Translational Research in Anatomy最新文献

Many definitions of the dimensions of cochlear measurements are described in the literature. However, these terminologies are typically not standardised or vary among disciplines. Confusion of the defined parameters may lead to ambiguity in the derived dimensions. Inconsistent terminology may, therefore, contribute to the variations reported in cochlear morphology. This article proposes using a standard set of terminology, including its associated landmarks and measurements, to describe the shape and dimensions of the human cochlea. To provide a basis for comparison for the dimensional description of ambiguous terms in the literature and to supplement existing data where terms are unique, micro-CT (μCT) scans of thirty temporal bones were subjected to landmarking and measuring according to the terminology standard. The results confirm that methodological techniques and definitions of cochlear measurements may affect the quantification of dimensions that describe cochlear morphology and may, therefore, introduce variations when reporting these measurements. Histology and μCT images, for example, could provide a more accurate and comprehensive measure of cochlear dimensions than measurements on casts.

Background

Hemifacial microsomia (HFM) results from the malformation of facial structures derived from the first and second pharyngeal arches. The ramus of the mandible is the most deformed part of the mandible in HFM, which subsequently affects the linear measurements of the different parts of the mandible. This study evaluated the anatomical differences between the affected and contralateral mandibular ramus and body (MRB) in a select cohort of HFM patients in South Africa.

Methods

This is a serial retrospective study of 20 HFM patients. They were categorised into mild or severe groups by the Pruzansky-Kaban grading and into three age-dependent groups (1–5, 6–12 and 13–19 years old). Linear and angular measurements of the MRB components were recorded from preoperative computed tomography scans to compare severity, age groups, ramus and body index (RBI), and the affected to contralateral (A/C) sides ratio.

Result

Significant differences existed in the linear and angular measurements of the mandible and RBI between affected and contralateral sides, except for the MBL. The mean differences between the mild and severe RBI deformities were insignificant. The A/C ratio was insignificantly smaller in the severe group than in the mild group. Age grouping did not significantly affect the A/C ratio in the mandible ramus and body.

Conclusion

Mandibular asymmetry is more noticeable in HFM patients between 13 and 19 years old. The A/C ratio of the MRB did not worsen with different age groups and severity grading in this study. Hence, clinicians should postpone surgery until HFM patients attain skeletal maturity.

Introduction

The biceps brachii (BB) muscle is a two-headed muscle of the arm composed of one long head (LH) and one short head (SH). Accessory heads have been described and classified; however, reports of three concurrent accessory heads are especially rare, and their structural and functional analyses still require investigation. This study aims to analyze the structural and functional properties of a bilateral case of BB muscles each with three accessory heads.

Methods

A case of bilateral BB muscles with three accessory heads were discovered during routine human cadaver dissection. The muscles were carefully cleaned of extraneous tissue and photographed in situ. All five heads were examined bilaterally for gross structural features, and sarcomere states were examined via light microscopy. Maximal isometric force (F_max) and contralateral comparability (δ) were calculated for each head.

Results

The three accessory heads originated sequentially from the mid-shaft of the humerus. The proximal accessory head inserted into the distal end of the SH, while the middle and distal accessory heads inserted separately into the adjoined LH and SH muscle mass just before the common tendon. All accessory heads were structurally similar (δ ≤ 0.17; mass = 2.10 g; length = 10.33 cm; PCSA = 0.23 cm²; F_max = 5.24 N) and were innervated by the musculocutaneous nerve. The left and right LH and SH collectively generated a F_max of 49.91 N and 53.05 N while the left and right accessory heads collectively generated a F_max of 18.04 N and 13.38 N, respectively.

Conclusions

The bilateral BB muscles with their accessory heads generated an almost equivalent total F_max (67.95 N vs. 66.43 N, respectively), ∼23.35% of which was generated by the accessory heads. Despite the conceivable advantage the accessory heads may offer to generating additional force, accessory muscles can also cause serious clinical implications. The gross imaging, biomechanical analyses, contralateral comparability data, and relevant clinical insights presented in this study may help guide diagnosis and treatment in related clinical cases.

