Deltoid muscle disruption is a partial or complete rupture of the deltoid muscle or its attachment to bone. The deltoid is an important muscle for shoulder function and motion. With this rare injury, the deltoid muscle pulls off the roof of the shoulder (acromion), end of the collarbone, or part of the shoulder blade (scapula), resulting in loss of one attachment of the deltoid muscle and thus loss of function of this muscle. It is even less common for the deltoid to pull off the humerus (arm bone). This condition happens most commonly following open shoulder surgery when a surgeon has surgically taken down and repaired the deltoid muscle from the acromion and the deltoid repair fails because the patient is not compliant after surgery. Deltoid muscle disruption can result in poor shoulder function.
Frequent Signs and Symptoms
- A “pop” or rip or tearing and severe sharp pain in the shoulder at the time of injury
- Tenderness, swelling, warmth or redness, and later bruising over and around the shoulder
- Pain and weakness trying to raise the arm to the side, front, or behind, depending on the portion which is torn
- Loss of contour of the shoulder; more evident when trying to contract the muscle and lift the arm
- Loss of firm fullness when pushing on the area where the tendon ruptured a defect between the end of the muscle and bone where they are separated from each other