The spread of tumour cells to the mandible has been well recognised and invasion of the edentulous alveolar ridge by tumour through accessory foramina has been documented. Tumour infiltration can also occur through the lateral cortical plate, but the number and distribution of accessory foramina on this surface has not been reported. Lateral surfaces of 89 mandibles were examined and accessory foramina which showed a direct communication with the underlying cancellous bone were charted. It was found that the number of accessory foramina varied greatly from specimen to specimen. Only 70.8% of mandibles showed foramina in the coronoid, sigmoid and condylar sections; of these 93.7% exhibited foramina in the condylar section, 23.8% in the coronoid and only 19% in the sigmoid section. This finding confirms that the current practice of conserving part of the ascending ramus posterior to the coronoid process following surgery is sound. Similarly in the rest of the lateral surface, foramina were present in the upper third section in 97.8% of mandibles, 61.8% in the lower third and 58.4% in the middle third sections. This result justifies the principle of rim resection in appropriate cases and the recognition that the alveolar section is commonly invaded before the rest of the body. The number and distribution of foramina may be of greater significance following radiotherapy when the foramina could provide multiple direct channels for invasion of tumour cells from the lateral surface to the medulla.

Using antiserum to human parathyroid hormone-related protein (1–16) [PTHrP(1–16)] we have examined tissues of the common frog (Rana temporaria) for the presence of immunoreactive PTHrP (irPTHrP) at the stage of emergence from water to land. irPTHrP was detected in dorsal and ventral stratum granulosum of the skin, in the developing ovary, striated muscle and the choroid plexus epithelium of the brain as well as in the olfactory gland epithelium and olfactory lobe neurons of the brain. In the pituitary and hypothalamus irPTHrP protein could be demonstrated in the median eminence, infundibular stem and principally in the neural lobe and pars distalis of the pituitary with weak reaction in the pars intermedia. In situ hybridisation of the same tissues with an oligonucleotide probe to chicken PTHrP 55–65 clearly showed the presence of mRNA for PTHrP-like molecule in all the tissues containing irPTHrP. There was a major inconsistency in the pituitary in that the highest level of gene expression, assessed by in situ hybridisation, was found in the pars intermedia with only very low expression in the pars distalis and neural lobe and undetectable levels in the infundibular stem and median eminence. These observations suggest that tissues of the frog synthesise a PTHrP-like molecule but that in the pituitary the pars intermedia cells may export the protein to cells in other regions of the pituitary and hypothalamus.

Nitric oxide synthase immunoreactivity (bNOS-ir) was examined in the sacral spinal cord of the cat, macaque monkey and human using an antibody to the c-terminal region of neuronal NOS. In S2 of all 3 species NOS-ir was identified in both dorsal and ventral horns. In cat, monkey and human, bNOS-r occurred in sensory neurons of superficial laminae and the base of the dorsal horn, in autonomic neurons around the central canal and in the intermediolateral sacral spinal nucleus. In all 3 species, a large proportion of somatic motor nuclei in the ventromedial (VM), ventrolateral (VL) nuclei, and Onuf's nucleus (ON) showed high bNOS-ir, while others exhibited markedly lower immunoreactivity. Validatory experiments showed separate cellular localisation for bNOS, inducible NOS (iNOS), and endothelial NOS (eNOS) with only bNOS being localised to neuronal perikarya. Comparative morphometric analyses of the relative proportions and diameters of motor neurons in the VL, VM and ON exhibiting high and low levels of bNOS-ir revealed statistically significant differences in proportions in individual nuclei, and differences in size were generally not statistically significant. Finally, a comparison between cat sacral and thoracic spinal cord showed bNOS-ir in motor neurons of S2 was subject to less animal and rostrocaudal segment variation than in T10.

