頚椎椎間孔と神経根の形態学的測定
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概要
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The purpose of this study was to clarify the onset of cervical myelopathy and cervical spondylotic radiculopathy as well as what influence the anatomy of the cervical spine and cervical nerves have on their onset and occurrence of various types of disease state. We conducted imaging and morphological measurements on specimens of cervical spine of Japanese people, focusing attention on the running of intervertebral foramen and dorsal nerve rootlets of the cervical spine. The subjects were cervical spine specimens from 12 cadavers (7 males and 5 females, age at the time of death ranged from 48 to 93 years with a mean of 71 years) obtained at Showa University School of Dentistry in 2005 and 2006. Specimens were prepared by removing the atlas through the 1<SUP>st</SUP> thoracic vertebra from the cadavers, then resecting the soft tissue such as muscles to expose the cervical spine in whole circumference. The removed cervical spine specimens, from 1<SUP>st</SUP> to 7<SUP>th</SUP> cervical spines, were imaged by volume scan of radiographic helical CT at 0.6 mm spacial resolution, and their images were stored as DICOM data. Image measurement on the vertebral body, vertebral foramen, and intervertebral foramen was conducted based on DICOM data. Furthermore, macroscopic observation and measurement were conducted on the dorsal nerve rootlets of cervical spine specimens. The image measurement of cervical spine specimens showed that the intervertebral foramen at C5/6 was the narrowest, followed by C3/4, C4/5, C6/7, and C2/3, respecting. With regard to angles in the frontal section and horizontal section of the groove for the spinal nerve, there was no significant difference in the angle between the right and the left. In the frontal section, the angle was about 63° at C3, about 57° at C4, about 52° at C5, and about 55° at C6, showing a significantly acute angle at C5, while in the horizontal section, it was about 54° at C3, about 59° at C4, about 63° at C5 and C6, showing a significantly obtuse angle at C5 and C6 compared with at C3. The measurement at the merging section of the dorsal spinal nerve root showed that the width was about 7.0 to 7.5 mm at C3 through C6 and about 6.5 mm at C7 which was significantly low, while the cephalocaudal length was about 12.5 mm at C3, about 11.5 mm at C4, about 12 to 13 mm at C5, about 11.5 mm at C6, about 10.5 mm at C7, and about 10 mm at C8; there was a difference between the right and the left at C5, whereas no difference was observed between the right and the left at C3, C4, C6, C7, and C8. The incidence angle from the inlet of intervertebral foramen of the dorsal spinal nerve root toward the superior part of the spine indistinct a gradual obtuse angle at C3 through C5, whereas the angle gradually become an acute angle at C6 or below. The incidence angle in the inferior part was obtuse at C4 and C5, and acute at C6 or below, showing that the distance obliquely running within the dura mater tended to be short in the dorsal nerve rootlets at C4 and C5. Based on the above results, it was considered that the anatomy of the intervertebral foramen of the cervical spine and the difference by level at the origin of dorsal root have an influence on the onset of cervical myelopathy and cervical spondylotic radiculopathy as well as the occurrence of various types of disease states.
- 学校法人 昭和大学・昭和医学会の論文