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OverviewAetiologyPathophysiologyClinical features and red flagsInvestigationsDifferential diagnosisManagementComplicationsMonitoring and follow-upSpecial situationsCommon pitfallsQuestionsSources
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Educational draft · awaiting clinical reviewThe full textbook explains uncertainty but does not replace live national or local guidance, specialist advice, or current prescribing information.

Shoulder dislocation and axillary-nerve assessment

Musculoskeletal medicine and orthopaedics · UK scope · Sources checked 27 Aug 2026 · Clinical review pending

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Dislocation threatens nerve and skin

Continued displacement causes pain and muscle spasm and can injure axillary nerve, vessels, rotator cuff or humeral head; an associated fracture makes forceful reduction hazardous.

Action: Give prompt analgesia, document pulses and axillary and distal nerve functions, obtain pre-reduction radiographs unless tissue or vascular threat makes delay unsafe, perform a controlled reduction with suitable sedation or analgesia, and repeat examination and imaging.

Overview

Recognise anterior and posterior shoulder dislocation, document axillary and wider neurovascular function, achieve safe timely reduction, confirm congruence and associated fracture, and prevent recurrent instability and stiffness.

Direction and associated injury determine management. Anterior dislocation is common after abduction and external rotation; posterior injury follows seizure, electric shock or direct force and can look deceptively normal on an AP film. Ask about previous instability, connective-tissue laxity, sport, seizure and mechanism. Inspect contour, but avoid repeated movement. Examine the whole limb because multi-nerve or arterial injury can accompany severe displacement.

Reduction should be timely, humane and planned. Radiograph first when practical to identify fracture, but do not allow unsafe tissue or vascular compromise to persist. Choose analgesia and sedation from physiology and resources and avoid unmonitored force. A successful reduction requires a post-reduction image and repeat nerve and vascular documentation. Persistent weakness in an older patient triggers early rotator-cuff assessment; recurrent instability requires shoulder-specialist review rather than repeated sling-only care.

Practice

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Musculoskeletal medicine and orthopaedicsOriginal SBA

Axillary-nerve examination

Before reducing an anterior shoulder dislocation, which assessment best documents axillary-nerve function rather than relying on one sensory question?

Choose one answer, then submit
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Sources and review status3 sources · checked 27 Aug 2026 · clinical review pending+
Sources

Sources and review status

National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 27 Aug 2026; clinical approval remains outstanding.

  • NICE NG38 fractures non-complex assessment and management
  • BOAST peripheral nerve injury
  • BOAST – Outpatient and on-call services for people with fractures or musculoskeletal injury

Editorial contact: Doctor’s Passport editorial team. Source-check date is separate from clinical approval. Report a content problem · Content changes

Authoring stateComplete draftClinical stateAwaiting reviewJurisdictionUnited Kingdom

Pre-reduction imaging must show the glenohumeral relationship in two planes. An AP view identifies obvious anterior displacement and associated greater-tuberosity injury; an axillary, modified axillary or scapular-Y view prevents posterior dislocation being overlooked. Review the surgical neck before traction because an unrecognised fracture can displace during manipulation. CT is reserved for complex fracture-dislocation, glenoid bone loss or a non-concentric joint rather than routine simple dislocation. When the hand is poorly perfused or skin is critically tented, urgent controlled realignment takes precedence over a perfect radiographic series.

Axillary-nerve documentation requires both deltoid contraction and lateral upper-arm sensation. Also test wrist, finger and thumb extension, thumb opposition, finger abduction and the relevant sensory territories because a high-energy displacement can injure the plexus rather than one terminal nerve. Palpate radial pulse and record temperature and capillary refill. If a deficit changes after reduction, splinting or transfer, repeat the full examination immediately and obtain senior peripheral-nerve or vascular input. A normal sensory patch does not compensate for absent deltoid motor function.

After reduction, compare the joint with the opposite side and identify Bankart, Hill-Sachs, greater-tuberosity or glenoid injury. Test stability only within a safe specialist-directed arc; repeated apprehension manoeuvres in emergency care add little. A short period of support followed by pain-limited rehabilitation suits a simple stable injury. Young contact athletes need counselling about recurrence and timely shoulder review. Older adults need early re-examination for rotator-cuff failure when active elevation or external rotation remains weak despite improving pain, because delayed recognition can limit repair options.

Sedation and aftercare require individual modifiers. Frailty, cardiorespiratory disease, intoxication, fasting uncertainty and concurrent opioids increase procedural risk and may favour theatre anaesthesia or a different analgesic technique. Pregnancy does not justify leaving a joint displaced; involve obstetric and anaesthetic teams when gestation or physiology warrants and select imaging and medicines appropriately. Recurrent prosthetic dislocation follows an implant-specific route because component orientation, infection, loosening and surgical approach alter both reduction technique and movement precautions.

