Translational Research in Anatomy最新文献

Background

The human body is a complex entity composed of organs and systems that pull together to fulfill specific functions necessary to sustain life. This seemingly simple definition, however, needs to be revised since the importance of the human body goes far beyond its biological role.

Aim

In anatomical literature, much attention is paid to the human body's material (morphological) aspects. Contrary to such an approach, the presented considerations aim to devote attention solely to the body itself, which for centuries has been an object of interest for scientists and a source of inspiration for artists.

Conclusions

With the progress of science and technology, the boundaries and taboos related to the human body are almost constantly changing. Modern anatomy and neuroanatomy can develop in greater depth and breadth, and the human body can be understood in a much more comprehensive range of contexts. Science is increasingly exploring the structure and functioning of the body and, thanks to the development of modern psychology, its association with the mind.

Background

This study was a prospective cadaver-derived skeletal study looking at the skeletal remains of a modern human population. The complete arcuate foramen (AF) is an anatomical variant of the atlas vertebra with a complete osseous bridge over the groove for the vertebral artery (VA). Awareness of the anatomic variations of the atlas related to the course of the VA, such as the AF, is important because the course and variations of VAs are critical to spine surgeons. We aimed to detect the prevalence of AF in sub-Saharan African subjects.

Materials and methods

We analyzed the prevalence of AF in 120 atlas vertebrae from the Raymond A Dart Collection of the University of the Witwatersrand, Johannesburg, South Africa.

Results

Twelve (13.3 %) atlases of the 90 that were from sub-Saharan African ancestry subjects presented at least one AF: the presence of AF frequency was 6.7 % in the Sotho sample, 23.3 % in the Xhosa sample and 10.0 % in the Zulu sample. However, no significant difference was found in their distribution regarding the presence of AF ratios (p = 0.221). The AF frequency was 3.3 % in the South African Caucasian subjects. No significant differences were found in their distribution regarding the presence of AF ratios between the Caucasian and the Sotho (p = 1.000), Zulu (p = 0.612) and Xhosa (p = 0.052) samples.

Conclusions

Our research shows a tendency for a higher AF presence in Xhosa subjects. It has increased the knowledge of the AF prevalence in sub-Saharan Africa, drastically increasing the population.

Age estimation in adults is a complicated task because of various external factors occur concurrently with increasing age. The geometric morphometric method (GMM) is an approach that focuses on shape analysis and is widely recognized for its high reliability and reproducibility. The aim of this study was to explore the variation of cervical vertebrae among different age groups of the Malaysian population by GMM. Lateral skull radiographs of 432 subjects comprising four adult age groups; young adult age group (20–30 years old), early middle age group (31–40 years old), late middle age group (41–50 years old) and, elder adult age group (51–60 years old) were selected. Fifty-three 2-dimensional (2D) landmarks were applied to the digitalized radiographs by TPSDig2 (Version 2.31) software. Geometric morphometric analysis was performed by MorphoJ software. Results showed that the first three principal components (PC) contributed to 47.71 % of the cervical vertebrae variation and were shown in both lollipop and wireframe graphs. Procrustes ANOVA indicated that the shape was significantly different among different age groups. Canonical variate analysis revealed significant differences of both mahalanobis and procrustes distances among age groups with substantial individual overlap within groups. Discriminant function analysis (DFA) showed a correct classification rate for 61.5 % of cases respective to age groups. In conclusion, this study found significant differences in the shape of cervical vertebrae among different age groups of the Malaysian population using the GMM.

Background

The abducens nerve palsy may be associated with various disease processes, as nerve damage may occur at any point of its transit from the pons to the lateral rectus muscle.

Aim

Our case report presents a rarely described variant of the abducens nerve's cavernous segment and an outline of the potential developmental background of the finding.

