A cadaveric study of the cervical nerve roots and spinal segments

Kobayashi, Ryuichi; Iizuka, Haku; Nishinome, Masahiro; Iizuka, Yoichi; Yorifuji, Hiroshi; Takagishi, Kenji

doi:10.1007/s00586-015-4070-3

Cited by 8 publications

(5 citation statements)

References 8 publications

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“…Shinomiya et al 17 investigated the width of the spinal segment from C5 to C8 using cadavers and reported that C6 was the widest and C8 the narrowest. Kobayashi et al 18 also confirmed that C8 was the narrowest, and this characteristic continued to the entry of the root in the foramen. Karatas et al 16 measured the widths from C2 to C8 and found that the longest longitudinal length was at C5, whereas the shortest was at C2.…”

Section: Discussionmentioning

confidence: 84%

Intradural Neuroanatomy in the Cervical Spinal Canal

Kong

Liu

et al. 2020

Spine

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Study Design. A dissection-based study of 10 embalmed human cadavers. Objective. To provide an anatomic basis to examine the underlying mechanisms of cervical spondylosis. Summary of Background Data. Detailed anatomical quantitative data of cervical spine is limited in current literature. Methods. Ten cervical spines from C2 to T1 were obtained. We defined three zones from midline to lateral part (zone I, II, and III) and two zones from cranial to caudal (zone P and zone IP) on the coronal plane within the cervical spinal canal. Quantitative anatomy of the zones at different cervical segments were measured including: (1) horizontal widths of zone I, II, and III; (2) length of the cervical spinal cord segment at the ventral rootlets (LV); (3) the pedicle height (PH, zone P) and the interpedicle height (IPH, zone IP); (4) the distance between the superior margin of pedicle and the exit of the uppermost ventral nerve rootlet (PN). Results. The value of zone II at C4 was significantly less than that at other levels. The value of zone III increases from C4 to C8, and the values at C7 and C8 were significantly higher than those at C4, C5, and C6. PHs and IPHs were not significantly different between different levels. The values of LV at C4 and C8 were smaller than those of C5, C6, and C7. The value of PN showed an increasing trend. At C4, the uppermost ventral rootlet was at about the same height as C3 pedicle, while C8 uppermost ventral rootlet was at the same level as the inferior part of C6 pedicle. Ventral intradural intersegmental connections were found in three intersegments out of 20 intersegments. Conclusion. The current definition of anatomic zones may be useful for an accurate diagnosis of cervical spondylosis and a safe and effective anterior decompression surgery.

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Section: Discussionmentioning

confidence: 84%

Intradural Neuroanatomy in the Cervical Spinal Canal

Kong

Liu

et al. 2020

Spine

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“…Shinomiya et al [17] investigated the width of the spinal segment from C5 to C8 using cadavers and reported that C6 was the widest and C8 the narrowest. Kobayashi et al [18] also con rmed that C8 was the narrowest, and this characteristic continued to the entry of the root in the foramen. Karatas et al [16] measured the widths from C2 to C8 and found that the longest longitudinal length was at C5, whereas the shortest was at C2.…”

Section: Discussionmentioning

confidence: 89%

A new anatomic zone division within the human cervical spinal canal

Kong

Liu

et al. 2020

Preprint

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Abstract Background: Anatomic details are important for identifying the origin and anatomic basis of symptoms in patients with cervical spondylosis. However, very little quantitative data has been reported. In an effort to provide an anatomic basis for the examination of cervical spondylosis mechanisms, we characterized the morphologic features of cervical spinal nerve rootlets and defined different zones of the human cervical spinal canal.Methods: In 10 cadaveric cervical cords from C2 to T1, we defined three zones bilaterally from the midline (zones I-III) and two zones from cranial to caudal (zones P and IP) on the coronal plane within the cervical spinal canal. We measured each anatomic zone, including 1) horizontal widths of zones I, II and III; 2) the length of the cervical spinal segment at the ventral rootlets (LV); 3) the pedicle height (zone P) and interpedicle height (zone IP); and 4) the distance between the superior margin of the pedicle and the exit of the uppermost ventral nerve rootlet (PN). Results: The horizontal widths of zone I tended to decrease gradually from C4 to C8 (p=0.98). The width of zone II at C4 was significantly less than that at other levels (p=0.008). The width of zone III increased from C4 to C8 and was significantly greater at C7 and C8 than at C4, C5, and C6 (p=0.032). Pedical and interpedical heights were not significantly different at different levels (p=0.365 and 0.240, respectively). LV values at C4 and C8 were smaller than those at C5, C6, and C7 (p=0.001). At C4, the uppermost ventral rootlet was at approximately the same height as the C3 pedicle, whereas at C8, the uppermost ventral rootlet was at the same level as the inferior part of the C6 pedicle. Ventral intradural intersegmental connections were found in three of 20 (15%) intersegments (two specimens).Conclusions: These anatomic zones may be useful for diagnosing cervical spondylosis and guiding anterior decompression surgery.

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“…; Kobayashi et al. ). This is defined by these authors as the distance measured over the cord between the border fila radicularia of adjacent roots where these fila radicularia leave the cord surface.…”

Section: Discussionmentioning

confidence: 96%

Revisiting the segmental organization of the human spinal cord

Leijnse

D’Herde

2016

Journal of Anatomy

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In classic anatomic atlases, the spinal cord is standardly represented in its anatomical form with symmetrically emerging anterior and posterior roots, which at the level of the intervertebral foramen combine into the spinal nerves. The parts of the cord delimited by the boundaries of the roots are called segments or myelomeres. Associated with their regular repetitive appearance is the notion that the cord is segmentally organized. This segmental view is reinforced by clinical practice. Spinal cord roots innervate specific body parts. The level of cord trauma is diagnosed by the de-innervation symptoms of these parts. However, systemically, the case for a segmentally organized cord is not so clear. To date, developmental and genetic research points to a regionally rather than a segmentally organized cord. In the present study, to what degree the fila radicularia are segmentally implanted along the cord was investigated. The research hypothesis was that if the fila radicularia were non-segmentally implanted at the cord surface, it would be unlikely that the internal neuron stratum would be segmented. The visual segmented aspect of the myelomeres would then be the consequence of the necessary bundling of axons towards the vertebral foramen as the only exits of the vertebral canal, rather than of an underlying segment organization of the cord itself. To investigate the research hypothesis, the fila radicularia in the cervical-upper thoracic part of five spinal cords were detached from their spinal nerves and dissected in detail. The principal research question was if the fila radicularia are separated from their spinal nerves and dissected from their connective tissues up to the cord, would it be possible to reconstruct the original spinal segments from the morphology and interspaces of the fila? The dissections revealed that the anterior fila radicularia emerge from the cord at regular regionally modulated interspaces without systematic segmental delineations. The posterior fila radicularia are somewhat more segmentally implanted, but the pattern is individually inconsistent. The posterior and anterior roots have notable morphological differences, and hypotheses are presented to help explain these. The macroscopic observations are consistent with a regionally but not a segmentally organized cord. This conclusion was visually summarized in photographs of spinal cords with ipsilateral intact roots and contralateral individually dissected fila radicularia. It was suggested that this dual view of the spinal cord be added to the standard anatomic textbooks to counterbalance the current possibly biased view of a segmented cord.

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A cadaveric study of the cervical nerve roots and spinal segments

Cited by 8 publications

References 8 publications

Intradural Neuroanatomy in the Cervical Spinal Canal

Intradural Neuroanatomy in the Cervical Spinal Canal

A new anatomic zone division within the human cervical spinal canal

Revisiting the segmental organization of the human spinal cord

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