Dead arm syndrome starts with repetitive motion and forces on the posterior capsule of the shoulder. The posterior capsule is a band of fibrous tissue that interconnects with

tendon A tendon or sinew is a tough, high-tensile-strength band of dense fibrous connective tissue that connects muscle to bone. It is able to transmit the mechanical forces of muscle contraction to the skeletal system without sacrificing its ability ...

s of the rotator cuff of the shoulder. Four

muscle Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of muscl ...

s and their tendons make up the rotator cuff. They cover the outside of the shoulder to hold, protect and move the joint. Overuse can lead to a buildup of tissue around the posterior capsule called hypertrophy. The next step is tightness of the posterior capsule called posterior capsular contracture. This type of problem reduces the amount the shoulder can rotate inwardly. Over time, with enough force, a tear may develop in the labrum. The labrum is a rim of

cartilage Cartilage is a resilient and smooth type of connective tissue. In tetrapods, it covers and protects the ends of long bones at the joints as articular cartilage, and is a structural component of many body parts including the rib cage, the neck an ...

around the shoulder socket to help hold the head of the

humerus The humerus (; ) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius and ulna, and consists of three sections. The humeral upper extremity consists of a roun ...

(upper arm) in the joint. This condition is called a superior labrum anterior posterior (SLAP) lesion. The outcome in all these steps is the dead arm phenomenon. The shoulder is unstable and dislocation may come next. Dead arm syndrome will not go away on its own with rest—it must be treated. If there is a SLAP lesion, then

surgery Surgery ''cheirourgikē'' (composed of χείρ, "hand", and ἔργον, "work"), via la, chirurgiae, meaning "hand work". is a medical specialty that uses operative manual and instrumental techniques on a person to investigate or treat a pat ...

is needed to repair the problem. If the injury is caught before a SLAP tear, then

physical therapy Physical therapy (PT), also known as physiotherapy, is one of the allied health professions. It is provided by physical therapists who promote, maintain, or restore health through physical examination, diagnosis, management, prognosis, patient ...

with stretching and exercise can restore it. It is common among baseball pitchers as they age, and it can also occur with quarterbacks in football and handball players also as they age.

References

* * * * * Musculoskeletal disorders Syndromes {{musculoskeletal-disease-stub