Acromioclavicular (AC) Joint Injury

Acromioclavicular (AC) Joint Injury

An AC injury is a shoulder injury of the ligaments that hold the Acromion and the Clavicle (collar bone) together. That's where the name Acromioclavicular or AC Injury comes from. The acromioclavicular joint is the the highest point of the shoulder.

Description: Acromioclavicular (AC) Joint Injury

  • The function of the AC joint is to help raise the arm above head level. There are 4 ligaments that attach the Clavicle (collar bone) to the rest of the shoulder.
    • Acromioclavicular Ligament
      Direct junction between Acromion and Clavicle.
    • Caracaoacromial Ligament, which goes from the Coracoid Process to the Acromion.
    • Coracoclavicular Ligaments: Conoid and the Trapezoid - See illustration above.
  • In an AC joint injury, one or more of the above ligaments get injured / inflamed / teared. Common injuries to the AC joints are dislocations (AC joint separations or shoulder separations). But careful, an AC dislocation is not the same as a shoulder dislocation.
    A shoulder dislocation is when the upper arm bone pops out and an AC dislocation is when the acromion gets separated from the collar bone.
  • AC dislocations are also graded from 1 to 3:
    • Grade 1: When the direct junction between acromion and clavicle gets teared. The gap between A and C is smaller than 4 mm.
    • Grade 2: Complete dislocation of AC ligament - Partial disruption of coracoclavicular ligaments. The gap between A and C is bigger than 5 mm.
    • Grade 3: You are in big trouble.
      AC and both CC ligaments are disrupted.

Symptoms: Acromioclavicular (AC) Joint Injury

  • Pain at the lower end of the collar bone. Especially when you are trying to raise the arm over head level.
  • Swelling
  • Visible deformation. Especially in grade 2 and grade 3 AC injuries.

Who is susceptible: Acromioclavicular (AC) Joint Injury

  • Wresterls
  • American Football Players
  • Ice Hockey Players

Treatment: Acromioclavicular (AC) Joint Injury

  • Rest and apply ice as soon as possible.
  • Use an arm sling to take stress from the shoulder.
  • Consult your doctor who may:
    • Tape your shoulder joint into the correct position.
    • Prescribe am anti-inflammatory to reduce pain and inflammation.
    • Put you on a rehabilitation program.
    • Operate

Advice: Acromioclavicular (AC) Joint Injury

  • Strengthen you shoulders.
  • Don't try wrestling / judo / aikido throws without the supervision of an experienced coach.
  • Warm up and stretch your upper body.
  • Rest, apply ice and see a sport injury specialist ASAP.