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the shoulder. The shoulder. Passive elements Active elements. Bony shoulder. Bony shoulder. Bony shoulder. Bony shoulder. ACROMION TYPES. Glenohumeral joint. Ball and socket Ball:1/3 of a sphere Bony glenoid:covers only 1/3 of the head Glenoid depth: Vertical:9mm
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The shoulder Passive elements Active elements
Bony shoulder ACROMION TYPES
Glenohumeral joint • Ball and socket • Ball:1/3 of a sphere • Bony glenoid:covers only 1/3 of the head • Glenoid depth: Vertical:9mm Horizontal:5mm
Glenohumeral joint AVERAGE GLENOID DEPTH DOUBLED VERTICAL >HORIZONTAL DEPTH
LABRUM • dense fibrous tissue • superior portion: resembles a meniscus loosely attached to the glenoid rim (12o'clock) inserts into the biceps tendon in The interval is a small (5 mm) recess • the lower portion: round, dense
Glenohumeral capsule • inserts primarily into the anatomic neck of humerus but inferiorly in to the surgical neck • Preservation of glenohumeral stability by an intraarticular vacuum • A cadaver study:with an intact capsule found no subluxation even with sectioning of all the supporting muscles
Glenohumeral Ligaments • arm dependent (abduction zero):all three ligaments are visibly slack; primary stabilizer is SGHL • + external rotation:tension in the MGHL and the superior band of the IGHL • >45° of abduction:tightens the superior band of the IGHL
Coracoacromial Ligament passively restrains humeral subluxation in the shoulder with a deficient rotator cuff
Coracohumeral Ligament forms part of the roof of the bicipital tendon sheath COVERS ROTATOR INTERVAL
MOTIONS OF THE SHOULDER JOINTS ROM:160˚─180˚
SHOULDER ROM Elevation: humerus→2/3 scapula→1/3 minimum in the first and the last 30˚ Rotation: max with the arm adjacent to the trunk(160˚) decrease to 120˚in 90˚ABD/FLEX min in full ABD/FLEX
SCAPULOTHORACIC MOBILITY ROTATION upward(60˚) downward(extension) ELEVATION DEPRESSION PROTRACTION(away from the spine) RETRACTION(toward the spine)
CLAVICULAR JOINTS • sternoclavicular: only 30° during the first 90° . . of arm elevation. . . Clavicularprotraction and rotation Clavicular rotation of 50˚ • acromioclavicular: 15° during the first and last . 40° of arm elevation
SHOULDER MUSCLES • deltoid (anterior, middle, posterior) • rotator cuff muscles (supraspinatus, subscapularis, infraspinatus, teres minor) plus the biceps • axiohumeral muscles (pectoralis major and latissimusdorsi) plus the teresmajor • Scapular muscle (serratus anterior, trapezius, rhomboid, and levator scapulae)
elevation • Deltoid: primary elevator • posterior part has minor role . except during abduction • Rotator cuff:sup.spinatus→ABD/Compression . inf.spinatus→ext.rot/depressor subscapularis→int.rot/depressor teresminor→ext.rot • Pec.major and lat.dorsi→depressor