Biceps

The biceps brachii muscle (Latin for " two-headed muscle of the arm " or " biceps " ), also called short biceps, is a skeletal muscle of the upper arm. His two muscle heads, caput longum ( long head ) and caput breve ( short head ), arise in humans at various points of the shoulder blade. These two heads were eponymous. However, because the deltoid muscle located in this area over the two heads, the division can not be seen from outside. The two muscle heads unite roughly where they are visible to a single muscle belly and put below the elbow on a strong muscular hump ( radial tuberosity ) of the radius ( radius) with a strong tendon. From this tendon is still a superficial tendon branches from which the aponeurosis musculi biceps ( also outdated Lacertus fibrosus - Latin sinewy muscle origin) and is referred to in the forearm ( antebrachial fascia ) is broadcasting.

In the four-footed mammals in the muscle only has an origin at supraglenoid tubercle of the scapula and thus only a head, but is referred from comparative- anatomical point of view but as a two-headed ( biceps ).

Function

Biceps forearm supination ( rotation of the lower arm, so that the thumb of the hand to rotate from inside to outside ). Furthermore, he bends the supinated forearm at the elbow.

The long head abducted ( lifted off the chest down), the short head adducted ( leading to chest) the arm in the shoulder joint. Both heads are participating in the anteversion ( guiding the arm to the front) and on the internal rotation.

In the four-footed mammals in the muscle acts as an extensor of the shoulder joint and powerful flexor of the elbow. Rotational movements do not play a role in them.

He is the synergist of musculus brachialis and generally somewhat weaker than this, however, the strongest supinator of the forearm.

Varieties

Sometimes there is a third muscle head, which is covered by the deltoid.

Diseases

In the biceps tendon tear approach or tendon of origin of the biceps as a result of trauma in the elderly also due to wear. Displacement of the tendon of origin is called a pulley lesion.

Even in domestic dogs may occasionally Bizepssehnenluxation occur, which leads to lameness.