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Shoulder Dislocation - Basics

DISLOCATON : Is complete loss of contact between to articular surfaces forming the joint.

SUBLUXATION :Is partial dislocation


Acute joint dislocations are medical emergency because of chances of injuries to surrounding blood vessels and nerve.


Shoulder Dislocation


•By the virtue of its anatomy & biomechanics, shoulder joint is one of the most unstable joint in body

•It has an excellent range of mobility, but at the cost of stability

•It constitutes bout 50% of all dislocations


ANATOMY


•The head of the humerus is 3 times that of glenoid cavity area wise

•It forms an 135 degree angle with the axis of the shaft of humerus & an angle of 30 degree with the frontal plane

•The anatomical neck makes an angle of 45 degree with the horizontal plane

•Glenoid labrum deepens the joint by 50% & increase the humeral contact by 75%


STABILITY FACTORS



ANATOMIC factors


1.Labrum increases socket depth

2.Labrum bonding strength

3.Adhesions

Dynamic Factors



1.Supraspinatus

2.Subscapularis

3.Infraspinatus

4.Long head of biceps


Static Factors



1.Superior glenohumeral ligament

2.Middle glenohumeral ligament

3.Inferior glenohumeral ligament

4.Coracohumeral ligament







Arterial supply


•Ant. Circumplex humeral artery

•Post. Circumflex humeral artery

•Suprascapular artery

•Circumflex scapular artery





Nerve supply

From posterior cord of brachial plexus & from suprascapular, axillary & lateral pectoral nerve


CLASSIFICATION

On basis of frequency

1.Acute

2.Recurrent

3.Chronic (fixed)

4.Habitual


On basis of etiology

1.Trumatic

2.Atraumatic

3.Congenital

4.Neuromascular (erb’s palsy, seizures, cerebral palsy)


On the basis of direction of dislocation


1.Anterior

2.Posterior

3.Inferior

4.Superior





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Superior Shoulder Dislocation

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