Anatomical evidence for an endocrine activity of the vomeronasal organ in humans.

The mammalian vomeronasal organ (VNO) is a well-adjusted chemosensory structure that facilitates social and reproductive behavior in mammals. The existence, locality, and function of this organ in human adults remain a matter of discussion. Most authors now agree that a neuroreceptive function of the adult human VNO can be excluded due to the absence of both neural receptive cells associated with the VNO in other mammals despite the enigmatic reports on the effects of pheromones on human behavior. Adult cadavers form European (Caucasoid) descent were used in this article and parasagittal dissection of the heads allowed access to the nasal septa, which were grossly examined for the VNO openings. Tissue samples were collected, embedded in gelatin and serially sectioned through cryomicrotomy. Nissl staining was performed as well as immunohistochemically stained with an antibody against calcium-binding protein. The findings presented here confirm the bilateral presence of the VNO in adult cadavers and demonstrate morphological connections of VNO receptor cells with the underlying capillaries. In addition, possible endocrine activity associated with the epithelium of this chemosensory structure has been demonstrated by the expression of calcium-binding protein in a part of these receptor cells.

Edinburgh, the Scottish pioneers of anatomy and their lasting influence in South Africa.

The history of the origin of anatomy education in South Africa is the history of an arduous journey through time. The lasting influence of Edinburgh came in the form of Robert Black Thomson. He was a student and assistant of Sir William Turner who gave rise to the first chair of anatomy and the establishment of a department at the South African College, known today as University of Cape Town. Thomson was later succeeded by Matthew Drennan, a keen anthropologist, who was revered by his students. This Scottish link prevailed over time with the appointment of Edward Philip Stibbe as the chair of anatomy at the South African School of Mines and Technology, which later became the University of the Witwatersrand. Stibbe's successor, Raymond Arthur Dart, a graduate of the University of Sydney, was trained in an anatomy department sculpted on that of Edinburgh by Professor James Thomas Wilson. Wilson's influence at the University of Sydney can be traced back to Edinburgh and William Turner through Thomas Anderson Stuart. Both Dart and Robert Broom, another Scot, were considered as Africa's wild men by the late Professor Tobias. Here, the authors explore the Scottish link and origins of anatomy pedagogy in South Africa.

The posterior intercostal vein: a thermoregulatory gateway to the internal vertebral venous plexus.

The internal vertebral venous plexus (IVVP) plays a putative role in thermoregulation of the spinal cord. Cold cutaneous venous blood may cool, while warm venous blood from muscles and brown fat areas may warm the spinal cord. The regulating mechanisms for both cooling and warming are still unknown. Warm venous blood mainly enters the IVVP via the intervertebral veins. In the thoracic area these veins are connected to the posterior intercostal veins. In this study, anatomical structures were investigated that might support the mechanisms by which warmed venous blood from the intercostal muscles and the recently described paravertebral patches of brown adipose tissue are able to drain into the vertebral venous plexus. Therefore, tissue samples from human cadavers (n = 21) containing the posterior intercostal vein and its connections to the IVVP and the azygos veins were removed and processed for histology. Serial sections revealed that the proximal parts of the posterior intercostal veins contained abundant smooth muscle fibers at their opening into the azygos vein. Furthermore, the walls of the proximal parts of the posterior intercostal veins contain plicae that allow the vessel to dilate, thereby allowing it to serve as a pressure chamber. It is suggested that a cold induced closure of the intercostal/azygos opening can result in retrograde blood flow from the proximal posterior intercostal vein towards the IVVP. This blood flow would be composed of warm blood from the paravertebral brown adipose tissue and blood containing metabolic heat from the muscles draining into the intercostal veins.

Possible thermoregulatory functions of the internal vertebral venous plexus in man and various other mammals: evidence from comparative anatomical studies.

Comparative anatomy was used to collect more evidence for a thermoregulatory function of the internal vertebral venous plexus (IVVP). The venous connections of the IVVP were studied and compared in various mammals in order to find evidence for the existence of climate related anatomical adaptations. Humans and vervet monkeys were chosen as representatives of mammals living in moderate climates, the IVVP of the dolphin was studied because this animal is always surrounded by cold water. The springbok was chosen as a representative of mammalian species living under very hot conditions. The present study was exclusively performed on post mortem material. After filling the venous system with latex the IVVP and its venous connections were dissected. It appeared that in the dolphin, veins from the trunk muscles were directly and exclusively connected to the IVVP in the absence of an azygos vein. In the vervet monkey and human specimens, veins originating in the muscles drained both into the caval veins and into the IVVP. In these mammals veins draining from brown fat areas were also connected to the IVVP. In the springbok, drainage of blood from the muscles was prevented to enter the IVVP by the presence of valves. In humans and vervet monkeys we found that the lumbar parts of the IVVP were connected to subcutaneous veins of the back. It was concluded that the anatomy of the IVVP and its connecting veins may serve to thermoregulate the spinal cord and that climate related anatomical adaptations were present in the species studied.

A morphological study of the vertebral venous plexus and its connections in the Cape dune mole-rat, Bathyergus suillus (Bathyergidae).

