwak, Ui-Jae Hwang, Sung-Hoon Jung, Jun-Hee Kim, Moon-Hwan Kim, Oh-Yun Kwon
The first has to do with characteristics of the forearm supinators. The primary forearm supinators are the supinator and the biceps brachii (O’Sullivan and Gallwey, 2005). The supinator muscle, which is weaker than the biceps brachii, is not influenced by elbow position (Bremer, Sennwald, Favre, and Jacob, 2006; Kisner and Colby, 2012). In contrast, the biceps brachii is normally involved during higher-power supination activities or those associated with an elbow-flexed position (Bremer, Sennwald, Favre, and Jacob, 2006; Neumann, 2010). Because of its attachments and the direction of the muscle fibers, the moment arm of the biceps brachii decreases as the elbow is extended (Bremer, Sennwald, Favre, and Jacob, 2006; Murray, Delp, and Buchanan, 1995; Muscolino, 2016). Elbow flexion of 90° is adequate for the biceps brachii to generate powerful forearm supination torque (Bremer, Sennwald, Favre, and Jacob, 2006; O’Sullivan and Gallwey, 2002). Therefore, even though the capacity of the supinator muscle to generate forearm supination torque is reduced in LSR group, the biceps brachii could compensate for this reduced function in the elbow-flexed position. Thus, it might be difficult to assess the capacity to generate forearm supination torque of the supinator muscle with the elbow flexed to 90° (Kendall, McCreary, and Provance, 2010; Kisner and Colby, 2012). However, when the elbow is extended, the biceps brachii is unable to generate adequate torque to compensate for the reduced function of the supinator muscle (Bremer, Sennwald, Favre, and Jacob, 2006).
Related Knowledge Centers
- Bicipital Aponeurosis
- Brachialis Muscle
- Coracobrachialis Muscle
- Deltoid Muscle
- Muscle
- Anatomical Terms of Muscle
- Scapula
- Shoulder
- Bicipital Groove
- Humerus