A Review of the Segmental Diameter of the Healthy Human Spinal Cord

Abstract

Knowledge of the average size and variability of the human spinal cord can be of importance when treating pathological conditions in the spinal cord. Data on healthy human spinal cord morphometrics have been published for more than a century using different techniques of measurements, but unfortunately, comparison of results from different studies is difficult because of the different anatomical landmarks used as reference points along the craniocaudal axis for the measurements. The aim of this review was to compute population estimates of the transverse and anteroposterior diameter of the human spinal cord by comparing and combining previously published data on a normalized craniocaudal axis. We included 11 studies presenting measurements of spinal cord cross-sectional diameters, with a combined sample size ranging from 15 to 488 subjects, depending on spinal cord level. Based on five published studies presenting data on the lengths of the segments of the spinal cord and vertebral column, we calculated the relative positions of all spinal cord neuronal segments and vertebral bony segments and mapped measurements of spinal cord size to a normalized craniocaudal axis. This mapping resulted in better alignment between studies and allowed the calculation of weighted averages and standard deviations (SDs) along the spinal cord. These weighted averages were smoothed using a generalized additive model to yield continuous population estimates for transverse and anteroposterior diameter and associated SDs. The spinal cord had the largest transverse diameter at spinal cord neuronal segment C5 (13.3 ± 2.2), decreased to segment T8 (8.3 ± 2.1), and increased slightly again to 9.4 ± 1.5 at L3. The anteroposterior diameter showed less variation in size along the spinal cord at C5 (7.4 ± 1.6), T8 (6.3 ± 2.0), and L3 (7.5 ± 1.6). All estimates are presented in millimeters ± 2 SDs. We conclude that segmental transverse and anteroposterior diameters of the healthy human spinal cord from different published sources can be combined on a normalized craniocaudal axis and yield meaningful population estimates. These estimates could be useful in routine management of patients with neurodegenerative diseases as well as for clinical research and experimental applications aimed at surgical spinal cord repair.

Morphometric Analysis of Spinal Cord Dimensions of Individuals Who Are Undergoing MRI at dept of Radio- Diagnosis in HSK Hospital and Research Center, SNMC, Bagalkot

“…[10][11][12] In our study, the AP diameter of spinal cord was greatest at C1 and it gradually decreased from 7.74 mm at C1 in males and 6.63 mm in females with the lowest at C7 vertebrae. This finding was in line with that of Frostell A et al 13 who also observed that the AP diameter was greatest at C1 (8.3mm) and gradually decreased till C7 (6.9mm). In the present study, however, gender wise there was statistically significant difference between the AP diameters at C1, C2 and C3 (P value <0.05) and not between that of C4, C5, C6 an C7.…”

Blood-spinal cord barrier leakage is independent of motor neuron pathology in ALS

“…While the majority of our cohort spinal cords were dissected and labelled according to neuronal segmental level of the cord, all controls and several ALS cords were dissected according to bony vertebral segmental level, therefore we first measured and plotted the transverse diameters of all spinal cord segments for each case. For cases cut according to vertebral level, we then employed a conversion scheme to relabel the segments according to neuronal level [30]. After relabelling (Fig 2A,B), the average transverse diameter for control and ALS spinal cords peaked at C5, but ALS cords were narrower at C5 (diameter 9.80 ± 0.43 mm) than controls (diameter 11.71 ± 0.23 mm, Fig 2B, p = 0.022).…”

“…Three spinal cord regions were analysed: cervical (C8), mid-thoracic (T7-T9), and lumbar (L4/L5). To select the appropriate segmental block for each case we first measured the transverse diameters of all spinal cord segments with Vernier callipers (Fig S1A) and compared them with population estimates of segmental diameter (Fig S1B) [30]. This demonstrated the disparity between cords sectioned and labelled according to vertebral level compared to neuronal level.…”

“…This demonstrated the disparity between cords sectioned and labelled according to vertebral level compared to neuronal level. Spinal cord segments were then relabelled for neuronal level using a conversion scheme [30].…”

Cervical Radiculopathy Alleviating by Manipulative Correction of Cervical Hypolordosis

“…In general, normal values have been reported to range from 20° to 35° for C2 to C7 [13]. A study conducted in 369 subjects of different occupations, researchers observed that cervical hypolordosis is the commonest defect, which leads to painful neck syndrome and to serious compression of cervical nerve roots [14]. Previous studies showed length changing of the spinal cord in flexion and extension.…”