Acromioclavicular Joint Separation

Last updated: February 8, 2026Reviewed date: February 8, 2026Reading time: 5 min read
Patient Tools

Read, save, and share this guide

Use these quick tools to make this medical article easier to read, print, save, or share with a family member.

Patient Mode

Understand this article easily

Switch between simple English and easy Bangla patient notes. This is for education and does not replace a doctor consultation.

An acromioclavicular joint separation, or AC joint separation or shoulder separation, occurs when the clavicle separates from the scapula. It is commonly caused by a fall directly on the 'point' of the shoulder or by a direct blow received in a contact sport. Grade I and...

For severe symptoms, danger signs, pregnancy, child illness, or sudden worsening, seek urgent medical care.

বাংলা রোগী নোট এখনো যোগ করা হয়নি। পোস্ট এডিটরে “RX Bangla Patient Mode” বক্স থেকে সহজ বাংলা সারাংশ যোগ করুন।

এই তথ্য শিক্ষা ও সচেতনতার জন্য। এটি ডাক্তারি পরীক্ষা, রোগ নির্ণয় বা প্রেসক্রিপশনের বিকল্প নয়।

Article Summary

An acromioclavicular joint separation, or AC joint separation or shoulder separation, occurs when the clavicle separates from the scapula. It is commonly caused by a fall directly on the 'point' of the shoulder or by a direct blow received in a contact sport. Grade I and II separations very rarely require surgery. Even Grade III injuries usually allow a return to full activity with few restrictions....

Key Takeaways

  • This article explains Other Names in simple medical language.
  • This article explains Background in simple medical language.
  • This article explains Causes in simple medical language.
  • This article explains Differential Diagnosis in simple medical language.
Educational health guideWritten for patient understanding and clinical awareness.
Reviewed content workflowUse writer and reviewer profiles for stronger trust.
Emergency safety firstUrgent warning signs are highlighted below.

Seek urgent medical care if you notice

These warning signs are general safety guidance. Local emergency numbers and clinical judgment should always come first.

  • Severe symptoms, breathing difficulty, fainting, confusion, or rapidly worsening illness.
  • New weakness, severe pain, high fever, or symptoms after a serious injury.
  • Any symptom that feels urgent, unusual, or unsafe for the patient.
1

Emergency now

Use emergency care for severe, sudden, rapidly worsening, or life-threatening symptoms.

2

See a doctor

Book a professional medical evaluation if symptoms persist, worsen, recur often, affect daily activities, or occur in a high-risk patient.

3

Learn safely

Use this article to understand possible causes, tests, treatment options, prevention, and questions to ask your clinician.

Before reading

RX Patient Tools

Use these quick guides before reading the article, or return to them when you need help preparing questions for a doctor.

Start here Choose the right pathway for symptoms, reports, medicines, or urgent warning signs. Disease article roadmap Read this topic step by step: meaning, symptoms, warning signs, diagnosis, treatment, prevention, and follow-up. Treatment planner Prepare questions about treatment choices, benefits, risks, side effects, and follow-up. Family & caregiver guide Organize symptoms, reports, medicines, questions, and follow-up safely. Nutrition & diet guide Prepare food, hydration, supplement, and medicine-timing questions safely. Prevention guide Organize risk factors, protective habits, screening, and warning signs. Recovery guide Prepare a safe plan for activity, rehabilitation, warning signs, and follow-up.
Definition

An acromioclavicular joint separation, or AC joint separation or shoulder separation, occurs when the clavicle separates from the scapula. It is commonly caused by a fall directly on the ‘point’ of the shoulder or by a direct blow received in a contact sport. Grade I and II separations very rarely require surgery. Even Grade III injuries usually allow a return to full activity with few restrictions. In some cases a painful lump may persist, necessitating partial clavicle excision in selected individuals such as high caliber throwing athletes. Leaving your AC joint injury untreated means your condition can worsen, which can have serious consequences, such as Severe shoulder separation. Serious displacement or collarbone fracture. pain, swelling, stiffness, or reduced movement. সহজ বাংলা: জয়েন্টের প্রদাহ।" data-rx-term="arthritis" data-rx-definition="Arthritis means joint inflammation causing pain, swelling, stiffness, or reduced movement. সহজ বাংলা: জয়েন্টের প্রদাহ।">Arthritis in your shoulder.

