The area of the body where the arm attaches to the trunk.Three bones meet here: the scapula, clavicle, and humerus. The ball-and-socket joint at the shoulder has a wide range of movement.
Common injuries include dislocation (see shoulder, dislocation of) and fractures of the clavicle or upper humerus. The shoulder may be affected by any joint disorder, which in severe cases may lead to frozen shoulder. Inflammation of a tendon or a bursa around a shoulder joint can cause painful arc syndrome.
The joint formed by the upper end of the HUMERUS and the shoulder-blade or SCAPULA. The acromion process of the scapula and the outer end of the collar-bone (see CLAVICLE) form a protective bony arch above the joint, and from this arch the wide and thick deltoid muscle passes downwards, protecting the outer surface of the joint and giving to the shoulder its rounded character. The joint itself is of the ball-and-socket variety, the rounded head of the humerus being received into the hollow glenoid cavity of the scapula, which is further deepened by a rim of cartilage. One tendon of the biceps muscle passes through the joint, grooving the humerus deeply, and being attached to the upper edge of the glenoid cavity. The joint is surrounded by a loose ?brous capsule, strengthened at certain places by ligamentous bands. The main strength of the joint comes from the powerful muscles that unite the upper arm with the scapula, clavicle and ribs.
Shoulder-blade or scapula. A ?at bone, about as large as the ?at hand and ?ngers, placed on the upper and back part of the With the arm hanging by the side, the scapula extends from the second to the seventh rib, but, as the arm is raised and lowered, it slides freely over the back of the chest. On the rear surface of the bone is a strong process, the spine of the scapula. This arches upwards and forwards into the acromion process. The latter forms the bony prominence on the top of the shoulder, where it unites in a joint with the outer end of the clavicle.
n. the ball-and-socket joint (see enarthrosis) between the glenoid cavity of the *scapula and the upper end (head) of the humerus. It is a common site of dislocation. The joint is surrounded by a capsule closely associated with many tendons: it is the site of many strains and inflammations (‘cuff injuries’).
A painful condition of the shoulder accompanied by sti?ness and considerable limitation of movement. The usual age-incidence is between 50 and 70. The cause is in?ammation and contracture of the ligaments and muscles of the shoulder joint, probably due to overuse. Treatment is physiotherapy and local steroid infections. There is practically always complete recovery, even though this may take 12–18 months.... frozen shoulder
Pain and stiffness affecting one shoulder and the hand on the same side; the hand may also become hot, sweaty, and swollen. Arm muscles may waste through lack of use (see Sudeck’s atrophy). The cause of shoulder–hand syndrome is unknown, but it may occur as a complication of myocardial infarction, stroke, herpes zoster, or shoulder injury. Recovery usually occurs in about 2 years. This period may be shortened by physiotherapy and corticosteroid drugs. In rare cases, a cervical sympathectomy is performed.... shoulder–hand syndrome
a difficult birth (see dystocia) in which the anterior or, less commonly, the posterior fetal shoulder impacts on the maternal symphysis or sacral promontory. It is an obstetric emergency and is diagnosed when the shoulders fail to deliver after the fetal head and when gentle downward traction has failed. Additional obstetric manoeuvres (e.g. *McRobert’s manoeuvre) are required to release the shoulders from below the pubic symphysis. It occurs in approximately 1% of vaginal births. There are well-recognized risk factors, such as maternal diabetes and obesity and fetal *macrosomia. There can be a high *perinatal mortality rate and morbidity associated with the condition; the most common fetal injuries are to the brachial plexus, causing an *Erb’s palsy or *Klumpke’s paralysis. Maternal morbidity is also increased, particularly *postpartum haemorrhage.... shoulder dystocia
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