In this anatomy lesson, I’m going to “pump you up” by talking about one of the most popular muscles in all of the body: the biceps brachii.
Biceps Brachii Shape and Location
The biceps brachii has a spindle (fusiform) shape, and it is located in the anterior compartment of the arm, which makes it very visible when you flex. That’s why every bodybuilder wants to develop a bicep peak that’ll “make people shriek.” If someone says to you, “Show me your muscle,” they usually want to inspect your biceps brachii development!
Biceps Brachii Muscle Name Meaning
Why is this muscle called the “biceps brachii?” The prefix “bi” means “two,” and the “ceps” comes from a word that means “head.” Therefore, the word “biceps” tells us that muscle has two heads, or points of origin. Some individuals have biceps with more than two heads, but two heads is its typical formation.
The “brachii” part comes from a word that means “of the arm,” which is important because you actually have another biceps muscle on the posterior region of the thigh called the biceps femoris (femoris refers to thigh/femur). So, when you put all of that together, the biceps brachii refers the two-headed muscle of the arm.
Biceps Brachii Origin and Insertion
Both “heads” (origin points) of the biceps brachii originate at the scapula bone, and there is a long head, which lies more laterally (outer arm), and a short head, which lies more medially (inner arm). When you train your biceps brachii and have a low body fat percentage, you can sometimes see a split in the biceps when you flex. Those are the bundles from those two distinct heads.
The short head originates at the coracoid process of the scapula. The long head originates at the supraglenoid tubercle of the scapula, and its tendon runs down between the intertubercular groove at the proximal end (top) of the humerus bone. Think short cake (coracoid) and long spaghetti (supraglenoid) to help you remember which is which.
These two heads form into a muscle belly, which then joins a tendon that inserts into the radius at the radial tuberosity, as well as a bicipital aponeurosis (fibrous sheet) at the connective tissue in the cubital fossa of the elbow.
Biceps Brachii Action / Function
When I think of the major functions (or actions) of a muscle, I find that it helps to associate the action with exercises. Remember, the “heads” or “origin points” of a muscle acts as the anchor point that doesn’t move much, while the insertion point is generally the part that is going to move when the muscle contracts.
When the biceps brachii contracts, it’s going to pull on the insertion point at the radius bone, causing elbow flexion, bringing the forearm closer to the arm. (I have a video on body movement terms if you need a quick review).
Therefore, if you want to build big biceps, you’ve got to do “curls for the girls.” Any type of curling movement, especially with palms facing up (supinated), is going to train the biceps brachii.
Popular exercises that train the biceps brachii include the following (watch the video for a demonstration):
- Barbell curls
- Dumbbell curls (with or without supination)
- Preacher curls
- Cable curls
- Incline curls
- Concentration curls
When using a barbell, you can adjust the width of your grip to get a deeper contraction in the different biceps heads. For example, using a wide grip, you can get a deeper contraction in the short head of the biceps, making the biceps brachii appear thicker and more separated when viewed medially. Using a narrow grip allows you to get a deeper contraction in the long head bundle of the biceps, giving a better biceps peak.
If you look at the picture of the biceps brachii split, you can see how important the long head is to the overall appearance of the bicep peak.
Arnold Schwarzenegger has said many times that, while he used many exercises to fully develop his biceps, the exercise he used to build his huge biceps peak was the concentration curl, which is where you perform elbow flexion while the arm is rotated internally.
One study measured the activation of the biceps brachii during various curling exercises, such as barbell curls, EZ curl, chin-ups, preacher curl, incline curls, concentration curls, etc. The study found that the concentration curl activated the biceps brachii much more than all other curling exercises tested. 
Another important function of the biceps brachii is to supinate the forearm, causing the palms to turn and face up. That’s why some people like to sometimes perform some of their curling exercises by starting in a neutral position with the palms facing medially, and then they will supinate the forearm during flexion, ending the curling motion with the palms facing up. It is especially important to tense the muscle at the end of the movement as you twist the pinky side of the hand as much as possible. Then reverse the motion on the way down.
Finally, the biceps can also play a lesser role in shoulder flexion and stabilization.
So to recap, the functions (or actions) of the biceps brachii include:
- Elbow flexion
- Supination of the forearm
- Shoulder flexion
- Stabilization of the shoulder joint
Biceps Brachii Innervation (Nerve Supply)
The biceps brachii is supplied by the musculocutaneous nerve (C5 and C6).
Free Quiz and More Anatomy Videos
Take a free comprehensive quiz on the biceps brachii to test your knowledge, or review our biceps brachii video. In addition, you might want to watch our anatomy and physiology lectures on YouTube, or check our anatomy and physiology notes.
American Council on Exercise, Scott Young, M.S., John P. Porcari, Ph.D., Clayton Camic, Ph.D., Attila Kovacs, Ph.D., and Carl Foster, Ph.D.