Biomaterial Database

Unmyelinated fibers in human spinal ventral roots: C4 to S2. 2009

H-Y Ko, and Y B Shin, and H J Sohn, and J H Chang, and Y H Ahn, and Y H Ha

Department of Rehabilitation Medicine, Pusan National University Hospital, Pusan National University School of Medicine, Busan, Korea. drkohy@gmail.com

METHODS Histological examination of human spinal ventral roots. OBJECTIVE To determine the proportion of unmyelinated fibers in human ventral roots from the 4th cervical (C4) to 2nd sacral (S2) segment, and to evaluate differences in the proportions of unmyelinated fibers between the cervical, thoracic, lumbar and sacral segments, and between autonomic and other segments. METHODS University Teaching Hospital, Busan, Korea. METHODS Eight embalmed adult human cadavers (six males and two females; mean age 56.3 years) were collected. The ventral root samples were obtained by transverse cuts of the ventral roots within 1 cm proximal to the medial portion of the dorsal root ganglion from the C4 to S2 segment. The number of unmyelinated and myelinated fibers was counted in four fields, and the mean number of unmyelinated fibers was calculated. The percentage of unmyelinated fibers was calculated from the ratio of unmyelinated fibers to total fibers (myelinated fibers+unmyelinated fibers). RESULTS The mean percentages of unmyelinated axons in cervical (C4-C8), thoracic (T1-T12), lumbar (L1-L5) and sacral (S1-S2) ventral roots were 16.3, 21.4, 17.8 and 20.7%, respectively. The percentage of unmyelinated fibers in thoracic ventral roots was higher than that for other segments (P<0.001). There was no significant difference in proportions of unmyelinated fibers between the sympathetic segments (T11-L2), parasympathetic segments (S2) and the other segments (C4-T10 and L3-S1) (P=0.1784). CONCLUSIONS Approximately 20% of human spinal ventral root fibers were unmyelinated. The proportion of unmyelinated fibers was highest in the thoracic segments.

UI	MeSH Term	Description	Entries
D008161	Lumbosacral Region	Region of the back including the LUMBAR VERTEBRAE, SACRUM, and nearby structures.	Lumbar Region,Lumbar Regions,Lumbosacral Regions,Region, Lumbar,Region, Lumbosacral,Regions, Lumbar,Regions, Lumbosacral
D008297	Male		Males
D008875	Middle Aged	An adult aged 45 - 64 years.	Middle Age
D009413	Nerve Fibers, Myelinated	A class of nerve fibers as defined by their structure, specifically the nerve sheath arrangement. The AXONS of the myelinated nerve fibers are completely encased in a MYELIN SHEATH. They are fibers of relatively large and varied diameters. Their NEURAL CONDUCTION rates are faster than those of the unmyelinated nerve fibers (NERVE FIBERS, UNMYELINATED). Myelinated nerve fibers are present in somatic and autonomic nerves.	A Fibers,B Fibers,Fiber, Myelinated Nerve,Fibers, Myelinated Nerve,Myelinated Nerve Fiber,Myelinated Nerve Fibers,Nerve Fiber, Myelinated
D002102	Cadaver	A dead body, usually a human body.	Corpse,Cadavers,Corpses
D005260	Female		Females
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D013126	Spinal Nerve Roots	Paired bundles of NERVE FIBERS entering and leaving the SPINAL CORD at each segment. The dorsal and ventral nerve roots join to form the mixed segmental spinal nerves. The dorsal roots are generally afferent, formed by the central projections of the spinal (dorsal root) ganglia sensory cells, and the ventral roots are efferent, comprising the axons of spinal motor and PREGANGLIONIC AUTONOMIC FIBERS.	Dorsal Roots,Spinal Roots,Ventral Roots,Dorsal Root,Nerve Root, Spinal,Nerve Roots, Spinal,Root, Dorsal,Root, Spinal,Root, Spinal Nerve,Root, Ventral,Roots, Dorsal,Roots, Spinal,Roots, Spinal Nerve,Roots, Ventral,Spinal Nerve Root,Spinal Root,Ventral Root
D018709	Statistics, Nonparametric	A class of statistical methods applicable to a large set of probability distributions used to test for correlation, location, independence, etc. In most nonparametric statistical tests, the original scores or observations are replaced by another variable containing less information. An important class of nonparametric tests employs the ordinal properties of the data. Another class of tests uses information about whether an observation is above or below some fixed value such as the median, and a third class is based on the frequency of the occurrence of runs in the data. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed, p1284; Corsini, Concise Encyclopedia of Psychology, 1987, p764-5)	Kolmogorov-Smirnov Test,Kruskal-Wallis H Statistic,Mann-Whitney U Test,Rank-Sum Tests,Spearman Rank Correlation Coefficient,Wilcox Test,Wilcoxon Rank Test,Non-Parametric Statistics,Nonparametric Statistics,Statistics, Non-Parametric,Kolmogorov Smirnov Test,Mann Whitney U Test,Non Parametric Statistics,Rank Sum Tests,Rank Test, Wilcoxon,Rank-Sum Test,Statistics, Non Parametric,Test, Kolmogorov-Smirnov,Test, Mann-Whitney U,Test, Rank-Sum,Test, Wilcox,Test, Wilcoxon Rank,Tests, Rank-Sum,U Test, Mann-Whitney