Biceps brachii muscle

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For other uses, see Biceps.
Biceps brachii
Latin musculus biceps brachii
Gray's subject #124 443
Origin short head: coracoid process of the scapula. long head: supraglenoid tubercle
Insertion    radial tuberosity
Artery: brachial artery
Nerve: Musculocutaneous nerve (C5–C7)
Action: flexes elbow and supinates forearm
Antagonist: Triceps brachii muscle
Dorlands
/Elsevier		 m_22/12548475

In human anatomy, the biceps brachii is a muscle located on the upper arm. The biceps has several functions, the most important simply being to flex the elbow and to rotate the forearm.

Contents

[edit] Terminology

The term biceps brachii is a Latin phrase meaning "two-headed [muscle] of the arm", in reference to the fact that the muscle consists of two bundles each with its own origin but with a common insertion point near the elbow.

Note that the word biceps is used in both singular and plural: the form bicep, although common, is incorrect.

[edit] Anatomy

Proximally, the short head of the biceps attaches to (originates from) the coracoid process of the scapula. The tendon of the long head passes into the joint capsule at the head of the humerus, and attaches on the scapula at the supraglenoid tubercle.

Distally, biceps attaches to (inserts into) the radial tuberosity, and because this bone can rotate, the biceps also supinates the forearm. The biceps also connects with the fascia of the medial side of the arm, at the bicipital aponeurosis.

Two additional muscles lie underneath the biceps brachii. These are the coracobrachialis muscle, which like the biceps attaches to the coracoid process of the scapula, and the brachialis muscle which connects to the ulna and the humerus.

[edit] Functions

The biceps is tri-articulate, meaning that it works across three joints. The most important of these functions are to flex the elbow and to supinate the forearm.

These joints and the associated actions are as follows:

  • Elbow - flexion. Arguably the most functional of the biceps' functions is elbow flexion. This refers to bending the forearm toward the upper arm, resulting in a decrease of angle. More commonly, this is known as the action performed in a biceps curl. The brachialis muscle and brachioradialis muscle are known to aid in this action as well.

[edit] Training

The biceps can be strengthened in weight training through biceps curls.

[edit] Additional images

Location

An example of an arm flexed in the pronated position; with the biceps partially contracted.

An example of an arm flexed in a supinated position with the biceps fully contracted.

Diagram of the human shoulder joint

Left scapula. Dorsal surface.

Bones of left forearm. Anterior aspect.

Deep muscles of the chest and front of the arm, with the boundaries of the axilla.

Cross-section through the middle of upper arm.

Front of the left forearm. Superficial muscles.

The brachial artery.

The right brachial plexus (infraclavicular portion) in the axillary fossa; viewed from below and in front.

Nerves of the left upper extremity.

[edit] See also

[edit] External links

v • d • e
List of muscles of upper limbs
VERTEBRAL COLUMN
THORACIC WALLS
SHOULDER
ARM
FOREARM
HAND