A geometric morphometric approach to the quantification of population variation in sub‐Saharan African crania

We report here on new data examining cranial variation in 18 modern human sub‐Saharan African populations. Previously, we investigated variation within southern Africa; we now extend our analyses to include a series of Central, East, and West African crania, to further knowledge of the relationships between, and variation and regional morphological patterning in, those populations. The sample comprises 377 male individuals; the three‐dimensional coordinates of 96 landmarks are analyzed using Procrustes‐based methods. Interpopulation variation is examined by calculating shape distances between groups, which are compared using resampling statistics and parametric tests. Phenotypic variance, as a proxy for genetic variance, is measured and compared across populations. Principal components and cluster analyses are employed to explore relationships between the populations. Shape differences are visualized using three‐dimensional rendered models. Observed disparity patterns imply a mix of differences and similarities across populations, with no apparent support for genetic bottlenecks, which is likely a consequence of migrations that may have influenced differences in cranial form; supporting data are found in recent molecular studies. The Pygmy sample had the most distinctive cranial morphology; characteristically small in size with marked prognathism. These features characterized, although less strongly, the neighboring Bateke, and are possibly related to similar selective pressures in conjunction with interbreeding. Small cranial size is also involved in the considerable distinctiveness of the San and Khoikhoi. The statistical procedures applied in this study afford a powerful and robust means of quantifying and visualizing the magnitude and pattern of cranial variation between sub‐Saharan African populations. Am. J. Hum. Biol., 2010. © 2009 Wiley‐Liss, Inc.     

Osteological features in pure-bred dogs predisposing to cervical spinal cord compression

Relative to body size, midsagittal and interpedicular diameters of the cranial and caudal aspects of cervical vertebral foramina (C3–C7) were found to be significantly ( P < 0·05) larger in small breeds than in large breeds and Dachshunds, and also larger in Dachshunds ( P < 0·05) than in large breeds. This condition increases the risk for spinal cord compression resulting from relative stenosis of the cervical vertebral foramina, especially in large dogs, and this is also exacerbated by the typical shape of the vertebral foramina (i.e. dorsoventrally flattened cranially and bilaterally narrowed caudally). Within large dogs those breeds highly predisposed to cervical spinal cord compression were Great Danes (the breed with the smallest midsagittal vertebral foramen diameters from cranial C6 to cranial T1) and Doberman Pinschers, because of the most strikingly cranially dorsoventrally narrowed cone-shaped vertebral foramina at C6 and C7. The existence of a small midsagittal diameter in the cranial cervical spine was a high risk factor predisposing to spinal cord compression in small breeds and Dachshunds. Remarkable consistency was noted between the spinal level of the maximum enlargement of the spinal cord which previously was reported to be at C6, and the site of maximum enlargement of the vertebral canal currently stated in Dachshunds and small breeds. In large breeds the maximum enlargement of the vertebral canal tended to be located more caudally at the caudal limit of C7. The average age at which large dogs were most susceptible to noxious factors causing abnormal growth of the pedicles was determined to be 16 wk.     

Intraspecies variation in ectotympanic tube length and orientation among humans

Ectotympanic bone morphology is commonly used as a large-scale phylogenetic indicator across primates. Less well-understood is the intraspecies variation in this characteristic and the dynamic ways in which it affects and is affected by overall basicranial shape. This study attempts to clarify relationships between the external ear canal and basicranial shape among humans in a sample of archaeological human crania. The ectotympanic length and orientation were hypothesized to correlate with the shape of the cranial base and particularly with shape variables associated with relative brachycephaly. Basicranial shape in 80 computed tomography (CT) scans of adult humans were quantified using landmark coordinate data, with particular emphasis on the cranial base and auditory structures. Scaled ectotympanic lengths were taken from interlandmark distances and then compared to shape variation of the whole basicranium as summarized by procrustes shape variables and principal components analysis (PCA). The length of the ectotympanic bone was correlated with total cranial base variation. Long ectotympanic bones were found to be associated with brachycephalic individuals and less flexed basicrania. Additionally, long ectotympanic bones were found to be more horizontally oriented, as opposed to inferiorly sloped. We suggest that as brachycephaly increases the distance between the otic capsule and the pinna, the ectotympanic bone lengthens in response.     

