Objectives:

The L5 vertebra is a vertebra which is located in the transitional zone between the lumbar and sacral vertebrae and can hold the morphometric features of both type of these vertebrae. Thus the L5 vertebra must be evaluated in a special aspect because of its different morphometry. The aim of our study is to determine the average morphometric features of the L5 vertebra in the Turkish population, to overcome the difficulties in spinal instrumentation by taking these features into account and to increase the success of the surgical applications .

Methods:

L5 vertebrae of the 40 patients who were operated due to degenerative disorders of the vertebral colums were evaluated by computerized tomography scanning. In the CT images, the values of axial pedicular lenghts, interpedicular lengths, sagittal pedicular width, pedicular cortical width, pedicular endosteal width, pedicule / midline angles, length of the corpus, heigth of the corpus, width of the corpus, antero-posterior diameter of the spinal canal, transvers diameter of the spinal canal, diameters of the L5-S1 foramina in sagittal and axial planes were measured. Also it was noted if the shape of the corpus was hemispherical or triangular and if the coronal cross section of the pedicle was circular or ovale.

Results:

The mentioned measurements were done and the avarage values were determined. We noticed that in the axial slices, the shape of the L5 vertebra was hemispherical in the superior part but it went triangular in the inferior.

Conclusions:

We claim that during spinal instrumentation of the L5 vertebra these measurements should be taken into account and because of the triangular shape of the vertebra, pedicular screws must be inserted in a more convergent angle than the other lumbar vertebrae.

Keywords: Lumbar vertebrae, L-5 vetrebra, morphometric characteritics, CT.