Translational Research in Anatomy最新文献

Background

Aim of study

Materials and methods

Results

Conclusion

Introduction

Intrinsic coordination of the fifth digit of the hand is largely controlled by the abductor digiti minimi (ADM), flexor digiti minimi brevis (FDMB), and opponens digiti minimi (ODM) muscles (i.e., the hypothenar muscles). Hypothenar muscle variations have been reported; however, biomechanical analyses are seldom performed and descriptions of rare variants such as the deep abductor-flexor of the fifth digit (DAF5) are especially scarce. This study aims to investigate an especially unique case involving the rare DAF5 among additional hypothenar muscle aberrations with biomechanical analysis and discussion of clinical implications.

Methods

An especially unique case of multiple unilateral (left) hypothenar muscle aberrations was discovered during routine human cadaver dissection. The aberrations were cleaned of extraneous fascia and photographed in situ. Mass and fascicle length were measured and mean postmortem fixed sarcomere states were determined via light microscopy to calculate a normalized maximal isometric force (F_max) for each muscle.

Results

The concurrent aberrations included two accessory ADM muscles, three accessory FDMB muscles, an accessory ODM muscle, and a bicipital DAF5. The curved long head of DAF5 (F_max = 4.77 N) originated from the transverse carpal ligament (across midline), while the straight short head (F_max = 1.23 N) originated from the pisiform. The two heads united to form a prominent 3 cm tendon which inserted on the medial aspect of the base of the fifth proximal phalanx. Notably, the long head separated the ulnar artery (superficial) from the ulnar nerve (deep).

Conclusions

The presence of consecutive hypothenar anomalies could influence fifth digit coordination for proper hand function, and the concomitant DAF5 could implicate the underlying median and ulnar nerves. Insights from this report may inform occupational and physical therapists, orthopedic surgeons, and medical anatomy educators when treating or deliberating related cases.

Background

One variation of the atlanto-occipital joint contains a groove or crest dividing the superior articulating facet of C1 and/or the corresponding occipital condyle. This study aimed to estimate the prevalence of bipartition of the facets associated with the atlanto-occipital joint and to determine the relationships between the corresponding joint surfaces, bilateral and unilateral facets as well as demographic factors in a South African sample.

Materials and methods

Data about shape and bipartition found on the superior articular facets of the atlas and the occipital condyles were collected from 109 skulls and atlases from the Pretoria Bone Collection, South Africa. Shape data was categorically classified according to existing criteria from literature.

Results

The results revealed the occasional occurrence of a double facet at both the superior articular facet of the atlas (15.6 %), and the occipital condyle (7.34 %). Shape and facet number of the superior articulating facet and corresponding occipital condyle were significantly correlated. The prevalence of bipartition of neither the superior articular facets nor the occipital condyles were statistically significantly different between the left and right sides. Sex and age did not statistically significantly contribute to prevalence of bipartition in this population. However, population group statistically significantly contributed to prevalence of bipartition (p = 0.019), with the White South African sample having a much higher prevalence (88.24 % superior articulating facet, 100 % occipital condyle) of bipartition compared to the Black South African sample (11.76 % superior articular facet, 0 % occipital condyle).

Conclusion

Awareness of this joint variation and instances where it is more likely to occur may be valuable for neuro-vascular and orthopaedic surgeons when doing invasive treatments around the craniocervical junction, and chiropractors when assessing and treating patients.

Research purpose

The sinoatrial node (SN) is the main pacemaker site, and it is located in the junctional area of the superior vena cava within the right atrium (RA). The precise micro-anatomy of the SN in males and females in ageing and obesity remains unclear.

Basic procedures

Human SN/RA specimens were dissected from 25 post-mortem hearts (preserved in 4 % formaldehyde solution), under Polish local ethical rules. The SN/RA tissue blocks were embedded in paraffin. Masson's Trichrome staining and immunohistochemistry for CD31 (a marker of endothelial cells) and CD68 (a marker of macrophages) were performed. Images at different magnifications were taken and analysed. 12-lead ECGs from 24 patients under Polish local ethical rules were obtained. Heart rate and P wave morphologies from lead II, lead III and lead aVF were analysed. Statistical analysis was performed with the unpaired t-test.

Principal results

Heart weight to body weight ratio was significantly higher in aged obese males vs. their female counterparts. In the RA samples, there was an increase in connective tissue and decreased myocyte content from aged obese females compared to aged obese males. Aged non-obese males had significantly increased cellular hypertrophy than the aged non-obese females. Both the aged obese and aged non-obese females showed more CD3 but less CD68 expressing cells than males. In the SN samples, CD31 and CD68 expressing cells were higher in both aged non-obese and aged obese males than their female counterparts.

Major conclusions

Ageing and/or obesity are more likely to impact these cardiac tissues through increased inflammation, increased immune response and hypertrophy.

Background

Arbor vitae cerebelli (tree-like branching white matter of the cerebellum) has a complex spatial configuration that is challenging to assess using conventional morphometric methods. This study proposes a fractal approach to describe and quantify the anatomy of Arbor vitae cerebelli. For this purpose, a new “contour scaling” method for fractal analysis of cerebellar white matter was developed.

Material and methods

The cerebella of 100 cadavers (50 male and 50 female) who died from causes unrelated to brain pathology, aged 20–95 years, were examined. Mid-sagittal sections of the cerebellar vermis were studied. The fractal dimension values of the cerebellar white matter were determined using both the developed fractal analysis method and the conventional “box counting” method, along with measurements of non-fractal parameters including cerebellar weight, area and perimeter of the vermis cross-section, perimeter-to-area ratio, and circularity.

