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PubMed1975

Cusp size, sexual dimorphism, and heritability of cusp size in twins.

Overall measures of mandibular molars reflect the combined size contributions of the component cusps and ridges. Until now, the size hierarchy of primary and permanent mandibular molar cusps remained unclear. This paper utilizes the relative plane surface areas (basal area dimensions) of the individual molar cusps, as assays of cusp size to demonstrate cusp size variations within populations, antimere cuspal variations, sexual dimorphism, and, the heritability of cusp size. Duplicate dental casts from 199 pairs of like-sexed twins provide the raw dats. Defined anatomic landmarks on the occlusal surfaces were reduced to X-Y rectangular coordinates prior to the computation of the basal areas dimensions. The results establish a cusp size hierarchy specific for molar type, i.e., five-cusped molars with a distal fovea and distal marginal ridge (5fd), five-cusped molars without a distal fovea and without a distal marginal ridge (5o), and four-cusped molars (4c). Sexual dimorphism in cusp size is apparent in 5fd molar cusped but not in 5o molar cusps. However, males have a significantly higher frequency of 5fd molars. Females have a higher frequency of smaller 5o and 4c molars which have fewer crown components. Moreover, female 5o molars have cusps as large as or larger than 5o male molor cusps. Right-side-left-side differences exist between antimere cusps based on relatively low correlations. The mirroring of molor types occurs infrequently. When observed, most intrapair differences for cusp size, using F-ratios, indicate a low component of hereditary variability.

Dentition↗
PubMed1991

Sexual dimorphism in the baboon facial skeleton.

Baboons exhibit marked sexual dimorphism in many aspects of their morphology. Dimorphism is especially pronounced in the face. We use finite-element analysis to investigate the ontogeny of sexual dimorphism in a cross-sectional sample of baboon (Papio sp.) faces. This method provides detailed quantitative information about size and shape changes at anatomical landmarks in the face during growth. Allometric results suggest that sexual dimorphism in facial size and shape is produced by ontogenetic scaling: males and females share a common ontogenetic trajectory. Analyses of growth in time, which complement allometric analyses, show that female growth slows much earlier than male growth, accounting for the differences between sexes. Local size and local shape follow similar patterns of growth, but changes in these variables are slower in females. Local and global facial size are much more dimorphic than local and global facial shape.

Animals↗
PubMed2006

Human osseous intervertebral foramen width.

Alterations of the width of the human intervertebral foramen can play a pathophysiological role in low back pain. Osseous dimensions of the human intervertebral foramen are rarely recorded. Therefore, we present reference data obtained from skeletal samples of known lifestyle, population affinity, sex, and age at death. Cervical, thoracic, and lumbar vertebrae of functional transition zones of 71 macroscopically normal spines from early 19th century AD Swiss burial sites were selected. The intervertebral foramen widths (IFW) were analyzed with respect to possible lateralization and the impact of sex, individual age, and stature. Neither a significant side difference nor a correlation of IFW with individual age or stature could be found. Females show somewhat larger IFW than males, especially in the lumbar region. Data comparisons with earlier studies are limited due to methodological differences and possible interpopulational variations. Furthermore, the osseous intervertebral foramen only reveals a glimpse of the clinically relevant in vivo structure. Nevertheless, more focus on the osseous dimensions of the intervertebral foramen will provide baseline data of this important anatomical landmark. These data could also explore the peculiarities of the intervertebral foramen, such as its reverse sex dimorphism.

Adult↗
PubMed1978

Venous angioma of the optic chiasm.

A 30-year-old man presented with decreased vision in the right eye of three weeks' duration. Examination indicated a chiasmal syndrome and evidence of subarachnoid hemorrhage. CAT scan showed a large suprasellar mass. Surgical intervention confirmed the presence of a globular lesion filled with blood clots involving mainly the right side of the optic chiasm. Following removal of the clots, the chiasm regained its shape and anatomical landmarks. Biopsy of the mass demonstrated a venous angioma located within the optic chiasm as well as recent and old bleeding. Following surgery the patient did well and recovered vision in the right eye, though a left homonymous hemianopia persisted.

Adult↗
PubMed1985

Ultrasonic microdissection of the mouse mandible: exposure of the vasculature of alveolar bone and myelinated axons of the pulp.