Introduction

Architectural characteristics of skeletal muscles are used to inform biomechanical analysis and candidacy for tendon transfer surgeries. Tendons of non-typical skeletal muscles may serve as optimal grafts, yet a thorough comparison of their parameters to those of typical musculature is not well represented in current literature. This study aims to analyze accessory extensor carpi radialis longus (aECRL) and accessory carpi radialis brevis (aECRB) muscles for their functional impact and suitability for use in tendon transfer surgeries.

Methods

Out of 122 dissected forearms examined, one right aECRB and one left aECRL were discovered and photographed in situ. The accessory muscles, along with eleven other muscles associated with ECRL and ECRB tendon transfers from the same forearms, were analyzed for their sarcomere contraction states, structural properties, and maximal isometric force (F_max) generating capacities. An architectural difference index was then calculated between each muscle to determine and discuss possible candidates for tendon transfer surgeries.

Results

The F_max of aECRL, ECRL, aECRB, and ECRB were determined to be 11.78 N, 57.24 N, 28.21 N, and 78.64 N, respectively. In this regard, aECRL and aECRB represented a 20.58% and 35.87% increase to ECRL and ECRB F_max, respectively. The aECRL inserted with ECRB, and the aECRB inserted with ECRL. The aECRL and aECRB tendons, measuring 188.33 mm × 2.98 mm and 217.17 mm × 3.00 mm respectively, coursed independently with the ECRL and ECRB tendons to their shared insertions. The aECRL and aECRB muscles were each most structurally similar to the extensor pollicis longus and adductor pollicis muscles.

Conclusions

Based on their morphology and structural characteristics, the aECRL and aECRB may be suitable grafts in adductorplasty or for extensor pollicis longus muscle/tendon repair. As the aECRL and aECRB tendons were relatively superficial and considerably long and wide, they may also be suitable for other musculotendon-based surgeries elsewhere in the body. This report may contribute new and beneficial insights for healthcare providers and medical educators when presented with cases where upper extremity musculotendinous reconstruction is warranted and/or non-typical musculoskeletal morphologies – particularly aECRL and aECRB – are present.

Background

This study of the human brachial plexus quantifies and compares the total number of fibers, fiber diameter, and fiber density within the lateral and medial roots of the median nerve in twenty-seven adult human cadavers. The lateral and medial cords give rise to the lateral and medial roots of median nerve, which join to form the median nerve. In this study, the fiber ratios of small-diameter Group III and IV sensory fibers as well as large-diameter Group I and II sensory fibers comprising the lateral and medial roots of the median nerve of the brachial plexus were investigated. Methods: Peripheral nervous tissue sections of twenty-seven lateral and twenty-seven medial roots were surgically removed from the axilla region of formalin-fixed cadavers in 2021. Excised tissue sections were fractured using liquid nitrogen-based freeze-cracking, and subsequently viewed using scanning electron microscopy. ImageJ 1.x, Microsoft Excel, and Statistica software were used to analyze fiber count, fiber diameter, fiber density, and fascicular bundle count. Results: A higher ratio of large-diameter Group I and II sensory fibers comprise the lateral root, and a higher ratio of small-diameter Group III and IV fibers comprise the medial root. Conclusions: Understanding the fiber composition of the lateral and medial roots of the median nerve can aid in interpreting why avulsive injury of the upper or lower roots of the brachial plexus can lead to different pain experiences post-injury.

Analyzing the structures of living specimens has always been an interest for human beings. Anatomy is one of the most important pillars of medicine, and its name comes from the Greek word anatomē which means to cut. The extended and rich history of anatomy is a reminder for modern generations about the value of the work of all the previous physicians, philosophers, and researchers and appreciation of the impact they have made in this field. Considering the importance and the role of anatomy as a pillar of medicine, every small step into establishing knowledge about the anatomical structures and their variations is crucial in developing science. Nowadays, the pace of both general scientific development and anatomical research itself is greater than ever before. Researchers, in their daily practices, mostly focus on three main types of articles published in the field of anatomy: (1) Case Reports, (2) Original Studies, and (3) Synthesis Studies. In the present article, the authors provide the brief history of human anatomy, and emphasize about the significance of this scientific discipline. The possible future shape of anatomical research and education is also discussed.

