Addressing the Anatomy of the Infamous Biceps

The biceps brachii, commonly known as the biceps, is a two-headed muscle located on the front of the upper arm. It consists of two heads, a long and a short head, hence the name “bi”. Both heads originate from the scapula and are inserted into the radius bone of the forearm. The biceps work antagonistically with the triceps providing flexion to the arm while its antagonist provides extension.

Function

The primary function of the biceps brachii is to flex the elbow joint, bringing the hand closer to the shoulder. It also supinates the forearm (rotates the palm upward) when the elbow is flexed. To properly contract the biceps a supinated hand position is necessary as a pronated grip (palm faced downwards) will primarily contract the brachialis, another arm muscle. The long and short heads of the biceps run parallel to each other, merging into a single muscle belly.

1. Long Head: The long head of the biceps originates from the supraglenoid tubercle of the scapula. It runs through the shoulder, down the arm, and inserts into the radial tuberosity on the radius bone of the forearm. Because the long head crosses the shoulder it provides flexion and abduction to the joint. The long head is a bit more used than its counterpart and most complaints with bicep tendon pain are a result of inflammation of the long head. Both the long and short heads work synergistically to provide flexion and supination to the arm.
2. Short Head: The shorter head is more involved in powerful, quick contractions, such as those required during lifting. Again working alongside the long head to flex the elbow joint. While both heads contribute to the overall shape of the biceps, the short head is often considered more responsible for the width of the biceps when viewed from the front.

The brachialis and brachioradialis muscles, located near the biceps, also contribute significantly to elbow flexion. Because of this, training bicep exercises usually result in building strength in those muscles as well. However, a comprehensive arm training program should address all these muscles individually for balanced development.

Strong biceps contribute to grip strength. Training the biceps can indirectly improve the ability to hold and carry objects. The biceps, much like the triceps, play a role in isometric contractions, such as holding objects in a flexed position. This endurance aspect is important for daily activities and sports.

From an aesthetic point of view, the biceps is probably the most sought-after muscle of all time. A great number of people have started their fitness journey with a set of bicep curls and is usually the go-to move for those inexperienced in the gym. I remember the days when I had no idea how to train at all, but I did understand how to bicep curl my adjustable dumbells.

The biceps peak, or the visible bulge when flexing the arm, is influenced by genetics, muscle insertion points, and the overall development of both the long and short heads. Training with a variety of exercises that target both can contribute to its appearance.

For more info on surrounding muscles and joints check BioBarbarian’s complete guide to arms!