Shoulder Essay

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  • Topic: Shoulder, Scapula, Rotator cuff
  • Pages : 4 (1525 words )
  • Download(s) : 79
  • Published : January 6, 2011
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The Shoulder Joint.The Shoulder is an enarthrodial or ball-and-socket joint. The bones entering into its formation, are the large globular head of the humerus, received into the shallow glenoid cavity of the scapula, an arrangement which permits of very considerable movement, whilst the joint itself is protected against displacement by the strong ligaments and tendons which surround it, and above by an arched vault, formed by the under surface of the coracoid and acromion processes, and the coraco-acromial ligament. The articular surfaces are covered by a layer of cartilage : that on the head of the humerus is thicker at the centre than at the circumference, the reverse being observed in the glenoid cavity. The ligaments of the shoulder are, the Capsular. Coraco-humeral.Glenoid.* The Capsular Ligament completely encircles the articulation ; being attached, above, to the circumference of the glenoid cavity beyond the glenoid ligament; below, to the anatomical neck of the humerus, approaching nearer to the articular cartilage above, than in the rest of its extent. It is thicker above than below, remarkably loose and lax, and much larger and longer than is necessary to keep the bones in contact, allowing them to be separated from each other more than an inch, an evident provision for that extreme freedom of movement which is peculiar to this articulation. Its external surface is strengthened, above, by the Supraspinatus ; above and internally, by the coraco-humeral ligament; below, by the long head of the Triceps ; externally, by the tendons of the Infraspinatus and* The long tendon of origin of the Biceps muscle also acts as one of the ligaments of this joint.Teres minor; and internally, by the tendon of the Subscapularis. The capsular ligament usually presents three openings: one at its inner side, below the coracoid process, partially filled up by the tendon of the Subscapularis; it establishes a communication between the synovial membrane of the joint and a...
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