What is the Subdeltoid?

In the human body, the subdeltoid is the muscle that is located beneath the deltoid muscle. It stretches across the shoulder joint and is attached to the collarbone and long bone of the upper arm. It assists in the movement and rotation of the shoulder joint.

This muscle is a part of the overall deltoid muscle group, which is also known as the common shoulder muscle. It forms the rounded shape of the shoulder, stretching from the top of the shoulder joint to cover the upper arm. It is so named due to its resemblance to the Greek letter delta, which is triangular in shape.

When pain occurs in the shoulder, it is typically located in or related to the subdeltoid. The shoulder joint and muscle configuration experiences more friction in daily movement than almost any other joint and muscle group in the human body. Pain in the shoulder related to the subdeltoid is typically treated by a physical therapist.

A bursa is a fluid-filled sac located in certain tissues with an increased potential for friction. Due to the high volume of movement in which the shoulder engages, the subdeltoid contains the subdeltoid bursa. This is located directly between the deltoid and the shoulder joint. Another, the subacromial bursa, lies beneath the acromion, the bony, peak-like projection of the shoulder, and extends between the deltoid and the humorous.

Bursitis is a joint disease in which the bursa sac becomes inflamed and irritated. Subdeltoid bursitis is the most common type. Therefore, most shoulder pain involving the subdeltoid is caused by bursitis.

There are a wide variety of treatments for bursitis. The most common is the injection of an anesthetic directly into the shoulder. Typically, two to four such injections sufficiently relive bursitis pain, and allow patients to return to normal activities.

For sufferers of this condition, pain occurs in the shoulder depending on the direction and type of movement of the shoulder joint. Forward and backward lateral movements typically generate different types of pain. Each movement is caused by a separate muscle, whether utilizing the subdeltoid, the deltoid, or the acromion. These differences can help doctors to diagnose which area of the shoulder is causing the pain. They may then more accurately direct treatment, and relieve the patient's suffering.