Hyung Suk Jang

Composite nerve fibers in the hypogastric and pelvic splanchnic nerves: an immunohistochemical study using elderly cadavers

To determine the proportion of nerve fibers in the hypogastric nerve (HGN) and pelvic splanchnic nerve (PSN), small tissue strips of the HGN and PSN from 12 donated elderly cadavers were examined histologically. Immunohistochemistry for neuronal nitric oxide synthase (NOS), vasoactive intestinal peptide (VIP), and tyrosine hydroxylase (TH) was performed. More than 70% of fibers per bundle in the HGN were positive for TH at the level of the sacral promontory. In addition, NOS- (negative) and/or VIP+ (positive) fibers were observed in small areas of each nerve bundle, although the proportion of each was usually less than 10%. In the PSN near the third sacral nerve root, the proportion of nerve fibers positive for NOS and/or VIP (or TH) was below 30%. In both the HGN and PSN, the number of VIP+ fibers was usually greater than that of NOS+ fibers, with frequent co-localization of NOS and VIP. More fibers in both nerves were positive for TH than for these other markers. In contrast to pelvic plexus branches, there were no differences in the proportions of NOS+ and VIP+ fibers between nerve bundles in each of the tissue strips. Thus, target-dependent sorting of nerve fibers was not apparent in the HGN at the level of the sacral promontory or in the PSN near the third sacral nerve root. The NOS+ and/or VIP+ fibers in the HGN were most likely ascending postganglionic fibers to the colon, while those in the PSN root may be preganglionic fibers from Onufs nucleus.

The Filum Terminale Revisited: A Histological Study in Human Fetuses

Previous studies have suggested that secondary neurulation provides no functional neurons but only the filum terminale. However, no studies have confirmed that the coccygeal and lower sacral nerves do not originate from the secondary neural tube but only from the primary tube. To obtain a better understanding of these relationships, we examined sagittal or frontal sections from 20 embryonic and fetal specimens ranging from 6 to 14 weeks of gestation. During the growth of the vertebral column as well as the subsequent upward migration of the caudal end of the dural sac, the secondary neural tube was stretched to maintain the original attachment to the coccyx or the lower sacral vertebra. The filum-like structure showed much individual variability but in all cases appeared to be derived from the stretched neural tube. Intermediate age morphology revealed that the secondary neural tube itself provided an initial filum terminale before the ascent of the dural sac. Given that the coccygeal and lower sacral nerves are likely to originate from the secondary neural tube, these parts of the tube persisted and differentiated into spinal neurons to form the anococcygeal nerves. Likewise, the filum terminale was also most likely to contain some neurons that persisted postnatally. Depending on the timing and site of degeneration of the secondary neural tube, individual variations could occur in proportion to the amount of sensory and motor elements in the anococcygeal nerve supply.

Median Sacral Artery, Sympathetic Nerves, and the Coccygeal Body: A Study Using Serial Sections of Human Embryos and Fetuses.

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.

Coccygeal body revisited: An immunohistochemical study using donated elderly cadavers

To describe the normal anatomy and histology of the adult coccygeal body (CB) and to discuss about the origin and function, using immunohistochemistry, we examined 29 CBs found in 32 elderly donated cadavers without macroscopic pathology in the pelvis. The CB was usually located in or near the anococcygeal ligaments. It was almost always composed of multiple masses or nodules of round glomus cells (smooth muscle actin or SMA++). However, the CB sometimes contained abundant dilated veins with scattered glomus cells. Thus, the CBs varied from the glomus cell nodule‐dominant type, through an intermediate morphology with a mixture of nodules and veins, to the vein‐dominant type. Each glomus cell mass was surrounded by abundant sympathetic nerves. In all specimens, we found multiple abnormal arteries, each of which carried a glomus‐like cell layer around the almost ‐obliterated vascular lumen; as well as an SMA‐negative thick arterial wall containing abundant sympathetic nerves. The ligaments around the CB are known to be under strong mechanical stress from the pelvic floor. We considered abnormal arteries containing the unique internal layer as an intermediate between a normal muscular artery and a glomus cell mass of CB. Under long‐termed mechanical stress, a muscular artery seems to lose smooth muscles with increased sympathetic nerve fibers, to compensate for the lack of muscle function. Taken together with fetal morphology (our recent report), some or most of the CBs might not be an arteriovenous shunt but a result of stress‐induced acquired transformation of pericytes. Anat Rec, 2017.

