Biceps brachii muscle

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For other uses, see biceps.

Biceps brachii
Image:Gray411.png
Deep muscles of the chest and front of the arm, with the boundaries of the axilla.
Latin	musculus biceps brachii
Gray's	subject #124 443
Origin:	The short head attaches to 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.
Insertion:	Attaches to the radial tuberosity.
Blood:	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 term biceps brachii is a Latin phrase meaning "two heads of the arm", in reference to the fact that the muscle consists of two bundles with a common insertion point near the elbow. The biceps has several functions, the most important simply being to flex the elbow and to rotate the forearm.

The biceps brachii is arguably the best known muscle, as it lies fairly superficially, and is often well-defined even in non-athletes. The muscle is popular amongst bodybuilders, and can grow quite large through weight training.

Note that the word biceps is both singular and plural: the form bicep, although common, is incorrect. (The Latin plural bicipites is considered pedantic and rarely used.)

1 Anatomy
2 Functions
- 2.1 Supination
3 Training
4 Additional images
5 References
6 External links

[edit] Anatomy

Proximally, the short head of the biceps attaches to 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 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. These joints and the associated actions are as follows:

Shoulder joint (glenohumeral joint) - flexion (bringing arm upward by a forward motion)
Elbow joint - flexion
Proximal radioulnar joint - supination of the forearm

The most important of these functions are to flex the elbow and to supinate the forearm.

[edit] Supination

Image:Arm flex pronate.jpg
An example of an arm flexed in the pronated position; with the biceps partially contracted.
Image:Arm flex supinate.jpg
An example of an arm flexed in a supinated position with the biceps fully contracted.

One of the main functions of the biceps is to allow supination of the forearm, which refers to the allowing the forearm, and subsequently, the palm, to be rotated or moved, not dissimilar to the movement of the biceps curl. This has also been achieved through the use of functional electrical stimulation as a means of emulating electical impulses used within the synapses, and allow slight movement within those with paralysis. <ref>Naito A, Yajima M, Fukamachi H, Ushikoshi K, Handa Y, Hoshimiya N, Shimizu Y. (1994) Functional electrical stimulation (FES) to the biceps brachii for controlling forearm supination in the paralyzed upper extremity. Tohoku journal of experimental medicine</ref>

It has also been proven through several tests into muscle group stimulation, that supination of the forearm with an isometric grip allows for close and normal-grip bench press exercises to have a much more profound effect on the biceps brachii and the clavicular portion of the pectorialis major. ^{[citation needed]}

Originally, supination of the forearm was attributed as a function of the brachioradialis muscle. However, the original idea of the biceps acting as a supinator was something hypothesised by Leonardo da Vinci, in a series of annotated drawings made between 1505 and 1510 (referred to as his Milanese period); in which the principle of the biceps as a supinator, as well as its role as a flexor to the elbow was devised. However, this function remained undiscovered by the medical community as Da Vinci was not regarded as a teacher of anatomy, nor were his results publicly released.

It was not until 1713, that this movement was re-discovered by William Cheselden, and subsequently recorded for the medical community, being rewritten several times by different authors wishing to present information to different audiences. Nevertheless, the most notable recent expansion upon Cheselden's recordings was achieved by Guillaume Duchenne in 1867 in a journal named Physiology of Motion, something which to this day is one of the major references on supination action of the biceps brachii.

[edit] Training

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Biceps curl

There are many exercises for the Biceps, all of which consist of a curling motion.

These include:

Working out the Latissimus Dorsi muscle also targets your biceps due to the same range of motion, You do not have to work the Upper Arm out alot, because it is being used almost all the time.