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February 7, 2011 by dailybolusoflr
The shoulder is the most frequently dislocated joint.
· The most common demographic is in 18-25 year old males and is due to sporting activities. The second most common is in the elderly due to falls.
· Anterior dislocations occur most commonly and have been cited as up to 98% of dislocations.
· The most common mechanism is force applied while the arm is held in abduction, extension, and external rotation. (Think of the motion or raising the arm to spike the ball in volleyball!).
· Classically, patients are said to hold the arm in slight Abduction and external rotation. They resist internal rotation and any further Abduction.(ask them to touch their other shoulder)
· The shoulder is said to appear “squared off” which means it has lost its normal curved shape.
(see the attached picture for a man in this position…note his right shoulder is squared and has lost the normal contour of the other side)
· Palpation of the anterior glenoid may reveal a fullness (the humeral head which has been anterior dislocated)
· 30% of shoulder dislocations have an associated fracture.
o The most common fracture is the Hill Sachs deformity- a compression fracture in the posterolateral aspect of the humeral head
o Between half to two-thirds of all dislocations may have this
The most important physical exam findings :
· Search for additional injuries….don’t be distracted by the most obvious
· Vascular exam of the arm
· Nerve injury- the axillary nerve should be tested which provides sensation over the upper and outer aspect of the upper arm. It also provides motor innervation to the deltoid
Linda Regan, MD FACEP
Program Director, Emergency Medicine Residency
Johns Hopkins Medical Institutions