Biceps Brachii (*Biceps)
Arm · Upper Limb
The biceps brachii is the prominent two-headed muscle of the front of the arm. Its short head arises from the coracoid process of the scapula and its long head from the supraglenoid tubercle, the latter's tendon running through the shoulder joint and along the intertubercular groove; both heads join to insert on the radial tuberosity and, through the bicipital aponeurosis, into the deep fascia of the forearm. It is the most powerful supinator of the forearm, a strong flexor of the elbow (especially when the forearm is supinated), and a weak flexor of the shoulder. Biceps brachii is supplied by the musculocutaneous nerve (C5, C6); rupture of the long head produces the classic bunched-up Popeye bulge in the arm.
Origin, Insertion, Action & Nerve
Origin
Short head: coracoid process of scapula; Long head: supraglenoid tubercle of scapula
Insertion
Radial tuberosity and bicipital aponeurosis (into deep fascia of forearm)
Action
Supination of forearm; flexion of elbow; weak flexion of shoulder
Nerve
Musculocutaneous nerve (C5, C6)
Attachments explained
The Biceps Brachii (*Biceps) is defined first by where it attaches. Its origin is the more fixed anchor, usually the proximal or more stable end that stays put during contraction, while its insertion is the more mobile point that is pulled toward the origin when the muscle shortens.
Origin
Short head: coracoid process of scapula; Long head: supraglenoid tubercle of scapula
Insertion
Radial tuberosity and bicipital aponeurosis (into deep fascia of forearm)
Action & function
When the Biceps Brachii (*Biceps) contracts, it produces the following movements: Supination of forearm; flexion of elbow; weak flexion of shoulder.
As part of the Arm group of the Upper Limb, it works alongside neighbouring muscles to generate smooth, coordinated movement and to stabilise the structures it acts on.
Nerve supply & clinical relevance
The Biceps Brachii (*Biceps) receives its nerve supply from the Musculocutaneous nerve (C5, C6). This nerve carries fibres from spinal segment(s) C5, C6.
Because a muscle can only contract when its nerve is intact, injury to the Musculocutaneous nerve or to its spinal roots (C5, C6) can weaken or paralyse the Biceps Brachii (*Biceps), impairing the movements it normally produces (supination of forearm). This is why knowing the innervation is central to localising nerve lesions in clinical practice.
How to study the Biceps Brachii (*Biceps) (the OIANS method)
Learn the biceps by remembering it crosses two joints, which is why it has two actions worth prioritising: it flexes the elbow and, more distinctively, it is the strongest supinator of the forearm. The corkscrew image helps: the muscle both bends the elbow and turns the palm up, exactly the motion of driving a screw with the right hand.
Fix the nerve with the whole anterior arm at once, since the musculocutaneous nerve (C5, C6) supplies biceps, brachialis, and coracobrachialis together. Then attach the Popeye deformity to a long-head tendon rupture as your clinical anchor, which also reminds you that the long head, not the short, is the one running through the shoulder joint.
Frequently asked questions
Where is the Biceps Brachii (*Biceps) located?
The Biceps Brachii (*Biceps) is a muscle of the Arm group, located in the Upper Limb.
What is the origin of the Biceps Brachii (*Biceps)?
Short head: coracoid process of scapula; Long head: supraglenoid tubercle of scapula
What is the insertion of the Biceps Brachii (*Biceps)?
Radial tuberosity and bicipital aponeurosis (into deep fascia of forearm)
What movements does the Biceps Brachii (*Biceps) produce?
Supination of forearm; flexion of elbow; weak flexion of shoulder
What nerve supplies the Biceps Brachii (*Biceps)?
Musculocutaneous nerve (C5, C6)
Is the Biceps Brachii (*Biceps) free to study in OIANS?
Yes. The Biceps Brachii (*Biceps) is free in OIANS: its full origin, insertion, action and nerve details are open to everyone in the Muscle Directory, and because it belongs to the Upper Limb it is also covered by the free Quiz and Flashcard decks. The other regions, the "All Muscles" deck, and the Progress and Explore tools are unlocked with a one-time Lifetime purchase.
Related muscles
Study the Biceps Brachii (*Biceps)
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