Anatomy & Cell Biology最新文献

The classical arrangement of renal hilar structures in popular anatomy texts is described as: renal vein, renal artery, and renal pelvis arranged from anterior to posterior. Variations in this arrangement frustrate the vascular surgeon while creating splenorenal anastomoses and performing segmental nephrectomies. The study was carried out in the Department of Anatomy in conjunction with the Department of Anatomy, Vardhman Mahavir Medical College and Safdarjung Hospital, New Delhi on 100 renal blocks in the period of 3 years (2019-2022). Course of renal arteries was classified in the following types: straight ascending, straight descending, straight horizontal, sinuous, tortuous, upward curved, and downward curved. Distance from superior mesenteric artery for left renal artery was 0.83±1.05 cm while it was 0.90±1.11 cm for right renal artery. Length of left renal artery was 2.85±1.29 cm, and right renal artery was 3.70±1.34 cm. The length of right renal artery was longer than left renal artery (P<0.001). Multiple arteries were seen in 24.5% of cases. Renal arteries commonly arose from lateral surface of aorta in 88.93% and from anterior surface in 11.07%. Most common course taken by either of the renal artery was straight horizontal (40.48% left, 33.59% right) followed by straight descending (33.33% left, 31.35% right). Hilar renal artery was the most common type observed (95.24% left and 93.75% right). On an average renal artery on either side gave three branches.

A median accessory anterior digastric muscle was identified during a routine dissection of the submental triangle in an embalmed 86-year-old Caucasian female cadaver. The muscle had a digastric and a mylohyoid variant. The digastric variant was triquetral, symmetrical, with a mandibular apex attachment at the symphysis between the digastric fossae and two base attachments at the right and left intermediate tendons, approximately 3 mm apart. A midline raphe connected the base fibers, extending cranially toward the apex. The mylohyoid variant presented as two thin muscle strands originating from the cranial mylohyoid near the raphe, and inserting into the intermediate tendons, parallel to the mylohyoid nerve's path. No enlarged lymph nodes were noted. This accessory muscle, a potential landmark in neck surgeries, may be mistaken for the digastric, risking incomplete tissue resection. This report describes its anatomy to guide surgeons in neck dissections.

Gonadal arteries (GAs) and gonadal veins (GVs) display substantial anatomical variation, which has direct implications for surgical procedures, radiological interpretation, and fertility management. This study aimed to systematically review and meta-analyze the prevalence, origin, course, and drainage patterns of gonadal vessels in human anatomy. A systematic review and meta-analysis were conducted in line with current Evidence-Based Anatomy and PRISMA 2020 guidelines. A comprehensive search of major databases and anatomical journals yielded 31 eligible studies, comprising data on 2,875 gonadal vessels. The typical GA anatomy (single artery arising from the abdominal aorta) was observed in 98.72% of cases. Accessory GAs were found in 1.12%, most commonly arising from the renal artery (5.52%), with rare origins (<0.01%) from the accessory renal or suprarenal arteries. A normal arterial course was present in 90.24%, while an arched course occurred in 9.76%. The typical GV pattern (single vein draining into the inferior vena cava [IVC] or renal vein) was seen in 94.97%, and accessory GVs in 5.03%. The right GV drained into the IVC in 96.51%, with aberrant drainage to the right renal vein in 4.41%. The left GV drained into the left renal vein in 95.35%, with aberrant IVC drainage in 4.17%. Although the typical gonadal vascular anatomy predominates, variants, especially in GA origin and GV drainage, are not rare and must be recognized. These findings underscore the clinical importance of anatomical awareness in surgical planning, radiological evaluation, and the management of urological and reproductive conditions.