Structure,blood supply,and lymphatic vessels of the sheep's visceral pleura

We investigated the morphology of the visceral pleura of 36 sheep, using macroscopic, histologic, and ultrastructural approaches to quantify regional pleural thickness, blood supply, and lymphatic drainage, including the pulmonary ligament and hilar lymphatic distributions. Pleural thickness increased caudally and dorsally, such that the costal pleura of the caudal lobes had a mean minimum pleural thickness of 83 μm. The blood supply to the entire visceral pleura came exclusively from the bronchial arteries. Lymph vessels formed an extensive plexus throughout the serous membrane of all lobes. Trunk lymphatics (> 100 μm diameter) had a density of about 2/cm of pleural length on all lobar surfaces except for the cranial and middle lobes, where their density on the costal surfaces was ≤ 1/cm. Pleural trunk lymphatics coursed to the pulmonary ligaments and to the hilum on their way to regional lymph nodes. At the hilum they anastomose with intrapulmonary lymphatic trunks. The principal lymph nodes to receive pulmonary lymph were the caudal mediastinal node and tracheobronchial nodes. The visceral pleura of sheep is thick, showing considerable regional diversity in morphology.     

100例颅骨视神经管及其周围关系的观察与测量

采用100个颅底(水平锯开颅顶),对视神经管进行测量,全长均值男11.0mm,女10.46mm;眶口的直径均值男4.48mm,女4.92mm;眶口横径均值男4.13mm,女3.38mm.视神经管口前缘点至眼眶前缘上、下、内、外四壁各点的距离均值分别为:男8.87、6.50、8.89、8.82mm;女8.72、6.00、8.22、7.35mm.视神经管眶口内侧缘中点至筛前孔、筛后孔、内眦部眶缘的距离均值分别为男34.4、20.7、43.96mm;女31.42、19.94、42.97mm.颅正中矢状轴与视神经管中轴的夹角均值男37.42度,女36.44度.两侧视神经管眶口均值男29.45mm,女27.51mm.并对眶口和颅口的形态进行了观察和测量.     

Biological factors that may contribute to regional and racial disparities in HIV prevalence

Despite tremendous regional and subregional disparities in HIV prevalence around the world, epidemiology consistently demonstrates that black communities have been disproportionately affected by the pandemic. There are many reasons for this, and a narrow focus on socio-behavioural causes may be seen as laying blame on affected communities or individuals. HIV sexual transmission is very inefficient, and a number of biological factors are critical in determining whether an unprotected sexual exposure to HIV results in productive infection. This review will focus on ways in which biology, rather than behaviour, may contribute to regional and racial differences in HIV epidemic spread. Specific areas of focus are viral factors, host genetics, and the impact of co-infections and host immunology. Considering biological causes for these racial disparities may help to destigmatize the issue and lead to new and more effective strategies for prevention.     

Anatomic variations in the course of the hypoglossal nerve: A case report

To achieve a successful surgical anatomy a detailed knowledge of regional anatomy and anatomical variations is an important fundamental. The extra cranial hypoglossal nerve has a well described course as it traverses the neck, and is frequently identified during neck dissection. This serves a guide to the surgeon of such atypical variations in anatomy to avoid injury to important structures during dissection. We are presenting a case report which demonstrates the extra cranial variation of Hypoglossal nerve.     

