The misrepresentation of the human pelvis.

A representative series of illustrations of the human bony pelvis dating from the sixteenth century to the present is used to demonstrate the persistent misrepresentation in the orientation of the pelvis and in the nomenclature. Early erroneous concepts were probably strongly reinforced by publications of the Belgian anatomist Vesalius in the sixteenth century. In mounting the vertebrae on a vertical iron rod, he erased much of the sacral curvature and, as a consequence, the orientation of the rest of the pelvis was distorted. True versions of the pelvis were executed by Leonardo da Vinci before the time of Vesalius but these drawings were apparently among those that were lost for many years. A relatively small number of similarly accurate depictions of the bony pelvis have appeared down through the centuries and some of these are also included. A persistent error in many anatomical textbooks used today presents a modified inferior view of the pelvis as the "front view" and a nearly accurate front view as a "view from above." No definitive conclusion can be reached concerning the reason(s) for the remarkably long persistence of this error. The figures referenced are presented in the Gallery immediately following this article.

Dermal extracellular lipid in birds.

A light and electron microscopic study of the skin of domestic chickens, seagulls, and antarctic penguins revealed abundant extracellular dermal lipid and intracellular epidermal lipid. Dermal lipid appeared ultrastructurally as extracellular droplets varying from less than 1 micron to more than 25 microns in diameter. The droplets were often irregularly contoured, sometimes round, and of relatively low electron density. Processes of fibrocytes were often seen in contact with extracellular lipid droplets. Sometimes a portion of such a droplet was missing, and this missing part appeared to have been "digested away" by the cell process. In places where cells or cell processes are in contact with fact droplets, there are sometimes extracellular membranous whorls or fragments which have been associated with the presence of fatty acids. Occasionally (in the comb) free fat particles were seen in intimate contact with extravasated erythrocytes. Fat droplets were seen in the lumen of small dermal blood and lymph vessels. We suggest that the dermal extracellular lipid originates in the adipocyte layer and following hydrolysis the free fatty acids diffuse into the epidermis. Here they become the raw material for forming the abundant neutral lipid contained in many of the epidermal cells of both birds and dolphins. The heretofore unreported presence and apparently normal utilization of abundant extracellular lipid in birds, as well as the presence of relatively large droplets of neutral lipid in dermal vessels, pose questions which require a thorough reappraisal of present concepts of the ways in which fat is distributed and utilized in the body.

Dermal-epidermal relationships in the skin of the bottlenose dolphin (Tursiops truncatus).

Using a variety of methods the outer surface of the dolphin dermis presents as a rather regularly arranged series of mainly longitudinal and approximately parallel ridges which are surmounted by laterally flattened, regularly distributed dermal papillae. At variable intervals groups of dermal ridges are supported by shallow elevations referred to here as basal dermal elevations. These tend to contain vessels and/or nerves for distribution to two or more dermal ridges. The opposing epidermal surface reveals an irregularly edged series of nearly parallel epidermal ridges alternating with the grooves which in the living state contain the dermal ridges. In the depths of these grooves are the crypts which in the intact skin contain the dermal papillae. Nothing is observable which could correspond to the epidermal pegs referred to in the literature. Small irregular epidermal projections (knobs) appear along the free edge of the epidermal ridge. Topographical variations in density and height of dermal ridges, height of basal dermal elevation plus dermal ridge and papillae as well as total epidermal thickness are illustrated by means of skin maps. Inconsistencies in the literature on Cetacean skin are discussed.

Electroacupuncture-induced analgesia in sheep: measurement of cutaneous pain thresholds and plasma concentrations of prolactin and beta-endorphin immunoreactivity.

