Anatomy Of The Upper Arm

Courtesy: Prof Nabil Ebraheim, University of Toledo, Ohio, USA

ANATOMY OF THE UPPER ARM
The muscles on the front of the upper arm consists of three muscles.
1. Biceps brachii muscle
2. Brachialis muscle
3. Coracobrachialis muscle

BICEPS BRACHII MUSCLE
• Biceps is a strong supinator of the forearm.
• Flexes the elbow joint.
• Long head of the biceps stabilizes the shoulder joint.

BRACHIALIS MUSCLE
• Primary flexor of the elbow joint.

CORACHOBRACHIALIS MUSCLE
• Flexion and adduction of the shoulder.

INNERVATION
• The musculocutaneous nerve arises from the lateral cord of the brachial plexus.
• It is the primary nerve supply to these 3 muscles.

Why it is musculocutaneous?
Musculo- It is the primary nerve supply of the muscles of the anterior compartment of the upper arm.
Cutaneous- It supplies sensation to the lateral half of the forearm.

TRICEPS MUSCLE:

• The triceps muscle is another muscle of the upper arm, but it is located on the back of the upper arm.

Function – Powerful extensor of the elbow joint.

Muscle has 3 heads :

1. Long head
2. Lateral head
3. Medial head

Innervation – Radial nerve from the posterior cord of the brachial plexus.