External Protuberance Research Articles

Mapping sexual dimorphism signal in the human cranium

The study of sexual dimorphism in human crania has important applications in the fields of human evolution and human osteology. Current, the identification of sex from cranial morphology relies on manual visual inspection of identifiable anatomical features, which can lead to bias due to user’s expertise. We developed a landmark-based approach to automatically map the sexual dimorphism signal on the human cranium. We used a sex-known sample of 228 individuals from different geographical locations to identify which cranial regions are most sexually dimorphic taking into account shape, form and size. Our results, which align with standard protocols, show that glabellar and supraciliary regions, the mastoid process and the nasal region are the most sexually dimorphic traits (with an accuracy of 73%). The accuracy increased to 77% if they were considered together. Surprisingly the occipital external protuberance resulted to be not sexually dimorphic but mainly related to variations in size. Our approach here applied could be expanded to map other variable signals on skeletal morphology.

Stimulation of the Greater Occipital Nerve: Anatomical Considerations and Clinical Implications

Background: Stimulation of the greater occipital nerve has been employed for various intractable headache conditions for more than a decade. Still, prospective studies that correlate stimulation of the greater occipital nerve with outcome of patients with respect to alleviation of headache are sparsely found in literature. Objective: To identify anatomical landmarks for a reproducible stimulation of the greater occipital nerve. For the clinical implication, the individual response to therapy of patients with refractory chronic cluster headache undergoing occipital nerve stimulation was correlated with the postoperative localization of the electrodes and with the distribution of the stimulation field. Study Design: Prospective observational study, approved by the local research ethics board (09-4143). Setting: University hospital, departments of neurosurgery and neurology, institute of anatomy and radiology. Methods: Ten formaldehyde fixed human cadavers were dissected to identify the passage of the greater occipital nerve through the trapezius muscle. The distance to the external occipital protuberance was triangulated measuring the distance of the nerve from the nuchal midline and the protuberance. Between December 2008 and December 2011, 21 consecutive patients suffering from chronic cluster headache underwent surgery in terms of bilateral occipital nerve stimulation, with electrodes placed horizontally at the level of C1. The postoperative x-rays were compared with the acquired landmarks from the anatomical study. The distribution of the stimulation field was correlated to the individual response of each patient to the therapy and prospectively analyzed with regard to reduction of daily cluster attacks and relief of pain intensity at 3 months and at last follow-up. Results: The greater occipital nerve crosses the trapezius muscle at a mean distance of 31mm below the occipital external protuberance and 14mm lateral to the midline as found in the anatomical subjects. The electrodes were targeted at this level in all of our patients and stimulated the greater occipital nerve in all patients. Eighteen of the patients (85.7%) reported a significant reduction of the frequency of their cluster attacks and/or declined intensity of pain during the attacks. Yet, 3 of 21 patients (14.3%) did not benefit from the stimulation despite an adequate spread of the stimulation over the occiput. The spread of the stimulation-induced paraesthesias over the occiput was not correlated to a reduction of cluster attacks, to the intensity of attacks, or to the response to treatment at all. Limitations: Single center non-randomized non-blinded study. Conclusions: From our study we conclude that a reproducible stimulation of the greater occipital nerve can be achieved by placing the electrodes parallel to the atlas, at about 30mm distance to the external occipital protuberance. The response to the stimulation is not correlated to the field width of the paraesthesia. We, therefore, consider stimulation of the main trunk of the greater occipital nerve to be more important than a large field of stimulation on the occiput. Still, an individual response to the occipital nerve stimulation cannot be predicted even by optimal electrode placement. Key words: Greater occipital nerve, occipital nerve stimulation, anatomical study, chronic cluster headache

Distance from the external occipital protuberance to the occipital artery for occipital nerve block