Results

Considering the cerebellar white matter as a tree-like fractal, it was found to have 7 or 8 primary branches, which subdivide into 10-18 second-iteration branches, 19–38 third-iteration branches, and 34–53 fourth-iteration branches. Females more often had 8 primary branches compared to males, while males had a greater number of branches in the second to fourth iterations. The mean fractal (Hausdorff) dimension was 1.697 (1.721 in males, 1.674 in females, P = 0.01). The fractal dimension correlated most strongly with the perimeter and area of the vermis cross-section and had no significant relationship with age.

Conclusion

The fractal (Hausdorff) dimension, determined using the novel “contour scaling” method, quantitatively assesses the degree of branching of the cerebellar white matter. An increase in the absolute size of the cerebellum leads to a higher degree of branching of its white matter and an increase in the number of its constitutive components – white matter branches and folia.

Background

The value of formalin-fixed postmortem computed tomography (PMCT) has significantly increased in human anatomy education and research. However, improving embalmed PMCT images with high noise, low contrast, and multiple artifacts is an important challenge in enhancing the quality of clinical images. Retrospective denoising methods for embalmed PMCT data are essential for anatomical education and research when new-generation CT scanners with denoising functions are unavailable.

Methods

The three currently available standalone software denoising methods, including image summation methods (Fused CT), noise-reduction system methods (iNoir), and iterative reconstruction (IR, SafeCT), were used to analyze the retrospective noise-reduction effect on 13 human formalin-fixed PMCT datasets.

Results

Fused CT had some advantages; however, it was not useful for embalmed cadavers because of high noise, which doubled with the addition. iNoir and SafeCT improved the visual image quality of the noisy cadaver images. Statistical examination showed a 22–67 % and 18–56 % improvement in noise reduction in the non-artifact and metal artifact parts, respectively, depending on the methods and denoising intensities. However, this improvement was not statistically or morphologically significant in the presence of strong metal artifacts. In contrast, the scattered metal and streak artifacts peculiar to cadaveric images showed effective morphological and statistical improvement.

Conclusions

Retrospective denoising of embalmed PMCT images showed significant morphological and statistical improvements in noise reduction and is feasible for current anatomy education and research.

Background

Occipitalisation is the most prevalent congenital abnormality at the craniovertebral junction; however, it is rare in the general population. There is a paucity of literature on osteological prevalence studies within the South African Black and broader African populations. This study aimed to establish baseline data for the prevalence of occipitalisation in the South African Black population group.

Methods

One thousand two hundred thirteen skulls from a South African Black population were initially sampled, and after exclusion criteria were applied, the sample was reduced to 1119 skulls (male 766; female 353). A morphological description of the skulls that exhibited occipitalisation was included in this study.

Results

Occipitalisation was observed in three skulls (3/1119; 0.27 %); two of the skulls were female (2/353; 0.57 %), and one was male (1/766; 0.13 %). The three occipitalised skulls exhibited fusion in three areas of the atlas: the anterior arch, lateral masses, and transverse processes. No skulls exhibited posterior arch fusion of the atlas.

Conclusion

This study established a baseline prevalence of occipitalisation in the South African Black population at 0.27 % and found no significant association between sex and occipitalisation (p = 0.236). This study highlights the need for further studies in the other African population affinity groups.

Background

Recurrent laryngeal nerve (RLN) injuries account for most successful litigations against surgeons following head and neck surgery. Most injuries to the RLN occur during thyroidectomy with the best strategy to reduce injury to the RLN being through intraoperative monitoring of its normal anatomy, extra-laryngeal trajectory and topography. Identification of the RLN during thyroidectomy is possible at the tracheoesophageal groove (TEG), where it crosses the inferior thyroid artery (ITA) and or pierces the suspensory ligament of the thyroid gland (ligament of Berry). The extra-laryngeal course and branching patterns of the RLN are highly variable, increasing the likelihood of iatrogenic injury.

Materials and methods

The current study investigated the extra-laryngeal course, branching patterns and topographical relationships of the RLN in the TEG in adult cadavers and patients who underwent thyroidectomy. The study examined 30 thyroidectomy patients and 50 adult cadavers.

Results

The mean diameters of the RLN were 1.74 ± 0.59 mm and 1.63 ± 0.47 mm on the left and right sides, respectively, with no statistically significant difference between the genders and sides (P ≥ 0.05). The majority of the RLNs on the left side coursed in the first 0–15⁰ relative to the TEG while on the right side the majority deviated from the TEG at an angle ranging between 0 and 30⁰. The distribution of the RLN in relation to the inferior thyroid artery in the cadaveric sample was as follows: 29.6 % posterior to the artery, 33.7 % anterior to the artery and 36.7 % in-between its branches with statistically significant differences between genders (P ≤ 0.05). The majority of the RLN exhibited two or more branches on both sides, with a maximum of four branches being observed. In the surgical cohort, majority of the RLN ran posterior to the ITA followed by the anterior course and least in-between the branches of the ITA.

Conclusions

The present findings augment the vital information about the course, topography and branching patterns of the RLN along the TEG by outlining differences between the a cadaveric and a surgical sample as well as between two major South African population groups in order to minimise the iatrogenic injuries to the RLN and also to improve the diagnoses and management of the disorders of the neck, larynx and voice production.