I. Muscles of the Arm

In common speech, the arm refers to the entire upper limb. However, in anatomy, the arm is only the region which extends from the shoulder to the elbow. This region is distinct from the forearm, which extends from the elbow to the hand. Use the information on the following pages to become familiar with the following terms.

• Brachial Fascia
  • medial intermuscular septum
  • lateral intermuscular septum
  • anterior fascial compartment
  • posterior fascial compartment
• Biceps Brachii
• Brachialis
• Corachobrachialis
• Triceps Brachii
• Anconeus
• Cubital Fossa
• Bicipital Aponeurosis

Brachial Fascia and Muscular Compartment

The Brachial Fascia is a stong sheath of deep fascia which encloses the arm. Two intramuscular septa extend from the brachial fascia and attach to ridges on the medial and lateral sides of the humerus. These intermuscular septa divide the arm into two compartments- an anterior fascial compartment and a posterior fascial compartment. This is shown in the schematic diagram below. These muscular compartments are anatomically significant. Each compartment has a unique function and nervous supply. The anterior fascial compartment contains all the flexor muscles of the arm (biceps, brachialis, and corachbrachialis) and is innervated by the musculocutaneous nerve. The posterior fascial compartment contains the extensor muscle of the arm (triceps) and is innervated by the radial nerve. Keep these functional considerations in mind when studying the muscles of the arm on the following page.

• Baby Moore, pg 309, fig 7.12

Muscles of the Arm

• Big Moore, pg 549

• Big Moore, pg 548, fig 6-51

Muscles of the Arm

• Baby Moore, pg 307, fig 7-10

• Baby Moore, pg 308, fig 7-11