Anterior vs Posterior vs Inferior Shoulder Dislocation

Summary

Anterior shoulder dislocation is by far the most common (about 85–95%), usually from an outstretched hand or forced abduction–external rotation; posterior dislocation is uncommon and classically follows seizures or electric shock; inferior dislocation (luxatio erecta) is rare and presents with the arm stuck overhead.
Immediate priorities are pain control, neurovascular checks (especially the axillary nerve), and confirming the type on X‑ray (AP, scapular Y, and axillary/Velpeau views).
First reductions should be performed by trained clinicians to avoid nerve and vessel injury; post‑reduction care includes brief immobilisation, early guided physiotherapy, and sport‑specific rehabilitation.
Recurrent instability risk is highest in young, contact or overhead athletes; surgery (e.g., arthroscopic Bankart repair, remplissage, or Latarjet) is considered for recurrent episodes or significant bone loss.
In Bengaluru, timely assessment by a shoulder specialist improves outcomes and shortens return‑to‑sport timelines. Book an evaluation with our shoulder specialist in Bengaluru for same‑day assessment when possible.

What Is a Shoulder Dislocation?

A shoulder dislocation occurs when the ball (humeral head) comes out of the socket (glenoid). The shoulder trades stability for mobility, which makes it the most commonly dislocated large joint. Dislocation differs from subluxation (partial, self‑reduced shift). Untreated, dislocations can injure cartilage, labrum, bone, nerves, vessels, and tendons—raising the risk of recurrence and arthritis over time.

Why Understanding the Type Matters

Correctly identifying anterior vs posterior vs inferior shoulder dislocation changes everything—from reduction technique to immobilisation position, rehab plan, and surgical decision‑making. Misclassification can lead to failed reduction attempts or missed injuries (e.g., reverse Hill‑Sachs in posterior dislocation).

Quick Anatomy Refresher

Glenohumeral joint: Ball‑and‑socket joint between the humeral head and glenoid fossa.
Labrum: Rim of cartilage that deepens the socket; anterior‑inferior labrum is often torn in anterior instability (Bankart lesion).
Rotator cuff: Muscles/tendons (supraspinatus, infraspinatus, teres minor, subscapularis) that stabilise the humeral head.
Capsule and ligaments: Inferior glenohumeral ligament complex (IGHL) is crucial for anterior stability.
Neurovascular structures: Axillary nerve, axillary artery, and brachial plexus are at risk in dislocations.

Types of Shoulder Dislocation: Anterior vs Posterior vs Inferior

Anterior Shoulder Dislocation (Most Common)

Prevalence: ~85–95% of all shoulder dislocations.
Mechanism: Forced abduction and external rotation (classic “ABER” position), fall onto an outstretched hand (FOOSH), tackle in contact sports, or during overhead movements.
Typical posture: Arm slightly abducted and externally rotated; patient cradles the forearm; shoulder looks “squared off” with a prominent acromion and a palpable/anteriorly displaced humeral head.
Associated injuries:

Bankart lesion (labral detachment, sometimes with bony fragment: osseous Bankart).
Hill‑Sachs lesion (posterolateral humeral head impression fracture).
Axillary nerve neurapraxia (deltoid numbness/weakness).
Rotator cuff tears, especially in patients over 40–50 years.

First‑line management: Analgesia/sedation and closed reduction by a trained clinician; early neurovascular and cuff assessment; post‑reduction X‑ray.

Posterior Shoulder Dislocation (Uncommon, Easily Missed)

Prevalence: ~2–4% of shoulder dislocations, often underdiagnosed on AP films.
Mechanism: Axial load on an adducted, internally rotated arm; seizures; electric shock; high‑energy trauma.
Typical posture: Arm adducted and internally rotated; patient cannot externally rotate; posterior prominence of humeral head; coracoid appears prominent anteriorly.
Imaging: Axillary or Velpeau view is critical; AP view can appear deceptively normal (light bulb sign). CT may be needed to size reverse Hill‑Sachs and glenoid lesions.
Associated injuries:

Reverse Hill‑Sachs (anteromedial humeral head impression).
Reverse Bankart (posterior labrum/glenoid injury).