The present scanning electron microscopic study describes a new method for the exposure of blood vessels of mouse alveolar bone and myelinated nerves of the dental pulp. This technique differs from others because it does not remove the periodontal ligament, allowing study of the vascular continuity between alveolar bone and periodontal ligament. Fixed and demineralized mandibles are digested with bacterial collagenase (1 mg/ml) at 37 degrees C for 12 hours, exposed to buffered osmium tetroxide for 24 hours, and ultrasonicated at 80 kHz for 5 minutes. The technique demonstrates that the vascular distribution of the interdental and interradicular septa is different. Vessels pass horizontally through the interdental septum and are continuous with vessels of the adjacent periodontal ligament. Vessels of the interradicular septum branch from a central vessel, pass toward the adjacent periodontal ligament, and become continuous with its vessels. Thus, the pattern of vessel distribution of the interdental septum of the mouse has little similarity to that of man or of research animals. The present study provides an improved method for demonstration of bone vasculature and pulpal axons while retaining valuable anatomical landmarks.

Alveolar Process↗
PubMed1986

Rotation of the junction of the outflow tract and great arteries in the embryonic human heart.

The factors which give rise to the normal relationship between the great arteries and their respective ventricles are unknown. The developmental anatomy of this region was studied by using frontal, sagittal, or transverse serial histologic sections of 17 normal human embryos of Carnegie stages 15-19 from the Carnegie Embryological Collection. Distances and angles between major anatomic landmarks were determined by using computer reconstructions of the serially sectioned embryos, three-dimensional analytic geometry, and Euclidean distance formulas. The findings show that between stages 15 and 19 there is a marked rotation of the axis of the semilunar valves: frontal 121 degrees counterclockwise, sagittal 196 degrees counterclockwise, and transverse 240 degrees clockwise. Simultaneously the great arteries lengthen at a faster rate than the rest of the heart; and there is also an increase in the caliber and wall thickness of the great arteries. These results suggest that the changing rate of growth between the great arteries and the heart is necessary to align the great arteries, the semilunar valves, and the muscular outflow tract septum appropriately with respect to the interventricular septum. Reductions in the rate of growth of the great arteries relative to the heart could, by causing changes in the rotation of great arteries and outflow tract septum, have a role in the pathogenesis of cardiovascular malformations such as tetralogy of Fallot and transposition of the great arteries.

Arteries↗
PubMed1991

Surgical anatomy of donor extended right trisegmentectomy before orthotopic liver transplantation in children.

Liver transplantation is now accepted as the treatment of choice for children with end stage liver disease. A major constraint has been the shortage of donor organs of appropriate size. The use of reduced size adult organs has partially alleviated this problem but the previous technique employed was limited to a donor:recipient body-weight disparity of not greater than 3:1. Recently a new technique has been described that allows safe transplantation with a donor:recipient weight ratio of greater than 10:1. This should greatly increase the paediatric donor pool. Anatomical landmarks and techniques necessary for donor reduction hepatectomy are described from the dissection of 50 adult cadaveric livers. Variations in all important biliary and vascular structures necessitated adjustments in operative technique.

Bile Ducts↗
PubMed2002

Brachiocephalic veins: an overlooked approach for central venous catheterization.

Central venous access is important in both assessment and treatment of the patient. In modern clinical practice, a percutaneous approach is preferred. The well-established subclavian and internal jugular vein catheterization techniques, however, still carry the risk of major acute complications. In this article we describe a trial study of a percutaneous brachiocephalic vein catheterization technique conducted on a total of 74 cadavers undergoing autopsy. Relying on constant and easily recognizable anatomical landmarks, we performed a total of 128 catheterizations of the right and left brachiocephalic veins. The success of catheterization was ascertained by regional dissection. Our results show very high reproducibility with a success rate of about 97% on the first attempt of catheterization on both right and left sides. Equally important, collateral injury of neighboring structures was consistently absent. We propose the introduction of this rather overlooked approach into clinical practice.

Adolescent↗
PubMed2004

Anatomy of the pelvic plexus and innervation of the prostate gland.

We have examined the anatomy of the pelvic (inferior hypogastric) plexus in six male cadavers, paying particular attention to gross anatomical landmarks that might aid in locating it and have used immunohistochemistry to study the small branches of the plexus that supply the prostate gland. The pelvic plexus was found two finger breadths lateral to the third anterior sacral foramina, lying deep to a line drawn from third sacral vertebra, the conventional level of the recto-sigmoid junction, and the palpable posterior superior surface of the pubic symphysis. Immunohistochemical staining showed small nerve branches from the pelvic plexus entering the prostate gland and the presence of ganglia within the prostate gland that contained both tyrosine hydroxylase positive and negative neuronal cell bodies. This information may be useful in nerve-sparing surgical procedures and in discussions of the functional implications of perturbations of prostate innervation.

