ANATOMY OF THE THORACIC PEDICLE

THORACIC PEDICLE ANATOMY (interpedicular distance, transverse and sagi ttal pedicle widths, transverse and sagittal pedicle angles, and the d istance from the axis of the pedicle to the axis of the transverse pro cess) was assessed in 11 cadavers of elderly people. The cadaveric spi nes were extensively dissected to augment the accuracy of the measurem ents via caliper and goniometer. The results were compared with those of previous studies that assessed pedicle anatomy with computed tomogr aphy, direct measurement, and three-dimensional morphometry. Between t he studies, significant differences were found in transverse pedicle w idth and transverse and sagittal pedicle angles. These morphometric di fferences may reflect either the diversity of the techniques used to m easure the pedicle anatomy or sampling variation. This article present s a previously unreported morphometric finding, the rostral-caudal dis tance from the thoracic pedicle to the midpoint of the base of the tra nsverse process. At T12 the transverse process is 5.45 +/- 1.2 mm rost ral to the pedicle. This relationship gradually changes as the thoraci c spine is descended, so that at T12, the transverse process is 6.6 +/ - 2.4 mm caudal to the pedicle. Crossover consistently occurs at the T 6-T7 region. Although the transverse process is a reliable external la ndmark for the location of the pedicle in the lumbar spine, this relat ionship in the thoracic spine is variable and only moderately predicta ble.