A patient fell on an outstretched hand and now presents with an externally rotated arm. What is the most likely dx?

• A. Anterior shoulder dislocation
• B. Posterior shoulder dislocation
• C. AC joint separation
• D. Clavicle fracture

Answer: (A)

When a person falls on an outstretched hand and the arm ends up in external rotation, the most common injury is a glenohumeral joint dislocation displaced anteriorly. The humeral head is driven forward beneath the coracoid, and the arm often holds slightly away from the body with the palm facing outward. This creates a flattened contour of the lateral shoulder and a relative hollow beneath the acromion, with pain and limited movement.

Posterior dislocations, by contrast, typically occur with seizures or electric shocks and the arm is held in internal rotation and adduction, not externally rotated. AC joint separation shows tenderness and a noticeable step-off at the top of the shoulder, not a primarily externally rotated limb. A clavicle fracture presents with deformity along the clavicle itself and focal tenderness over the bone. The externally rotated position after a FOOSH points toward an anterior shoulder dislocation as the most likely diagnosis.