Beyond the peak of the anterior glenoid rim: A cadaveric study

PURPOSE: The purpose of this study was to quantify the width of bone beyond the peak of the anterior glenoid rim and to determine if this anatomic region of the glenoid significantly affects measurement of the anteroposterior glenoid diameter. MATERIALS AND METHODS: 19 cadaveric scapulae were examined and the width of bone beyond the peak of the anterior glenoid rim was measured. The percent width of this region relative to the anteroposterior diameter of the glenoid was evaluated. Male and female specimens were compared. Measurements of the anteroposterior diameter of the glenoid, both including and excluding this region, were compared. RESULTS: The mean width of bone beyond the peak of the anterior glenoid rim was 3.2 ± 0.7 mm, corresponding to 10.5% of the anteroposterior glenoid diameter. This anatomic region is of similar relative size in males and females (11% vs 10% of the glenoid diameter). Measurement of the anteroposterior diameter of the glenoid is significantly different depending on whether this region is included or not (P = 0.0064). CONCLUSIONS: There exists a portion of the anterior glenoid that is beyond the peak of the anterior rim, and is not part of the concave articular surface. The width of this anatomic area comprises a significant percent of the anteroposterior glenoid diameter, and should be understood when quantifying and describing anterior glenoid bone loss in cases of glenohumeral instability. CLINICAL RELEVANCE: Understanding of anterior glenoid anatomy is important in the evaluation of glenohumeral instability. The portion of glenoid bone beyond the anterior rim peak is likely important for its soft tissue attachments, but its contribution to bony stability may be misunderstood.