OBJECTIVETo evaluate an alternative landmark for thoracic vertebral screw insertion using the nutrient artery entrance on the posterolateral wall of thoracic vertebral bodies, and to discuss its clinical significance.

METHODSTwenty normal adult cadaver thoracic vertebral specimens were obtained randomly. Measurements included the number of nutrient artery entrance on left and right wall of thoracic vertebral bodies from T5 to T12, the diameter of the maximal nutrient artery entrance (d), the distance from nutrient artery entrance to the superior (A) or posterior (B) margin of the vertebral body, the distance between the posterior edge of the vertebral body and the nutrient artery entrance line (C) or the upper costal facet line (D). The length between left and right nutrient artery entrance (a) or costal facet (b) was measured too.

RESULTSFrom T5 to T12, the nutrient artery entrance were all underneath the upper costal facet. There were no significant differences between left and right side of anatomic measurements of each vertebral body from T5 to T12. The distance of A increased from T5 to T12, and the diameter and distance of B were no significant differences from T5 to T12. There were significant differences between the value C and the value D from T5 to T10.

CONCLUSIONSThe anatomical position of the nutrient artery entrance is relatively settled, and it could be used as a new landmark for screw placement.