An ultrastructural study was undertaken on cartilage resorption at the site of initial endochondral bone formation in the mouse mandibular condyle on d 16 of pregnancy. After resorbing the bone collar, the osteoclasts extended their cell processes into the cartilage matrix and made contact with hypertrophic chondrocytes. By means of cell processes or vacuolar structures, these osteoclasts entrapped the calcified cartilage matrices, cell debris, and the degraded uncalcified cartilage matrices. In particular, since the calcified cartilage matrices were sometimes seen to be disrupted within the osteoclastic vacuolar structures, they were probably disposed of by the osteoclasts. Invading endothelial cells giving rise to capillaries also directly surrounded the degraded uncalcified cartilage matrices and small deposits of cell debris. In addition, hypertrophic chondrocytes that had attached to or were in the process of attaching to the invading osteoclasts often enclosed the small calcified cartilage matrices. Other cell types that have often been reported in other regions of cartilage resorption were not seen at the site of initial endochondral bone formation in this study. Our findings in relation to cartilage resorption may therefore represent unique features of the site of initial endochondral bone formation site. We consider that the manner of cartilage resorption is likely to vary by site, age, and species.

The amount of time officially available for the teaching of gross anatomy to medical undergraduates was substantially curtailed during the 1960s, both in the USA and in Europe (Kahn, 1966; Todd, 1968). Since then, this trend has been further enhanced by the expanding introduction of problem-based learning (Pallie & Miller, 1982; Albanese & Mitchell, 1993) deplored by many gross anatomists, radiologists and surgeons (Collins et al. 1994; Anderson & Brown, 1996). But a modification of the content of anatomical teaching has become unavoidable, and is a matter for concern — although very little rejoicing — to the professional morphologist involved in teaching. The few studies which have been aimed at defining a suitable core programme were designed to determine the anatomical knowledge required for various clinical specialties (Lippert & Bernsau, 1972; Quast-Höttge, 1972). These studies showed that the identified knowledge exceeds by far any currently available time for teaching anatomy to medical undergraduates (Lippert, 1974). Against this background, the present study was designed from a different concept, our aim having been to investigate the requirement of anatomical knowledge in general medical practice. The actual paper is a synopsis of the results obtained for 12 topics of systematic gross anatomy evaluated under this criterion. It is an attempt to contribute to a pragmatic solution to a pressing problem.

The degrees of mediolateral asymmetry of the patellar articular facet, as well as the median and lateral articular angles of the facet, were compared across samples of recent humans and of Pleistocene archaic and modern fossil humans. All samples exhibit considerable variability in these patellar proportions. The articular angles are similar across the different samples, but there is a trend towards decreasing lateral angles with decreasing robusticity. The archaic humans exhibit significantly more symmetry of the medial and lateral facets than do any of the recent human samples. However, given the variability in medial versus lateral patellofemoral contact forces documented for extant humans and the roles of the distal oblique portions of vastus medialis and vastus lateralis in patellar stabilisation, it is unclear to what extent this variation in patellar articular proportions may affect knee kinesiology. The contrasts may be related to different levels of patellar stability and/or musculoskeletal hypertrophy, but they appear unlikely to have affected primary knee function.

The effects of lithium on vascular development were examined using the chick embryo area vasculosa in shell-less culture as an experimental model. Embryos were explanted after 48 h in ovo and LiCl (50, 100, 150 and 200 μg in 10 μl water) was applied to the centre of the blastodisc. Controls were untreated or given equimolar amounts of NaCl. At 24 h and 48 h after treatment, untreated and NaCl controls were identical, having well developed extraembryonic vessels. At doses of 100 μg and greater, LiCl significantly inhibited normal vascular development and expansion of the area vasculosa in the majority of explants. In many specimens blood islands continued to form but their assembly into primitive vessels was prevented, indicating that lithium affects the mechanism regulating the assembly of vascular endothelium. At the same time the embryos were alive but retarded in development compared with controls. When LiCl (150 μg) was applied to cultures explanted after 72 h in ovo (when the primary vascular network had already formed through vasculogenesis) no adverse effects were seen. This suggests that lithium affects vasculogenesis but not angiogenesis. Treatment with myo-inositol completely reversed the effects of lithium in a time dependent manner indicating that the phosphatidylinositol second messenger cycle may be involved in the cellular events of vasculogenesis. Finally the results of this study show that the yolk sac vasculature is particularly vulnerable to lithium and the consequent effects of this interference on embryonic development are discussed.

