Abdominal liposarcoma.
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Abdominal Neoplasms↗
Biomedical subjects
J P Van Schaik
Publications and source records attributed to J P Van Schaik.
Isolated spinous process deviation. A pitfall in the interpretation of AP radiographs of the lumbar spine.
A new type of spinous process deviation is described. This variant may cause confusion in the interpretation of anteroposterior (AP) radiographs of the lumbar spine. In the literature, two types of lumbar spinous process deviation (SPD) have been described: 1) SPD due to rotation of the entire vertebra (as in rotatory scoliosis and degenerative arthritis), and 2) SPD as a consequence of developmental asymmetries of the neural arch. The present study demonstrates that spinous process deviation in the AP radiograph is not a reliable diagnostic guide. The authors' quantitative morphologic analysis of computed tomographic (CT) sections of over 200 lower lumbar vertebrae in vivo revealed a third type of SPD, namely isolated deviation of the spinous process, ie, deviation without any associated rotation or asymmetry of the vertebral body or arch. Since the oval shadow cast by the spinous process in AP radiographs is caused by its tip, rather than by its base (as was demonstrated by in vitro tests), it is concluded that the position of the spinous process shadow in AP radiographs cannot be used as a reliable landmark to differentiate between the three types of SPD. This is only possible by means of a CT examination.
Diagnosis, Differential↗
Effects of hemicastration, testis implantation and administration of testosterone propionate on the female embryonic genital tract in various breeds and strains of chickens.
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Animals↗
The orientation of laminae and facet joints in the lower lumbar spine.
The relationship between the angulation of the facet joints and that of the caudad parts of the corresponding laminae in the transverse plane was investigated with computed tomography (CT) at the vertebral levels L3-L4, L4-L5, and L5-S1. At the level of L3-L4, both the facet joints and the caudad portions of the laminae tend toward a sagittal orientation, while at L5-S1 this is more toward the frontal plane. At the level of L4-L5, they occupy an intermediate position. A highly significant correlation between the orientation of these structures is demonstrated. The caudad parts of the laminae may be considered buttresses for the inferior articular processes of the same vertebra.
Biomechanical Phenomena↗