When any of the four shoulder muscles of the rotator cuff receive excessive or prolonged force, the tendons that attach them to the humerus bone of the upper arm can be damaged. While tendon elasticity aids muscular function, when stretched too far or too often, tissue gives way.
Shoulder tendonitis can result from a single incident of extreme motion or from repetitive stress that causes tendon degeneration. The body's response is inflammation, along with related symptoms that aid in diagnosis and prescriptive treatment.
Shoulder Pain
Tendonitis primarily causes shoulder pain, which may develop swiftly after an acute injury or which may build as tendons deteriorate and finally tear. According to the Mayo Clinic, shoulder pain may start as a dull ache and sharpen when a patient moves the shoulder, especially when raising the arm overhead.
The inflammatory response may cause mild swelling around the glenohumeral joint, where the tendons attach to bone. This can spread tenderness beyond the local area, making other parts of the shoulder and arm painful to the touch. These widespread tendonitis symptoms of pain and swelling can mimic or be exacerbated by related shoulder conditions, such as bursitis and arthritis.
Restricted Range of Motion
As the tendons of the rotator cuff swell, they squeeze the muscles that inhabit the small space between the joint and supportive shoulder bones. This impingement marks another symptom of tendonitis that manifests as restricted mobility.
The shoulder pain caused by impingement may make it too painful to move, or the muscles may not have enough room to run their full course. The American Orthopaedic Society for Sports Medicine (AOSSM) notes that diagnostic tests involving manipulation can determine the source of impingement symptoms, ruling out muscle and joint problems and pointing definitively toward shoulder tendonitis.
Muscle Weakness
Damage caused by shoulder tendonitis affects muscle strength across the rotator cuff. Dynamic muscle movement depends upon healthy tendons to reduce the work load and to absorb shock. When shoulder tendonitis sets in, the muscles may take on more stress than they can handle.
As the University of Maryland Medical Center notes, weakness symptoms make it difficult for patients to reach overhead or perform everyday tasks. Combing hair and carrying even light objects can cause pain or become physically impossible.
Difficulty Sleeping
Any extra stress on the rotator cuff area increases inflammation and, therefore, pain. Side sleeping positions put weight on the damaged area, and muscle impingement during movement can be painful enough to wake patients. The AOSSM relates that symptoms this severe warrant seeking a medical diagnosis, pain relief and rehabilitative treatment.