Management: Gentle reduction techniques suitable for posterior position; immobilisation often in slight external rotation; assess size/location of bone defects to guide surgery (e.g., posterior Bankart repair, bone grafting for significant defects).

Inferior Shoulder Dislocation (Luxatio Erecta; Rare, a True Emergency)

Prevalence: <1% of dislocations.
Mechanism: Hyperabduction forcing the humeral head inferior to the glenoid.
Typical posture: Arm locked in abduction overhead; forearm often rests on or behind head; severe pain and spasm.
Associated injuries: High rate of neurovascular injury (axillary nerve/artery), rotator cuff tears, capsulolabral injury; potential brachial plexus stretch.
Management: Prompt reduction with careful traction and counter‑traction; urgent neurovascular reassessment; often requires advanced imaging and a tailored rehab plan.

How to Recognise Each Type: Signs and Symptoms

Common symptoms across all types:

Sudden shoulder pain, deformity, and loss of motion
Visible asymmetry; contour changes
Muscle spasm and guarding
Numbness or tingling around the shoulder or down the arm (axillary nerve distribution over lateral shoulder is key)

Type‑specific clinical clues:

Anterior: “Squared‑off” shoulder; arm held slightly abducted/external rotation; humeral head palpable anteriorly; deltoid contour loss.
Posterior: Arm fixed in internal rotation/adduction; inability to externally rotate; posterior fullness; coracoid prominence; subtle on AP X‑ray.
Inferior: Arm stuck overhead; inability to adduct; marked pain and apprehension; high suspicion for neurovascular compromise.

Red Flags Requiring Urgent Care

Numbness over the “regimental badge” area or deltoid weakness (possible axillary nerve injury)
Absent or diminished distal pulses, cool limb (vascular injury)
Severe swelling or suspicion of associated fractures (proximal humerus, glenoid)
Polytrauma, seizures, electric injury
Recurrent dislocations with increasing frequency or easier “popping out”

Diagnosis: Tests and Imaging

Clinical examination

Neurovascular exam: Assess axillary nerve (sensation over lateral shoulder and deltoid activation), radial pulse, capillary refill, motor and sensory of radial/median/ulnar nerves.
Instability tests (post‑reduction and after pain subsides):

Anterior instability: Apprehension test (abduction + external rotation), Relocation test, Load‑and‑Shift, Anterior drawer.
Posterior instability: Posterior drawer, Jerk test.
Generalised laxity: Beighton score (relevance for recurrence risk).

Imaging roadmap

Pre‑reduction: AP, scapular Y, and axillary/Velpeau views to confirm direction and exclude fracture interposition.
Post‑reduction: Repeat views to confirm concentric reduction and screen for Hill‑Sachs/Bankart.
Advanced imaging:

MRI/MR‑arthrogram: Labral tears (Bankart/posterior Bankart), capsular injury, rotator cuff tears.
CT (3D preferred): Quantify glenoid bone loss, Hill‑Sachs size/location; essential for surgical planning (e.g., Latarjet vs Bankart ± remplissage).

Ultrasound: Useful for rotator cuff tears, especially in older patients, and for quick joint effusion assessment.

First Aid: What to Do (and Not Do)

Support the arm in a comfortable position (sling or pillow).
Apply ice packs intermittently (15–20 minutes every 2–3 hours).
Seek prompt medical evaluation for reduction and imaging.
Keep the patient nil per os (NPO) if sedation might be needed.

Do Not

Force the shoulder back in if you are not trained; this risks fractures and nerve/artery injuries.
Delay assessment after seizures or electrical injuries—even if pain seems modest.
Perform repeated reduction attempts if the first attempt fails; escalate to imaging and specialist care.

Reduction Techniques (For Clinical Context)

Reduction should be performed by trained clinicians with appropriate analgesia/sedation, monitoring, and resources.

Anterior dislocation: Techniques include external rotation method, Milch, Stimson (prone, weighted arm), traction–counter‑traction, Spaso, and scapular manipulation. Choice depends on habitus, spasm, and associated injuries.
Posterior dislocation: Gentle traction with gradual external rotation and anterior pressure; avoid forcing external rotation if entrapped.
Inferior dislocation: Gentle traction with counter‑traction, progressing to adduction; continuous neurovascular monitoring.

