Fascial Compartments of the Upper Arm-Contents of the Anterior Fascial Compartment of the Upper Arm-Muscles of the Anterior Fascial Compartment-Lymphangitis-Lymphadenitis-Biceps Brachii and Osteoarthritis of the Shoulder Joint-

Fascial Compartments of the Upper Arm

The upper arm is enclosed in a sheath of deep fascia. Two fascial septa, one on the medial side and one on the lateral side, extend from this sheath and are attached to the medial and lateral supracondylar ridges of the humerus, respectively. By this means, the upper arm is divided into an anterior and a posterior fascial compartment, each having its muscles, nerves, and arteries.

Contents of the Anterior Fascial Compartment of the Upper Arm

■■ Muscles: Biceps brachii, coracobrachialis, and brachialis

■■ Blood supply: Brachial artery

■■ Nerve supply to the muscles: Musculocutaneous nerve

■■ Structures passing through the compartment: Musculocutaneous, median, and ulnar nerves; brachial artery and basilic vein. The radial nerve is present in the lower part of the compartment.

Muscles of the Anterior Fascial Compartment

The muscles of the anterior fascial compartment ,Note that the biceps brachii is a powerful supinator, and this action is made use of in twisting the corkscrew into the cork or driving the screw into wood with a screwdriver. The biceps also is a powerful flexor of the elbow joint and a weak flexor of the shoulder joint.

 

Lymphangitis

Infection of the lymph vessels (lymphangitis) of the arm is common. Red streaks along the course of the lymph vessels are characteristic of the condition. The lymph vessels from the thumb and index finger and the lateral part of the hand follow the cephalic vein to the infraclavicular group of axillary nodes; those from the middle, ring, and little fingers and from the medial part of the hand follow the basilic vein to the supratrochlear node, which lies in the superficial fascia just above the medial epicondyle of the humerus, and thence to the lateral group of axillary nodes.

Lymphadenitis

Once the infection reaches the lymph nodes, they become enlarged and tender, a condition known as lymphadenitis.

Most of the lymph vessels from the fingers and palm pass to the dorsum of the hand before passing up into the forearm. This explains the frequency of inflammatory edema, or even abscess formation, which may occur on the dorsum of the hand after infection of the fingers or palm.

Biceps Brachii and Osteoarthritis of the Shoulder Joint

The tendon of the long head of biceps is attached to the supraglenoid tubercle within the shoulder joint. Advanced osteoarthritic changes in the joint can lead to erosion and fraying of the tendon by osteophytic outgrowths, and rupture of the tendon can occur.