International Journal of Anatomy and Physiology

International Journal of Anatomy and Physiology | Vol. 15, No. 9, September 2026 | pp. 001-009

DOI: 10.46882/2026/IJAP/000210

Article Type: Review

Title: Rigor Mortis Revisited: Does Fascia Contribute to Post-Mortem Stiffness?

Names of Authors: John Sharkey*,¹ and Karen B. Kirkness²

Authors’ Affiliations: ¹Irish College of Osteopathic Medicine, National Training Centre, Dublin, D07 F6CR, Ireland. ²Health Professions Education Unit, Hull York Medical School, York YO10 5DD, UK.

Abstract:
Rigor mortis has conventionally been explained as the consequence of adenosine triphosphate depletion and persistent actin-myosin cross-bridge formation within skeletal muscle fibres. More than two centuries after Nysten's description of post-mortem rigidity, the explanatory framework has remained overwhelmingly muscle-centred. This hypothesis-generating narrative review examined whether fascia may contribute to post-mortem rigidity alongside skeletal muscle. Evidence from living tissues and experimental models was synthesised to identify three candidate processes: altered calcium-sensitive myofibroblast activity, changes in extracellular matrix hydration and viscoelastic behaviour, and loss of distributed force transmission across the fascial-muscular continuum. Their specific contributions after death have not been established. Regional variation in fascial density, hydration, cellular composition and loading history may help explain uneven onset, variable timing and non-linear resolution. The proposed fascia-inclusive model did not replace the established actomyosin account. It broadened the anatomical field of enquiry and identified testable questions for direct forensic and anatomical investigation.

Keywords: post-mortem physiology; calcium signalling; tensegrity; forensic science; anatomy; thanatology; mechanotransduction; extracellular matrix; myofibroblasts; post-mortem interval.

Manuscript Timeline: Received: August 12, 2026; Revised: August 31, 2026; Accepted: September 02, 2026; Published: September 29, 2026.

Citation: Sharkey J., & Kirkness K.B. (2026). Rigor Mortis Revisited: Does Fascia Contribute to Post-Mortem Stiffness? International Journal of Anatomy and Physiology, 14(9), pp. 001-009. DOI: 10.46882/2026/IJAP/000210

International Journal of Anatomy and Physiology | Vol. 15, No. 9, September 2026 | pp. 001–005

DOI: 10.46882/2026/IJAP/000159

Article Type: Full Length Research Paper

Title: Duodenal Mucosa Variations in Functional Gastrointestinal Disorders

Names of Authors: Ahmed Medhat¹, Nadia Abd El Salam², Sahar M. Hassany¹, Howida I. Hussein², & Hubert E. Blum³*

Authors’ Affiliations: ¹Tropical Medicine and Gastroenterology Department, Assiut University, Egypt. ²Pathology Department, Assiut University, Egypt. ³Department of Medicine II, Freiburg University Hospital, Freiburg, Germany.

Abstract:
The micro-anatomical boundaries between functional gastrointestinal disorders and low-grade structural mucosal alterations remain an active area of pathological inquiry. This study aimed to quantitatively analyze the morphometric and histological variations of the duodenal mucosa in patients diagnosed with functional gastrointestinal disorders presenting with chronic bowel symptoms. Duodenal tissue biopsies from 113 adult patients who underwent upper gastrointestinal endoscopy at Assiut University Hospital were retrospectively evaluated by histopathologic and morphometric profiling. Microscopic variables measured included villus height, crypt depth, villus-to-crypt ratio, and the density of intraepithelial lymphocytes (IELs) per 100 enterocytes. Morphometric analysis revealed that 22.1% of patients exhibited a subtle reduction in mean villus height (385.4 ± 32.6 μm compared to standard anatomical references of >500 μm, p < 0.05). Additionally, an isolated increase in IEL count exceeding 25 per 100 enterocytes was documented in 14.2% of the tissue samples, signaling localized, low-grade mucosal immune activation despite macroscopically normal endoscopic findings. Crypt depth variations showed no significant correlation with patient age or gender dynamics (p > 0.05). These micro-structural changes indicate that a substantial subset of patients categorized with functional gastrointestinal conditions possess underlying low-grade duodenal enteropathy characterized by villous blunting and intraepithelial lymphocytosis. Recognizing these subtle histopathological variations is vital for clinical pathologists and gastroenterologists, as it points to organic structural modifications that may alter intestinal permeability and contribute to chronic diarrheal states.