The recurrence consultation considers age, sport, occupation, hyperlaxity and bony defects rather than counting episodes alone. A first traumatic dislocation in a young contact athlete can produce a substantial labral lesion and merits early shared discussion of rehabilitation versus stabilisation. Repeated anterior events may enlarge glenoid and humeral defects until they engage in functional positions. CT quantifies bone loss when surgical planning requires it; MRI or arthrogram defines capsulolabral injury. Physiotherapy restores scapular control, rotator-cuff endurance and confidence without repeatedly provoking apprehension.

Give explicit return precautions after discharge. New hand coolness, weak deltoid contraction, expanding axillary swelling, recurrent deformity or uncontrolled pain needs urgent reassessment. Persistent numbness is tracked against a mapped baseline; protection of an insensate skin area prevents pressure injury. The patient should know how long to use the sling, which movements are allowed, when therapy and fracture review occur and how to obtain help if the joint redislocates. Self-reduction attempts are discouraged because an associated fracture or nerve injury can be worsened.

Key points

  • Anterior dislocation usually produces loss of rounded contour and an abducted slightly externally rotated arm; posterior injury holds internal rotation.
  • Before reduction, document radial pulse, refill, deltoid contraction, lateral upper-arm sensation and radial, median and ulnar motor and sensory findings.
  • Obtain AP plus axillary or scapular-Y radiographs to confirm direction and identify greater-tuberosity or neck fracture.
  • Give adequate analgesia and use a trained controlled technique with procedural sedation or intra-articular analgesia according to patient and setting.
  • Stop repeated force if reduction fails or an associated fracture is suspected and escalate to anaesthesia and orthopaedics.
  • After reduction, repeat the same neurovascular examination and obtain radiographs confirming congruence and associated bony injury.
  • Use short sling support and early guided movement; prolonged immobilisation increases stiffness, particularly in older adults.
  • Arrange follow-up for first-time instability, fracture, nerve deficit or persistent cuff weakness and give clear recurrence precautions.

Aetiology

01

Abduction external rotation

A fall or collision with the arm abducted and externally rotated levers the humeral head anteriorly, the commonest direction of native shoulder dislocation.

02

Seizure or electric shock

Powerful internal rotators can drive the humeral head posteriorly during seizure or electrocution, sometimes affecting both shoulders.

03

Recurrent instability

Previous capsulolabral injury, glenoid bone loss, hyperlaxity or young contact sport participation permits recurrence after progressively smaller forces.

Pathophysiology

  1. 1
    Capsulolabral failure

    Anterior translation detaches or stretches the anteroinferior labrum and capsule, producing a Bankart-type lesion and loss of restraint.

  2. 2
    Humeral-head impaction

    The head impacts the glenoid rim, creating a Hill-Sachs defect in anterior dislocation or reverse impaction in posterior injury.

  3. 3
    Axillary-nerve stretch

    Inferior displacement stretches the nerve around the surgical neck, affecting deltoid contraction and sensation over the lateral upper arm.

  4. 4
    Age-related cuff injury

    In older adults, dislocation can tear the rotator cuff, causing persistent weakness even when axillary sensation and joint position recover.

Clinical features and red flags

Anterior dislocationRed flag

Flattened shoulder contour, prominent acromion and an abducted externally rotated supported arm are typical.

Posterior dislocationRed flag

Fixed internal rotation and inability to externally rotate after seizure or electric shock should trigger dedicated views.

Axillary deficitRed flag

Reduced deltoid contraction or lateral-arm sensation suggests axillary-nerve injury, but normal sensation alone is insufficient.

Vascular compromiseRed flag

Pulse loss, coolness, delayed refill or expanding axillary swelling requires immediate orthovascular action.

Associated cuff tear

Persistent active abduction or external-rotation weakness after reduction is especially concerning in an older patient.

Red flags requiring action

  • Absent pulse, cool hand, expanding axillary swelling or progressive neurological deficit requires immediate reduction and vascular or nerve specialist escalation.
  • An open wound, skin tenting, proximal humeral or surgical-neck fracture, or irreducible joint makes repeated closed attempts unsafe.
  • Posterior dislocation after seizure or electric shock is easily missed; fixed internal rotation and inability to externally rotate requires an axillary or scapular-Y view.

Investigations

  1. 01
    AP and axillary or scapular-Y radiographsFirst step
    Why
    Confirm direction, exclude fracture and document the joint before reduction.
    Interpretation and limitations
    An AP view alone can miss posterior dislocation; obtain an orthogonal view without forcing painful abduction.
  2. 02
    Post-reduction shoulder radiographs
    Why
    Confirm congruent reduction and identify greater-tuberosity, glenoid or humeral-head injury.
    Interpretation and limitations
    A palpable clunk and pain relief do not prove a concentric joint.
  3. 03
    Serial named neurovascular examination
    Why
    Distinguish pre-existing axillary or plexus injury from deterioration after manipulation.
    Interpretation and limitations
    Test deltoid contraction plus sensation and distal motor and sensory functions before and after every attempt.
  4. 04
    Ultrasound or MRI for cuff injury
    Why
    Assess persistent weakness after reduction, particularly in an older adult.
    Interpretation and limitations
    Early pain can inhibit effort, but continuing true weakness requires imaging and shoulder review.

