title: Median Sacral Artery, Sympathetic Nerves, and the Coccygeal Body: A Study Using Serial Sections of Human Embryos and Fetuses.
abstract: To examine how the median sacral artery (MSA) is involved with the coccygeal body or glomus coccygeum, we studied serial frontal or sagittal sections of 14 embryos (approximately 5-6 weeks of gestation) and 12 fetuses (10-18 weeks). At five weeks, the caudal end of the dorsal aorta (i.e., MSA) accompanied putative sympathetic ganglion cells in front of the upper coccygeal and lower sacral vertebrae. At six weeks, a candidate for the initial coccygeal body was identified as a longitudinal arterial plexus involving nerve fibers and sympathetic ganglion cells between arteries. At 10-18 weeks, the MSA exhibited a highly tortuous course at the lower sacral and coccygeal levels, and was attached to and surrounded by veins, nerve fibers, and sympathetic ganglion cells near and between the bilateral origins of the levator ani muscle. Immunohistochemistry demonstrated expression of tyrosine hydroxylase and chromogranin A in the nerves. However, throughout the stages examined, we found no evidence suggestive of an arteriovenous anastomosis, such as well-developed smooth muscle. An acute anterior flexure of the vertebrae at the lower sacrum, as well as regression of the secondary neural tube, seemed to induce arterial plexus formation from an initial straight MSA. Nerves and ganglion cells were likely to be secondarily involved with the plexus because of the close topographical relationship. However, these nerves might play a major role in the extreme change into adult morphology. An arteriovenous anastomosis along the MSA might be an overinterpretation, at least in the prenatal human. Anat Rec, 299:819-827, 2016. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Department of Anatomy, Histology and Embryology, Yanbian University Medical College, Yanji City, Jilin Province, China.
authors.forename: Zhe Wu
authors.initials: ZW
authors.lastname: Jin
authors.affiliation: Department of Neurology, Wonkwang University School of Medicine, Iksan, Republic of Korea.
authors.forename: Kwang Ho
authors.initials: KH
authors.lastname: Cho
authors.affiliation: Division of Physical Therapy, Ongoul Rehabilitation Hospital, Jeonju-si, Republic of Korea.
authors.forename: Hyung Suk
authors.initials: HS
authors.lastname: Jang
authors.affiliation: Division of Internal Medicine, Iwamizawa Kojin-kai Hospital, Iwamizawa, Japan.
authors.forename: Gen
authors.initials: G
authors.lastname: Murakami
authors.affiliation: Department of Anatomy and Human Embryology, Institute of Embryology, Faculty of Medicine, Complutense University, Madrid, Spain.
authors.forename: Jose Francisco
authors.initials: JF
authors.lastname: Rodríguez-Vázquez
mesh_terms: D001158:Arteries / Q000033:anatomy & histology* / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism; D003050:Coccyx / Q000033:anatomy & histology* / Q000378:metabolism; D004622:Embryo, Mammalian / Q000033:anatomy & histology* / Q000378:metabolism; D005333:Fetus / Q000033:anatomy & histology* / Q000378:metabolism; D006801:Humans; D012447:Sacrum / Q000033:anatomy & histology* / Q000098:blood supply / Q000378:metabolism; D013564:Sympathetic Nervous System / Q000033:anatomy & histology* / Q000378:metabolism
chemical_list: D015415:Biomarkers
keywords: coccygeal body; dorsal aorta; glomus coccygeum; median sacral artery; sympathetic nerve