How to diagnose an anterior shoulder dislocation

Does your patient have a dislocated shoulder? Learn the physical signs and tests to perform to diagnose one in this article!
Last update19th Nov 2020

The shoulder has the most range of motion of any joint in the body because the glenoid (shoulder joint) is very shallow. Unfortunately, this also means that the shoulder is the most frequently dislocated joint!

Figure 1. Anatomy of the shoulder joint.

How does a shoulder dislocation happen?

Most shoulder dislocations are anterior, meaning that the humeral head pops out of the glenoid socket and rests in front of it. The most common way to dislocate a shoulder is falling on an outstretched arm.

Figure 2. Falling on an outstretched arm is the most common way to dislocate a shoulder joint.

For patients with multiple recurrent dislocations, even a minor pull can cause a dislocation. For example, rolling over in bed or reaching for a car seat belt may result in a dislocation! The younger the patient the more likely that a recurrence will happen.

The most important thing to realize is that the shoulder’s natural tendency will be to go back into the socket. Muscle spasms, swelling, and sometimes trapped soft tissue will prevent it from going back in. For this reason, you want to reduce the shoulder as soon as possible to stop the patient from favoring their shoulder and decrease the patient’s anxiety and guarding as soon as possible.

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What are the types of anterior shoulder dislocations?

There are four types of anterior dislocations:

  1. Subcoracoid dislocation (75% of anterior shoulder dislocations)
  2. Subglenoid dislocation
  3. Subclavicular dislocation (less than 1% of anterior shoulder dislocations)
  4. Intrathoracic dislocation (less than 1% of anterior shoulder dislocations)
Figure 3. Types of anterior shoulder dislocations. Subcoracoid and subglenoid dislocations are the most common types of shoulder dislocations. Subclavicular and intrathoracic dislocations occur in less than 1% of anterior shoulder dislocations.

How to diagnose a shoulder dislocation

Physical signs of an anterior shoulder dislocation

Usually, a dislocated shoulder is obvious! There are seven signs to look for when diagnosing a shoulder dislocation:

  1. Patient is leaning towards the injured side.
  2. Patient is holding the arm away from the body.
  3. The arm is slightly externally rotated.
  4. There is a loss of the rounded shape of the normal shoulder (more obvious in thin patients).
  5. The acromion is prominent.
  6. There is a fullness under the collarbone (humeral head prominent).
  7. Patient cannot touch opposite shoulder with their injured arm.
Figure 4. Physical signs of an anterior shoulder dislocation.

Physical tests for an anterior shoulder dislocation

For your physical exam, it is very important to document each physical test:

  1. Distal pulse on injured arm—rule out axillary artery injury. This is rare and usually happens in the elderly.
  2. Light touch sensation over deltoid muscle—rule out axillary nerve injury. In anterior shoulder dislocations, it is common for the axillary nerve to be injured.
  3. Ulnar, median, and radial nerve exam—rule out brachial plexus injury.
  4. Anterior-posterior (AP) x-ray or scapular Y view—confirm dislocation.
  5. Pre-reduction fractures—15% of the time, there may be an associated fracture of the proximal humerus, humeral head, or glenoid fossa that should be documented.
Figure 5. Physical tests for a shoulder dislocation. Document distal pulse, sensation over deltoid muscles, brachial plexus exam, and confirm dislocation with x-ray, as well as document any pre-reduction fractures.

Documenting the exam before the reduction also proves that you didn’t cause injury with your reduction. And if there is a nerve injury, you’ll have to be especially gentle. Don’t hesitate to send your patient to the operating room.

Great job! Now you know the basics for how to diagnose an anterior shoulder dislocation.

Recommended reading

  • Alkaduhimi, H, van der Linde, JA, Willigenburg, NW, et al. 2017. A systematic comparison of the closed shoulder reduction techniques. Arch Orthop Trauma Surg137: 589–599. PMID: 28251280
  • Cunningham, N. 2003. A new drug free technique for reducing anterior shoulder dislocations. Emerg Med (Fremantle)15: 521–524. PMID: 144992071
  • Marinelli, M, de Palma, L. 2009. The external rotation method for reduction of acute anterior shoulder dislocations. J Orthop Traumatol10: 17–20. PMID: 19384630
  • Sayegh, FE, Kenanidis, EI, Papavasiliou KA, et al. 2009. Reduction of acute anterior dislocations: a prospective randomized study comparing a new technique with the Hippocratic and Kocher methods. J Bone Joint Surg Am91: 2775–2782. PMID: 19952238
  • Stafylakis, D, Abrassart, S, and Hoffmeyer, P. 2016. Reducing a shoulder dislocation without sweating. The Davos technique and its results. Evaluation of a nontraumatic, safe, and simple technique for reducing anterior shoulder dislocations. J Emerg Med50: 656–659. PMID: 26899512

About the author

Siamak Moayedi, MD
Professor and Director of Medical Student Education, University of Maryland and Course Director, Essential and Critical Procedures, Emergency Medicine.
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ACCME accredited, UEMS accredited, Comenius EduMedia Siegel 2017, BMA Highly recommended