Gerber et al. used CT imaging of 47 normal shoulders to define the normal subcoracoid space in two arm positions. The study identified which skeletal variables predict subcoracoid impingement risk and quantified how arm position and surgical changes alter available clearance. This is the foundational anatomic reference for understanding subcoracoid impingement syndrome.
Subcoracoid impingement was recognized clinically before this paper, but no anatomic data existed to explain which patients were at risk or why surgical procedures sometimes caused or cured it.
When a patient presents with anterior shoulder pain reproduced by forward flexion to 90–100° with internal rotation, evaluate CT for two specific variables: the coracoglenoid angle and the coracoid overlap. A small angle combined with small overlap is the at-risk combination, not an enlarged coracoid in isolation.
Before any procedure that alters coracohumeral geometry — coracoid osteotomy for instability (Latarjet), posterior glenoplasty, or proximal humerus fixation. Account for the 1.5× amplification effect in flexion. A few millimeters of coracoid medialization or humeral head deformity can convert a borderline space into a symptomatic one.
Women warrant extra scrutiny: 1.4 mm less baseline clearance means their margin for tolerating any additional anatomic change is narrower than men with identical radiographic morphology.
Gerber et al. used CT imaging of 47 normal shoulders to define the normal subcoracoid space in two arm positions. The study identified which skeletal variables predict subcoracoid impingement risk and quantified how arm position and surgical changes alter available clearance. This is the foundational anatomic reference for understanding subcoracoid impingement syndrome.
Subcoracoid impingement was recognized clinically before this paper, but no anatomic data existed to explain which patients were at risk or why surgical procedures sometimes caused or cured it.
When a patient presents with anterior shoulder pain reproduced by forward flexion to 90–100° with internal rotation, evaluate CT for two specific variables: the coracoglenoid angle and the coracoid overlap. A small angle combined with small overlap is the at-risk combination, not an enlarged coracoid in isolation.
Before any procedure that alters coracohumeral geometry — coracoid osteotomy for instability (Latarjet), posterior glenoplasty, or proximal humerus fixation. Account for the 1.5× amplification effect in flexion. A few millimeters of coracoid medialization or humeral head deformity can convert a borderline space into a symptomatic one.
Women warrant extra scrutiny: 1.4 mm less baseline clearance means their margin for tolerating any additional anatomic change is narrower than men with identical radiographic morphology.