Aged↗
PubMed2005

Surgical anatomy of the cervical sympathetic trunk.

Lack of knowledge of the anatomy of the cervical sympathetic trunk (CST) may complicate surgical procedures on the cervical spine. This study aims to define linear and angular relations of the CST with respect to consistent structures around it, including the number and size of the cervical ganglia, the distances between the CST and the longus colli muscle and the anterior tubercles of the transverse processes of cervical vertebrae. Morphometric parameters of the 24 CSTs of 12 adults were measured on both sides. The CST had superior, middle, and inferior (or cervicothoracic) ganglia in 20.8% of specimens; superior and inferior (or cervicothoracic) ganglia in 45.8%; superior, middle, vertebral, inferior, or cervicothoracic ganglia in 12.5%, and superior, vertebral, inferior or cervicothoracic ganglia in 20.8% of specimens. The superior ganglion was observed in all specimens, the middle ganglion and vertebral ganglion were each observed in 33.3%. There was no difference between the number of superior and vertebral ganglia between the right and left sides. The average distance between the CST and the medial border of the ipsilateral longus colli muscle (LCM) was 17.2 mm at C3 and 12.4 mm at C7. As the CSTs converged caudally, the LCMs diverged. The average distance between the anterior tubercles of transverse processes of the cervical vertebrae and the lateral borders of the ipsilateral CST was 3.4 mm at C4, 3.2 mm at C5, and 3.9 mm at C6. The presence of a vertebral ganglion and variations, such as the localization of the CST within the carotid sheath, are important. The anatomical landmarks described should assist the spinal surgeon to avoid injury of the CST.

Adult↗
PubMed2005

Clinical anatomy of the posterior maxilla pertaining to Le Fort I osteotomy in Thais.

This article studies the anatomy of the posterior maxilla pertaining to bone-cut design of Le Fort I osteotomy to avoid the injury to the descending palatine artery in Thais. Fifty-five skulls (38 males, 17 females) were assessed for the anatomical landmarks by a combination of direct inspection, computerized imaging, and computed tomography scan analysis. The results showed that 27.28% of the pterygomaxillary junction (PMJ) became synostosis. The mean heights of the PMJ, posterior maxilla, and maxillary tuberosity were 15.14 +/- 2.46 mm, 22.51 +/- 3.50 mm, and 7.45 +/- 2.76 mm, respectively. The mean length of the medial sinus wall measuring from the piriform rim to the descending palatine canal at the Le Fort I level was 34.40 +/- 2.96 mm. The mean widths of the posterior incision of Le Fort I osteotomy at the maxillary tuberosity and PMJ were 20.38 +/- 2.82 mm and 11.60 +/- 1.57 mm. The mean length of the posterior maxilla was 27.18 +/- 2.49 mm. Distances from the greater palatine foramen to the maxillary tuberosity incision and PMJ incision were 1.76 +/- 1.12 mm and 3.59 +/- 1.40 mm. The mean angle between the descending palatine canal and the hard palate was 57.33 +/- 4.54 degrees . There were no significant differences in any measurements between sides and genders, except the pterygoid process width and posterior maxilla length of males were longer than those of females (P < 0.05). This study could provide better understanding of the posterior maxillary anatomy that is important for the bone-cut design of Le Fort I osteotomy to avoid excessive intraoperative and postoperative hemorrhage including ischemia of the mobilized maxilla.

Female↗
PubMed2007

Aberrant branch of the superior laryngeal artery passing through the thyroid foramen.

This study examines the microsurgical anatomy of the aberrant superior laryngeal artery (ASLA) which passes through the thyroid foramen. It defines the location of the ASLA and its main branches. The aberrant superior thyroid artery was looked for in 20 randomly selected Chinese adult cadavers, and when found, was dissected and measured under an operating microscope (7-30x magnification). The ASLA passed through the thyroid foramen, which only occurred in the presence of the artery. The foramen was observed in six of the 20 cadavers: one on the right, three on the left, and two on both sides. The study provides detailed information concerning the ASLA, which we hope will help explain the arterial bleeding that may occur during laryngeal surgery. The results might be helpful in improving surgery to the larynx and other neck operations. Incidental intraoperative injury of the aberrant artery could be avoided by understanding details of its course in relation to surrounding anatomic landmarks.