To the Editor: Greater occipital nerve block is indicated for cervicogenic or cluster headache. Identifying the location of the nerve is important for differential diagnosis of cervicogenic headache, because it is necessary to block this nerve and not neighboring structures [1]. The blocking point is where the greater occipital nerve crosses the superior nuchal line approximately halfway between the external occipital protuberance and the mastoid process [2, 3]. The nerve emerges on this line in association with the occipital artery, and thus this artery is the most reliable anatomical landmark [2, 3]. However, it may be difficult to detect pulsation of the occipital artery, because the artery is thin, its course is variable, and hair may make palpation of the scalp difficult. Although the use of sonography has been suggested for detection of the nerve [4], it is likely to be difficult because of interference from the hair of the head. In such a case, textbooks generally describe that the blocking point should be 2.5–3.0 cm from the external occipital protuberance [2, 3]. In our daily clinical practice, we thought that this distance may be too short in men. Therefore, we formally studied this by pulsation, and by a Doppler flowmeter, which we previously reported to be useful [5]. The institutional review board approved the study, and written informed consent was obtained from 330 healthy volunteers (200 men and 130 women). Each volunteer was placed in the prone position and attempts were made to palpate the bilateral occipital arteries. If neither side could be palpated, it was judged a failure. The Doppler flowmeter probe (Nihon Kohden ES-1000 SP, Tokyo, Japan) was then placed and moved along the superior nuchal line until artery flow became audible. When the artery was detected, we measured the distance between the artery and the external protuberance. The artery could not be palpated on either the right or the left side in 15 of 200 (7.5 %) male subjects and 12 of 130 (9.2 %) female subjects. With the Doppler flowmeter, the artery could not be detected in 5 (2.5 %) men and 3 (2.3 %) women, and in all of whom the artery also could not be detected by palpation. The mean distance from the external occipital protuberance to the occipital artery in females (Table 1) was within the textbook range (2.5–3.0 cm), but the distance in males was significantly longer than that in females (P ≤ 0.05, Student’s t test) (Table 1), and the distance was between 2.5 and 3.0 cm in only 27 of 195 (13.8 %) volunteers (in whom the distance could be measured). Table 1 Volunteer characteristics and distance between the occipital artery and the external occipital protuberance (mean (standard deviation), [range]) We have confirmed that the occipital artery sometimes cannot be detected by palpation, or even by Doppler flowmeter. The volunteers we studied were all young, and it is possible that the failure rate of detection may be higher in senior people with headache, who may have neuralgia-induced vasoconstriction. We suggest that, when the occipital artery could not be detected, the blocking point should be about 2.5 cm from the external occipital protuberance in women and about 4.0 cm (and not 2.5–3.0 cm) in men.

Histopathological and ultrastructural studies on a novel pathological condition in Solea senegalensis

A new parasitic disease affecting cultured sole Solea senegalensis (Kaup, 1858) is characterised by the presence of external protuberances in the skin of the affected fish. These lesions correspond to nodules in the muscular tissue showing an abscess-like aspect. Similar lesions were found in the kidney, heart, liver and digestive tract. Histological sections of these nodules revealed the presence of a large core formed mainly of necrotic tissue surrounded with fibroblasts and macrophages. Round-shaped plasmodial organisms were found in the external layer of the nodules and usually inside macrophages or fibroblasts. These organisms were also observed in the intestinal mucosa inside phagocytic cells or parasitophorous vacuoles within the enterocytes. The morphological and ultrastructural characteristics of these organisms are similar to the morphology of some groups of parasites described as fish pathogens. The main features suggest that these organisms could be amoebae or parasites with an amoeboid or plasmodial form in their developmental cycle.

Biofilm architecture of Phanerozoic cryptic carbonate marine veneers

Thin (<150 μm) micritic veneers lining crypts in Paleozoic and Mesozoic reef, microbial, and bioclastic carbonates have the dimensions and architecture of modern uncalcified bacterial biofilm. Morphologic attributes include rounded aggregate nanofabric, internal channels, external towers, mushrooms, and plumes. All can be interpreted as characteristics of attached bacterial communities, i.e., aggregates as microcolonies, originally embedded in a matrix of extracellular polymeric substances; channels as water conduits and/or uncolonized nutrient-poor spaces; external protuberances as localized growths; and plumes as surface streamers. Cryptic habitat favored pristine biofilm preservation by precluding disturbance and overgrowth, and suggests aphotic and anoxic conditions. These examples provide diagnostic morphologic criteria for wider recognition of biofilm in Phanerozoic and older carbonates.

Report of eight cases of occipital dermal sinus: an update, and MRI findings.

