Rotator cuff tear rotator cuff tear. Generally, the incidence of rotator cuff tears or injuries increases by age while corticosteroid injection for pain relief increases the risk of tendon tear and delays tendon healing. The shoulder is a complex mechanism involving bones, ligaments, joints, muscles, and tendons. The two main causes are injury (acute) and degeneration (chronic and cumulative), and the mechanisms involved can be either extrinsic or intrinsic or, probably most commonly, a combination of both. The cuff is responsible for stabilizing the glenohumeral joint, abducting, externally rotating, and internally rotating the humerus. When shoulder trauma occurs, these functions can be compromised.
Rectus sheath transversalis fascia, in contrast to the upper layers, where part of the internal oblique also runs beneath the rectus. Because of the thinner layers below, this region is more susceptible to herniation. Since the tendons of the internal oblique and transversus abdominis only reach as high as the costal margin, it follows that above this level the sheath of the rectus is deficient behind, the muscle resting directly on the cartilages of the ribs, and being covered only by the tendons of the external obliques. Rectus sheath The rectus sheath, also called the rectus fascia, is formed by the aponeuroses