Arteries↗
PubMed2007

The pillars of the scapula.

Total shoulder replacement has been shown to provide predictable pain relief and functional improvement in patients with glenohumeral arthritis. Loosening of the glenoid component remains the most frequent indication for revision surgery at long-term follow-up. The component most widely used is an all-polyethylene keeled or pegged design cemented to the glenoid cavity of the scapula. The glenoid is small and its cup-shaped morphology allows only a restricted site for limited fixation devices. This is particularly so in revision surgery where there are often large bony defects of the glenoid. In an anatomical study, we investigated the scapula in order to identify substantial bony pillars for better component fixation. Forty cadaveric shoulders (mean age 86, range 67-101) were dissected, the glenoids were denuded from cartilage, and the subchondral and cancellous bone was removed. Two bony pillars approaching the glenoid were consistently identified in all scapulae investigated. These pillars were outlined by three cortices and orientated to the circle formed by the rim of the inferior quadrants of the glenoid. One pillar is directed inferiorly near the margo lateralis and the other pillar is directed superiorly into the spine of the scapula. We defined these pillars in length and direction, and three-dimensionally located them in relation to the joint surface. This study demonstrated two bony pillars as important anatomical landmarks in the scapula. They were constant in presence, surgically accessible, and have not been described before. These results can be used as a guideline in the development of prosthetic designs to improve the fixation of glenoid components.

Acromion↗
PubMed2001

Balloon atrial septostomy in end-stage pulmonary hypertension guided by a novel intracardiac echocardiographic transducer.

Blade and balloon atrial septostomy has been used to reduce cardiopulmonary symptoms and as a bridge to lung or heart lung transplant in primary pulmonary hypertension. Due to severe right atrial dilatation and resultant loss of anatomical landmarks, the procedure is technically difficult, and the reported postprocedure mortality rate varies between 5% and 50%. Among others, marked systemic desaturation and systemic hypotension presumably secondary to an excessively large atrial septal defect have been reported as causes of postprocedure death. We report a case where a novel intracardiac catheter-based phased-array 5.5--10 MHz transducer with spectral and color-flow Doppler capabilities was used to assist a balloon atrial septostomy and to obtain hemodynamic data in a patient with end-stage pulmonary hypertension.

Catheterization↗
PubMed2001

Architectonic identification of the core region in auditory cortex of macaques, chimpanzees, and humans.

The goal of the present study was to determine whether the architectonic criteria used to identify the core region in macaque monkeys (Macaca mulatta, M. nemestrina) could be used to identify a homologous region in chimpanzees (Pan troglodytes) and humans (Homo sapiens). Current models of auditory cortical organization in primates describe a centrally located core region containing two or three subdivisions including the primary auditory area (AI), a surrounding belt of cortex with perhaps seven divisions, and a lateral parabelt region comprised of at least two fields. In monkeys the core region can be identified on the basis of specific anatomical and physiological features. In this study, the core was identified from serial sets of adjacent sections processed for cytoarchitecture, myeloarchitecture, acetylcholinesterase, and cytochrome oxidase. Qualitative and quantitative criteria were used to identify the borders of the core region in individual sections. Serial reconstructions of each brain were made showing the location of the core with respect to gross anatomical landmarks. The position of the core with respect to major sulci and gyri in the superior temporal region varied most in the chimpanzee and human specimens. Although the architectonic appearance of the core areas did vary in certain respects across taxonomic groups, the numerous similarities made it possible to identify unambiguously a homologous cortical region in macaques, chimpanzees, and humans.

Acetylcholinesterase↗
PubMed2005

Mapping auditory core, lateral belt, and parabelt cortices in the human superior temporal gyrus.

