Rotator cuff tear oxidative stress induces tenocyte apoptosis causing further rotator cuff tendon degeneration. A neural theory also exists that suggests neural overstimulation leads to the recruitment of inflammatory cells and may also contribute to tendon degeneration. Tears of the rotator cuff tendon are described as partial or full thickness, and full thickness with complete detachment of the tendons from bone. Shoulder pain is variable and may not be proportional to the size of the tear. Neer promoted the concept of three stages of rotator cuff disease. Stage I, according to Neer, occurred in those younger than 25 years and involved edema and
Posterior compartment of the forearm De Quervain's syndrome is a medical condition when the synovial sheath surrounding tendons in the first extensor tendon compartment becomes inflamed, so called tenosynovitis. The tendons of the abductor pollicis longus and the extensor pollicis brevis run narrower due to the thickening of the synovial sheath, which causes pain when extending and moving the thumb outward. Carpal tunnel syndrome is a condition when the median nerve is compressed as it passes through the carpal tunnel, which causes pain, numbness and tingling. The presence of an additional tendon may result in a condition called fourth compartment syndrome. Supernumerary tendons are common