Eleven male and 15 female sheep were subjected to electroacupuncture (EA) treatment, using 2 needle loci described in the Chinese veterinary literature as Yao Pang (lumbar region) and San Yang Lu (1 thoracic limb). Noninjurious cutaneous stimuli were applied, using a calibrated pin-prick probe, a clamp, and a contact heat (75 to 95 C) probe. Cutaneous pain thresholds (PT) were quantified in 7 body areas during control (no acupuncture needles and no electrostimulation) and EA experiments, before and after IV injection of naloxone. Using each animal as its own control, each EA experiment was classified as inducing either good or poor anagelsia on the basis of whole-body PT values. Plasma concentrations of immunoreactive beta-endorphin (beta E) and prolactin were quantified in sequential plasma samples collected at 9-minute intervals throughout all experiments. Electroacupuncture at each locus increased (P less than 0.01) PT (ie, caused cutaneous analgesia) in 6 of 7 body areas, and increased (P less than 0.05) plasma concentrations of immunoreactive beta E and prolactin. In EA experiments in which good analgesia was induced, plasma beta E was increased more (P less than 0.05) than in EA experiments in which poor analgesia was induced. This difference was more evident for the Yao Pang locus. Generally, plasma prolactin concentrations were increased more with good analgesia than with poor analgesia for the Yao Pang locus. Electroacupuncture stimulation of the San Yang Lu locus was associated with higher plasma beta E concentrations than that associated with the Yao Pang locus. Increases in plasma prolactin concentrations were comparable between loci.(ABSTRACT TRUNCATED AT 250 WORDS)

Production of cutaneous analgesia by electroacupuncture in horses: variations dependent on sex of subject and locus of stimulation.

Cutaneous pain thresholds to pinprick, pinch, and heat stimuli were quantified during control and electroacupuncture trials in 23 horses. Pain thresholds for 8 areas of the body during control trials (no needles) were statistically compared with pain thresholds measured in the same areas of the same horse when given electroacupuncture treatment. Statistically significant increases of pain threshold were interpreted as induced analgesia and occurred mainly in 5 areas of the trunk, but not in the head or extremities. Analgesic efficacy varied between sexes and among 3 groups of points chosen from Chinese traditional veterinary literature. Analgesia was induced equally well in both castrated males and intact females by the electrostimulation of 5 needles inserted on the gluteal (rump) and lumbar (loins) regions. However, stimulation of 2 needles located only in the gluteal region caused a significant analgesia in females only. In contrast, stimulation of 2 needles located in the thoracic limb was analgesic in males, but infrequently so in females. Therefore, we observed differential analgesia due to an interaction between needle location and sex of subject.

Plasma cortisol and beta-endorphin in horses subjected to electro-acupuncture for cutaneous analgesia.

Electro-acupuncture (EA) treatment of horses to induce cutaneous analgesia also increased plasma concentrations of beta-endorphin (beta-EP) and cortisol. The magnitude of these increases did not relate consistently to the degree of EA-induced analgesia. Respiration and heart rates were also markedly increased during EA treatment. Intact female horses had higher packed cell volume and plasma beta-EP as well as lower plasma total protein than castrated male horses. Plasma cortisol, heart rate, and respiration rate did not differ significantly between sexes. None of the parameters measured before or during EA treatment provided an explanation for the differential cutaneous analgesia which depended on sex of subject and locus of stimulation as reported elsewhere.

Interfollicular smooth muscle in the skin of the domesticated pig (Sus scrofa).

An interfollicular smooth muscle that spans the triad of hair follicles has been identified in the skin of the domesticated pig (Sus scrofa). This muscle has been previously noted by other investigators and identified as an arrector pili muscle. However, it cannot be interpreted as such for the following reasons: 1) It lies opposite the arrector pili muscle on the follicle; 2) the orientation of its fibers is perpendicular to those of the arrector pili; 3) the two muscles are not continuous; their attachments are different; and 4) contraction of the interfollicular muscle would have little effect on erection of the hairs. Based on structural evidence, it is postulated that upon contraction the muscle draws the base of the three aligned follicles together into a triangular conformation. In so doing, it may rotate the outer two follicles of the triad. Its specific functional role is unknown.