经鼻内镜下视神经管减压术的应用解剖

目的 通过对视神经管及其毗邻结构的研究,为临床视神经管减压术提供解剖学依据.方法 结构完整的成人头颈部标本12例,经红色乳胶灌注、10％的福尔马林固定,观察和测量如下指标:①观察视神经管的形态;②视神经管隆突的类型;③视神经管颅口、眶口及管中部的横径、纵径及横截面;④测量视神经管上、下、内、外侧壁的厚度;⑤视神经管内侧壁毗邻关系;⑥视神经管内眼动脉与视神经的位置关系.结果 视神经管由两口(颅口、眶口)和四壁(上壁、下壁、内侧壁、外侧壁)组成,其横截面积在眶口最大,管中部最窄;视神经管的内侧壁最薄,内侧壁的毗邻结构主要有3种类型:①前为同侧后筛窦、后为同侧蝶窦;②全为同侧蝶窦;③全为同侧后筛窦,眼动脉在视神经管的颅口、眶口分别以视神经的内下方和外上方多见.结论 本研究结果为经鼻内镜视神经管减压术提供了解剖学参数;当打开视神经管骨壁,鞘膜的切开选择内侧壁稍上方.     

Racial disparity in primary hepatocellular carcinoma: tumor stage at presentation, surgical treatment and survival

OBJECTIVES: The incidence and mortality rates from primary hepatocellular carcinoma (HCC) are higher in black Americans compared to whites. The goal of this study was to determine if there are racial disparities in HCC stage at diagnosis and treatment. METHODS: We compared patient age, tumor stage, rates of surgical intervention and survival in black (n=1718) and white (n=9752) HCC cases between 1992 and 2001 in the Surveillance, Epidemiology and End Results (SEER)-11 + Alaska database. RESULTS: Black HCC cases were significantly younger at diagnosis (p < 0.0001). Black cases were more likely to have regional and distant metastasis at presentation (p < 0.0005) and were less likely to have surgery performed (p < 0.001). The racial difference in surgery treatment was significant among patients with localized (p = 0.001) and regional (p = 0.012) HCC, but not with distant HCC. Overall survival rates were lower in blacks (p = 0.0033). Survival was similar in blacks and whites with regional and distant disease. Yet, among patients with localized HCC, survival rates were lower in blacks (p = 0.0030). CONCLUSIONS: Black HCC patients have more advanced tumor stage at diagnosis and lower rates of both surgical intervention and survival. The racial disparities in surgical treatment utilization and survival were most striking between black and white HCC patients with localized HCC.     

Microsurgical anatomy of the pituitary gland (hypophysis cerebri) and the sellar region. Part IV: The optic nerves and optic chiasma

The anatomical relationships of the optic nerve and optic chiasma to the different structures of the sellar region were studied in 100 cadaver sphenoidal blocks and in patients during transfrontal surgery to the sellar region. This study includes the relationships with the bony structures (tuberculum sellae, dorsum sellae, sella turcica, optic canal), with the meninges (arachnoidal cisterns, tentorium of the optic nerve), with the vessels (carotid and ophthalmic arteries), and finally with the neural structures (hypophysis cerebri, cranial nerves third ventricle). Relevant clinical or surgical aspects in relation to normal anatomy and anatomical variations of the optic nerves and optic chiasma are discussed. The varieties of the chiasma (normal, prefixed, postfixed) and the measurements of the optic nerves and optic chiasma (width, length, height, distance, and angle between optic nerves) were studied in the cadaver only. Different transfrontal approaches to the sellar region are discussed according to the morphology of the chiasma.     

Neurovascular relationships in the posterior cranial fossa,with special reference to trigeminal neuralgia. 1. Review of the literature and development of a new method of vascular injection-filling in cadaveric controls

Vascular compression of cranial nerves adjacent to the brain stem has been implicated in a wide variety of disorders affecting their function. The considerable conflicts in published results relate primarily to flaws in study design. The design required of an adequate study is defined and a technique is presented, in 16 fresh human cadavers, of reliable and physiological injection-filling of both the cerebral arterial and venous systems. It allowed for the accurate observation of the normal neurovascular relationships in the posterior cranial fossa during operative simulation. Part 2 of this article concerns the use of this design in the study of trigeminal neuralgia, a disorder thought to relate to vascular compression of the fifth cranial nerve. Clin. Anat. 10:371–379, 1997. © 1997 Wiley-Liss, Inc.     

