the shoulder

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 joint

Slap lesion

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

ROTATOR INTERVAL

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

ACROMIOCLAVICULAR JOINT

Sternoclavicular joint

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

Scapular motion

SCAPULOTHORACIC MOBILITY I.ROTATION upward(60 ˚ ) downward(extension) I.ELEVATION II.DEPRESSION III.PROTRACTION(away from the spine) IV.RETRACTION(toward the spine)

CLAVICULAR JOINTS sternoclavicular: only 30° during the first 90°.. of arm elevation... Clavicular protraction 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 latissimus dorsi) plus the teres major 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 teres minor→ext.rot Pec.major and lat.dorsi→depressor

The end