Other Names

  • Shoulder Separation
  • Shoulder Sprain
  • AC Sprain
  • AC Dislocation
  • Acromioclavicular Joint Dislocation

Background

  • This page refers to all traumatic injuries to the Acromioclavicular Joint including
    • Sprains
    • Dislocations
    • Separations
  • Thought to be under-estimated due to many mild injuries not seeking medical attention
  • Represents 9% of all shoulder injuries (need citation)
  • 50% of all AC dislocations occur to individuals in their 20s (need citation)
  • Types 1 and 2 injuries account for most AC separations
  • Mechanism of injury is primarily by direct impact over the AC joint
    • From fall or contact sport
    • Arm is adducted

Causes

  • Many causes
    • Simple falls
    • High energy trauma
    • Sports

Pathoanatomy

  • AC Joint
    • Diarthrodial joint
    • Motion: primarily gliding, only 8° rotation through AC joint
    • fibrocartilaginous intraarticular disc (similar to meniscus of knee)
  • Stabilizers
    • Joint Capsule
    • Acromioclavicular Ligament (anterior-posterior stability)
    • Coracoclavicular Ligaments (superior-inferior stability)
    • Muscles: Deltoid, Trapezius

Associated Injuries

  • Intra-articular shoulder injury (18.2%)[1]
    • SLAP ulcer. সহজ বাংলা: শরীরের অস্বাভাবিক দাগ, ক্ষত বা ফোলা অংশ।" data-rx-term="lesion" data-rx-definition="A lesion is an abnormal area of tissue such as a spot, wound, patch, lump, or ulcer. সহজ বাংলা: শরীরের অস্বাভাবিক দাগ, ক্ষত বা ফোলা অংশ।">Lesion
    • Rotator Cuff Injury
  • Male > Female
  • Sports
    • Contact and collision sports
    • Skiing
    • Cycling

diagnosis: Differential diagnosis is a list of possible conditions that may explain symptoms. সহজ বাংলা: একই লক্ষণের সম্ভাব্য রোগের তালিকা।" data-rx-term="differential diagnosis" data-rx-definition="Differential diagnosis is a list of possible conditions that may explain symptoms. সহজ বাংলা: একই লক্ষণের সম্ভাব্য রোগের তালিকা।">Differential Diagnosis

  • Fractures
    • Proximal Humerus Fracture
    • Humeral Shaft Fracture
    • Clavicle Fracture
    • Scapula Fracture
    • First Rib Fracture (traumatic or atraumatic)
  • Dislocations & Seperations
    • Acromioclavicular Joint Separation
    • Glenohumeral Dislocation (Acute)
    • Sternoclavicular Joint Dislocation
    • Glenohumeral Instability (Chronic)
  • Arthropathies
    • Glenohumeral pain, swelling, stiffness, or reduced movement. সহজ বাংলা: জয়েন্টের প্রদাহ।" data-rx-term="arthritis" data-rx-definition="Arthritis means joint inflammation causing pain, swelling, stiffness, or reduced movement. সহজ বাংলা: জয়েন্টের প্রদাহ।">Arthritis
    • Acromioclavicular Joint pain, swelling, stiffness, or reduced movement. সহজ বাংলা: জয়েন্টের প্রদাহ।" data-rx-term="arthritis" data-rx-definition="Arthritis means joint inflammation causing pain, swelling, stiffness, or reduced movement. সহজ বাংলা: জয়েন্টের প্রদাহ।">Arthritis
  • Muscle & Tendon Injuries
    • Pectoralis Major Injuries
    • Pectoralis Minor Injuries
    • Proximal Biceps Tendon Injuries
    • Scapular Dyskinesis
  • Rotator Cuff
    • Rotator Cuff Tear
    • Rotator Cuff Tendonitis
    • Calcific Tendinitis of the Rotator Cuff
    • Subcoracoid Impingement Syndrome
  • Bursopathies
    • Subacromial Bursitis
    • Scapulothoracic Bursitis
  • Ligament Injuries
    • Glenoid Labral Tears
  • Neuropathies
    • Suprascapular Nerve Injury
    • Parsonage-Turner Syndrome
    • Quadrilateral Space Syndrome
    • Winged Scapula
  • Other
    • Adhesive Capsulitis
    • Paget-Schroetter Syndrome
  • Pediatrics
    • Coracoid Avulsion Fracture
    • Humeral Head Epiphysiolysis (Little League Shoulder)