We report our experience with 8 patients who were ultimately diagnosed as having occipital dermal sinuses. Clinical presentation, imaging findings and outcome are discussed, along with a review of the literature. In eight patients with occipital dermal sinuses, we retrospectively collected the following data: time to diagnosis, presenting signs, dermal anomalies, location of bone defects, intraparenchymal extension, surgical techniques and clinical outcome. Conventional radiography was performed in all patients; computerized tomography (CT) scans and magnetic resonance imaging (MRI) in all but two. Time to diagnosis ranged from 3 months to 9 years. Presenting symptoms were: infection of a cutaneous mass (n = 4), occipital mass (n = 2), intracranial hypertension related to intra-cerebral abscess (n = 2). In all patients, dermal sinus was located near the external protuberance of the occipital bone. In all patients but one, a cutaneous orifice was associated. Other cutaneous anomalies were: hairy nevus (n = 2) and subcutaneous cysts (n = 4). One patient had associated cranio-facial malformations. Plain skull films revealed linear bony defects in all cases but one; CT scans revealed linear bony defects in all cases, osteitis and intra-parenchymal abscesses if present but they did not allow the delineation of the sinus tract. MRI performed in six patients allowed a better appreciation of the malformation revealing intracranial abscess (n = 1), the sinus tract (n = 2), inclusion cysts (n = 2), and associated venous anomalies (n = 1). Surgery was performed in all patients: a complete removal of the dermal sinus was obtained in all patients but one; inclusion cysts were found in six patients. Total recovery without sequelae was obtained in all patients, except one who suffered from developmental delay and a polymalformative syndrome. In newborns, a meticulous visual exploration of the midline skin along the craniospinal axis is necessary to detect congenital dermal abnormalities. Early surgery is required to prevent severe intracranial infection. MRI could help to determine the surgical approach by delineation of the sinus tract, its extension into deeper tissues and its association with cysts, abscesses or venous anomalies.

Estimation of stature from somatometry of skull

In order to investigate the possibility of estimating stature from somatometry of the skull, we carried out a study on 124 Japanese cadavers (comprising 77 males and 47 females) that had been autopsied at our laboratory between July 1986 and June 1991. Somatometry of the skull was performed on diameter (distance between glabella and external protuberance) and circumference (length around the skull through two points: the glabella and the external protuberance). The regression equations calculated were as follows: stature in males=(diameter+circumference)×1.35+70.6 (standard error of estimate (S.E.)=6.96 cm); stature in females=circumference×1.28+87.8 (S.E.=6.59 cm); stature in both sexes=(diameter+circumference)×1.95+25.2 (S.E.=7.95 cm). These S.E.s appear to be larger than those obtained for other parts of the body. However, in cases where identification is required by means of only the skull, this method could prove useful.

New Pile Handling Techniques

Summary The handling of large-diameter piling has not changed since the inception of the offshore construction industry. The hazards, as well as the time loss, associated with conventional techniques never have been questioned until recently. A newly developed set of automatic gripping and holding tools has transformed pile handling from a brute force, manual, labor-intensive operation to a remotely controlled automatic grip or release operation. Introduction As well depths increase, steel platform structures increase in height and in base dimensions. Concurrently, pin piles basically have become larger in diameter and longer, resulting in heavier strings of piling. This in turn has necessitated larger shackles to support the hoisting load and corresponding pad eyes welded to the piles for attaching the shackles. As a result, handling piles from the material barge to the platform under construction has become harder to accomplish and has required a longer time to accomplish. For each add-on section of piling, it is not uncommon to spend several hours removing the pad eyes once the pile connection has been made. This time-consuming task, which has to be repeated for each section of add-on piling, has become a significant part of the construction cost, particularly as more piles are required on deep structures to pin the jacket to the ocean floor.In 1973, the first North Sea structure containing large numbers of skirt piles was being designed for the Forties field. It was felt by the designers that conventional pile-handling methods would result in prohibitive construction costs, and they sought an alternative, more economical, way of gripping and holding on to the pile. Field operators approached us to develop a method for handling large-diameter piling. We were able to take basic casing handling equipment, which required no pad eyes or external protuberances on the pipe, and adapt it to the larger-diameter piles. The largest previously manufactured casing handling tools could handle a maximum diameter of 20 in.The first set of pile-handling tools was designed to grip 54-in. OD piling. These large-diameter tools, or spiders as they are called, borrowing nomenclature from similar casing-handling equipment, were used on the Forties field platform and then on what was then the world's deepest platform constructed in the Santa Barbara Channel in the Hondo field.The development of these tools and their subsequent improvements, as well as their uses, are the subjects of this paper. Description of Previous Methods When platforms were constructed in shallow water, it was generally possible to pick up the intended pin piles in one section and lower them to the ocean floor through the jacket legs. Since there were no known methods of gripping the OD of a smooth round pipe of this size, it was natural for early construction contractors simply to weld pads onto the outside of the piling and to attach slings and shackles to it so that it could be picked up by the crane on the derrick barge. Since these smaller, shorter sections of piling were fairly light, the shackles and stings posed no particular handling problem, and it was quite expedient once the pile had reached the mudline to cut off those pad eyes with a cutting torch. Similarly, if additional sections of piling had to be added to the string as it was driven into the mud of the ocean floor, these add-on sections would be picked up and stabbed into the initial pile, and then would be welded together.As construction jobs became more complex, it was desirable to use the derrick barge came for other tasks while this welding process was performed. JPT P. 2455^

