The subacromial bursa lies on the top portion of the supraspinatus tendon. The bursa is a fluid-filled sac and acts to cushion and reduce friction during motion between the overlying bone of the acromion and the soft rotator cuff muscles below. It often extends out to be continuous with the sub-deltoid bursa.
Posterior Shoulder Anatomy. These muscles work to extend the arm and rotate the shoulder outward or externally. The layer deeper to the muscles includes the labrum and joint capsule. These structures help to stabilize the shoulder from the back. If you would like to learn more about the anatomy of the shoulder, go to our Shoulder Trending Section.
If you need an appointment with a Jacksonville Orthopedic Institute Shoulder Specialist, please call JOI , schedule online, or click the link below. Shoulder Anatomy The human shoulder is a ball-in-socket joint and in turn, is the most mobile joint in the body. Anatomy of the Shoulder These two joints work together at the arm to allow the shoulder to move in a large circle and to rotate around its axis. Anatomy of Shoulder and Shoulder Joints Bones in the Shoulder Scapula The scapula is a triangular-shaped bone that functions mainly as a site for muscular attachment.
Glenoid Fossa The glenoid fossa is the socket of the shoulder joint. Clavicle The clavicle is an S-shaped bone that forms the front portion of the shoulder girdle and keeps the arm away from the trunk, allowing it to move freely. Humeral Head The top portion of the humerus is referred to as the humeral head. Labrum The glenoid labrum is a ring composed of mostly dense fibrous tissue. Ligaments in the Shoulder Coracoclavicular Ligaments The conoid and trapezoid ligaments make up the coracoclavicular ligaments.
Glenohumeral Ligaments There are three glenohumeral ligaments: The superior glenohumeral ligament, middle glenohumeral ligament, and inferior glenohumeral ligament.
Coracohumeral Ligament The coracohumeral ligament originates on the base and outside the border of the coracoid process of the scapula and attaches to a landmark on the humerus called the greater tuberosity. Soft Tissue Structures in the Shoulder Soft Tissue in the Shoulder Rotator Cuff Injuries The Rotator Cuff is made up of 4 muscle including the: supraspinatus infraspinatus teres minor subscapularis The muscles and tendons of the rotator cuff form a cover around the anterior, superior, and posterior humeral head and glenoid cavity of the shoulder by compressing the gleno-humeral joint.
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Gray's Anatomy. The labrum is described like a clock face with 12 o'clock being at the top superior , 3 o'clock at the front anterior , 6 o'clock at the bottom inferior and 9 o'clock at the back posterior. Clinicans may reverse the 3 o'clock and 9 o'clock for left shoulder describing 3 o'clock at the back. An injury to the shoulder with shear forces either in the anterior or posterior or superior directions leads to a labral tear in the affected area.
An injury between 3 and 6 o'clock is known as a Bankart tear. Superior labral injury is known as a SLAP tear superior labral anteroposterior. A posterior tear of the posterior labrum is known as a posterior labral tear of reverse Bankart lesion. Sublabral foramen are anatomical variants, which is where the labrum can be 'lifted up' between 12 and 3 o'clock. It should not be confused with a labral tear, as its edge is clearly round and smooth and not red and ragged.
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