Despite a long history of anatomical studies, the vascular organization of the brainstem is poorly known in most vertebrates. This review examines results from the past 150 years and compares them with a series of new vascular microdissections to provide an overall assessment of vertebrate hindbrain vasculature. The gross anatomy and embryology of cyclostomes, elasmobranchs, actinopterygians and tetrapods reveal a conserved suite of hindbrain vascular features including the: 1) origin and branching of cerebral carotids; 2) ontogenetic origins of the basilar artery from paired precursors, often followed by midline fusion to form an unpaired basilar; and 3) presence of a quasi-segmental series of transverse basilar artery branches that extend circumferentially around the brainstem giving off penetrating vessels. Phylogenetic analysis suggests that paired basilars are primitive for jawed vertebrates, with unpaired basilars arising independently in chondrichthyes, teleosts and tetrapods. Teleosts present a major exception to the general pattern, as penetrating arteries are restricted to a series of midline segmental basilar arterial stems that branch only within the neuroepithelium. This is clearly derived relative to all other vertebrates. Given the dissimilar body plans/lifestyles of groups served by the general brainstem vascular design, the conservation of adult hindbrain macrovasculature likely results from the similarity of embryonic cerebral blood supply across groups, rather than from convergence towards similar neurovascular functional designs. With the high degree of conservation in vertebrate brainstem neuronal anatomy, vascular patterning cues provided by the neuroepithelium practically assure that homologous brain regions are supplied by roughly similar arteries across taxa.
This research has been conducted in order to describe the normal anatomical structures of the stifle joint in buffaloes (Bos bubalis) by using the magnetic resonance imaging and the corresponding anatomical sections. The anatomical slices were used to facilitate the interpretation of the MRI images, and therefore the diagnosis for stifle related diseases would be much easier. The hind limbs of ten healthy adult buffaloes (Twenty stifle joints) were used. After slaughtering, MR images were made in sagittal, transverse, and dorsal planes. After that, the limbs were sectioned by using an electric band saw according to the corresponding MRI images after freezing at -20° for 48 hours. Clinically relevant anatomic structures were identified and labeled at each level of the matching images (MR and anatomic slices).
Ulnar nerve compression has been reported in association with variations in the contents of Guyon's canal, such as the presence of accessory muscles. In the current case study we report on two variations found concurrently in the same hand. Firstly, the presence of an accessory head of the abductor digiti minimi that originated principally from the tendon of palmaris longus in the lower third of the forearm, descended superficial to the ulnar nerve and artery in Guyon's canal, and joined three other heads of the same muscle in the hypothenar eminence. Secondly, the ulnar nerve within the canal showed trifurcation into superficial, deep and muscular branches. A study of 120 hands from cadavers of South Australian population revealed the presence of an accessory head of the abductor digiti minimi that occupied Guyon's canal in 2.5% of the cases, a much lower incidence than previously reported in other populations. Trifurcation of the ulnar nerve seen here was also noted in the left hand of the same cadaver, but without any accessory muscles in Guyon's canal. Knowledge of such variations is relevant to hand surgery.
The parathyroid glands hold a special place in human anatomy, since they were the last major organ to be recognized by humans.The glands are recognized in all vertebrate animals higher than fish, and are derived from the pharyngeal pouches.The molecular signaling pathways that are involved in determining the differentiation of the glands are being elucidated.Studies in mice have demonstrated that the transcription factor encoded by Glial cells missing 2 (Gcm2) is a key regulator of parathyroid development.Recent studies indicate that the tetrapod parathyroid glands and the gills of fish are evolutionarily related structures, and that the parathyroid glands likely come into being as a result of the transformation of the gills during tetrapod evolution.The parathyroid chief cells play a central role in calcium homeostasis by sensing changes in extracellular calcium and releasing parathyroid hormone (PTH) to correct or maintain normal blood calcium levels.Chief cells undergo morphologic changes corresponding to different stages of the secretory cycle.Parathyroid oxyphil cells derived from chief cells as aging or some metabolic derangements, have the potential to produce PTH, PTH-related protein, and calcitriol.The existence of water-clear cells is confirmed in some kinds of animals, which may represent hyperfunction of the parathyroid gland.The presence of water-clear cell is associated with parathyroid hyperplasia or parathyroid adenoma.The molecular regulation of PTH synthesis and release indicates that parathyroid cells detect changes of the extracellular calcium levels by calcium-sensing receptor, which plays a central role in regulating PTH secretion.
