Quantitative three-dimensional anatomy of cervical, thoracic and lumbar vertebrae of Chinese Singaporeans

Abstract

This paper details the quantitative three-dimensional anatomy of cervical, thoracic and lumbar vertebrae (C3-T12) of Chinese Singaporean subjects based on 220 vertebrae from 10 cadavers. The purpose of the study was to measure the linear dimensions, angulations and areas of individual vertebra, and to compare the data with similar studies performed on Caucasian specimens. Measurements were taken with the aid of a three-dimensional digitiser. The means and standard errors for linear, angular and area dimensions of the vertebral body, spinal canal, pedicle, and spinous and transverse processes were obtained for each vertebra. Compared to the Caucasian data, all the dimensions were found to be smaller. Of significance were the spinal canal area, and pedicle width and length, which were smaller by 31.7%, 25.7% and 22.1% on average, respectively. A slight divergence, instead of convergence, was found from T8 to T12. According to the findings, the use of a transpedicle screw may not be feasible. The results can also provide more accurate modelling for analysis and design of spinal implants and instrumentations, and also allow more precise clinical diagnosis and management of the spine in Chinese Singaporeans.

Figures

Fig. 1a–c

Four views (front, side, top and isometric) of a cervical, thoracic and lumbar vertebra. EPAl Lower end-plate area, EPAu upper end-plate area, EPDl lower end-plate depth, EPDu upper end-plate depth, EPWl lower end-plate width, EPWu upper end-plate width, PDH pedicle height, PDIs left pedicle, sagittal inclination, PDIt left pedicle, transverse inclination, PDW pedicle width, SCA spinal canal area, SCD spinal canal depth, SCW spinal canal width, SPL spinous process length, TPW transverse process width, VBHa anterior vertebral body height, VBHp posterior vertebral body height. (Reproduced with permission from Panjabi et al. [13, 14, 15])

Fig. 2

Setup of specimen prior to measurement. The clay prevents the specimen from moving during digitising

Fig. 3

Definition of the vertebra co-ordinate system with the origin at the centre of the upper end-plate

Fig. 4

The plan and side views of the best-fit upper (selected) end-plate are shown. The linear and area dimensions can be obtained from the plan section, while the side view is used to yield the angles

Fig. 5

Linear dimensions of the vertebral body as functions of vertebral levels C3–L5. The linear dimensions are the upper (u) and lower (l) end-plate width (EPW) and depth (EPD), and the anterior (a) and posterior (p) vertebral body height (VBH)

Fig. 6

Linear dimensions of the spinal canal, spinous process and transverse process as functions of vertebral levels C3–L5. The linear dimensions are the spinal canal width (SCW) and depth (SCD), and the spinous process length (SPL) and transverse process width (TPW)

Fig. 7

Linear dimensions of the pedicles as functions of vertebral levels C3–L5. The linear dimensions are the left (l) and right (r) pedicle height (PDH) and width (PDW)

Fig. 8

Areas of end-plates, spinal canal and pedicles as functions of vertebral levels C3–L5. The areas are the upper (u) and lower (l) end-plates (EPA), spinal canal (SCA), and left (l) and right (r) pedicle (PDA)

Fig. 9

Angular dimensions of the end-plates and pedicles as functions of vertebral levels C3–L5. The angles are the upper (u) and lower (l) end-plate transverse inclinations (EPI), and the left (l) and right (r) pedicles, and sagittal (s) and transverse (t) inclinations (PDI)

Fig. 10

Comparison of the spinal canal width (SCW) and depth (SCD) of the present study with that of Panjabi et al. [13, 14, 15]. The results from the latter are represented by P

Fig. 11

Comparison of the pedicle sagittal inclination (PDIs) of the present study with that of Panjabi et al. [13, 14, 15] and Zindrick et al. [16]

Fig. 12

Comparison of the pedicle length (PL) of the present study with that of McLain et al. [11] and Zindrick et al. [16]