山羊迷走神经中的交感节后纤维成分

在山羊颈前部或后部手术分离迷走神经与颈交感干,将辣根过氧化物酶(HRP)注入颈迷走神经干内,在所有实验例,均在颈前节看到标记细胞。但是,将HRP注入颈交惑干,在颈前节无标记细胞.这个结果表明,颈前节的交感节后神经元发出纤维加入迷走神经,下行到达所支配的颈、胸和腹腔内脏器官。     

颅中窝进路内耳道手术的应用解剖学

为经颅中窝进入内耳道施行手术提供更简便的方法,在100侧成人颅骨标本上.对棘孔、岩大神经管裂孔、弓状隆起和内耳门等表面标志进行了观测,运用几何知识、找出形态规律;在20侧成人整颅标本上进行了摹拟手术;讨论了与临床应用有关的问题.     

僰人颅骨的测量研究

测量“僰人”头颅１０个（男６,女４）;每例测量线距８２项;弦、弧、周长１６项;角度２６项;计算指数４５种;观察各颅颅型、颌型、眶型、鼻型及腭型并观察“僰人”与汉族、壮族人颅的差异,发现“僰人”与汉族人颅差异显著,表明它们各属不同民族;“僰人”与壮族人颅差异较小,似可说明他们具有共同族源。     

视神经管显微解剖学研究

目的　为视神经管减压术提供解剖学依据。方法　利用解剖学方法对 10 0个颅骨和 6 7个尸头视神经管口及四壁的结构与毗邻进行了观察和测量。结果　视神经管由蝶骨小翼两根与喋骨体构成 ,管自后内向前外斜行 ,分内、外、上、下四壁和颅、眶两口。其上壁、下壁、内侧壁、外侧壁的长度分别为 10 70±0 2 3mm ,6 2 5± 0 18mm ,9 6 7± 0 18mm ,7 91± 0 17mm。内侧壁向筛窦、蝶窦内突入形成视神经管隆凸。视神经在颅口处有硬脑膜压迹 ,视神经腹侧有眼动脉形成的压迹。结论　视神经管隆凸可作为确定视神经管位置的解剖标志。视神经管下壁和内侧壁与视神经、眼动脉、颈内动脉等结构毗邻 ,切除管壁时应注意保护邻近结构。     

Morphologic changes of the cranial nerves, spinal cord ganglia and roots in botulism

Peripheral nervous system was studied morphologically in 4 patients who had died from botulism. The results indicate considerable alterations in cranial and spinal nerves as well as in spinal cord ganglia. This may explain a neurological symptoms (radiculoneuritis, radiculoganglionitis) in botulism.     

Implementing Boissonnat's method for generating surface models of craniofacial cartilages

Surface modeling of embryonic craniofacial morphology typically is accomplished using data derived from planar contours. Methods currently available for reconstructing embryonic craniofacial anatomy from contour data rely on shortest-path algorithms in order to interpolate surfaces. However, these techniques either fail or require a considerable amount of user interaction when complex surfaces are modeled since foramina and structural divisions cannot be interpolated properly. Recently, a new approach has been described by Boissonnat that constructs a polyhedral volume between sets of planar contours. Surfaces are interpolated by identifying the planes formed when the contours intersect the polyhedron. The purpose of this study is to determine whether craniofacial cartilages from embryonic mice can be reconstructed in an accurate and reliable fashion using this method. Embryonic mice were collected and processed for routine histological sectioning. Serial sections of the anterior cranial base and nasal capsule were obtained, subjected to videomicroscopy, and modeled. Reconstructions of the anterior cranial base and nasal capsule from embryonic mice were compared to the same structures in age-matched specimens that were processed with whole-mount staining procedures. The models compared well with the whole-mount preparations. In addition, the reconstruction technique accurately rendered complex surface features of the embryonic anterior cranial base and nasal capsule including foramina and structural branches.     