Case description

Early division of the abducens nerve's prefissural segment was found during the cavernous sinus dissection. The nerve was divided into the superior (of 0.68 mm diameter) and inferior (of 0.54 mm diameter) divisions before reaching the superior orbital fissure just after crossing the internal carotid artery. Both divisions entered the orbit separately through the superior orbital fissure. The innervation of the lateral rectus muscle was typical.

Conclusions

Early division of the abducens nerve can be defined as the presence of two separate nerve trunks in the anterior cavernous sinus, superior orbital fissure, and orbit. Anatomical variations of the abducens nerve should be kept in mind during diagnostic and surgical procedures.

Background

The tendons of the flexor hallucis longus (FHL) and flexor digitorum longus (FDL) are commonly utilized in reconstructive foot surgery to address deformities. These tendons intersect on the plantar surface and exhibit varying interconnections that can significantly impact graft length and complicate the tendon harvesting process. The objective of this study was to comprehensively categorize these interconnections using a modified classification system and precisely determine their positional relationships with surgically significant bony landmarks.

Methods

Sixty embalmed feet of 30 cadavers were studied to analyze the interconnections between FHL and FDL in the planta pedis, classify them in a modified classification system and measure distances to surgically relevant anatomic landmark.

Results

The study revealed three primary types of interconnections. Type I, representing a proximal-to-distal connection from the FHL to the FDL, was observed in 85% of the feet. Type II, signifying a proximal-to-distal connection from the FDL to the FHL, was found in 11.66% of the feet. Type III, characterized by a crossed connection, was identified in 3.33% of the feet. The average point of branching for the FHL and FDL tendons was situated 4.5 cm and 3.5 cm distal to the navicular tuberosity, respectively.

Conclusion

The presence of atypical proximal-to-distal interconnections from the FHL to the FDL may play a role in preserving residual function in the lesser toes following FDL transfer procedures. Awareness of anatomical variations in the location of these interconnections is crucial for preserving them during surgical interventions, ultimately mitigating the risk of functional impairment in the lateral toes post-tendon grafting.

Background

Variations in the roots of the brachial plexus and their branches may cause unexpected complications during surgical procedures of the neck. In this report, we show an extremely rare variation of the long thoracic nerve.

Methods

During routine dissection of the posterior triangle of the neck in a white female cadaver, a variation in a branch of the brachial plexus was observed and documented. Further dissection of the axilla and anterolateral thoracic wall were performed to follow the course of the anomalous superficial nerve.

Results

The abnormal nerve was discovered to be a variation of the long thoracic nerve (LTN) formed from a supraclavicular union of only the C6 and C7 spinal nerve roots.

Conclusions

Variations in the anatomy of the brachial plexus are not uncommon, but variations of the LTN are rare. Awareness of the LTN in relation to the brachial plexus is useful for the head and neck surgeon operating in less often encountered spaces to prevent injury.

Background

Modern research in the morphological sciences field requires various specialized research methods, including histological techniques. This concise review presents considerations on applying selected histochemical techniques in anatomical research.

Aim

This article presents selected metal-based stains and their application in examining tissue morphology and structure using an optical microscope. Additionally, the article will explore the benefits, drawbacks, and widespread usage of these stains.

Conclusions

Morphological research requires reliable observations. Thus, specific pros and cons of applying metallic stains must be evaluated. However, the use of metal-based stains in microanatomical and neuroanatomical research is still current.

Introduction

Surgeons employ central venous catheterization as a therapeutic or preventive measure in the pediatric population. These catheters are introduced into the internal jugular, subclavian, or femoral veins using the central approach, involving the insertion of the needle into the apex of Sedillot's triangle, a well-defined anatomical reference point. Using a neonatal sample, this study ascertained the precise positioning of the internal jugular vein to evaluate its suitability as a central venous catheter insertion site. We also determined the location of the vein in relation to Sedillot's triangle.

Materials and methods

Nineteen formalin-fixed neonatal cadavers, encompassing both the left and right sides of the neck region (totaling 38 sides), were dissected to expose the underlying soft tissues and neurovascular structures. Thereafter, the three boundaries of Sedillot's triangle were identified, demarcated, and measured. The internal jugular vein's position within Sedillot's triangle was meticulously recorded, and the diameter of the vein was measured.