Light microscopic morphology of low resistance skin points in the guinea pig.

This study compares the light microscopic structure of low resistance skin points (LRSP) to high resistance skin points (HRSP) of the guinea pig, Previously, LRSP have been shown to coincide with acupuncture loci. Epidermal nuclei and dermal nuclei were counted at both LRSP and at control points or HRSP. In addition, hair follicles, blood vessels, and sebaceous nuclei were likewise quantitated. This data, collected in a blind manner, was then subjected to statistical analysis using a nested analysis of variance and a Student's "t" test. The former test indicated an increase in density of hair follicles at LRSP, while both demonstrated a decrease in dermal nuclei at LRSP. An interesting finding is that the epidermis at both LRSP and HRSP is indistinguishable at the light microscopic level. This was indicated by both statistical procedures. Finding of a Haarscheibe, an aggregation of Merkel cell-neurite complexes, only at HRSP tends to preclude its role as an acupuncture neurotransducer. Finally, there appeared to be no obvious qualitative differences between LRSP and HRSP observable at the light microscopic level.

Effects of low-level x-irradiation on cat cerebella at different postnatal intervals. I. Quantitative evaluation of morphological changes.

Whole head fractionated doses of 200 r and 150 r were initiated postnatally in five experimental age groups (birth, 1-week, 2-week, 3-week and 4-week) and continued over a period of 14 or 20 days to prevent reconstitution of the external granular layer. Animals irradiated at birth displayed minor deficits in behavior, which included ataxia, tremor, hypertonus and dysmetria, while animals irradiated at 1-week showed only mild symptoms of hypermetria. All other animals displayed no motor deficits. Animals irradiated at birth had smaller eyes and ears, a reduction in the size of the entire head and were susceptible to seizures. All animals were sacrified at 70 days of age. The cerebellum was found to be reduced in size and weight, the greatest deficit being seen in animals x-irradiated at the very early ages. Newborn condition animals were found to have large compliments of interneurons in the molecular layer, an established internal granular layer, and Purkinje cells were found to have a normal orientation, position, and to be unreduced in number or size. Total granule cell deficits were found to range from 83% at birth to 29% at four weeks. Quantitative changes for the molecular layer, internal granular layer, medullary layer, Purkinje cell to granule cell ratio, and granule cell density, all depicted the greatest changes in the newborn, 1-week and 2-week conditions. This experiment confirmed that the critical period in the development at which damage would result in behavioral abnormalities was from birth to five days, while for neuroanatomical abnormalities, this critical period was from birth to 18 days.

Effects of low-level x-irradiation on cat cerebella at different postnatal intervals. II. Changes in Purkinje cell morphology.

The whole-head of infant kittens was irradiated with fractionated doses of 150 R and 200 R at different postnatal intervals. Experimental age conditions consisted of an irradiated newborn, 1-week, 2-week, 3-week, and a 4-week age condition while the age of sacrifice remained constant at 70 days. The molecular layer thickness was reduced by 47% in the newborn, 40% in the 1-week group, 17% in the 2-week group, 19% in the 3-week group and by 9% in the 4-week group. An evaluation of Golgi impregnated material revealed that the dendritic arborizations of purkinje cells were consistently reduced the earlier the age at which radiation was begun. A reduction in spiny branchlets was seen in all of the experimental conditions. All experimental age conditions displayed the phenomenon of dendritic "damming" at the pial surface, which consisted of an excessive crowding of spiny branches at this level. An increased growth of the primary dendrite before branching tood place was seen in the newborn and 1-week group. This became less but was still significant in the 2-week group. A correlation of this phenomenon with the presence or lack of stellate cells is disclssed. Purkinje cells with two or more dendrites emerging from their soma were classified and analyzed separately. It was found that the primary dendritic branching in these cells often followed separate morphological patterns and appeared to be independent of each other. Climbing fibers were found to conform to the abnormal dendritic arborizations of the Purkinje cells, and were reduced in complexity in the early radiation treatment groups. This suggested that climbing fibers had no influence upon the dendritic growth pattern, but instead were under the influence of the Purkinje cell dendritic growth.