Mesenteric lymph nodes and gut-associated lymphoid tissue (GALT) from juvenile eastern grey kangaroos were investigated. The mesenteric nodes had a similar structure to that described for eutherian mammals. They contained distinct regions of medulla and cortex, with prominent follicles and germinal centres. Gut associated lymphoid tissue consisted of areas of submucosal follicles. These varied from areas of densely packed lymphocytes with darkly staining, prominent coronas to areas with no defined follicles. The distribution of T cells in these tissues was documented by use of species-crossreactive antibodies to the surface markers CD3 and CD5; B cells were identified by antibodies to CD79b. Within the lymph nodes T cells were located mainly in the paracortex and cortex, with limited numbers observed in the follicles; B cells were located on the marginal zone of the follicles. In GALT, T cells were located in the peripheral regions of the germinal centres of secondary follicles, while B cells were abundant in primary follicles. These observations are consistent with those made in a range of other marsupials (metatherian) and eutherian mammals and are indicative of the capacity to respond to antigens entering via the mouth.

The distribution of nerves immunoreactive to protein gene product 9.5 (PGP 9.5), tyrosine hydroxylase (TH), neuropeptide Y (NPY), substance P (SP) and calcitonin gene related peptide (CGRP) antisera was investigated in the atrioventricular valves of the Sprague–Dawley rat and the Dunkin–Hartley guinea pig using confocal and epifluorescence microscopy. No major differences were noted between the innervation of the mitral and tricuspid valves in either species. For all antisera the staining was more extensive in the guinea pig valves. Two distinct nerve plexuses separated by a ‘nearly nerve free’ zone were identified in both species with each antiserum tested. This was most apparent on the anterior cusp of the mitral valve. The major nerve plexus extends from the atrioventricular ring through the basal, intermediate and distal zones of the valves towards the free edge of the valve cusp. These nerve bundles, arranged as primary, secondary and tertiary components, ramify to the free edge of the valve and extend to the attachment of the chordae. They do not contribute to the innervation of the chordae tendineae. The second, minor chordal plexus, runs from the papillary muscles through the chordae tendineae and passes parallel to the free edge of the cusp. The nerves of this minor plexus are interchordal, branching to terminate mainly in the distal zone, free edge of the valve cusp and adjacent chordae tendineae. Some interchordal nerve fibres loop from a papillary muscle up through a chorda, along the free edge and pass down an adjacent chorda into another papillary muscle. The nerve fibres of the major and minor plexuses intermingle although no evidence was found for interconnectivity between them. In the distal zone between the major plexus which extends from the base of the valve and the minor chordal plexus there is a zone completely free of nerves staining with antisera to TH and NPY. Occasional nerves which stained positive for PGP 9.5, SP and CGRP immunoreactivities crossed this ‘nearly nerve free zone’ passing either from the chordal/free edge nerves to the intermediate and basal zones or vice versa. An additional small nerve plexus which displayed immunoreactivity to CGRP antiserum extended from the atrioventricular ring into the basal zone of the valve cusp. Not all chordae tendineae displayed immunoreactive nerve fibres. It is concluded that the innervation patterns of the sensory and sympathetic neurotransmitters and neuropeptides examined in the atrioventricular valves of the rat and guinea pig are ubiquitous in nature. The complexity of the terminal innervation network of the mammalian atrioventricular valves and chordae tendineae may contribute to the complex functioning of these valves in the cardiac cycle.

The position of taste buds around the human mouth, pharynx and larynx is outlined in many texts. While their distribution, histological differences and taste sensitivity on the dorsum of the tongue are well described, extralingual taste buds are described in far less detail both in adults (Bannister, 1995) and neonates (Lalonde & Eglitis, 1961). Studies on a variety of grazing mammals (e.g. Bradley et al. 1980 in sheep; Shrestha et al. 1993 in buffalo), omnivores (Andrew & Oliver, 1951 in rat) and carnivores (Palmieri et al. 1983 in cat and dog) have shown abundant taste buds on the laryngeal surface of the epiglottis. Some authors have suggested that these taste buds may be important in initiating reflexes protecting the airway (Bradley et al. 1980) and in this context it is surprising that literature on their distribution on the human epiglottis is not available.