Results

Among the 38 sides examined, only three exhibited fully formed triangles, with most of the samples featuring a groove instead. When the needle was placed at the apex of Sedillot's triangle (or within the groove), the needle consistently accessed the internal jugular vein only 65.8% of the time. In 23.7% of cases, the apex was observed lateral to the internal jugular vein, and in 10.5% of cases, the apex was positioned medially.

Conclusion

The apex of Sedillot's triangle is an unreliable anatomical landmark for the insertion of central venous catheters in neonates. Caution should be exercised when employing this landmark in the absence of ultrasound guidance.

Background

Quantitatively assessing age-related atrophic changes in cerebral hemispheres remains a crucial challenge, particularly in distinguishing between normal and pathological brain atrophy caused by neurodegenerative diseases. In this study, we introduced a new fractal analysis algorithm, referred to as the “contour smoothing” method, to quantitatively characterize age-related atrophic changes in cerebral hemispheres.

Materials and methods

MRI scans from 100 healthy individuals (44 males, 56 females), aged 18–86 (mean age 41.72 ± 1.58), were analyzed. We used two fractal analysis methods: the novel “contour smoothing” method (with stages: 1–6, 1–5, 2–6, 1–4, 2–5) and the classical “box-counting” method to assess cerebral cortex pial surface contours.

Results

Fractal dimensions obtained using the “box-counting” method showed weak or statistically insignificant correlations with age. Conversely, fractal dimensions derived from the “contour smoothing” method exhibited significant age-related correlations. The “contour smoothing” method with 1–4 stages proved more suitable for quantifying atrophic changes. The average fractal dimension for 1–4 coronal sections was 1.402 ± 0.005 (minimum 1.266, maximum 1.490), and for all five tomographic sections, it was 1.415 ± 0.004 (minimum 1.278, maximum 1.514). These fractal dimensions exhibited the strongest correlations with age: r = −0.709 (p < 0.001) and r = −0.669 (p < 0.001), respectively.

Conclusion

The “contour smoothing” fractal analysis method introduced in this study can effectively examine cerebral hemispheres to detect and quantify age-related atrophic changes associated with normal or pathological aging. This method holds promise for clinical application in diagnosing neurodegenerative disorders, such as Alzheimer's disease.

Background

The use of extensor indicis proprius (EIP) muscle tendon for tendon grafting and transplantation in the management of hand injuries is common. Anatomical variations of the EIP tendons have been reported with variable prevalence and presentation in different populations worldwide. Knowledge of possible variation patterns is crucial in reconstructive surgery. The current study aims to describe the prevalence of anatomical variations of the EIP in the Burmese population.

Methods

A total of 50 cadavers (39 males, and 11 females) were dissected. Both upper limbs of each cadaver were observed. The presence of the EIP, the number of tendons, the origin and insertion of the muscle and its relation with the extensor digitorum communis (EDC) were recorded and variations reported.

Results

Of the 100 limbs studied in the 50 cadavers, only 1/100 limb was reported to have an absent EIP muscle and tendon. Of the remaining 99/100 limbs examined, one of them consists of a double tendon, that is, EIP and extensor indicis et medii communis (EIMC) were inserted separately onto the index finger and middle finger respectively on the dorsum of the left hand. Further to this, there is one case in which an extra muscle belly was observed in the EIP tendon, this muscle is commonly known as the extensor digitorum brevis manus muscle. All the EIP variations were observed in the male cadavers only.

Conclusion

Of the 50 cadavers studied, 3/100 limbs exhibited EIP variations in the current studied population. Population-specific studies on these variations may aid in a better understanding of the different anatomical patterns of the muscles in the dorsum of the hand. This may lead to improved diagnosis and surgical management of injuries to the dorsum of the hand and for the use of the EIP tendon in surgical grafts and transplantations.