Anatomy Lesson: Biceps

In a previous post, I educated you on the anatomy of the shoulder which included the bicep. So today I will be going into more detail about the bicep and its counterparts. The bicep is the main elbow flexor of the arm…however it has side kicks as well that include the brachialis and the brachioradialis.

Because of its attachment sites, the bicep is commonly injured as a result of another injury near the shoulder joint. For example, shoulder impingement, rotator cuff tears, and joint laxity often lead to an injury to the bicep as well. Especially in athletes who throw overhead repetitively like baseball players. So knowing how the bicep works and how to properly strengthen it is important in avoiding injury.

Biceps Anatomy:

Long Head of the Bicep: Runs from the top of the scapula down to the radial tuberosity (forearm bone). Its actions include shoulder flexion, elbow flexion, elbow supination. It also assists with shoulder adduction and internal rotation.
Short Head of the Bicep: Runs from the coracoid process (bone at front of scapula) down to the radial tuberosity as well (forearm bone). Its actions are the same as the long head.
The coracobrachialis muscle runs from the coracoid process down to the humerus and assist with these motions as well. It is deep to the pectoralis muscle.

Brachialis Anatomy:

The brachialis muscle is deep to the biceps and wider. It runs from the middle of the humerus (upper arm bone) down to the ulnar tuberosity (forearm bone). Its actions include elbow flexion only.

Brachioradialis Anatomy:

The brachioradialis muscle is at the elbow. It runs from the bottom of the humerus (upper arm bone) down to the bottom of the radius (at your wrist). It does elbow flexion and pronation.

Stretching:

To stretch any muscle, you want to do the exact opposite of the muscle’s action.

Bicep stretch: Shoulder extension, external rotation, abduction + Elbow extension, pronation.
Brachialis stretch: Elbow extension
Brachioradialis stretch: Elbow extension, supination.