Symptoms

  • General: Physical Exam Shoulder
  • History
    • Patient should describe some trauma
    • Shoulder pain at or close to AC joint
  • Physical
    • Most commonly, pain when an area is touched or pressed. সহজ বাংলা: চাপ দিলে ব্যথা।" data-rx-term="tenderness" data-rx-definition="Tenderness means pain when an area is touched or pressed. সহজ বাংলা: চাপ দিলে ব্যথা।">tenderness over AC joint
    • Inspection may show asymmetry of shoulders or swell at the AC joint
    • Range of Motion is usually reduced due to pain acutely
    • Pain with adduction of the shoulder and possibly with shoulder abduction and flexion
    • Deformity (step-off) of AC joint with type III injuries and higher
    • Type III and V may show instability of the lateral clavicle when depressed manually (“piano key” phenomenon)
  • Special Tests
    • Crossover Test: shoulder flexed to 90°, passively adducted across chest, reproduces pain over the AC joint
    • Resisted AC Joint Extension Test: abduction against resistance with shoulder flexed to 90°
    • OBriens Test: Arm flexed to 90° and then supinated and pronated against resistance

Diagnosis

Radiographs

  • Standard Radiographs Shoulder
  • Zanca view (sometimes referred to as the AC joint view)[2]
    • Beam is tilted cephalic 10 – 15°
    • Provides superior AC joint evaluation
    • Recommend bilateral evaluation for comparison
    • The average distance between the inferior aspect of the clavicle and the coracoid is 1.1 to 1.3 cm
  • Basmania view: scapular Y performed with cross-body adduction stress
  • Stryker notch views can assess for coracoid fracture
  • Note: Weighted stress views are no longer used

CT

  • CT has not been shown to improve diagnostic yield

MRI

  • Can directly assess AC and CC ligaments
  • Useful if surgical intervention is being considered

Ultrasound

  • Can be used to evaluate the AC joint

Classification

Rockwood Classification of Acromioclavicular Injuries

Type AC Ligaments CC Ligaments Deltopectoral Fascia CC Distance AC Joint (Xray)
I Sprained Intact Intact Normal Normal
II Disrupted Sprained Intact <25% Widened
III Disrupted Disrupted Disrupted 25%-100% Widened
IV Disrupted Disrupted Disrupted Increased Posterior displaced clavicle
V Disrupted Disrupted Disrupted 100-300% N/A
VI Disrupted Disrupted Disrupted Decreased Inferior displaced clavicle

Treatment

Types I and II

  • Universally nonoperative
  • Analgesia with ice, NSAIDS, Acetaminophen, et
  • Immobilization: Shoulder Sling
    • Discontinue once asymptomatic
    • Type I: Typically 1-3 weeks
    • Type II: Longer, up to 4 weeks[3]
  • Activity modification
    • Type II injuries may require early rehabilitation program with passive and active shoulder ROM exercises
    • Rotator cuff, scapular stabilization, and trunk strengthening exercises as pain resolves
    • Heavy lifting and contact activities only once extremity is pain free and symmetric ROM is acheived
  • Consider Corticosteroid Injection in refractory cases

Type III

  • Management is controversial
    • Not a lot of high level evidence to guide decision making
    • General consensus is to advocate for initial nonoperative management.
    • Individualized treatment based on patient activity level, impairment, and occupation
    • Consider surgical repair in acute, young patients
    • Comparably high satisfaction with operative and nonoperative treatment though higher complication rates in those treated surgically[4]
  • Nonoperative treatment
    • Similar to Type I, II

Type IV – VI

  • Generally considered surgical
  • Technique
    • Many described in the literature
    • ORIF most common

Rehab and Return to Play

Rehabilitation

  • Needs to be updated

Return to Play

  • Return to play once pain completely resolved and equal active ROM in bilateral shoulders. Followed by adequate strength training.
  • Recovery generally takes 6 weeks for Type II injuries and 12 weeks for Type III injuries

Complications

  • Acromioclavicular Joint Pain
    • Experienced by 1/3 of patients at 6 months after injury and up to 6 years of follow up[5]
  • Decrease in bench press strength (need citation)
  • Cosmetic deformity is very common
  • Crepitus, clicking
  • AC Joint Arthritis
  • Distal Clavicle Osteolysis
Doctor visit helper

Prepare before seeing a doctor

A simple rural-patient checklist to help you explain symptoms clearly, ask better questions, and avoid unsafe self-treatment.

