As usual the approach is look, feel, move
So with the patient in a sitting position, first observe both posteriorly and anteriorly looking for obvious effusions or scars. Then feel. The shoulder joint starts, effectively at the sterno-clavicular joint so start palpating there and then work your way around and up to the clavicular-acromion joint. Then palpate down the shoulder joint “down the sleeves”, return to the acromion and feel underneath it, feel for the bicep tendon insertion and other tendons if possible. Feel the muscle bulk of the deltoid and surrounding muscles and finally feel down the scapular spine. Feel for crepitus.
Now move the shoulder, actively at first, getting the patient to raise the arms above the horizontal, point to the sky then place them behind the neck. Then separate and place them behind the lower back in internal rotation. The test flexion and extension. Try and quantify the movements. Now test passive movements and here it is important o fix the scapula, either from behind (holding the tip of the scapula) or anteriorly holding the acromion. Go through the range of movements. Next fix the elbow to the patients side and test the range of internal and external rotation.
Finally test for sensation over the axillary nerve and do a functional assessment. If you suspect you have missed something move onto a neurological shoulder girdle examination.
Investigations include x-ray and ultrasound (often forgotten).