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The first thing you need to know about a dislocation is that it is completely different from a fracture. Oftentimes, these two terms have been used interchangeably when used to describe an injury to a joint but they do not mean the same thing.

A fracture describes a break in continuity when referring to a single bone (like breaking a pencil into two) and there are different types of fractures; but a dislocation describes a complete separation of a bone from its articulating surface within the joint it is housed in (sort of when lego blocks are separated from each other).

Another term often used is “subluxation” which describes a partial separation or partial dislocation of a component bone within a joint.

Have you ever one day went about your normal everyday routine, maybe try to lift a heavy object above your head or someone gave you a light punch on the shoulder and you just heard a pop and a “give” in your shoulder? Well, that might just be a shoulder dislocation or subluxation.

A shoulder dislocation is when the head of the humerus (the long bone in the upper arm) in your shoulder “pops out” of the scapula’s socket in your upper back. This can come out all the way or some of the way and may go back in on its own.

The Shoulder

The shoulder joint also known as the glenohumeral (gleniod fossa/humerus) joint is a ball and socket joint located right where your arm is joined to your chest, consisting of the head of the humerus and the glenoid fossa, which is formed by a slightly deepened portion of the end of the shoulder blade (scapula) in your upper back.

The head of the humerus maintains very little contact with the glenoid fossa itself during movement and so, the shoulder relies on a group of ligaments, muscles and tendons to help keep the humerus in the proper place and to provide stability to the joint.

Considering that these bones come together at a point i.e., the joint, it is held in place by powerful ligaments, tendons and muscles like a group of muscles called the rotator cuff and the deltoid which also double as a means to movement hence, it is capable of flexion (when swinging the arm in front), abduction (outward movement of the arm), extension (when swinging the arm to the back), internal rotation (rotating the fist toward the body with the elbow bent at 90 degrees), external rotation (rotating the fist away from the body with the elbow bent at 90 degrees), and circumduction (rotation of the arm in a clockwise or counter-clockwise direction). Let’s just say that because of this powerful and multidirectional joint, you can move your arm like a carousel roundabout (merry-go-round) in full 360 degrees!

Source: sequencewiz.org

What causes a shoulder dislocation?

Sometimes, accidents that involve a blow, a punch to the shoulder or a fall on an outstretched arm can cause a dislocation but there are times when even slight or simple movements like twisting the arm to pick an object behind or even rolling over to sleep on the shoulder or not even doing anything at all would cause a dislocation (although, this is common in people who have very flexible bodies or joints).

As the arm moves in all these directions, the ligaments and muscles maintain the proper position of the humeral head in the glenoid fossa socket. But as a result of force or injury to the shoulder, or even laxity, the ligaments can become stretched or torn causing the head of humerus to “slip out or pop out” of place. Thus, the shoulder can be dislocated anteriorly which is the case 90% of the time or posteriorly which occurs 10% of the time. 

Source: Continentalhospitals.com

Some people may be more susceptible to shoulder dislocation. It would interest you to know that studies have shown that young men and older women are prone to having frequent shoulder dislocations. It has been found that the rate of shoulder dislocations has doubled over the years with maximum incidence rate occurring in those between the ages of fifteen to twenty-nine years. Most shoulder dislocations result from a fall and often occur at home or at sites of sports or recreation activities.

Although generally, a shoulder dislocation is borne out of the force applied to the joint during injury however it happened, it frequently occurs in these two categories.

It is important to note that once a shoulder dislocation has occurred, there is a high risk of re-occurrence. This is because the muscles and soft tissue holding the joint in the place can become stretched and it is of utmost importance that this laxity or injury is taken care of.

How to detect a shoulder dislocation and give a proper first-aid

In no particular order, you might hear a “pop” sound accompanied by pain (which could range from average to excruciating), numbness in the arms a result of nerve injury, difficulty moving the arm and a slight awkwardness or droopiness to how your arm looks when you look in a mirror. 

Source: Anaesthesia key

Once a dislocation has occurred, it is important to stay calm and protect your shoulder by keeping it close your body in a make-shift arm sling which you could make from your T-shirt at home, a scarf or better still, an orthopaedic arm sling and then present to the nearest health care centre.

Here’s how to make an arm sling from a scarf.

Source: Gowerstreetpractice.org.uk

Using ice to reduce pain and swelling is also important as it has been proven to be the best possible line of first aid home management.

Effectively Managing shoulder dislocation

You stand a better chance of receiving adequate management and prevent re-injury through physiotherapy.

After a detailed assessment by a physiotherapist following a shoulder dislocation, you will be required to wear an arm sling for some weeks after your shoulder has been reduced or “popped” back in place but there are times when some dislocations would require immediate surgery depending on injury severity. Hence the need for a thorough clinical management.

Pain relief medications and ice therapy would be prescribed to help cope with the pain for a few days.

Physiotherapy plays a crucial role in the overall management of shoulder dislocations. Initial management of an acute shoulder dislocation consists of a variable period of immobilization i.e., in a sling, followed by rehabilitation focused on restoration of active motion and muscle strengthening.

After an acute shoulder dislocation, your physiotherapist would recommend immobilization in a sling for comfort for about 3–4 weeks although, this varies with age, it is then followed by range-of-motion exercises as tolerated and progression to strengthening exercises up until you can return to your activities of daily living, pain and instability free.

Coping with an unstable shoulder joint can be quite embarrassing as one might live in constant fear and apprehension but you should be reassured that once you undergo proper management, your shoulder issues might just be a thing of the past.

Source

Darren L.J and Scott D.M (2006). Clinical Sports Medicine. Mosby, Inc., an affiliate of Elsevier Inc.

Walter R.F, Stanley A.H, Lyle J.M and Julie K.S (2007). Clinical Sports Medicine: Medical Management and Rehabilitation. Mosby, Inc., an affiliate of Elsevier Inc.

Scott Gudeman. Orthoindy (Bone/Joint/Spine/Muscle). Available at OrthoIndy.com ScottGudemanMD.com

George M. Bridgeforth, Shane J. Nho, Rachel M. Frank, and Brian J. Cole. Chapter 30: Shoulder Dislocations

Patient information: Shoulder dislocations/ shoulder instability. Available at Barts Health Physiotherapy Website: www.bartshealth.nhs.uk/physiotherapy.

Zacchilli M.A, et al (2010). Epidemiology of shoulder dislocations presenting to emergency departments in the United States. Journal of Bone and Joint Surgery; American edition.