Safety note: This is not a prescription or diagnosis. For severe symptoms, pregnancy danger signs, children with serious illness, chest pain, breathing difficulty, stroke-like weakness, or major injury, seek urgent care.

Which doctor may help?

Orthopedic doctor, rheumatologist, or physiotherapist depending on cause.

What to tell the doctor

  • Write which joints hurt, swelling, morning stiffness duration, fever, injury, and walking difficulty.
  • Bring X-ray, uric acid, ESR/CRP, rheumatoid factor, or previous reports if available.

Questions to ask

  • Is this injury, osteoarthritis, rheumatoid arthritis, gout, infection, or another cause?
  • Which exercises, supports, or lifestyle changes are safe?
  • Do I need blood tests or X-ray?

Tests to discuss

  • Joint examination and range of motion
  • X-ray when chronic arthritis or injury is suspected
  • ESR/CRP, uric acid, rheumatoid tests when inflammatory arthritis is suspected

Avoid these mistakes

  • Do not ignore hot swollen joint with fever.
  • Avoid repeated steroid injections/tablets without a clear diagnosis and follow-up.

Medicine safety and first-aid guide

This section is for patient education only. It does not replace a doctor, pharmacist, or emergency care.

Safe first steps

  • Avoid heavy lifting, sudden bending, and prolonged bed rest.
  • Use comfortable posture and gentle movement as tolerated.
  • Discuss physiotherapy, X-ray, or MRI only when clinically needed.

OTC medicine safety

  • For mild back pain, pain-relief medicine may be discussed with a doctor or pharmacist.
  • Avoid repeated painkiller use if you have kidney disease, stomach ulcer, uncontrolled blood pressure, or are taking blood thinners.

Avoid these mistakes

  • Do not start antibiotics without a proper medical decision.
  • Do not use steroid tablets or injections casually for quick relief.
  • Do not delay emergency care because of home remedies.

Get urgent help if

  • Back pain with leg weakness, numbness around private area, loss of urine/stool control, fever, cancer history, or major injury needs urgent care.
Medicine names, dose, and timing must be decided by a qualified clinician or pharmacist after checking age, pregnancy, allergy, other diseases, and current medicines.

For rural patients and family caregivers

Patient health record and symptom diary

Write your symptoms, medicines already taken, test results, and questions before visiting a doctor. This note stays on your device unless you print or copy it.

Doctor to discuss: Doctor / qualified healthcare provider
Tests to discuss with doctor
  • Basic vital signs: temperature, pulse, blood pressure, oxygen level if needed
  • Relevant blood, urine, imaging, or specialist tests only after clinical assessment
Questions to ask
  • What is the most likely cause of my symptoms?
  • Which warning signs mean I should go to emergency care?
  • Which tests are really needed now?
  • Which medicines are safe for my age, pregnancy status, allergy, kidney/liver/stomach condition, and current medicines?

Emergency warning signs such as chest pain, severe breathing difficulty, sudden weakness, confusion, severe dehydration, major injury, or loss of bladder/bowel control need urgent medical care. Do not wait for online information.

Safe pathway to proper treatment

Care roadmap for: Acromioclavicular Joint Separation

Use this simple roadmap to understand the next safe steps. It is educational and does not replace examination by a doctor.

Go to emergency care if you notice:
  • Severe or rapidly worsening symptoms
  • Breathing difficulty, chest pain, fainting, confusion, severe weakness, major injury, or severe dehydration
Doctor / service to discuss: Qualified healthcare provider; specialist depends on symptoms and examination.
  1. Step 1

    Check danger signs first

    If danger signs are present, seek emergency care and do not wait for online information.

  2. Step 2

    Record the symptom story

    Write when symptoms started, severity, medicines already taken, allergies, pregnancy status, and test results.

  3. Step 3

    Visit a qualified clinician

    A doctor, nurse, or qualified healthcare provider can examine you and decide which tests or treatment are needed.

  4. Step 4

    Do only useful tests

    Do tests after clinical assessment. Avoid unnecessary tests, random antibiotics, or repeated medicines without diagnosis.

