Vulnerable neurovasculature with a posterior approach to the scapula.

Anatomic studies have described areas where there is no direct threat of inadvertent suprascapular nerve injury; however, these studies did not describe danger zones during open reduction and internal fixation of the fractured scapula. We therefore sought to define the topographic distribution in which these vulnerable structures most commonly are found, thus establishing danger zones. Twenty-four nonpaired cadaveric specimens were dissected. The infraspinatus and teres minor musculature were elevated off the posterior scapula body to reveal critical areas where the suprascapular neurovasculature and circumflex scapular artery were vulnerable to injury. We established radial coordinates to determine this relation to osseous landmarks. The mean distance from the spinoglenoid notch to the inferior border of the danger zone was 2.4 cm (range, 1.2-3.8 cm). The mean distance from the medial extent of the scapular spine to the medial border of the danger zone was 4.3 cm (range, 3.0-6.7 cm). The entry of the ascending branch of the circumflex scapular artery was located at the lateral border 5.6 cm (range, 4.5-7.0 cm) inferior to the spinoglenoid notch. These danger zones can aid the surgeon in determining the risk for suprascapular nerve injury, specifically with scapula fractures involving the spinoglenoid notch and/or lateral border.