The encephalomyocarditis virus of the diabetogenic M-strain (EMC-M) is known to cause diabetes in mice. The EMC-M virus has also been shown to cause paresis in some of the infected animals. The clinical features include an acute ascending predominantly motor paralysis, developing within days. This resembles acute idiopathic polyneuritis. The alpha motor neurons would be a possible target for the virus, so two parameters, the total number and the size distribution of motor neurons, were therefore selected for further investigation in 6 mice with neurological involvement and compared with 6 control mice. The optical fractionator method was applied for estimating the total number of motor neurons and the 3D size distribution was estimated using the rotator method in a vertical design. No difference was found in the total number of motor neurons and the size distributions were similar in the 2 groups. This design can be used as a model for the estimation of the total number of motor neurons and their size distribution in other experimental animal models.

The expression of carbonic anhydrase in the chorioallantoic membrane (CAM) of the chick embryo was investigated by means of the histochemical localisation of the enzyme catalytic sites and the immunohistochemical identification of its isoenzymatic forms. The results show that carbonic anhydrase is developmentally expressed in a subset of cells both in the ectodermal and the endodermal epithelium. The distribution patterns from both methodological approaches indicated that carbonic anhydrase is a marker of the villus cavity cells and the mitochondria-rich cells in the ectodermal and the endodermal epithelium, respectively. Such a cell-specific pattern of the enzyme expression provides a further contribution to characterising the heterogeneous cell population of the chick CAM and supports specific functional involvement for the distinct cell types in CAM-mediated processes, such as calcium transport, maintenance of acid-base balance and water and electrolyte reabsorption, during chick embryogenesis.

Age-associated neurodegenerative diseases such as Alzheimer's disease are characterised by neuronal impairment that leads to cognitive deficits. As certain affected neurons depend on trophic factors such as neurotrophins (NTs), impairment in NT function has been suggested to be a component of neuronal damage associated with such disorders. Age-related neurodegenerative diseases are also characterised by high levels of proinflammatory cytokines such as tumour necrosis factor alpha (TNFα) in the CNS. Because TNFα receptors and certain NT receptors share a high degree of homology and are capable of activating similar signalling pathways, one possibility is that altered cytokine levels may affect NT function in the aged or diseased CNS. Here we wish briefly to review the evidence suggesting a role for cytokine and NT in the onset of age-associated neurodegenerative diseases. We propose that cytokine/NT interactions may alter neuronal homeostasis, thus possibly contributing to some of the neuronal degeneration occurring during such age-associated CNS diseases.

The cavernous sinus is traditionally described as a single anatomical compartment that contains cranial nerves, blood vessels, and connective tissue. A detailed analysis of 45 infant and 4 fetal parasellar regions shows that this view must be modified. The spatial arrangement, the topographic relations, and the expansion of the adipose and connective tissue spaces were analysed and reconstructed 3-dimensionally on a computer. It is shown that 3 different anatomical compartments, which are strictly demarcated by connective tissue, compose the parasellar region of infants. Two represent intracranial continuations of extracranial tissue spaces. The 3rd compartment corresponds to the so-called ‘cavernous sinus’ of the adult. Each of the 3 compartments contains characteristic adipose tissue bodies. Because the cavernous sinus represents only one compartment of the area, we propose to use the term ‘parasellar region’ to designate the entire anatomical region on either side of the sella turcica.

We analysed a large series of axillary lymph nodes, with and without metastases following radical mastectomy for breast cancer. We found left/right asymmetry in numbers of lymph nodes, and also asymmetry of lymph node dimensions, which could have been the caused by tumoral antigenic stimulation. The distribution of hyperplastic node patterns differed significantly.