Two hundred years ago, the first of the nine volumes of Paolo Mascagni's Anatomia universa was published posthumously. This work was the fruit of a project that preoccupied Mascagni for most of his life: the Atlas of anatomy, which was the perfect replica on paper of the dissection, a fundamental part of the teaching of this discipline.

Mascagni's treatises testify to the modernity of his approach to medical education, and his deep conviction that the main objective was to educate young people and to enable them to acquire the most perfect knowledge of the structure of the human body.

Introduction

Trigeminal ganglia (TG) are bilateral collections of cell bodies from the first-order pseudounipolar neurons in each trigeminal nerve. Branches of the internal carotid artery (ICA), middle meningeal artery (MMA), accessory meningeal artery (AMA), and superior cerebellar artery (SCA) have been known to supply the TG, but information about the prevalence and patterns of these vessels supplying the TG is limited despite their important clinical relevance to basicranial surgeries. The objective of this study is to investigate the arterial sources and supply patterns to the TG and discuss their clinical implications.

Methods

Gross arterial sources and supply patterns were examined on 139 TG from 90 embalmed human cadavers from ethically approved anatomical donor programs. Select specimens were photographed, and color replacement was utilized to aid structure identification. Vascular histology was examined with light microscopy and photographed on one specimen for methods validation.

Results

One hundred and one TG (72.7%) received arterial supply from a single source: 71 (51.1%) from ICA, 18 (12.9%) from AMA, and 12 (8.6%) from MMA. Thirty-seven TG (26.6%) exhibited two distinct arterial sources from ICA, AMA, or MMA in either anastomotic (n = 25; 18.0%) or dual-independent (n = 12; 8.6%) patterns. One TG (0.7%) received supply from ICA, AMA, and MMA in a complex pattern. No gross arterial supply from SCA was found.

Conclusions

The TG is predominantly supplied by ICA (prevalence = 76.3%), though AMA and MMA also represent considerable contributions (31.7% and 20.1%, respectively) in various supply patterns. The TG arterial sources and supply patterns reported in this study should be considered when deliberating treatment of meningiomas, schwannomas, and dural arteriovenous fistulas within and around Meckel's cave.

Background

Although research on anatomical variability has a long tradition, the reports on anatomical variations differ considerably in the detail of the descriptions provided. Modern anatomical studies and case reports should include in-depth morphological analysis and involve a wide range of scientific tools that could complement and expand the knowledge of the specific anatomical variant.

Aim

This report aims to highlight the opportunities of modern research techniques in reporting anatomical variations. The main goal is to draw attention to the need for research in the spirit of evidence-based anatomy and to provide a proposed checklist that can inspire the study and reporting of anatomical variations in a more in-depth and sophisticated manner.

Conclusions

There is a need for a generally accepted protocol (checklist) for describing anatomical variations in the spirit of evidence-based anatomy. Such a checklist could help standardize the way anatomical variations are reported.

Introduction

The third head of the biceps brachii is the predominant variation of the arm muscles. Awareness of muscular variations is essential for the management of upper limb pathologies. Variations in the shape of the muscles are rarely explored. This study aimed to describe the prevalence and anatomical presentation of the third head of the biceps brachii muscle (origin, insertion and innervation) with an emphasis on the shape and form variations.

Materials and methods

Biceps brachii of eighty-nine cadavers were examined. The presence of the third head, its origin, shape patterns, blood supply, and nerve innervation were determined and recorded.

Results

The third head of the biceps brachii was present in 20.2 %, with a prevalence of 22.2 % in males and 18.2 % in females. Half (50 %) of these were bilateral presentations. Most (92 %) of the third head of the biceps brachii variations were flat, thin and straight in shape. All the shape variation patterns were observed in males and on the left arm. The third head originated from the humerus on its anteromedial aspect in 92 % of cases. The musculocutaneous nerve innervated the third head of the biceps brachii in 96 % of the cases, and a nerve anomaly of musculocutaneous and median nerves innervated it in a single (4 %) case. The muscular branches of the brachial artery supplied the third head of the biceps brachii in all cases.

Conclusion

Studies on the variation of arm muscles may assist in identifying new patterns of morphological variations like the shape of the muscle and may aid in the accurate diagnosis and management of arm pathologies.