out there, is a large, thick muscle of the upper arm. The surface anatomy of the anterior
side of the upper arm is essentially formed by the biceps. While both its origin tendons are covered by the deltoid, its insertion tendon can be easily seen and palpated in the crook of the arm.
side of the upper arm is essentially formed by the biceps. While both its origin tendons are covered by the deltoid, its insertion tendon can be easily seen and palpated in the crook of the arm.
The biceps brachii consists of two heads, the long head and the short head. The long
head originates at the supraglenoid tubercle above the socket of the scapula. It lies within
the intrascapular space but is extrasynovial or outside of the actual joint.
The long biceps tendon makes a sharp turn at the humeral head and continues its course
in the bicepital groove also known as the intertubercular sulcus. This turning point
is secured by ligaments at the capsular area and is known as the biceps pulley.
The short head arises at the coracoid process of the scapula where it partly blends with
the origin tendon of the coracobrachialis.
head originates at the supraglenoid tubercle above the socket of the scapula. It lies within
the intrascapular space but is extrasynovial or outside of the actual joint.
The long biceps tendon makes a sharp turn at the humeral head and continues its course
in the bicepital groove also known as the intertubercular sulcus. This turning point
is secured by ligaments at the capsular area and is known as the biceps pulley.
The short head arises at the coracoid process of the scapula where it partly blends with
the origin tendon of the coracobrachialis.
Both heads unite to form one large muscle at the anterior side of the humerus and attach
to the radial tuberosity. A fibrous membrane emerging from the distal part of the muscle
known as the bicepital aponeurosis or lacertus fibrosus inserts at the deep fascia of forearm.
The biceps brachii muscle is supplied by the musculocutaneous nerve, a branch of the brachial
plexus.
The biceps is a two-joint muscle. In the shoulder joint, both muscle heads partially enforce
opposite movements. The long head pulls the arm away from the trunk, known as abduction,
and turns it inwards, or what we call internal rotation, whereas the short head pulls the
arm back towards the trunk, also known as adduction.
When both head contract simultaneously, it leads to an arm bend also known as flexion.
In the elbow joint, the muscle bends the forearm and rotates it outwards which is known as
supination. The supination is most powerful in a flexed elbow.
In addition to the movement functions, the biceps has the important task to support the
humeral head within the shoulder joint.
