MRI Shoulder Anatomy (RSMI 4320) PDF

MRI technique 2 (RSMI 4320) - Shoulder anatomy- Dr. Salman Al-harthi [email protected]  Shoulder The shoulder joint is a shallow ball-and socket joint and is considered the most mobile joint of the body. Shoulder girdle is composed of the clavicle, scapula, and humerus.  Sho...

MRI technique 2 (RSMI 4320) - Shoulder anatomy- Dr. Salman Al-harthi [email protected]  Shoulder The shoulder joint is a shallow ball-and socket joint and is considered the most mobile joint of the body. Shoulder girdle is composed of the clavicle, scapula, and humerus.  Shoulder-bony anatomy Four projections of the scapula provide attachment sites for the muscles and ligaments: Scapular spine, acromion, coracoid process and glenoid process. Shoulder-labrum and ligaments Glenoid labrum: the edge of the glenoid fossa is surrounded by a fibrocartilaginous ring, and it deepens the articular surface. Coronal oblique MR with glenoid labrum Shoulder-labrum and ligaments Ligaments contributing to the formation of the glenoid labrum include: Glenohumeral ligaments (three fibrous bands) Coracoacromial ligament is located on the anterior portion of the shoulder, and it protects the humeral head and rotator cuff tendons from direct trauma Coracoclavicular ligament helps to maintain the position of the clavicle Sagittal oblique MR with coracoclavicular ligament Shoulder-bursae The tendons and ligaments of the shoulder joint are cushioned by bursae. Two prominent shoulder bursae include subacromial- subdeltoid and subscapular bursae. Subacromial-subdeltoid bursa is the largest bursa within the body. Coronal oblique MR with subacromial- subdeltoid bursa SASD-subacromial-subdeltoid bursa  Shoulder-muscles and tendons Muscles that provide stability for the shoulder joint and movement of the upper arm include: Deltoid, and the four rotator cuff muscles: supraspinatus, infraspinatus, teres minor and subscapularis muscles.  Shoulder-muscles Primary function of deltoid muscle is to abduct the arm. The four remaining muscles closely surround the shoulder joint and comprise the rotator cuff. Rotator cuff provides stability to the shoulder joint and allows for abduction and rotation of the humerus Is best seen on oblique coronal MR images that are aligned parallel to the supraspinatus muscles.  Shoulder-muscles and tendons Muscle Origin Insertion Function Supraspinatus Supraspinous fossa Greater tubercle of humerus Abduct arm of scapula Infraspinatus Infraspinous fossa Greater tubercle of humerus Rotate arm of scapula outward Teres minor Axillary border of Greater tubercle of humerus Rotate arm scapula outward Subscapularis Subscapular fossa Lesser tubercle of humerus Rotate arm of scapula medially End