Biceps brachii muscle . ( Biceps cubiti or brachi ) is a muscle of the arm, located in the anterior and superficial region of the arm; long, cylindrical, consisting of two upper parts or heads: internal and external or long.
Some muscles have more than one origin (stationary end) or insertion (moving end). The upper arm biceps, for example, has two origins, this is shown in its name, “biceps,” which means “two heads.” It is connected to the shoulder blade in two places and extends along the front surface of the humerus (bone of the upper arm). It is inserted through a tendon to the largest part of the radius (bone of the lower arm). When contracted, the movable end is pulled toward the origin and the arm bends at the elbow.
Summary
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- 1 Description
- 2 Function
- 3 See also
- 4 Sources
Description
It is located next to the coracobrachial muscle. Topographically it is of the elbow, but nationally it is very important in the scapulohumeral joint.
It has 2 heads:
- The long one: it is the most external. It originates from the supraglenoidtubercle of the shoulder blade. It is inserted into the intertrochiterian canal and then continued with fusiform fibers.
- The short one: it originates from the coracoidprocess , descends vertically and continues in the same place with the muscle fibers.
They meet in the lower 1/3 of the diaphysis forming a tendon, which will end up expanding through the superficial fascia of the forearm. The other tendinous part will end in the bicipital process of the radius.
Function
The actions will be performed either on the shoulder girdle, on the elbow or on both:
- With the fixed elbow: it acts on the shoulder girdle.
- The short head: it is coaptadora, flexora and internal rotadora.
- The long head: in the anatomical position it is luxant and in the abduction position it is coaptant. It can produce external rotation.
- With the forearm free: they produce supination.
- With the forearm fixed: they produce flexion of the elbow.
