What is an AC Joint Injury?

Written By Nick Stamatiou
Description: AC (acromioclavicular) joint sprains, often referred to as shoulder separations, are injuries that occur at the joint where the collarbone (clavicle) meets the highest point of the shoulder blade (acromion). These injuries can range fro

Description:

AC (acromioclavicular) joint sprains, often referred to as shoulder separations, are injuries that occur at the joint where the collarbone (clavicle) meets the highest point of the shoulder blade (acromion). These injuries can range from mild to severe and are typically the result of trauma or direct impact to the shoulder. To effectively manage AC joint sprains, it's crucial to understand their anatomy and how they develop.

Anatomy of the AC Joint:

The AC joint comprises several key components:

  1. Clavicle (Collarbone): This S-shaped bone extends horizontally across the front of the chest, connecting the sternum (breastbone) to the scapula (shoulder blade).

  2. Acromion: The highest point of the scapula, the acromion forms the other half of the AC joint.

  3. Articular Cartilage: A smooth, protective layer covers the ends of the clavicle and acromion where they meet in the joint, allowing for frictionless movement.

  4. Ligaments: Strong bands of connective tissue, including the acromioclavicular ligament and the coracoclavicular ligaments, provide stability to the joint.

Development of AC Joint Sprains:

AC joint sprains typically occur due to:

  • Direct Trauma: Falls, sports injuries, or accidents that impact the shoulder can lead to ligament sprains or tears in the AC joint.

Grading of AC Joint Sprains:

AC joint sprains are often classified into three grades based on the severity of the injury:

  1. Grade I: Mild sprain with minimal ligament damage. The joint remains stable.

  2. Grade II: Moderate sprain with partial ligament tearing. The joint may be slightly displaced.

  3. Grade III: Severe sprain with complete ligament tearing. The joint is significantly displaced.

Signs and Symptoms:

Common signs and symptoms of AC joint sprains include:

  • Pain: Typically localized at the top of the shoulder.

  • Swelling: Swelling may occur around the AC joint.

  • Tenderness: The area around the AC joint can become tender to the touch.

  • Instability: In severe cases (Grade III), the joint may feel unstable, and there may be a noticeable bump on the shoulder.

By Charlie Molloy

 

Nick Stamatiou

Nick has a strong interest in sports and musculoskeletal physiotherapy and is motivated to help people reach their desired goals and to achieve their full potential.

His experience includes:

  • Sports and musculoskeletal physiotherapist in a private practice setting

  • Orthopaedic and Rehabilitation inpatient physiotherapist at Brisbane Private Hospital

  • Clinical Reformer and Mat-work Pilates instructor

  • Football gameday physiotherapist

While Nick is skilled in managing all areas of musculoskeletal physiotherapy, he has a particular interest in the rehabilitation of muscle strains, hip, knee and lower back conditions. Nick offers dry needling, massage and joint mobilisation to compliment exercise prescription.

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