Matt Cornwall, Physiotherapist, looks at the anatomy of the shoulder, the likely causes for instability and dislocation, what to do in case of a dislocation, what your options are post dislocation and some basic rehabilitation principles.
anatomy of the shoulder

The shoulder is one of the most mobile joints in the body, and this mobility allows us to perform a wonderful variety of movements with our hands – from more sedentary movements such as undoing a bra or washing our hair to more active movements such as rock climbing or playing tennis.

This mobility can lead to problems however as the body has to decide between mobility and stability. Increased mobility inevitably leads to decreased stability and vice versa. For comparison the hip joint by necessity is more stable than the shoulder because it needs to hold up the torso and upper body and we spend long periods of the day moving – a less stable hip would invariably lead to an increase in falls.

The shoulder joint gets its mobility from the shape of the socket – known as a ball and socket joint. This allows the shoulder and therefore the handas an extension to move in pretty much any direction. The ball (humeral head) sits in the socket (glenoid fossa) part of the scapular. The joint has been compared to a golf ball sitting on a golf tee.

The shoulder gets its stability from 3 factors:
• Bony structure of the joint – further increased by cartilage
• Ligament attachments around the joint
• Muscular attachments around the joint


Causes of shoulder dislocation

The shouldeCauses of shoulder dislocationr joint is the most commonly dislocated joint in the body. The most common type of dislocation is an anterior dislocation (97%). This usually occurs under high mechanical traumatic stress when the shoulder is forced into an excessive amount of abduction and external rotation – think a high five position. As the dislocation usually occurs during a traumatic event the most common people to dislocate their shoulder are young males, usually due to their high involvement in contact sports. Dislocations are however common in the elderly usually due to falls on an outstretched hand and this affects both females and males.


Signs of a dislocated shoulder

• The patient with anterior dislocation holds the arm at the side of body in external rotation.
• The shoulder loses its usual roundness. An anterior bulge may be seen in thinner patients. The humeral head is palpable anteriorly.

• Pain – which is increased with breathing as the humeral head pushes against the rib cage.

Signs of a dislocated shoulder


Potential Complications of a dislocation

• Fracture
• Nerve damage
• Artery damage
• Rotator cuff injury – the deep muscles that surround the shoulder joint
• Bony lesions


What to do if you suspect a dislocation

If you suspect you may have dislocated your shoulder your immediate concern should be to get to accident and emergency as quickly and safely as possible. The shoulder should be stabilized using a sling if this is not possible then tucking your arm into your shirt will suffice. No attempt should be made to re-locate the shoulder unless you are with a trained professional as there may be an underlying fracture.

If you have not had a shoulder dislocation but feel your shoulder is unstable consult with your Physiotherapist who can assess, treat and refer onwards for imaging if needs be.


What to do once the shoulder has been relocated

Once leaving A&E the hard part of rehabilitating your shoulder begins. Initially you will be given a sling to wear. The duration of wearing the sling depends on whether you are a first time dislocator or a repeat offender.

Rehabilitation consists of three phases, which are on a continuum and overlap. *These exercises can also apply for those with shoulder instability who have not yet had a dislocation.

Phase 1: Healing and mobilising stage – allowing adequate healing time of the shoulder whilst also incorporating simple movement exercises to prevent stiffening of the shoulder and regain full shoulder range.Serratus Push-Ups

Phase 2: Strengthening stage – an extremely important phase and one that if not carried out probably will increase your risk of repeat dislocation.external rotation of shoulder

Phase 3: Proprioception and return to sport – this phase looks at ensuring the shoulder has sufficient control at slow and fast speeds in multiple directions and also re-train the shoulder for specific positions related to that sport.

Armband Exercise

If you have dislocated your shoulder or are getting feelings of instability (times where you feel the shoulder may come out of the socket) and you feel it is preventing you from returning to full function or sport then book in with one of trained physiotherapists who will assess the shoulder and design a fully comprehensive and individualised rehabilitation program to get you back doing what you love without any fear.




Matt is a UK trained physiotherapist working at the Guthrie House branch of  City Osteopathy and Physiotherapy. Matt’s expertise and passion for shoulder injury management stems from his personal experience of recurrent shoulder dislocations, operations and rehab! His background is in rugby and he is still a keen athlete playing touch rugby and participating in many running and triathlon events across Asia.