Careful analysis of the morphological phenotype of malformed mouse fetuses is an essential step in researching the genesis of cardiovascular malformations. The detection of arterial stenosis and dilation requires metric analysis and reference data defining the normal dimensions of the fetal arteries. Since the genetic background of inbred strains strongly influences the dimensions of the arteries, reference data are strain specific. We aimed at creating objective reference data for diagnosing the stenosis and dilation of important segments of the great intrathoracic arteries of early mouse fetuses bred on the C57BL/6 background. Employing the high-resolution episcopic microscopy (HREM) technique, we created volume data and three-dimensional (3D) computer models of the great intrathoracic arteries of 30 mouse fetuses of developmental stage 22 according to Theiler (TS22). We then defined reproducible measurement positions along the ascending aorta, the pulmonary trunk, the ductus arteriosus and the descending aorta and used a recently published protocol to measure the diameter of the lumen of the arteries at these positions. We present the values obtained for the diameters as measured in µm. We also present the relation of the diameter measured for each blood vessel and the diameters of the lumen of the ascending aorta and pulmonary trunk. The measurements and relative values we provide objectively define the dimensions of important segments of the great intrathoracic arteries of normally developed TS22 mouse fetuses of the C57BL/6 strain. They will function as reliable reference data for diagnosing stenosis and dilation of the measured segments in malformed fetuses.
Objectives/Hypothesis: The aim of this study is to indicate anatomic and immunologic peculiarities of the temporal bone which leave it vulnerable to traumatic, infectious and neoplastic insult.Study Design: Seven patients' cases are described in which the clinical pathology of the temporal bone was bilateral.The bilaterality of these cases serves to illustrate the anatomic points which are the focus of this study.Methods: This is a case series.Results: The seven paradigmatic cases are described and the relevant anatomy is explored.These are bilateral tuberculosis of the middle ear and mastoid, bilateral histiocytosis X, bilateral external canal amyloidosis, bilateral middle ear polyposis in Samter's triad, bilateral temporal bone fractures, bilateral middle cranial fossa encephaloceles, and bilateral congenital enlarged superior vestibular nerve canals.The thinness of the skull base, the many fluid-filled and tissue-filled canals which enter the temporal bone and the thinness of the tissues investing all the surfaces contribute to the temporal bone's vulnerability to trauma, infection and neoplasm. Conclusion:Cases of bilateral temporal bone pathology demonstrate the temporal bone's structural and immunologic weaknesses.
In the present study the brain mass to body mass ratio and external morphological features of the brain of Mobula japanica, Mobula thurstoni and Manta birostris (devilrays) are described. The Mobulids extended the upper boundary of the minimum convex polygon described earlier by other authors for batoids, which is plotted on a double logarithmic scale of brain to body mass, causing some change in the allometric coefficient. The encephalization quotient of Mobulas was higher than unity, therefore it can be concluded that the actual brain mass is greater than expected by the given body mass. M. japanica had the highest percentage (61%) of telencephalic mass from all batoids, while the brain mass of M. birostris was the highest of all fish studied so far. The gross morphology of the enlarged Mobulid telencephalon and cerebellum prominently resembled to that of Sphyrna mokarran (great hammerhead shark). A structural dimorphism of the highly foliated cerebellum was detected between genders of the M. japanica, albeit with a small sample size. No such gender-related dimorphism was detected in brain mass/body mass ratio. Other brain parts were similar to those of other elasmobranch species. The data are discussed in terms of their ecological and evolutionary significance
The trigeminal nerve supplied muscles share many traits due to their common embryological derivation from the mandibular branchial arch.Many of these muscles, especially the masticatory, exhibit very complex intra-and intermuscular anatomical and functional specializations which continue to be investigated.Two schemes have been proposed to classify the intramuscular and extramuscular slips associated with these muscles: 1) based on recognizable laminae within each muscle; 2) based on the pattern of nerve distribution to definable parts of each muscle.The extramuscular slips have been identified on the bases of their nerve supply.The second scheme is beginning to yield results which confirm Edgeworth's (1914Edgeworth's ( , 1935) ) hypothesis regarding the ontogeny and phylogeny of the trigeminal nerve supplied musculature.These advances in the rational classification of these muscles have resulted from improved methods to expose the deeper parts of the masticatory and related spaces.However, because of the piecemeal exposure of parts of the spaces which contain some of the deeper trigeminal muscles there remain several issues that still need to be resolved.We provide a detailed protocol by which all the trigeminal nerve supplied muscles can be isolated from the upper cranium so that the entire mandibular nerve tree along with its musculature may be described as a connected complex of related structures.The practical and clinical implications of this new methodology are evaluated and discussed.
