Marius C. Bosman

The anatomical basis of venographic filling defects of the transverse sinus

Obstruction of the intracranial dural venous sinuses would result in an increase in intracranial dural venous pressure. This intracranial hypertension is not only the result of poor cerebral venous drainage but also life threatening. The aim of this study was to identify the structures, which may show signs of potential venographic filling defect qualities, including trabeculae/septa (also described as “fibrous bands”) and arachnoid granulations, which ultimately can lead to increased intracranial dural sinus venous pressure. A total of 102 cadavers and living patients were used for the study. Fifty‐three percent of the subjects presented with structures in their transverse sinuses that could be potential venous filling defects. Thirty percent of the subjects presented with arachnoid granulations in the right transverse sinus, which were found to be significantly dominant (Chi‐square; p < 0.05). The study also revealed the presence of 1 to 5 septa in 29.4% of the subjects. The septa were found to be more dominant in the central (30%) and lateral (22%) thirds of the right transverse sinuses, while the central third of the left transverse sinus proved to be the least dominant occurring site (8%). In general, the right transverse sinus is highly more significantly dominant in septal occurrence (Chi‐square; p < 0.01) than the left transverse sinus. We conclude from the statistical evidence that the right transverse sinus demonstrates significantly more potential venographic filling defects than the left sinus and submit that this information may assist in management options for patients diagnosed with idiopathic intracranial hypertension as well as direct future research. Clin. Anat. 23:153–159, 2010.

Descriptive study of the differences in the level of the conus medullaris in four different age groups

In performing neuraxial procedures, knowledge of the location of the conus medullaris in patients of all ages is important. The aim of this study was to determine the location of conus medullaris in a sample of newborn/infant cadavers and sagittal MRIs of children, adolescents, and young adults. The subjects of both the samples were subdivided into four developmental stages. No statistical difference was seen between the three older age groups (P > 0.05). A significant difference was evident when the newborn/infant stage was compared with the other, older stages (P < 0.001 for all comparisons). In the newborn/infant group the spinal cord terminated most frequently at the level of L2/L3 (16%). In the childhood stage, the spinal cord terminated at the levels of T12/L1 and the lower third of L1 (21%). In the adolescent population, it was most often found at the level of the middle third of L1 and L1/L2 (19%). Finally, in the young adult group, the spinal cord terminated at the level of L1/L2 (25%). This study confirmed the different level of spinal cord termination between newborns/infants less than one‐year‐old and subjects older than one year. In this sample the conus medullaris was not found caudal to the L3 vertebral body, which is more cranial than the prescribed level of needle insertion recommended for lumbar neuraxial procedures. It is recommended that the exact level of spinal cord termination should be determined prior to attempting lumbar neuraxial procedures in newborns or infants. Clin. Anat. 28:638–644, 2015.

Perspectives on the use of PDAs as assessment tools

T he aim of every tertiary education programme is to produce competent professionals who are capable of meeting the challenges of their profession. They must possess certain personal, cognitive and technical attributes that enable them to perform the required tasks successfully. It is therefore the responsibility of all tertiary institutions to create opportunities for students to acquire these competencies.

Clinical anatomy of the maxillary nerve block in pediatric patients.

Anatomical landmarks in children are mostly extrapolated from studies in adults. Despite this, complex regional anesthetic procedures are frequently performed on pediatric patients. Sophisticated imaging techniques are available but the exact position, course and/or relationships of the structures are best understood with appropriate anatomical dissections. Maxillary nerve blocks are being used for peri‐operative analgesia after cleft palate repair in infants. However, the best approach for blocking the maxillary nerve in pediatric patients has yet to be established.

Degenerative trends of the palmaris longus muscle in a South African population.

The literature reports that the palmaris longus muscle (PL) is only found in mammals in which the forelimbs are weight‐bearing extremities. It is suggested that the function of this muscle has been taken over by the other flexors in the forearm. Terms used in the literature to describe the diminishing of this muscle include retrogressive or phylogenetic degenerative trends. The aims of this study were to determine the prevalence of PL in a South African population and whether a phylogenetic degenerative trend for the PL exists. To determine the prevalence of the PL, five groups, representing different age intervals (Years 0–20, 21–40, 41–60, 61–80, and 81–99) were used. A sample of 706 participants of various ages was randomly selected. Statistical analysis included comparisons of the prevalence of the muscle between males and females and left and right sides, using a student t‐test. A Chi‐squared test was used to determine a possible phylogenetic degenerative trend of PL within the five groups. The sample yielded a bilateral absence of the PL in 11.9% of the cases. The muscle was unilaterally absent on the left side in 7.65% and 6.94% on the right side. The Chi‐squared tests revealed a P‐value of 0.27 for the left arm and 0.39 for the right arm. No obvious trend could be established for the phylogenetic degeneration of the PL in this study. It would appear that the PL muscle should not be considered as a phylogenetically degenerating muscle in a South African population. Clin. Anat. 27:222–226, 2014.