Segmental variations in the elastic fiber content of the lateral costotransverse ligaments in the vervet monkey (Cercopithecus pygerythrus aethiops)

The segmental and zonal variations in the quantitative relationships between elastic and collagen fibers within the lateral costotransverse ligaments have been investigated in the vervet monkey. The lateral costotransverse ligaments of the caudal segments have a largely elastic structure in contrast to those of the cranial segments, which are characteristically collagenous. In the transitional zone extending from the 4th through to the 6th costotransverse joints, the lateral costotransverse ligaments show a zonal differentiation into a superficial collagenous portion and a deep elastic portion. It is noted that the craniocaudal structural differentiation in the lateral costotransverse ligaments corresponds with similar changes in the vertebral ligaments in that the ligamenta flava gradually extend into the interspinous spaces from the 1st thoracic vertebra (T1) so that at T5 the ligaments occupy 50% of the interspinous space and at T7 the elastic fibers almost completely replace the interspinous ligament. Functionally, however, the regional differences in the elastic fiber content of the lateral costotransverse ligament may have no collateral relationship with the morphology of the ligamenta flava, but are conditioned by movements of the ribs. Whereas movements of the upper six joints are limited by virtue of the configuration of their articular surfaces, which are reciprocally curved, on the 7th to 10th joints the articular facets are almost flat and, therefore, allow considerable movements between the ribs and the corresponding transverse processes.     

乙状窦前入路迷路后区应用解剖学研究

目的：为临床乙状窦前入路迷路后区域手术操作提供解剖学资料。方法：经10％甲醛溶液固定成人尸头标本15具共30侧。在外耳道后上棘、乳突上嵴、乳突尖之间磨除骨质，暴露乙状窦、岩上窦、岩上窦-乙状窦交点、颅中窝硬膜、乙状窦前方的颅后窝硬膜。磨出后骨半规管、外骨半规管、上骨半规管及面神经垂直段、颈静脉球。测量相关数据。结果：乙状窦前入路迷路后区域的骨质可分为三层：表面骨皮质，乳突蜂房骨质，覆盖深部结构的坚硬骨质。外耳道后上棘至后骨半规管的最近距离为（17．88±1．27）mm；面神经垂直段在外半规管下方、后半规管的前方走向二腹肌嵴前缘的内侧，其长度为（7．58～14．02）mm；外耳道后上棘．乙状窦最短距离为（13．84±2．74）mm。结论：此区域骨质分层明显的解剖学特点及测量的数据可以指导手术操作，避免损伤重要结构，为乙状窦前入路迷路后锁孔入路提供了重要的解剖学资料。     

High-Resolution Computed Tomography Imaging of the Cranial Arterial System and Rete Mirabile of the Cat (Felis catus)

The objective of this study was to investigate the possibility of obtaining high-resolution multiplanar computed tomography (CT) imaging of the cranial arterial circulation of the cat (Felis catus), the rete mirabile, and components of the skull, utilizing preserved cat specimens with an arterial system that was injected with a radiopaque contrast compound in the early 1970s. Review of the literature shows no high-resolution CT studies of the cat's cranial circulation, with only few plain radiographic studies, all with limited cranial vascular visualization. In view of the inability of the radiographic techniques available from 1970s to mid-2000s to provide high-resolution imaging of the arterial circulation within the intact skull and brain of the cat, without dissection and histologic sectioning and disruption of tissues, no further imaging was performed for many years. In 2010, a high-resolution micro CT scanner became available, large enough to scan the entire nondissected head of the arterially injected cats. All the obtained CT images were processed with a software program that provided 3D volume rendering and multiplanar reconstruction with the ability to change the plane angulation and slab thickness. These technical features permitted more precise identification of specific arterial and bony anatomy. The obtained images demonstrated, with a nondestructive method, high-resolution vascular anatomy of the cerebral, orbital, facial arterial system, the rete mirabile, and skull bone components of the cat, with details not previously described in the literature. Anat Rec, 302:1958–1967, 2019. © 2019 The Authors. The Anatomical Record published by Wiley Periodicals, Inc. on behalf of American Association of Anatomists.