Natural sciences are considered to be exact sciences. However, despite usually being effectively usually more 鄂objective 鈂 than for instance social sciences, they are not immune to a problem common to all sciences: the intrinsic psychological, sociological and/or historical biases of the scientists. In the present paper I will briefly discuss the influence of these biases in natural sciences, using anthropology, archaeology and comparative anatomy as case studies. I will specifically discuss how these influences have lead scientists to 鄂actively search 鈂 and s upposedly 鄂find 鈂 data to support that the first 鄂humans 鈂, the first 鄂behaviorally modern humans 鈂 and the first 鄂fully civilized or sophisticated humans 鈂 were mostly originated in Europe, in some cases to the extent of fabricating false scientific evidence.
A detailed knowledge of the branching patterns and the variations of the cutaneous nerves of the extremities will help to decrease iatrogenic injury to these nerves. A case of abnormal distribution of the superficial peroneal nerve, observed during the routine dissection of the right leg of an 81 year old male cadaver at AIMST University, Kedah, Malaysia is reported here. The nerve after supplying the peroneal muscles of lateral compartment gave a medial dorsal cutaneous branch and a lateral dorsal cutaneous branch. The medial dorsal cutaneous branch descended in front of the middle of the ankle to the dorsum of the foot and supplied the skin of medial side of the great toe, the medial side of the 1 st metatarsal region and the 1 st web space including the adjacent sides of great and second toes. The lateral dorsal cutaneous branch descended in front of the lateral malleolus to enter the lateral aspect of the dorsum of the foot where it divided into medial and lateral terminal branches to supply adjacent sides of the 2nd, 3rd, 4 th and 5th toes. On the other hand, the deep peroneal nerve after supplying the muscles of anterior compartment of leg continued on dorsum of foot without dividing into terminal branches and without supplying the skin of first web space and adjacent sides of great and second toes. It ended by supplying the extensor digitorum brevis muscle. Surgical and clinical significance of this rare variation of the superficial peroneal nerve is discussed and relevant literature is reviewed.
In this paper an alternative preparation and imaging method is presented that allows investigation of the fine structure of hepatic tissue within one hour after the initial fixation step. This approach involves, besides traditional fixation with glutaraldehyde, chemical drying and subsequent investigation of the samples with the new generation of user-friendly desktop scanning electron microscopes. The data presented herein reveal comparative preservation of liver ultrastructure to those that are prepared using classical sample preparation protocols. This low-cost approach permits the swift study of liver tissue subjected to various testing conditions and hence bridges the time gap between experiment and subsequent ultrastructural observation at the nanoscale.
Knowledge of hepatic arterial vascularization and its variations have a significant relevance for the daily practice of hepato-biliary surgeon as well as radiologists. Human cadaver livers (n=60) were obtained from routine autopsies. Resections were carried out en bloc with liver, celiac trunk (CT), left gastric artery (LGA), lesser omentum, superior mesenteric artery (SMA) and head of the pancreas. We have found one case with an exceptional anatomic variation, replaced left hepatic artery (LHA) coming off the SMA directly to the hepatic left lobe. We would like to draw attention for this particularly anatomic variation of the origin of the LHA ensuring that no damage will be made during gastrointestinal surgery.
Sufficient knowledge of eyelid and orbit anatomy is essential for achieving optimal functional and cosmetic results in ophthalmic plastic and reconstructive surgery.Utilizing the surgical techniques used in vivo can result in difficulties in correct exposure and identification of structures in cadavers.Therefore, special techniques are required to perform appropriate post-mortem anatomical dissections of the eyelid and orbit.In addition, as the number of cadavers for teaching and dissections is very limited, systematic anatomical dissections will maximize their efficient utilization.Here, we present detailed techniques of eyelid and orbital dissections with modernized anatomical findings for anatomists as well as ophthalmologists, focusing on preparation for dissection, dissection of the upper and lower eyelids, handling of the conjunctival fornix, the medial and lateral canthi, and identification of extraocular muscle insertions. Preparation for Dissection and Exposure of the Orbicularis Oculi MuscleA. The dissection area is first marked with a fine tip marker (Fig. 1-1).
