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