Effects of low-level x-irradiation on cat cerebella at different postnatal intervals. III. Changes in the morphology of interneurons in the molecular layer.

The whole head of infant kittens was irradiated with fractionated doses of 150 R and 200 R at different postnatal intervals. Experimental age conditions consisted of a newborn, 1-week, 2-week, 3-week, and a 4-week age condition while the age of sacrifice remained constant at 70 days. Going analysis revealed that the interneurons found in the molecular layer of the newborn, 1-week and 2-week condition were basket cells. Stellate cells were found in increasing numbers in the 3-week and 4-week conditions. Basket calls were found to occupy the entire molecular layer in the newborn and 1-week conditions resulting in an abnormal axonal plexus. The position of the basket cell soma was found to be in the same plane as its axonal projection. The branching point of the primary dendrite of Purkinje cells was found to correlate with the amount of molecular layer occupied by the abnormal basket cell plexus. Interneurons in the molecular layer were found to show different dendritic growth patterns dependent upon where their soma was located. Interneurons in the deep molecular layer showed only a decreased dendritic field, whereas interneurons in the middle and superficial moledular layer had an abnormal growth of dendrites into the deep molecular layer. A hypothesis is presented to account for the decreased dendritic arborization and the increased length of the primary dendrite before branching, the ectopic basket cell and their abnormally directed dendritic growth, and the difference in behavioral deficits between the newborn and the 1-week conditions.

Comparative study of the dorsal motor nucleus of the vagus nerve.

Quantitative studies were made of cells in the dorsal motor nucleus of the vagus nerve in the horse, dog, cat, pig, sheep, goat, and calf. This nucleus was larger in ruminants than in nonruminants. Some cells in all parts of the nucleus supplied visceral structures in the head, cervical, thoracic, and abdominal regions; however, a definite topographic localization did exist within the nucleus. Eighty percent of the cells which supplied the abdominal viscera were in the rostral and rostral-middle regions. The cells which supplied the thoracic viscera were distributed almost equally within the rostral three-quarters of the nucleus. Seventy-three percent of the cells which supplied viscera in the head and neck regions were in the caudal-half of the nucleus. The rostral region of the nucleus was much larger in ruminants than in nonruminants. It is proposed that cells in the rostral region of the nucleus supply the highly developed rumen and reticulum.

Morphological characteristics of dendrite bundles in the lumbar spinal cord of the rat.

The finding of motoneuron dendrites organized into small compact bundles in cats, monkeys and pigs suggested that a study of this phenomenon in rats should be undertaken. An analysis was performed with electron microscopy, light microscopy and Golgi methods. An extensive dendrite bundle organization was found in the sixth lumbar segment of the spinal cord. Two discrete bundles were localized bilaterally: a lateral bundle in the ventrolateral gray substance, and a medial bundle in the ventral funiculus. The lateral bundle was found to consist of longitudinally oriented dendrites, neurocytons, glial cells and capillaries. As many as 1678 closely packed dendrites were observed in the lateral bundle. The medial bundle contained dendrites directed across the midline and also longitudinally oriented dendrites. Neurocytons in the medial dendrite bundle were found singly or in clusters, and many radiating bundles of dendrites were observed projecting toward the lateral bundle. Golgi analysis confirmed that neurons in the lateral bundle had most of their dendrites oriented longitudinally. It was possible to trace several dendrites into the lateral bundle from dorsally and medially lying neurons. Electron microscopy substantiated the fact that the bundles were composed of dendrites. It also revealed numerous dendrodendritic and dendrosomatic contacts which were desmosomal in type as well as an abundance of small unidentified processes. Various functions which have been attributed to the dendrite bundles are discussed.