External jugular vein pierced by supraclavicular branches in a neonatal cadaver : a case report

Anatomical variations in the venous structure and drainage patterns in the neck are not uncommon. However, this is the first known report on the external jugular vein being pierced by supraclavicular branches. In the lateral cervical region of a neonatal cadaver, the supraclavicular branches penetrated the external jugular vein superior to the clavicle, resulting in a circular venous channel formed around the nerve trunk. Variations such as these are important to note in order to minimize possible intra-operative complications sustained during surgical interventions such as venous catherization or nerve grafts.http://link.springer.com/journal/12565hj2022Anatom

A quantitative analysis of the dimensions and content of the vertebral triangle

PURPOSE : The vertebral triangle (VT) located in the root of the neck most commonly contains the vertebral artery (VA), cervical sympathetic chain and certain roots of the brachial plexus. Although other structures have been reported, few studies have reported on the overall content of this space. Based on the current literature, there is a general paucity of anatomical information pertaining to the dimensional anatomy of the VT and specifically the structures related to it. Therefore, this study aimed to quantitatively analyze the size, position, content, and anatomical structures in relation to the vertebral triangle in a South African sample. METHODS : Forty-three VTs were dissected on bodies donated to science. Measurements taken include the dimensions of the triangle, as well as distances between prominent structures and landmarks of the VT. Observations were made on the presence/absence of the varying neurovascular structures within the VT. RESULTS : Mean height was 30.1 ± 1.51 mm (R) and 32.9 ± 1.78 mm (L). Mean width was 18.3 ± 0.74 mm (R) and 19.3 ± 0.98 mm (L). The C8 spinal nerve was found on average approximately halfway [16.4 ± 0.74 mm (R) and 15.9 ± 0.95 mm (L)] in the VT. The VA was present in the VT in 100% of the sample and the C7 spinal nerve and inferior sympathetic ganglia were present in more than 80% of the sample. CONCLUSION : Understanding the VT and the content is of the utmost importance and of great interest to neurosurgeons, to avoid these important neurovascular structures and prevent iatrogenic complications during surgery.https://link.springer.com/journal/276hj2022Anatom

Exploring the relationship between soft and hard tissues : the example of vertebral arteries and transverse foramina

Understanding how the brain is provided with glucose and oxygen is of particular interest in human evolutionary studies. In addition to the internal carotid arteries, vertebral arteries contribute significantly to the cerebral and cerebellar blood flow. The size of the transverse foramina has been suggested to represent a reliable proxy for assessing the size of the vertebral arteries in fossil specimens. To test this assumption, here, we statistically explore spatial relationships between the transverse foramina and the vertebral arteries in extant humans. Contrast computed tomography (CT) scans of the cervical regions of 16 living humans were collected. Cross-sectional areas of the right and left transverse foramina and the corresponding vertebral arteries were measured on each cervical vertebra from C1 to C6 within the same individuals. The cross-sectional areas of the foramina and corresponding arteries range between 13.40 and 71.25 mm2 and between 4.53 and 29.40 mm2 , respectively. The two variables are significantly correlated except in C1. Using regression analyses, we generate equations that can be subsequently used to estimate the size of the vertebral arteries in fossil specimens. By providing additional evidence of intra- and inter-individual size variation of the arteries and corresponding foramina in extant humans, our study introduces an essential database for a better understanding of the evolutionary story of soft tissues in the fossil record.Erasmus plus programme; National Research Foundation of South Africa; South Africa/France (PROTEA) Joint Research Programme; National Research Foundation.http://www.wileyonlinelibrary.com/journal/joaAnatom

Clinical anatomy of the maxillary nerve block in pediatric patients

BACKGROUND : 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. OBJECTIVE : To determine the best approach for blocking the maxillary nerve within the pterygopalatine fossa. METHODS : In an attempt to define an optimal approach for maxillary nerve block in this age group three approaches were simulated and compared on 10 dried pediatric skulls as well as 30 dissected pediatric cadavers. The needle course, including depth and angles, to block the maxillary nerve, as it exits the skull at the foramen rotundum within the pterygopalatine fossa, was measured and compared. Two groups were studied: Group 1 consisted of skulls and cadavers of neonates (0–28 days after birth) and Group 2 consisted of skulls and cadavers from 28 days to 1 year after birth. RESULTS : No statistically significant difference (P > 0.05) was found between the left and right side of each skull or cadaver. Only technique B, the suprazygomatic approach from the frontozygomatic angle towards the pterygopalatine fossa, exhibited no statistical significance (P > 0.05) when other measurements made on the skulls and cadavers were compared. Technique A, a suprazygomatic approach from the midpoint on the lateral border of the orbit, as well as technique C, an infrazygomatic approach with an entry at a point on a vertical line extending along the lateral orbit wall, showed statistical significant differences when measurements of the skulls and cadavers were compared. CONCLUSIONS : On the basis of these findings technique B produces the most consistent data for age groups 1 and 2 and supports the clinical findings recently reported.National Research Foundation (NRF)http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1460-95922015-07-30hb201