Significant Differences in Sympathetic Nerve Fiber Density Among the Facial Skin Nerves: A Histologic Study Using Human Cadaveric Specimens

Sympathetic nerve fibers in the skin nerves are connected with vasomotor, thermoregulatory, sensory input modulatory, and immunologic events; however, to our knowledge, no histological information is available for skin nerves in the human face. Using specimens from 17 donated cadavers (mean age, 86 years), we measured a sectional area of tyrosine hydroxylase (TH)‐positive fibers in (1) the frontal nerve (V1), (2) the infraorbital nerve (V2), (3) the mental nerve (V3), (4) the greater auricular nerve (C2), (5) the auriculotemporal nerve (ATN), and (6) the zygomatic branch of the facial nerve (VII). The V1, V2, and V3 were obtained at their entrances to the subcutaneous tissue from the bony canal or notch. The V1, C2, ATN, and/or VII usually contained abundant TH‐positive fibers (almost 3%–8% of the nerve sectional area), whereas the V2 and V3 consistently carried few TH‐positive fibers (<1%). The difference between these two groups was quite significant (P < 0.001). Thus, from the superior cervical ganglion, the sympathetic nerve fibers reached the forehead through the frontal nerve trunk, whereas artery‐bounded fibers came to the cheek, nose, and mouth. The sympathetic palsy caused by trigeminal nerve involvement is mainly characterized by the symptoms seen in the distribution of the ophthalmic division of the trigeminal nerve, such as in Horners syndrome. It suggests that the forehead and the other facial areas are representative parts of those different sympathetic innervations that could be useful for evaluating the sympathetic function of the face in various diseases. Anat Rec, 299:1054–1059, 2016.

Topographical relationships of intramuscular nerves and vessels of the motor endplates in the thigh and gluteal regions of human fetuses: an immunohistochemical study

PurposeThe aim of this study was to describe topography of vessels and nerves in striated muscles to understand individual muscle function.Materials and methodsImmunohistochemistry for nerve and artery was used to examine the thigh and gluteal muscles of six human midterm fetuses.ResultsThe supplying nerves often accompanied arteries along epimysium bundling muscle fibers as well as in the covering fascia surrounding the entire muscle mass. However, courses of nerve twigs were usually independent of those of vessels in muscle bundles. Notably, irrespective of whether or not the vascular bundle accompanied the nerves at the muscle surface or hilus, most of the motor endplate bands did not accompany the vessels.ConclusionSince the motor endplates were low vascularised, a chemical induction of vessels for nerve terminal development (or the reversed induction) seemed unlikely in striated muscles. In contrast to proprioceptive neuromuscular facilitation, manual stimulation of the endplate bands may stimulate muscle activity without sympathetic reflexes through vessel-accompanying nerves.

Anterior Corticospinal Tract Revisited: A Study Using Human Fetuses

In the human corticospinal tract (CST), the anterior CST is known to be much thinner than the lateral CST, but fetal development of the CST remains obscure. In this study, we examined horizontal histological sections of the cervical spinal cord from 50 midterm fetuses (crown-rump length, CRL, 70-150 mm; 12-18 weeks) as well as 15 late-stage fetuses (CRL 230-250 mm; 28-30 weeks). While the lateral CST appeared at 14-15 weeks in the cervical cord of the midterm fetuses, we found the anterior CST in only 3 fetuses: CRL 117 mm (15 weeks), and CRL 144 and 150 mm (18 weeks). However, in the late-stage fetuses, the anterior CST exhibited a spectrum of variations, including bilaterally thick tracts (3 fetuses), a unilaterally thick tract (5 fetuses) and a thin or absent tract (7 fetuses). In the group with the thickest anterior CST, the cross-sectional area reached 40% of that of the lateral CST. In contrast to the stable morphology of the lateral CST, the shape of the anterior tract varied slightly between the cervical segments. Immunohistochemical observations demonstrated no difference between the lateral and anterior CSTs: (1) in macrophage infiltration, which suggests apoptosis, and (2) in the arrangement of radial glial fibers. Our findings indicate that the development of the anterior CST starts later than that of the lateral tract, with significant individual variations. The functional relevance of the anterior CST, if present, might not be found in an independent cortical input to motor neurons but in a remodeling of the ascending tracts.

Human nasociliary nerve with special reference to its unique parasympathetic cutaneous innervation.

The frontal nerve is characterized by its great content of sympathetic nerve fibers in contrast to cutaneous branches of the maxillary and mandibular nerves. However, we needed to add information about composite fibers of cutaneous branches of the nasociliary nerve. Using cadaveric specimens from 20 donated cadavers (mean age, 85), we performed immunohistochemistry of tyrosine hydroxylase (TH), neuronal nitric oxide synthase (nNOS), and vasoactive intestinal polypeptide (VIP). The nasocilliary nerve contained abundant nNOS-positive fibers in contrast to few TH- and VIP-positive fibers. The short ciliary nerves also contained nNOS-positive fibers, but TH-positive fibers were more numerous than nNOS-positive ones. Parasympathetic innervation to the sweat gland is well known, but the original nerve course seemed not to be demonstrated yet. The present study may be the first report on a skin nerve containing abundant nNOS-positive fibers. The unique parasympathetic contents in the nasocilliary nerve seemed to supply the forehead sweat glands as well as glands in the eyelid and nasal epithelium.