Differential diagnosis

01

Proximal humeral fracture

Upper-arm bruising and bony crepitus with altered contour can mimic dislocation and must be excluded before forceful manipulation.

02

AC joint injury

Focal superior tenderness and a distal-clavicle step with relatively preserved glenohumeral rotation favours AC disruption over true dislocation.

03

Rotator-cuff tear

Pain and weakness after injury without fixed deformity may reflect cuff failure, particularly in an older adult.

04

Brachial-plexus injury

Multi-nerve weakness or sensory loss extending beyond axillary distribution suggests broader traction injury and needs complete mapping.

Management

01Before reductionDefine direction and limb safetyFirst stepClinical deformity suggests a shoulder dislocation.+
  1. 1Give analgesia, inspect skin and document pulses, refill and named nerve functions.
  2. 2Obtain orthogonal imaging unless vascular or skin threat makes delay unacceptable.
  3. 3Identify fracture, previous instability and sedation risk and call appropriate reduction support.
02Controlled reductionRestore congruence without repeated forceImaging and examination support a closed reduction attempt.+
  1. 1Use suitable analgesia or sedation with monitoring and airway rescue capability.
  2. 2Apply one controlled familiar technique and stop if resistance or unexpected crepitus occurs.
  3. 3Repeat neurovascular findings and obtain post-reduction radiographs before discharge or transfer.

Complications

01

Recurrent instability

Young age, contact sport, labral disruption and bone loss increase repeated dislocation, apprehension and activity restriction.

02

Axillary neuropathy

Persistent deltoid weakness or lateral-arm sensory loss may reflect neurapraxia or more severe injury requiring serial review.

03

Rotator-cuff tear

Older patients can develop ongoing abduction or external-rotation weakness that should not be attributed only to post-reduction pain.

04

Stiffness and arthritis

Prolonged immobilisation, cartilage impact and repeated instability cause restricted shoulder movement, chronic pain and later degenerative joint change.

Monitoring and follow-up

  • Record every reduction attempt and the operator so repeated force is visible.
  • Repeat pulse, refill, deltoid contraction and mapped sensation immediately after reduction.
  • Confirm radiographic congruence before leaving emergency care.
  • Review pain and active cuff function when acute inhibition settles.
  • At follow-up, assess instability, stiffness, nerve recovery and return-to-sport requirements.

Special situations

Sensation alone misses axillary injury

Deltoid motor testing is essential because sensory sparing can occur despite clinically important nerve dysfunction.

Posterior needs an orthogonal view

The AP image may appear subtly abnormal, whereas axillary or scapular-Y imaging reveals displacement.

Age changes the hidden injury

Young patients tend toward recurrence; older patients have greater rotator-cuff and neurovascular injury risk.

Reduction has three endpoints

Pain relief, repeat neurovascular findings and radiographic congruence are all required before success is declared.

Common pitfalls

  1. 01

    Writing only 'neurovascularly intact' without testing deltoid contraction and lateral-arm sensation.

  2. 02

    Missing posterior dislocation after seizure because only an AP radiograph was reviewed.

  3. 03

    Using repeated force despite an associated surgical-neck fracture or failed first attempt.

  4. 04

    Discharging after a clunk without post-reduction imaging and repeat examination.

  5. 05

    Attributing persistent weakness in an older patient to pain without assessing the rotator cuff.

03AftercareRestore movement and detect associated injuryThe joint is reduced and no immediate operative threat remains.+
  1. 1Use a sling briefly for comfort and provide a pain-limited movement plan.
  2. 2Arrange follow-up for first-time injury, fracture, nerve deficit, older age or recurrent instability.
  3. 3Reassess persistent weakness for cuff tear and educate about recurrent dislocation warning signs.
Key medicines and prescribing safety2 treatments · regimens, roles and cautions+
Provides baseline analgesia before and after reduction.

Paracetamol for adult shoulder pain

Use 500 mg to 1 g by mouth as needed for adult arm pain, allowing 4 hours between administrations and limiting the total to 4 g daily.

Lower the maximum for low body weight or hepatic risk and include combination products in the total.

Provides humane muscle relaxation and amnesia for a controlled reduction when simpler analgesia is insufficient.

Procedural sedation medicines

Use only a locally approved weight-based regimen administered by a credentialed clinician with continuous monitoring, airway equipment and formal recovery.

Shock, fasting, cardiorespiratory disease, pregnancy and interacting sedatives alter selection; analgesic opioid alone is not full procedural sedation.