The shoulder’s problem
The shoulder trades stability for range of motion. It moves further in more directions than any other joint in the body, and it does so because the socket is shallow and the joint is held together largely by muscle and tendon. That design is why the shoulder does what it does, and why it fails in the ways it does.
What it usually turns out to be
Rotator cuff tendinopathy or impingement. The most common shoulder complaint. Pain on the outside of the upper arm, worse reaching overhead or behind, and classically worse lying on it at night — the symptom that finally sends people to make an appointment.
Rotator cuff tears, partial or full thickness. Weakness is the giveaway, particularly if lifting the arm to the side or holding it out is difficult.
Adhesive capsulitis — frozen shoulder. The joint capsule thickens and contracts, and movement is lost in every direction, including when somebody else moves the arm for you. More common in people with diabetes or thyroid disease.
Glenohumeral or acromioclavicular arthritis, producing deep ache, stiffness and grinding.
Referred pain from the neck, which frequently masquerades as shoulder pain.
The examination
Active and passive range of motion in every direction — the single most informative part, because the gap between what you can do and what can be done for you separates a weak shoulder from a stiff one. Then strength testing of each cuff muscle, the specific impingement tests, palpation of the AC joint and the biceps tendon, an assessment of how the shoulder blade moves, and a neck screen.
Treatment
Injections to settle the inflamed structure, whether subacromial, intra-articular or into the AC joint. In a frozen shoulder, an injection during the painful phase can be the thing that makes the months tolerable and lets you keep the range you still have.
PRP in selected tendon problems, where supporting repair rather than suppressing inflammation is the goal.
Rehabilitation, which for the shoulder is not optional. Cuff strength and scapular control are what hold the joint together, and no injection substitutes for them. This is where a physician trained in Physical Medicine & Rehabilitation earns their keep: the programme is specific to the diagnosis, and it is progressed rather than handed over on a sheet.