The goal of the present study was to determine whether the architectonic criteria used to identify the core, lateral belt, and parabelt auditory cortices in macaque monkeys (Macaca fascicularis) could be used to identify homologous regions in humans (Homo sapiens). Current evidence indicates that auditory cortex in humans, as in monkeys, is located on the superior temporal gyrus (STG), and is functionally and structurally altered in illnesses such as schizophrenia and Alzheimer's disease. In this study, we used serial sets of adjacent sections processed for Nissl substance, acetylcholinesterase, and parvalbumin to identify the distinguishing cyto- and chemoarchitectonic features of the core, lateral belt, and parabelt in monkey. These criteria were evaluated in postmortem tissue from a human subject, leading to the identification of additional criteria specific to human. The criteria were validated in an additional set of eight human subjects. Regions were delineated and their volumes estimated using the Cavalieri method in these subjects, and the sources of methodologic contribution to variability of the estimates was assessed. Serial reconstructions of the auditory cortex in humans were made showing the location of the lateral belt and parabelt with respect to gross anatomical landmarks. Architectonic criteria for the core, lateral belt, and parabelt were readily adapted from monkey to human. Additionally, we found evidence for an architectonic subdivision within the parabelt, present in both species. Variability of regional volume estimates was readily constrained using a multifaceted approach to reduce potential sources of variability in regional delineation.

Adult↗
PubMed1995

Topography of projections to posterior cortical areas from the macaque frontal eye fields.

Frontal eye field (FEF) projections to posterior cortical areas were mapped by autoradiography of tritiated amino acids (Leu, Pro) in six macaque monkeys. In three monkeys, the large saccade part of the FEF (IFEF) was identified by microstimulation and injected with tracers. In a fourth monkey, the small saccade part of the FEF (sFEF) was identified by microstimulation and injected with tracer. Tracer injections were placed into the sFEF region of two other monkeys using anatomical landmarks. The IFEF and sFEF generally had distinct and largely segregated projections to posterior cortical areas, and the overall pattern of labeling in visual areas with established topology indicates that IFEF neurons preferentially project to areas having large and eccentric receptive fields, whereas sFEF neurons project to areas having smaller, more centrally located fields. The terminal fields from the sFEF were more widespread than those from IFEF. Projections from sFEF terminated in the lateral intraparietal area (LIP), the ventral intraparietal area (VIP), and the parietal part of visual area V3A, in the fundus of the superior temporal visual area (FST), the middle temporal area (MT), the medial superior temporal area (MST), the temporal part of visual area V4, the inferior temporal area (IT), and the temporal-occipital area (TEO) and in occipital visual areas V2, V3, and V4. Projections from IFEF terminated in parietal areas 7a, LIP, and VIP and the medial part of parietal area PE; in temporal areas MST and the superior temporal polysensory area (STP); and in occipital area V2 and posterior cingulate area 23b. Projections from IFEF and sFEF appeared to terminate in different parts of common target areas in MST, LIP, and V2. The topography of IFEF and sFEF projections to LIP suggests that this posterior eye field may also be organized by saccade amplitude. Most terminal labeling from FEF injections was bilaminar to layers I and V/VI, but labeling in area LIP, area MT, the medial part of area PE, and area 23b was columnar-form to all layers.

Animals↗
PubMed2004

Evaluating requirements for spatial resolution of fMRI for neurosurgical planning.

The unambiguous localization of eloquent functional areas is necessary to decrease the neurological morbidity of neurosurgical procedures. We explored the minimum spatial resolution requirements for functional magnetic resonance imaging (fMRI) data acquisition when brain mapping is used in neurosurgical planning and navigation. Using a 1.5 Tesla clinical MRI scanner, eight patients with brain tumors underwent fMRI scans using spatial resolution of approximately 4 x 4 x 4 mm(3) to map the eloquent motor and language areas during the performance of cognitive/sensorimotor tasks. The fMRI results were then used intra-operatively in an open MRI system to delineate eloquent areas. Retrospectively, activation patterns were visually inspected by a neurosurgeon to determine qualitatively whether ambiguity with respect to the activation boundaries, due to low spatial resolution, could be of potential significance for surgical guidance. A significant degree of ambiguity in both the extent and shape of activation was judged to be present in data from six of the eight patients. Analysis of fMRI data at multiple resolutions from a normal volunteer showed that at 3 mm isotropic resolution, eloquent areas were better localized within the gray matter although there was still some potential for ambiguity caused by activations appearing to cross a sulcus. The data acquired with 2-mm isotropic voxels significantly enhanced the spatial localization of activation to within the gray matter. Thus, isotropic spatial resolution on the order of 2 x 2 x 2 mm(3), which is much higher than the resolutions used in typical fMRI examinations, may be needed for the unambiguous identification of cortical activation with respect to tumors and important anatomical landmarks.

Adult↗