Evaluation of the inion and asterion as neurosurgical landmarks for dural venous sinuses: osteological study on a sample of South African skull specimens

BACKGROUND : Sub-Saharan neurosurgeons most likely need to perform invasive procedures without the latest imaging and navigation technology in the operating room. Therefore, these surgeons need to utilize other methods such as superficial surface landmarks for neuro-navigation. Bony landmarks, including the inion and asterion, are commonly used during invasive procedures to pinpoint the location of the confluence of sinuses and transverse-sigmoid sinus junction, respectively. The purpose of this study was to investigate whether the inion and asterion can be used as superficial landmarks for the confluence of sinuses and the transverse-sigmoid sinus junction, respectively, in a South African population. METHODS : Fifty South African human skulls were used (25 male, 25 female). The micro-focus X-ray radiography and tomography facility (MIXRAD) at Necsa scanned and created three-dimensional virtual images of the skull specimens. Reference points were then inserted on the images and the relation between bony landmarks and venous sinuses was documented. RESULTS : The inion was directly related to the confluence of sinuses in 4% of the sample, whereas the asterion was directly related to the transverse-sigmoid sinus junction in 28% of the cases, on both the right and left sides. CONCLUSIONS : This study confirmed that neither the inion, nor the asterion, are directly related the confluence of sinuses and transverse-sigmoid sinus junction, respectively. These bony landmarks are more likely to be located either inferior, or not related at all, to the investigated dural venous sinuses.https://www.minervamedica.it/en/journals/neurosurgical-sciences2022-04-01hj2022Anatom

Evaluation of paediatric regional anaesthetic procedures in the head and neck region

Advancements in the medical field with regard to the development of new techniques, reassessment and analyses of the old and unsatisfactory techniques and the expansion and improvement of acceptable techniques have led to an increase in the use of regional anaesthetic nerve blocks in paediatric patients. However, several regional anaesthetic procedures are currently not being performed by anaesthetists due to the high number of complications and difficulties experienced. Some medical practitioners are under the impression that they lack the knowledge and confidence to perform these regional nerve blocks, especially on neonatal and infant patients. In order to assist these doctors in refining their anatomical knowledge and increasing their confidence in performing these nerve blocks, the procedures which are experienced as problematic need to be identified and evaluated. The aim of this study was therefore: (1) to establish the most efficient method of blocking the maxillary nerve within the pterygopalatine fossa; (2) to investigate which head and neck regional nerve blocks are performed most frequently on paediatric patients and identify problem procedures that are performed by practicing anaesthesiologist in South Africa; (3) to develop a clinical anatomy information base for the selected procedures. Three methods / techniques for maxillary nerve blocks were simulated and compared on 24 dry paediatric skulls and 30 dissected paediatric cadavers. The depth and angles at which the needle travels to block the maxillary nerve in the pterygopalatine fossa, after existing the skull through the foramen rotundum, was measured and compared. The method using the supra-zygomatic approach (method B), from the frontozygomatic angle towards the pterygopalatine fossa, exhibited no statistical significance (p > 0.05) when comparing the measurements in the skulls and cadavers. Method A, a supra-zygomatic approach from the midpoint on the lateral border of the orbit, as well as method C, an infra-zygomatic approach with an entry at the site of a vertical line extending along the lateral orbit wall, showed statistical significance when comparing measurements in the skulls and cadavers. It can therefore be concluded that method B produces the most consistent data and should be tested in a clinical setting. Seventeen commonly performed paediatric regional nerve blocks were identified. A detailed questionnaire was completed by 111 respondents, either electronically or from others attending either the Pain Interventions and Regional Anaesthesia Conference or the South African Society of Anaesthesiologists Conference. Difficulties in performing the regional anaesthetic nerve blocks, and complications encountered, were the main areas of focus, when selecting the four problem procedures. The problem procedures selected are the following: supra-orbital and supra-trochlear nerve blocks, infra-orbital nerve block (Extra-oral approach), superior laryngeal and recurrent laryngeal nerve blocks. A detailed anatomical information base was developed through an extensive literature review. This will aid in educating and facilitating doctors in performing paediatric regional nerve blocks, thereby enabling them to successfully practice medicine.Dissertation (MSc)--University of Pretoria, 2013.gm2014Anatomyunrestricte

