Sciatica refers to back pain caused by a problem with the sciatic nerve. This is a large nerve that runs from the lower back down the back of each leg. When something injures or puts pressure on the sciatic nerve, it can cause pain in the lower back that spreads to the hip, buttocks, and leg.
Osteoarthritis of the shoulder is a gradual wearing of the articular cartilage that leads to pain and stiffness. As the joint surface degenerates, the subchondral bone remodels, losing its sphericity and congruity. The joint capsule also becomes thickened, leading to further loss of shoulder rotation.
Thickening of the acromion and the acromioclavicular joint that occur with age, and the development of osteophytes (spurs) on the underside of the acromion and acromioclavicular joint, are the most common causes of shoulder impingement. Usually, the acromion has a flat inferior or lower surface (Type I acromion).hickening of the acromion and the acromioclavicular joint that occur with age, and the development of osteophytes (spurs) on the underside of the acromion and acromioclavicular joint, are the most common causes of shoulder impingement. Usually, the acromion has a flat inferior or lower surface (Type I acromion).