Post‑Reduction Care and Immobilisation

Immobilisation: Typically 1–3 weeks in a sling for first‑time anterior dislocations in adults; shorter in older patients to reduce stiffness risk. For posterior dislocations, immobilisation may include slight external rotation. Inferior dislocations often need a more tailored plan.
Early movement: Start pendulum and gentle range‑of‑motion exercises as advised to minimise stiffness.
Pain control: Ice, appropriate medications, and sleep positioning guidance (often semi‑reclined initially).

Rehabilitation and Return to Sport

A phased, criterion‑based program is ideal, guided by an orthopaedic specialist or sports physiotherapist:

Phase 1 (Protection and pain control, 0–2 weeks): Immobilisation, edema control, pendulum exercises, gentle passive range as tolerated; isometrics.
Phase 2 (Range restoration, 2–6 weeks): Gradual increase in passive to active‑assisted and active ROM; scapular kinematics; begin closed‑chain stability.
Phase 3 (Strength and dynamic stability, 6–12 weeks): Progressive rotator cuff and periscapular strengthening; proprioception; kinetic chain integration.
Phase 4 (Sport‑specific conditioning, 3–4+ months): Plyometrics, overhead mechanics, return‑to‑throw or contact progressions when pain‑free, symmetric strength, and no apprehension.

Typical timelines (individualised):

Non‑contact sports: 4–8 weeks if strength and stability criteria are met.
Contact/overhead sports: 3–6 months; longer after surgical stabilisation.

Risk of Recurrence and Who Needs Surgery

Recurrence risk is highest in:

Age under 25, male sex, collision/overhead sports, hyperlaxity, and first dislocation with significant labral/bony injury.
Glenoid bone loss or engaging/off‑track Hill‑Sachs lesions.
Multiple prior dislocations or failed rehab.

Surgical options (tailored to pathology):

Anterior instability:

Arthroscopic Bankart repair (labrum/capsule repair) for soft‑tissue lesions with minimal bone loss.
Remplissage (infraspinatus/posterior capsule tenodesis) for engaging Hill‑Sachs.
Latarjet or other bone‑block procedures for significant glenoid bone loss (commonly >15–20%) or off‑track lesions.

Posterior instability:

Arthroscopic posterior Bankart repair; posterior capsulolabral plication; bone grafting for large reverse Hill‑Sachs or posterior glenoid defects.

Associated rotator cuff tears (especially in patients >40–50 years): Repair combined with stabilisation as indicated.

Complications to Monitor

Nerve injury: Axillary nerve neurapraxia (usually transient); broader brachial plexus involvement in inferior dislocations.
Vascular injury: Axillary artery injury (consider in older patients and high‑energy injuries).
Fractures: Greater tuberosity, proximal humerus, glenoid rim.
Chondral damage and early osteoarthritis.
Stiffness/adhesive capsulitis: More common with prolonged immobilisation in middle‑aged/older adults.
Recurrent instability: Especially in young athletes if returned too soon or with untreated bony lesions.

Anterior vs Posterior vs Inferior: At‑a‑Glance Clinical Differences

Mechanism: ABER/FOOSH (anterior) vs seizure/electrocution (posterior) vs hyperabduction (inferior).
Arm position: Abduction/external rotation (anterior) vs adduction/internal rotation (posterior) vs arm locked overhead (inferior).
Key lesions: Bankart + Hill‑Sachs (anterior) vs reverse Bankart + reverse Hill‑Sachs (posterior) vs multi‑structure “traction” injuries (inferior).
Reduction nuance: Technique selection differs; inferior requires particular caution due to neurovascular risk.
Immobilisation: Sling in internal rotation (anterior, common); external rotation braces sometimes used selectively; posterior often immobilised in slight external rotation.

Patient‑Centred Guidance in Bengaluru

If this is your first shoulder dislocation, seek prompt imaging and specialist assessment to lower recurrence risk.
If your shoulder keeps “popping out,” ask about labral and bone assessments (MRI/CT) and stabilisation options.
If you are an athlete, request a return‑to‑sport plan with objective criteria, not just timelines.
Over 40 and had a dislocation? Early assessment for rotator cuff tears is essential to avoid chronic pain/weakness.