An anatomical study of the nerves targeted for sensory blocks of the head and neck in neonates and infants

The father of modern regional anaesthesia, Gaston Labat, made this very important statement: “Anatomy is the foundation upon which the entire concept of regional anaesthesia is built. Anyone who wishes to be an expert in the art of regional anaesthesia must be thoroughly grounded in anatomy.” This statement is as true today, as in 1922 when it was first made. Adult anatomy applicable to regional anaesthesia has been extensively investigated, resulting in the improvement of techniques and a decrease in complications. However, in the paediatric population, in most cases, the anatomy of adults are used and disproportionately modified in order to perform paediatric regional anaesthetic techniques. This is not considered favourable, and can lead to failed blocks or complications. Therefore, knowledge of the anatomy of paediatric patients is not only required, but considered vital for the successful performance of regional nerve blocks in paediatric patients. The overall aim of this research study was, therefore, to effectively describe the paediatric anatomy of five head and neck nerve blocks commonly performed, based on dissections and measurements of paediatric formalin-fixed cadavers, as well as osteological samples. Based on easily identifiable bony~ and soft tissue landmarks, easily performed techniques are proposed in order to safely and successfully perform these regional nerve blocks in paediatric patients. This will not only minimise possible opioid-related complications, but will ensure optimal management of postoperative pain. In conclusion, the importance of anatomical knowledge applicable to the paediatric population is beyond discussion, and techniques based on the applicable neonatal and infant anatomy will not only educate and facilitate doctors during the performance of these regional nerve blocks, but will also greatly benefit the paediatric patients undergoing these procedures.AnatomyPhDUnrestricte

Anatomy of the greater occipital nerve block in infants

BACKGROUND : Pain relief for posterior fossa craniotomies as well as occipital neuralgia, are indications for the use of the greater occipital nerve block in children. The greater occipital nerve originates from the C2 spinal nerve and is accompanied by the occipital artery as it supplies the posterior scalp. AIMS : The aim of this study was to develop a unique, yet simple technique for blocking the greater occipital nerve in children through the evaluation of the anatomy of this nerve and the accompanying occipital artery in the occipital region. METHODS : The greater occipital nerve and occipital artery were dissected and exposed in six formalin‐fixed cadavers (five infants [average age of 51.4 days] and one 2‐year‐old) from the Department of Anatomy, University of Pretoria. Measurements between the nerve and selected bony landmarks were obtained. The relationship between the greater occipital nerve and the occipital artery at the trapezius muscle hiatus was also evaluated. RESULTS : The greater occipital nerve is on average 22.6 ± 5.6 mm from the external occipital protuberance in infants. The average width of the medial three fingers measured at the proximal interphalangeal joint, for each respective cadaver is 20.4 ± 4.0 mm, with a strong correlation coefficient of 0.97 between the aforementioned distances. In 83.3% of the specimens, the occipital artery lies lateral to the greater occipital nerve at the trapezius muscle hiatus. CONCLUSION : In infants, the greater occipital nerve can be blocked approximately 23 mm from the external occipital protuberance, medial to the occipital artery. This distance is equal to the width of the medial three fingers at the proximal interphalangeal joint of the patient.http://wileyonlinelibrary.com/journal/pan2020-09-01hj2019Anatom

Ptch1 is required locally for mammary gland morphogenesis and systemically for ductal elongation

Systemic hormones and local growth factor-mediated tissue interactions are essential for mammary gland development. Using phenotypic and transplantation analyses of mice carrying the mesenchymal dysplasia (mes) allele of patched 1 (Ptch1mes), we found that Ptch1mes homozygosity led to either complete failure of gland development, failure of post-pubertal ductal elongation, or delayed growth with ductal dysplasia. All ductal phenotypes could be present in the same animal. Whole gland and epithelial fragment transplantation each yielded unique morphological defects indicating both epithelial and stromal functions for Ptch1. However, ductal elongation was rescued in all cases, suggesting an additional systemic function. Epithelial function was confirmed using a conditional null Ptch1 allele via MMTV-Cre-mediated disruption. In Ptch1mes homozygotes, failure of ductal elongation correlated with diminished estrogen and progesterone receptor expression, but could not be rescued by exogenous ovarian hormone treatment. By contrast, pituitary isografts were able to rescue the ductal elongation phenotype. Thus, Ptch1 functions in the mammary epithelium and stroma to regulate ductal morphogenesis, and in the pituitary to regulate ductal elongation and ovarian hormone responsiveness