The shoulder. The shoulder Passive elements Active elements

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 Horizontal:5mm

Glenohumeral jointAVERAGE 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

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

Glenohumeral Ligaments

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 ROMElevation: 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 MOBILITYI. ROTATION upward(60˚) downward(extension)II. ELEVATIONIII. DEPRESSIONIV. PROTRACTION(away from

the spine)V. 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