Objective To elucidate the configurational relationship of the anterior inferior pancreaticoduodenal artery (AIPD) and embryological ventral/dorsal pancreas anlagen.
Why do men and women think differently?Why do they behave differently in stressed situations?Why do women act more emotionally as compared to men?Why do men and women excel at different types of tasks?Why do boys like to play with cars and trucks and superman?These are the common questions which arise commonly in minds.The human brain is a highly complex organ.Studies of perception, cognition, memory and neural functions have found apparent gender differences.These differences may be attributed to various genetic, hormonal, and environmental factors and do not reflect any overall superiority advantage to either sex.Both sexes are equal in intelligence, but tend to operate differently.Men and women appear to use different parts of the brain to encode memories, sense emotions, recognize faces, solve certain problems and make decisions.Indeed, when men and women of similar intelligence and aptitude perform equally well, their brains appear to go about it differently, as if nature had separate blueprints.Sex differences in the brain may play a role in learning processes, language development, and progression of neurologicallybased diseases.Sex differences need to be considered in studying brain structure and function and may raise the possibility of sex-specific treatments for neurological diseases.In this article it is reviewed that how does the brain of a male look and function differently from a female's brain, and what accounts for these differences?
A male Holstein Friesian calf affected with superior cervical ectopia cordis was examined macroscopically and histologically to assess the severity and elucidate other anomalies.This calf died 10 minutes after birth.The heart was round, weighed 380gm, was enveloped in the pericardium, and situated in the swollen part of the ventrocervical region underneath the skin.Inside the spacious pericardial cavity, the heart was characterized by a duplicated and cranioventral apex.The heart was Histologically normal.The cranial vena cava and vena azygos were also duplicated.The sternum was short, especially in the body and xyphoid process.No other anomaly was seen in association with this case.
Introduction: Argyrophil cells are neuroendocrine cells which react with silver stain resulting in brown or black coloration with the help of an external reducer. Argyrophil cells occur rarely in the normal human uterine cervix but are found in a variety of invasive tumors arising in the cervix.
Synchondrosis is defined as the development of a union between two bones by the formation of either hyaline cartilage or fibro-cartilage. This paper reviews the relationship between cranial base synchondroses and craniofacial development. The cranial base synchondroses are important growth centers of the craniofacial skeleton. Their abnormalities lead to numerous growth and developmental conditions in the craniofacial region. In dentofacial orthopedics, mechanical forces are commonly applied to cranial bones for growth modification to treat such conditions. Molecular biology and genetics provide tools to investigate the molecular mechanisms, genes and transcription factors responsible for synchondrosis and craniofacial development.
Some morphometric parameters of the buffalo gonad and epididymis were compared in the mating (late autumn-winter) versus non-mating (late spring to the beginning of autumn) seasons. Organs from mature bulls of proven fertility were collected at slaughtering in February and September and used for this study. Testicular and epididymal diameters and weights were measured. The diameters of the testicular seminiferous tubules, as well as the diameters of the ductal lumen in sections taken from caput, corpus and cauda, were compared on haematoxylin and eosin-stained sections. The height of epididymal principal cells was also measured, from the basement to the apical membrane. The data obtained in the two seasons were analyzed by ANOVA, co-variating the histometric data for testicular and epididymal weight, respectively. Season-related differences were observed. Testicular and epididymal weights were higher during the mating period, as well as the organ lengths. Spermatogenesis was conserved in the resting period, but the testis showed smaller tubular diameters. In the epididymal caput and corpus the tubular diameters and epithelial cell height were significantly diminished in summer. On the contrary, tubular diameter and epithelial cell height of cauda epididymis increased during the summer, due to accumulation of non-ejaculated spermatozoa. Seasonal variations of genitalia recorded in buffalo bulls could represent an interesting aspect affecting fertility, which might influence the quality of semen and, in turn, the chance of cryopreservation. Morphometric studies of reproductive organs could contribute to better develop the reproductive potential in this species.