Mobilisation of the latissimus dorsi muscle as a functional graft necessarily involves division of perforating arteries that enter the distal portion of the muscle, rendering it vulnerable to ischaemic damage when the muscle is stimulated electrically. Using a fluorescent microsphere technique we showed that the blood flow contributed by the thoracodorsal artery decreases in a proximal-to-distal direction, and that of the perforating arteries in a distal-to-proximal direction, but for neither does the flow decline to zero. This is consistent with earlier reports of anastomotic connections between the 2 arterial territories. We went on to use fluorescence microscopy to demonstrate the existence of these vascular anastomoses, the first such evidence obtained under physiological conditions of pressure and flow. In clinical applications, the existence of anastomotic connections offers the prospect of maintaining flow to the distal part of the grafted muscle without the delays inherent in neovascularisation procedures.

The histology and structure of 38 spleens of the dromedary (aged 0.5–15 y) were studied in relation to age. The spleen was found to have a thick capsule (292±106 mm) divided into an outer layer (113±39 mm) composed mainly of connective tissue and an inner layer (180±81 mm) consisting mainly of smooth muscle cells. Vascular and avascular trabeculae extend from the capsule, the former containing arteries and nerves but no trabecular veins, the latter being divided structurally into primary and secondary trabeculae. Subcapsular and peritrabecular blood sinuses around primary and vascular trabeculae are unique to the camel spleen. The central artery emerges from the periarterial lymphatic sheath and branches into up to 4 penicilli which extend as sheathed arterioles (42±8 μm). These are found near or surrounded by blood sinusoids of the red pulp. A wide marginal zone surrounds the white pulp and contains sheathed arteries but no marginal sinuses. The red pulp is characteristically divided into cords by secondary trabeculae and contains venous sinusoids of different sizes. The camel spleen is of a sinusal type that can store blood. The thick muscular capsule and trabeculae pump the stored blood according to the body's need. Both closed and open circulations are found. The venous return is unique as the blood flow is from the venous sinusoids of the red pulp to the peritrabecular sinuses to the subcapsular sinuses to the splenic vein. No significant structural differences related to age were found.

The chondroepitrochlearis is an extremely rare muscular anomaly. Bergman et al. (1988) in their book on anatomical variations refer to ‘costoepitrochlearis, chondroepitrochlearis, or chondrohumeralis’ and describe the anomaly as a muscular slip which arises from one or more ribs, crosses the axilla, and inserts into the median intermuscular septum or medial humeral epicondyle. The phylogenetic significance of the muscle has received attention (Landry, 1958; Chiba et al. 1983; Bergman, 1991), and case reports with ulnar nerve entrapment and restriction of arm movements (FitzGerald, 1935–1936; Voto & Weiner 1987; Lin, 1988; Spinner et al. 1991) have emphasised its clinical relevance.

In this study we have examined in the chick embryo chorioallantoic membrane (ChAM) the expression of the matrix metalloproteinase 2 (MMP-2) and have correlated this parameter with the expansion of the ChAM vasculature and with the expression of 3 extracellular matrix components (fibronectin, laminin and type IV collagen), which differentially modulate angiogenesis. In the early phases of ChAM development, between d 6 and d 8 of incubation, when the increase of the ChAM vasculature is maximal, higher values of MMP-2 and, respectively, of fibronectin immunoreactive area, are detectable. These results indicate that MMP-2 activity and fibronectin expression are 2 strictly related components of angiogenesis occurring in vivo.

The results obtained using morphometric variables which describe fin ray regeneration patterns are reported for individual fin ray amputations in the goldfish (Carassius auratus) and zebrafish (Brachydanio rerio). Classical and updated experiments are compared to verify previous morphogenetic models of cell tractions (Oster et al. 1983) or epidermis-mesenchyme induction (Saunders et al. 1959) applied to the limb of other vertebrates. Position-dependent patterns within the fin of Carassius auratus are analysed under a comparative protocol using morphometric methods. Conditions in which the apical epidermis is separated from blastema may differentiate small fin rays, thus suggesting this epidermis is involved in blastemal formation. Blastemal cells differentiating as lepidotrichia forming cells (LFCs) may also be related to morphological changes in covering epidermis. Long-range interactions from neighbouring fin ray blastemas or short-range interactions within the blastema, may be postulated through the analysis of segmentation.