The external granular layer (EGL) is a transient yet crucial layer for the formation of cerebellar cortex. Genetic mechanisms, including the sonic hedgehog (SHH) pathway is key to the proliferation of granule cell progenitors (GCPs), and disruptions in this process can lead to cerebellar disorders like medulloblastoma and Dandy-Walker malformation (DWM). The review consolidates findings from studies on human cerebellar development, primarily focusing on neurogenesis, the role of genetic pathways in EGL regulation, and its involvement in congenital disorders. In total 42 articles were comprehensively reviewed and the research gaps in current research on human foetal cerebellum development was highlighted. The key findings from various sections of the review are summarized as follows. In terms of gestational development, the timeline for the appearance and regression of the EGL in humans remains imprecise. Regarding morphometry, the EGL thickness shows a marked increase between 16 and 28 gestational weeks, reaching an average peak of approximately 50.05 μm around 24th to 28th weeks, and then declines during the late third trimester. In the context of gene expression, SHH signalling plays a critical role in driving the proliferation of GCPs within the EGL. When considering congenital disorders, disruptions in EGL development are associated with conditions such as medulloblastomas, DWM, and pilocytic astrocytoma. The review highlights major research gaps and underscores the need for further human-specific studies to enhance understanding and guide therapies for cerebellar disorders.

The orbital tubercle, also known as Whitnall's tubercle, was first described by S.E. Whitnall in 1911 and is a significant anatomical landmark on the zygomatic bone that serves various structural and clinical functions. Understanding its anatomy is essential for protecting adjacent soft tissues during surgical procedures and its role in forensic studies. This study aims to assess the prevalence, precise location, and morphological characteristics of Whitnall's tubercle in adult human skulls. A cross-sectional observational study was conducted on 108 orbital fossae of 54 well-preserved adult human skulls. Whitnall's tubercle was classified as apparent if visible or non-apparent if detectable only by palpation. Its dimensions and distances from nearby anatomical landmarks were measured. Statistical analyses were performed to compare measurements between sides. Whitnall's tubercle was present in 106 (98.1%) out of 108 examined orbital fossae, with 67 classified as apparent and 39 as non-apparent. The mean longitudinal length was 6.59±0.99 mm on the right and 6.86±1.30 mm on the left (P=0.025), while the transverse lengths showed no significant difference (P=0.63). The majority of Whitnall's tubercle presented an oval shape (92.5%), with no significant difference between sides (P=0.63). The distances between Whitnall's tubercle and selected anatomical landmarks showed minor variations, but none reached statistical significance. This study provides valuable insights into the anatomical characteristics of Whitnall's tubercle, emphasizing its clinical relevance in orbital surgery and forensic applications. Understanding these features can enhance surgical precision and improve patient outcomes.

Although human lymph node architecture varies by site, the intranodal distribution of interdigitating dendritic cells (DCs) remains poorly understood. To address this, we compared the morphology of submandibular, paratracheal, mesenteric, and inguinal nodes obtained from 24 donated cadavers. Immunoreactivity was evaluated by comparing these cadaveric nodes with surgically resected lymph nodes obtained from five old-aged patients with nonmetastatic cancer. Despite the limited number of dendritic cell-specific ICAM-3-grabbing nonintegrin (DC-SIGN)-positive cells (candidate DCs) in cadaveric specimens, these tissues were deemed suitable for analysis. The submandibular and paratracheal nodes exhibited a belt-like cortex, with paracortical lymph sinus extending from the subcapsular sinus and surrounding the follicle. In contrast, the mesenteric and inguinal nodes contained multiple island-like cortices separated by thick paracortical lymph sinuses. Endothelial cells lining all lymph sinuses showed reactivity for smooth muscle actin and DC-SIGN. Macrophages and candidate DCs were abundant in the paratracheal and mesenteric node sinuses but scarce in the submandibular and inguinal nodes. Notably, the medullary sinus in the submandibular and inguinal nodes was filled with fibrous tissue, and the surrounding paracortical sinuses formed a "sea" around the island-like cortices, often resulting in loss of nodal polarization. Although the proportional area occupied by candidate DCs per nodal section was almost the same at the four sites, the overlap between DCs and macrophage clusters was small in paratracheal and inguinal nodes. The amount of afferent lymph and the retention of efferent lymph might determine the site-dependent architecture. Therefore, in aged nodes, DCs were preferentially localized in the paracortical sinus.

