Which motion is most indicative of AC joint pathology as the primary pain generator?

Which motion is most indicative of AC joint pathology as the primary pain generator?

• A. Elevation of the shoulder
• B. Horizontal adduction
• C. External rotation of the arm
• D. Anteroposterior gliding

Answer: (B)

Horizontal adduction of the shoulder is particularly indicative of acromioclavicular (AC) joint pathology due to the anatomy and biomechanics of the shoulder complex. When an individual performs horizontal adduction, the movement places significant stress on the AC joint, especially when the shoulder is flexed and moved across the midline of the body. This position can compress the joint and irritate any underlying pathology, such as arthritis, joint inflammation, or acute injury, leading to pain that is typically felt localized to the AC joint area. Additionally, in cases of AC joint pathology, horizontal adduction often reproduces the characteristic pain associated with conditions like AC joint sprains or degenerative changes, making it a reliable movement to assess during examination and evaluation of shoulder pain. Other motions, while they may involve the shoulder joint, do not primarily target the AC joint in the same way. For example, elevation of the shoulder engages multiple structures beyond the AC joint, and external rotation focuses more on glenohumeral mechanics. Anteroposterior gliding relates to joint mobilization techniques rather than specific motion patterns that provoke pain due to AC joint issues. Thus, horizontal adduction stands out as the motion most closely associated with the pain experienced in AC joint pathology

Horizontal adduction of the shoulder is particularly indicative of acromioclavicular (AC) joint pathology due to the anatomy and biomechanics of the shoulder complex. When an individual performs horizontal adduction, the movement places significant stress on the AC joint, especially when the shoulder is flexed and moved across the midline of the body. This position can compress the joint and irritate any underlying pathology, such as arthritis, joint inflammation, or acute injury, leading to pain that is typically felt localized to the AC joint area.

Additionally, in cases of AC joint pathology, horizontal adduction often reproduces the characteristic pain associated with conditions like AC joint sprains or degenerative changes, making it a reliable movement to assess during examination and evaluation of shoulder pain.

Other motions, while they may involve the shoulder joint, do not primarily target the AC joint in the same way. For example, elevation of the shoulder engages multiple structures beyond the AC joint, and external rotation focuses more on glenohumeral mechanics. Anteroposterior gliding relates to joint mobilization techniques rather than specific motion patterns that provoke pain due to AC joint issues. Thus, horizontal adduction stands out as the motion most closely associated with the pain experienced in AC joint pathology