A subluxed shoulder will often look subtle on an X-ray and sometimes even appear nearly normal if the bone has already popped back into place.
A subluxed shoulder, which is a partial and temporary slip of the upper arm bone out of the socket.
The key X-ray signs of a subluxed shoulder include the V-sign, partial misalignment and AC Joint Subluxation.
For the V-sign, instead of fitting smoothly and evenly across the socket also known as the ([glenoid fossa]), the ball of the upper arm also known as the ([humeral head]) shifts slightly out of place.
This makes the joint space look narrower on one side and wider on the other, forming a "V" shape that points toward the direction the bone is moving.
And unlike a full shoulder dislocation where the ball is separated from the socket completely, a subluxation shows an abnormal, off-center overlap between the humeral head and the glenoid.
And for AC Joint Subluxation, if the separation is at the top of the shoulder (the acromioclavicular joint), you might even see a visible gap or a mismatch where the collarbone (clavicle), rides higher than the shoulder blade's tip (acromion.
X-rays can also miss subluxation due to a temporary shift and need for special views.
Standard front facing views (AP views) can hide minor shifts.
And doctors often rely on specialized angles like an axillary view or a scapular Y-view to spot subtle displacements.
And because a subluxation often reduces or realigns on it's own before imaging takes place, a standard X-ray might even look completely normal.
You can also tell if your shoulder is subluxed (partially dislocated) if you feel the joint slip out of the socket and quickly pop back into place.
Common Symptoms of a shoulder being subluxed include:
Sensation of slipping: A feeling that the arm bone is moving in and out of the shoulder socket or giving way.
Pain: A deep ache or sharp pain in the shoulder joint.
Instability: A loose feeling in the shoulder when you move your arm.
Limited movement: Trouble moving your arm freely or lifting it overhead.
Weakness: A lack of strength in the affected arm.
Numbness: Tingling or numbness down the arm or in the fingers.
Subluxation vs. Full shoulder Subluxation:
Subluxation: The bone only partially slips out and returns on its own; you can still move the arm (though it is painful or weak).
Shoulder Dislocation: The bone completely separates from the socket; the arm locks and cannot move until a doctor resets it.