The value of Tuffier's line for neonatal neuraxial procedures

The spine of L4 usually lies on a line drawn between the highest points of the iliac crests (Tuffiers line) in adults. Although its accuracy has been questioned, it is still commonly used to identify the spinous process of the 4th lumbar vertebra before performing lumbar neuraxial procedures. In children, this line is said to cross the midline at the level of L5. A literature search revealed that the description this surface anatomical line is vague in neonates. The aims of this study were to determine the vertebral level of Tuffiers line, as well as its distance from the apex of the sacrococcygeal membrane (ASM), in 39 neonatal cadavers in both a prone and flexed position. It was found that when flexed, Tuffiers line shifted from the level of L4/L5 (prone position) to the upper third of L5. The mean distance from the ASM to Tuffiers line was 23.64mm when prone and 25.47 mm when flexed, constituting a statistically significant increase in the distance (P=0.0061). Therefore, in the absence of advanced imaging modalities, Tuffiers line provides practitioners with a simple method of determining a level caudal to the termination of the spinal cord, at approximately the L4/L5 in a prone neonate and the upper margins of L5 when flexed. Clin. Anat. 27:370–375, 2014.

The Contribution of Prenatal Stress to the Pathogenesis of Autism as a Neurobiological Developmental Disorder: A Dizygotic Twin Study.

This paper reports on the contribution of prenatal stress to the pathogenesis of autism as a neurobiological developmental disorder in a dizygotic study. The aim was to explore whether the neurobiological impact of stress prior to week 28 of gestation might be related to the pathogenesis of autism. The following data‐generating strategies were employed: a diagnostic stress inventory, the 16‐Personality Factor Questionnaire, magnetic resonance imaging and blood plasma sampling. It was found that maternal stress during pregnancy may have produced elevated leucocytes and glucocorticoids during gestation, because stress affects cellular immunity due to involvement of the hipothalamic–pituary–adrenal axis. These were implicated in suboptimal placental functioning, heightened exposure of the foetus to glucocorticoids and altered neural development. The autistic subject’s blood plasma pathology results showed elevated glucocorticoids and serotonin. Significant cortisol and serotonin differences were noted in the blood plasma pathology results of the autistic subject and the control. Hyperserotonemia and elevated glucocorticoids were therefore implicated in altered programmed neural development, as suggested by the autistic subject’s magnetic resonance images. Differences in head circumference were also noted. It was concluded that prenatal maternal stress might have significantly contributed to the pathogenesis of autism.

Revisiting the anatomy of the ilio-inguinal/iliohypogastric nerve block

The ilio‐inguinal/iliohypogastric nerve block (INB) is one of the most common peripheral nerve block techniques in pediatric anesthesia, which is largely due to the introduction of ultrasound (US) guidance. Despite the benefits of US guidance, the absence of an US machine should not deter the provider from performing INB, considering that many institutions, especially in developing countries, cannot afford to provide ultrasound machines in their anesthesiology departments. The aim of this study was to revisit the anatomical position of the ilio‐inguinal and iliohypogastric nerves in relation to the anterior superior iliac spine (ASIS), in a large sample of neonatal cadavers, and compare the results with a similar group in a previously published US‐guided study.

Preliminary results on a study to locate the pterygopalatine fossa using mathematical formulae

Blocking the contents of the pterygopalatine fossa (PPF) has been shown to be effective in treating most orofacial pain including that associated with trigeminal neuralgia. However, the technique is not widely used, and we propose it to be due to the vague descriptions of the techniques in the literature. The aim of this study was therefore to achieve an alternative method of locating the PPF. One hundred and sixty skulls from the department of Anatomy, University of Pretoria, were used. Distinct landmarks (both anthropometric and clinical) accompanied by existing and new anthropometric measurements were used to define the location of the PPF. Regression analysis was used to measure the reliability of predicting the location of the PPF. From the results, two mathematical formulae were devised (one for each side). These formulae were tested on 47 cadavers by inserting a needle at the calculated points after which the areas where dissected to determine whether or not the needle had entered the PPF. Our results showed an accuracy of 65.2% on the right and 54.4% on the left. In conclusion, improvement in the accuracy of the technique could aid in the management of various pain disorders as well as pain management during surgery. Clin. Anat. 23:931–935, 2010.

Determining the extent of the dural sac for the performance of caudal epidural blocks in newborns

Information regarding the position and relationship of vital structures within the caudal canal is important for anesthesiologists who perform a caudal block. This information can be acquired by anatomical dissection, with ultrasound technology, or radiological studies.