When to Choose a Shoulder Specialist

A dedicated shoulder specialist offers nuanced decisions about:

Whether to immobilise in internal vs external rotation.
Which athletes can trial early return with bracing vs those needing surgery.
How to interpret glenoid track and bone‑loss thresholds.
Whether to add procedures like remplissage or bone‑block for durable stability.
Meet our shoulder specialist and book a consultation in Bengaluru
Sports Orthopedics home

If you’ve experienced a shoulder dislocation, or recurrent episodes, book an expert evaluation with our shoulder specialist in Bengaluru for an accurate diagnosis, personalised rehab, and clear return‑to‑sport planning.

Frequently Asked Questions (FAQs)

Q1. Which is more common: anterior vs posterior vs inferior shoulder dislocation?

Anterior dislocation is by far the most common (roughly 85–95%). Posterior is uncommon and often related to seizures or electric shock. Inferior (luxatio erecta) is rare but carries higher risks to nerves and vessels.

Q2. How can I tell which type I might have?

Arm posture is a clue: external rotation/abduction suggests anterior; internal rotation/adduction suggests posterior; arm stuck overhead suggests inferior. Only a clinician with proper X‑rays can confirm.

Q3. What tests confirm the diagnosis?

X‑rays with AP, scapular Y, and an axillary (or Velpeau) view identify direction and associated fractures. MRI detects labral and rotator cuff injuries; CT quantifies bone loss for surgical planning.

Q4. Can a dislocated shoulder go back in by itself?

It can occasionally “slip back,” especially in subluxations, but self‑reduction is risky and can worsen damage. Always seek professional care for imaging and post‑reduction checks.

Q5. How is a first‑time anterior shoulder dislocation treated?

Analgesia/sedation and closed reduction, short‑term immobilisation, and guided physiotherapy. Young athletes with significant labral/bony injuries may need stabilisation surgery to prevent recurrence.

Q6. What is the recovery time after dislocation?

Pain improves over 1–2 weeks; functional recovery can take 6–12 weeks with rehab. Return to contact or overhead sports often requires 3–6 months, longer after surgery.

Q7. Will I need surgery?

Surgery is considered for recurrent instability, significant bone loss, engaging Hill‑Sachs lesions, high‑demand athletes, or failed conservative care. The specific procedure (Bankart, remplissage, Latarjet) depends on your anatomy and sport.

Q8. What are the risks of not treating a dislocation properly?

Recurrent dislocations, labral and cartilage damage, bone loss, nerve or vessel injury, and early arthritis. Poorly managed cases can prolong downtime and impair athletic performance.

Q9. Are there exercises I should do or avoid early on?

Initially, focus on pain‑free pendulums and gentle range‑of‑motion as prescribed; avoid heavy lifting, overhead loads, and positions that triggered the dislocation until cleared by your clinician.

Q10. How soon can I get back to the gym or sport?

Non‑contact training may resume at 4–8 weeks if you meet strength and stability criteria. Contact/overhead sport typically requires 3–6 months and a graded return protocol.

Trusted Resources and Further Reading

American Academy of Orthopaedic Surgeons (AAOS) OrthoInfo: Shoulder Dislocation — https://orthoinfo.aaos.org/en/diseases--conditions/dislocated-shoulder/
Orthobullets: Anterior Shoulder Instability — https://www.orthobullets.com/shoulder-and-elbow/3050/anterior-shoulder-instability
Radiopaedia: Shoulder Dislocation — https://radiopaedia.org/articles/shoulder-dislocation
NCBI Bookshelf (StatPearls): Shoulder Dislocation — https://www.ncbi.nlm.nih.gov/books/NBK541001/

Medical Disclaimer

This article is for educational purposes only and does not replace a clinical examination. If you suspect a shoulder dislocation or have persistent pain/instability, please seek prompt medical care.

Anterior vs Posterior vs Inferior Shoulder Dislocation: A Detailed Guide