A modified technique for the selective perfusion of the fourth cerebral ventricle in conscious dogs

A method is described which permits selective and repetitive perfusion of the fourth cerebral ventricle in the conscious dog. An inflow needle is introduced stereotaxically at an angle of 42°–44° through the occipital bone and the cerebellum until its tip reaches the ventricular space. The outflow guide needle is placed vertically above the cisterna cerebello-medullaris. Later a matching outflow needle is introduced through the guide needle, punctures the atlanto-occipital membrane and drains the cisterna magna. A retaining ring with a set-screw, which fits into the hub of the guide cannula, is used to adjust the outflow needle in the vertical plane. The inflow needle and outflow cannula are fixed permanently in place with the aid of a kneadable solidifying dough (Technovit) to two self-threading screws at the external protuberance. In a separate study fentanyl perfused through the fourth cerebral ventricle in increasing concentrations (2.5, 5, 10, and 20 μg/ml) induced a dose-related hypotension, bradycardia, and electroencephalograph-synchronization. These effects could be reversed by subsequent naloxone (20 μg/ml) perfusion.

Functional Anatomy of the Alimentary Canal in the Fruit Bat, Eidolon helvum, and the Insect Bat, Tadarida nigeriae

AbstractThe gastrointestinal anatomy of the frugivorous bat, Eidolon helvum was compared with that of the insectivorous bat, Tadarida nigeriae. Both show modifications related to differences in their food habits as well as other anatomical peculiarities. The gastroesophageal junction in Eidolon helvum possesses a sphincter‐like protrusion. The posterior 10 mm of the esophagus in the same bat has well developed gastric glands, while the stomach is unexpectedly very rich in zymogenic and parietal cells. The intestine in this species is about 170 cm long; the posterior 30 cm of this is of colonic histology, though showing no external morphological difference from the small intestine. The anterior duodenum of Tadarida nigeriae has an external protuberance consisting of mucus secreting glands. The intestine of this bat has no colon, but a very short rectum of goblet cells is present.

A simple method for the sampling of respiratory gas in conscious dogs.

A method is presented for the sampling of respiratory gas in conscious animals, using a catheter with the tip implanted in the roof of the nasal cavity and the other end exteriorized beyond the external protuberance of the occiput. The operation procedure is simple and serious postoperative complications have not been encountered. The method has been used extensively for the continuous measurement of Po2 and PCO2 in respiratory gas of conscious dogs.

Embryonal adenocarcinomas (a type of malignant teratoma) of the sacrococcygeal region. Clinical and pathologic aspects of 21 cases.

Sacrococcygeal teratomas in 21 consecutive patients admitted to Memorial Hospital were all embryonal adenocarcinomas having a common histologic appearance. Seventeen of the patients were female, and all except one were Caucasians. The average age at diagnosis was 2 years, and the average survival after diagnosis was 1 year, with a range of 1 to 68 months. All had large presacral tumors, but 2 had no external deformity. Seven had a midline external protuberance, and 12 presented with enlargement of a buttock. Prior to diagnosis, in 12 patients, the primary tumor produced one or more of a symptom triad of constipation, urinary frequency, and lower extremity weakness, and, in 12 patients, the tumor had metastasized. The primary tumor was resected in 6 patients but recurred in 4 of the 5 patients surviving the operation. Eighteen patients received radiation therapy to the primary tumor and/or metastases, and tumor regression occurred in all. Regression was also obtained in several patients who received chemotherapy. Because of the large size of the tumors and the metastases present at the time of diagnosis at a relatively young age, it is likely that the tumors were present in the presacral space at birth. The failure of surgery to cure the tumors in this series and tumor sensitivity to radiation and chemotherapy suggest that their treatment should consist of a combination of therapeutic modalities.

Scientific Serials

Scientific Serials