Bathyergus suillus are subterranean rodents found in the Western Cape of South Africa, where they inhabit sandy, humid burrows. Vertebral venous plexuses around the vertebral column have been implicated in aiding the maintenance of a constant central nervous system temperature via its connections with muscles and interscapular brown adipose tissue. The morphology of the vertebral venous plexuses and its connections in B.suillus were investigated. Frozen (n = 10) animals were defrosted; the venous system injected with latex and the vertebral venous plexuses, azygos- and intercostal veins dissected along the dorsal and ventral aspects of the vertebral column. Specimens (n = 4) were used for histological serial cross sections of the thoracic vertebrae. Veins drained from the interscapular brown adipose tissue to the external vertebral venous plexus, via a dorsal vein at the spinous process of T2 which might represent the "vein of Sulzer" described in rats. The intercostal veins cranial to the level of T8 drained directly into the ventral external vertebral venous plexus instead of into the azygos vein as seen in rats. The azygos vein was situated ventrally on the thoracic vertebral bodies in the median plane as opposed to most rodents that have a left sided azygos vein. The internal vertebral venous plexus consisted of two ventrolateraly placed longitudinal veins in the spinal epidural space. Veins from the forelimbs entered the internal vertebral venous plexus directly at the levels of C7 and T1 and have not been described in other rodents. Serial histological sections, revealed no regulatory valves in vessels leading toward the internal vertebral venous plexus, allowing blood to presumably move in both directions within the vertebral venous plexus. The vertebral venous plexus of B. suillus shows similarities to that of the rat but the vessels from the forelimbs draining directly into to the internal vertebral venous plexus and the position of the azygos vein and the intercostal veins draining into the external vertebral venous plexus are notable exceptions.

Musculotendinous transfer as a treatment option for irreparable posterosuperior rotator cuff tears: teres major or latissimus dorsi?

Irreparable posterior cuff tears can cause pain and lack of shoulder function. Surgical treatment includes musculotendinous transfers of either latissimus dorsi (LD) or teres major (TM). This study aimed to give a detailed description of the morphology of these two muscles with particular regard to their suitability for use in transfers. Sixty-two shoulders in 31 cadaveric specimens (mean age 50 years) were dissected. The mean length of the TM was 13.7 cm at its superior edge while the distance from the muscle origin to the greater tuberosity (GT) was 19.2 cm. The tendon of the TM had a length of 1.5 cm, a width of 3.4 cm, and a thickness of 1.3 mm. The mean length of the LD was 26.0 cm and the distance from its origin to the GT was 32.9 cm. The mean length of the LD tendon was 5.2 cm, its width 2.9 cm, and its thickness 1.0 mm. The increased length required to achieve transfer was 47% (of the original length) for TM and 33% for LD. Both TM and LD could reach the GT with ease, according to the potential muscle excursions. Tension of the neurovascular bundle is more probable with LD because it enters the muscle relatively closer to the tendon. Problems with regard to reattachment may be more likely to occur in a transfer of the TM because of its short tendon.

Teratogenicity of 3-hydroxynorvaline in chicken and mouse embryos.

3-Hydroxynorvaline (HNV; 2-amino-3-hydroxypentanoic acid), a microbial L-threonine analogue, is toxic to mammalian cells and displays antiviral properties. In view of this, we investigated the toxicity and/or potential teratogenicity of HNV in developing chicken and mouse embryos. HNV was administered to chicken embryos (in ovo; dose 75-300 mumole/egg; 48 h post-incubation) and pregnant Hanover NMRI mice (per os; total dose 900-1800 mg/kg body mass; gestation days 7-9). Control animals received sterile saline solutions. Harvested embryos (chicken embryos, 10 days post-incubation; mouse embryos; gestation day 18) were fixed in glutaraldehyde and stereomicroscopically inspected for signs of dysmorphogenesis. Body mass, body and toe length and mortality of chicken embryos, and the body mass and mortality of mouse embryos were recorded. HNV exposure significantly increased the incidence of embryotoxic (growth retardation, toxic mortality) and congenital defects in both chicken and mouse embryos. All the observed effects were dose-dependent. In conclusion, HNV is an embryotoxic and teratogenic compound, which caused significant developmental delay and congenital defects in developing chicken and mouse embryos.

Carotid stenosis and carotid plaque analysis relevant to carotid endarterectomy and stent-assisted angioplasty.