The occipital bone squamosa (OCS) is unique because of its double origin from both endochondral and membranous bones. The present study attempted to demonstrate the process of connection between these two bone types. We examined sagittal and frontal histological sections from 29 human fetuses with a crown-rump length ranging from 38 to 328 mm (approximately 7-39 weeks of gestational age [GA]). An initial cartilage plate appeared in the posterior side of the fourth ventricle at GA 7-8 weeks and extended inferiorly to connect with the cartilaginous basioccipital and condyle. At GA 9-10 weeks, on the superior side of the cartilage plate, membranous bone fragments appeared and adopted an arrangement resembling a chain of irregularly-shaped beads. They did not form a complete plate-like bone until late-term. At GA 11-12 weeks, endochondral ossification centers appeared at the upper and lower ends of the cartilage plate. At GA 12-15 weeks, a bar-like periosteal bone developed near and superior to the upper ossification center. Notably, sinusoidal structures, which were surrounded by growing periosteal bones, contained island-like clusters of calcified cartilage fragments. Therefore, the upper ossification center appeared likely to "migrate" downward and become distant from membranous bones. The extending periosteal bone reached and joined the membranous bone fragments. Consequently, the periosteal bones connected between the endochondral and membranous bones in the OCS. This connection was quite different from the other components of the calvaria, where membranous bones overlap the skull base cartilages at the margin.

The sella turcica, part of the sphenoid bone located at the base of the skull, is associated with multiple important neurovascular structures. Hence, a detailed knowledge of its variations is critical to clinicians who interpret imaging or surgeons who operate in this region. Our aim was to better understand the pathology of osteophytosis, often found related to the sella turcica. The study sample (n=1,083, human skulls) was obtained from the skeleton collection housed in the Natural History Museum, Cleveland, OH, USA. All skulls were assessed for osteophytes in the sella turcica region (defined as an overgrowth of 1 mm or more). Morphometrical measurements included skull length, width, and thickness, correlated to seller osteophytes. Cranial shape was related to the presence of osteophytes. Greater prevalence was seen in the brachycephalic skulls, with a significantly higher ratio of presence in older people (79.6%) compared to a younger population (26.4%); greater prevalence was also observed in female skulls with a composite thickness of the frontal, parietal and occipital bones. A multifactorial analysis using a logistic regression model defined a statistically significant model, by explaining 37.0% of the variance in osteophyte presence and correctly classifying 77.2% of the cases. Female skulls were 1.76 times more likely to display osteophytes of the sella turcica. Increasing age and increased skull thickness were associated with an enhanced likelihood of exhibiting osteophytes involving the sella turcica, thereby, the shape of the skull, age, and sex partially explain the variations observed for the presence of sella turcica osteophytes.

As dental schools increasingly share anatomy curricula with medical programs, a growing mismatch is emerging between what dental students need and receive. While head and neck anatomy is essential for all health professionals, dental students require significantly more detailed, region-specific anatomical knowledge, especially regarding the oral cavity, neurovascular structures, and surgical landmarks. Yet, this level of instruction is often delivered by medical school faculty unfamiliar with the unique clinical demands of dentistry. This commentary highlights the limitations of the "borrowed" faculty model and argues for dedicated, dental-aware anatomy educators actively engaged in anatomical research to ensure competent, confident clinical performance by future dentists.

The iliocapsularis muscle (ICM), a small and often overlooked muscle of the anterior hip, has recently gained attention for its potential clinical and surgical relevance. Despite being anatomically distinct and commonly present, the ICM remains underappreciated among clinicians and anatomists. This narrative review aims to synthesize recent anatomical and clinical literature on the ICM, focusing on its origin, insertion, innervation, vascular supply, anatomical variations, histological features, and functional significance. The ICM originates from the anteromedial hip capsule and the anterior inferior iliac spine, typically inserting distal to the lesser trochanter. Its proposed function includes tightening the anterior hip capsule and stabilizing the femoral head. Electromyographic studies suggest that the ICM plays an active role during hip flexion and dynamic gait phases. Anatomical variations, including variant origins and insertions, have been documented, along with unique innervation and fascial compartmentalization. Clinically, the ICM serves as a useful landmark in total hip arthroplasty and periacetabular osteotomies. Its hypertrophy or atrophy has been linked to hip pathologies such as acetabular dysplasia and femoroacetabular impingement. Imaging modalities, including ultrasound and elastography, have further supported its diagnostic utility. This review emphasizes the need for greater recognition of the ICM's structure and function, underscoring its relevance in orthopedic procedures and hip pathology diagnostics.