  5. Step 5

    Follow up and return early if worse

    If symptoms worsen, new warning signs appear, or treatment is not helping, return for review quickly.

Rural patient practical tips
  • Take a written symptom diary and all previous prescriptions/test reports.
  • Do not hide medicines already taken, even herbal or over-the-counter medicines.
  • Ask which warning signs mean urgent referral to hospital.

This roadmap is for education. A real diagnosis and treatment plan requires history, examination, and clinical judgment.

RX Patient Help

Ask a health question safely

Write your symptom story. A health professional or site editor can review it before any answer is prepared. This box is not for emergency care.

Emergency first: Severe chest pain, breathing trouble, unconsciousness, stroke signs, severe injury, heavy bleeding, or rapidly worsening symptoms need urgent local medical care now.

Frequently Asked Questions

Is this article a replacement for a doctor?

No. It is educational content only. Patients should consult a qualified clinician for diagnosis and treatment.

When should I seek urgent care?

Seek urgent care for severe symptoms, rapidly worsening condition, breathing difficulty, severe pain, neurological changes, or any emergency warning sign.

References

Add references, clinical guidelines, textbooks, journal articles, or trusted medical sources here. You can edit this area from the RX Article Professional Blocks panel.

More from this topic
  1. Axial osteosclerosis

    DefinitionAxial osteosclerosis means the bones of the axial skeleton become extra dense and hard. The axial skeleton is the spine, ribs, sternum, and pelvis. In axial...

    October 15, 2025 • Arthritis, and Chronic Pain (A - Z)
  2. Phlebectatic Osteohypoplastic Angiodysplasia

    DefinitionPhlebectatic osteohypoplastic angiodysplasia—much better known to clinicians as Servelle–Martorell syndrome (SMS)—is a rare, congenital? venous malformation that mostly affects one limb. The hallmark triad is (1)...

    September 19, 2025 • Arthritis, and Chronic Pain (A - Z)
  3. Angio Osteohypotrophic Syndrome

    DefinitionAngio-osteohypotrophic syndrome (Servelle–Martorell syndrome) is a very rare, congenital? (present at birth) vascular anomaly. The core problem is a network of abnormally formed, slow-flow veins (venous...

    September 19, 2025 • Arthritis, and Chronic Pain (A - Z)
  4. Giant Cell Arteritis

    DefinitionGiant cell arteritis is a serious condition in which the walls of medium- and large-sized arteries (the blood vessels carrying blood away from the heart) become...

    August 5, 2025 • Arthritis, and Chronic Pain (A - Z)
  5. Osteitis

    DefinitionOsteitis is the medical term for inflammation? of bone tissue. In simple terms, it means the bone itself is reacting with redness, swelling, and sometimes pain,...

    July 12, 2025 • Arthritis, and Chronic Pain (A - Z)
  6. Pseudogout

    DefinitionPseudogout, also known as calcium pyrophosphate deposition disease (CPPD), is a joint condition where tiny calcium crystals build up in the cartilage? and fluid of a...

    July 12, 2025 • Arthritis, and Chronic Pain (A - Z)
  7. Juvenile Idiopathic Arthritis (JIA) Dactylitis

    DefinitionJuvenile Idiopathic? Arthritis? (JIA) Dactylitis refers to an inflammatory condition in which an entire finger or toe becomes diffusely swollen, often resembling a “sausage digit.” It...

    July 12, 2025 • Arthritis, and Chronic Pain (A - Z)
  8. Neoplastic (Leukemic) Dactylitis

    DefinitionNeoplastic (leukemic) dactylitis is a rare form of “sausage digit” swelling? caused not by infection? or autoimmune? disease, but by direct infiltration of malignant? blood cells—most...

    July 12, 2025 • Arthritis, and Chronic Pain (A - Z)
  9. Traumatic Dactylitis

    DefinitionTraumatic dactylitis is a specific form of dactylitis—often called “sausage digit”—in which inflammation? affects an entire finger or toe following a physical injury to that digit....

    July 12, 2025 • Arthritis, and Chronic Pain (A - Z)
  10. Osteomyelitis-Induced Dactylitis

    DefinitionOsteomyelitis‐induced dactylitis is the inflammation? of an entire finger or toe (“digit”) that arises when an infection of the bone (osteomyelitis) spreads into the surrounding soft...

    July 12, 2025 • Arthritis, and Chronic Pain (A - Z)