The primary objective of this cadaveric study was to review the morphological variations of the anatomy of the human carotid artery bifurcation relevant to carotid endarterectomy (CEA) and carotid artery stent-supported angioplasty (CSSA). We quantify carotid bifurcation plaque morphology. Results showed that the angle of deviation at the origin of the internal carotid artery (ICA), in relation to the common carotid artery (CCA), measured a mean of 21.8 degrees with a range from seven to 45 degrees. This anatomical finding is important for the interventionalist concerned with insertion of a carotid stent. The angle of the ICA origin may be an independent risk factor for early atherosclerotic changes at the ICA bulb. Carotid bifurcation plaque was observed in a small, random cohort of seven out of 13 cadavers, and contributed to a mean stenosis of 15.2% (range 5.0-34.8%). Plaque morphology (n = 7) showed haemorrhage (29%), superficial thrombosis (57%), calcification (71%), areas of focal necrosis (71%), neovascularisation (14%) and infiltrates (29%). Ulcerations were not detected. Although four out of 13 patients (31%) died of a cerebrovascular accident, the cause of cerebral apoplexy was thought not to be associated with the carotid bifurcation pathology. 'Re-boring' of occluding plaque, as in CEA, offers potential volumetric anatomical advantage over CSSA within the carotid bifurcation and bulb. In conclusion, precise and applied knowledge of carotid bifurcation anatomy is critical to reduce technical complications during CEA or CSSA. This information may reduce potential dangers of iatrogenic thrombo-embolism and ensuing neurologic deficits. Patients with low-grade carotid stenosis, evidence of focal plaque necrosis, are at risk of spontaneous plaque cap rupture, distal thromboembolism and stroke.

EVAR: critical applied aortic morphology relevant to type-II endoleaks following device enhancement in patients with abdominal aortic aneurysms.

Endovascular repair (EVAR) of abdominal aortic aneurysms (AAA) is an established alternative option to conventional surgery for AAA, provided optimal anatomical morphology of the aneurysm sac, neck and outflow exists. In most documented series of EVAR, type-II endoleak occurrence is a universal procedural drawback. This is referred to as the Achilles heel of EVAR. This morphological study, addressing predominantly non-aneurysmal aortic anatomy, reveals the dyssynchronous origins of the renal ostia, ectopia of the superior mesenteric artery and median sacral artery, variations in the length of the infrarenal abdominal aorta, multiple mainstem renal arteries, and the presence of accessory renal arteries (in 13% of cadavers). Such potential vascular anomalies need careful consideration pre-operatively prior to EVAR. In a prospective, clinical study of EVAR in 163 patients over 60 months, using four different aortic stent devices, we demonstrated an intraprocedural type-II endoleak rate, before exclusion, of 3% (5/163). Most were related to patent lumbar arteries. An active policy of intraprocedural aneurysm pressure sac measurement and angiography was used to demonstrate type-I and type-II endoleaks, focusing on the applied anatomy of aortic side branches and variations. Selective intraprocedural coil embolisation and thrombin injection into the sac was utilised to thrombose persisting and large lumbar arteries that predisposed to retroleaks. We recorded a low incidence of persisting type-II endoleaks using this proactive treatment strategy by addressing variant aortic morphology and patent lumbar arteries during EVAR. One aneurysm-related death (0.6%) was observed due to late rupture after EVAR, and a single intraprocedural death was related to unpredictable aneurysm rupture. In conclusion, comprehensive anatomical knowledge of the abdominal aorta and its main collateral side branches, including variations, is a fundamental prerequisite if satisfactory and predictable results are to be achieved after EVAR, especially regarding prevention, diagnosis and treatment of type-II endoleaks. Intraprocedural aneurysm sac pressure monitoring, coil embolisation and the use of injection of thrombin into the aneurysm sac of selected patients is useful in reducing the incidence of post-EVAR type-II persisting endoleaks.

Abnormal origin of internal thoracic and vertebral arteries.

The aim of this study was to evaluate the variability of the origin of the internal thoracic and vertebral arteries after a cadaver demonstrated abnormal origins for both vessels. The arteries were studied in 60 adult cadavers and measurements taken to adjacent structures. In one cadaver the right internal thoracic artery originated from the third part of the subclavian artery (one of 120 arteries; 0.83%). The same cadaver presented with the left vertebral artery originating directly from the aortic arch between the left common carotid and left subclavian arteries. Two other cadavers also presented with abnormal vertebral arteries, making it three of 60 left vertebral arteries (5%). These results are comparable to the established range in the literature. The internal thoracic artery is used for revascularization in coronary artery diseases and as this area is also used for subclavian vein catheterization, it is important to be aware of this rare variation concerning the internal thoracic artery. This study reports an important variation in the origins of the internal thoracic and vertebral artery in a singular cadaver.

The development of the chondrocranium of Gallus gallus.

An account of six stages of the development of the chondrocranium up to the beginning of ossification is given. The tip of the chorda does not pierce the anterior surface of the acrochordal in the early stages and the fenestra basicranialis posterior develops through resorption of the basal plate. The posterior part of the orbital cartilage develops a laterally situated orbitocapsular commissure and a medially situated pila antotica spuria. The pila antotica is resorbed leaving the posterior orbital cartilage connected to the basal plate only by the pila antotica spuria. In the earliest stage the cochlear portion of the otic capsule is fused to the basal plate, but can be distinguished from the basal plate and the canalicular portion. The tectum synoticum is attached to the otic capsule by two roots with the ventral attachment spreading over the lateral surface of the pila occipitalis. The trabecula communis forms without the intervention of an intertrabecula. The interorbital and nasal septa develop from the trabecula communis. An ethmoid plate forms the roof of the nasal capsule and the rest of the capsule develops as outgrowths from the roof. A transitory floor for the posterior part of the nasal capsule is present in the young stages and an incomplete floor for the anterior part develops late during the ontogeny.