Keywords: Duodenal mucosa, Morphometry, Villus height, Intraepithelial lymphocytes, Histopathology, Functional dyspepsia

Manuscript Timeline: Received: May 12, 2026; Revised: June 18, 2026; Accepted: July 04, 2026; Published: September 15, 2026

Citation: Ahmed Medhat, Nadia Abd El Salam, Sahar M. Hassany, Howida I. Hussein, & Hubert E. Blum (2026). Duodenal Mucosa Variations in Functional Gastrointestinal Disorders. International Journal of Anatomy and Physiology, 15(9), 001–005. DOI: 10.46882/2026/IJAP/000159

International Journal of Anatomy and Physiology | Vol. 15, No. 9, September 2026 | pp. 485–496

DOI: 10.46882/2026/IJAP/000208

Article Type: Original Research Article

Title: Variations in the Course and Branching Structure of the Superficial Palmar Arch Within an Anatolian Population

Names of Authors: Caner K. Özkan¹, Bülent S. Demir²

Authors’ Affiliations: ¹Department of Anatomy, Faculty of Medicine, Ege University, İzmir, Turkey; ²Department of Plastic, Reconstructive and Aesthetic Surgery, Ankara City Hospital, Ankara, Turkey

Abstract:
The vascularization of the hand is characterized by rich anastomotic networks, where the superficial palmar arch (SPA) serves as the core distribution pathway for the fingers. This study categorized the completeness, source vessels, and branching variations of the SPA to improve clinical safety margins during hand surgery. Dissections were performed on 60 hand specimens from 30 formalin-fixed adult human cadavers. The SPA configurations were classified into complete arches (where anastomotic connections are fully established) and incomplete arches based on standard classifications. A complete SPA was observed in 78.3% of hands (n = 47). The most common variant within this group was the radio-ulnar configuration, where the arch was formed by the anastomosis of the superficial branch of the ulnar artery with the superficial palmar branch of the radial artery (55.0%). In contrast, an incomplete SPA was documented in 21.7% of hand specimens (n = 13), wherein the ulnar artery failed to anastomose with a corresponding radial or median vessel, terminating directly as the common digital artery of the thumb or index finger. The mean diameter of the ulnar contributor to the arch was 2.15 ± 0.32 mm. These vascular statistics highlight that incomplete palmar networks are highly prevalent, reinforcing the importance of performing pre-operative Allen tests or duplex Doppler assessments prior to harvesting radial forearm flaps or performing palmar incisions.

Keywords: Superficial Palmar Arch, Ulnar Artery, Radial Artery, Anatomical Variations, Hand Surgery, Cadaveric Dissection

Manuscript Timeline: Received: August 25, 2026; Revised: September 20, 2026; Accepted: September 28, 2026; Published: September 30, 2026

Citation: Özkan C.K., & Demir B.S. (2026). Variations in the Course and Branching Structure of the Superficial Palmar Arch Within an Anatolian Population. International Journal of Anatomy and Physiology, 15(9), 485–496. DOI: 10.46882/2026/IJAP/000208

International Journal of Anatomy and Physiology | Vol. 15, No. 9, September 2026 | pp. 473–484

DOI: 10.46882/2026/IJAP/000207

Article Type: Original Research Article

Title: Histological Changes in the Renal Medulla and Papilla of Adult Wistar Rats Following Chronic Intake of High-Sodium Drinking Solutions

Names of Authors: Fatimah H. Al-Zahrani¹, Mustafa A. Al-Hassan²

Authors’ Affiliations: ¹Department of Anatomy, College of Medicine, King Saud University, Riyadh, Saudi Arabia; ²Department of Physiology, Faculty of Medicine, Cairo University, Cairo, Egypt

Abstract:
Excessive dietary sodium intake induces vascular stress and compromises the countercurrent multiplier system within the kidney. This study evaluated the structural modifications occurring within the renal medulla and papilla of adult Wistar rats following chronic consumption of a high-sodium drinking solution. Twenty-four male rats were randomly assigned to two equal groups (n = 12): a control group receiving standard tap water and a high-sodium group receiving a 2.0% sodium chloride (NaCl) drinking solution ad libitum for 12 consecutive weeks. Renal tissue sections were processed and stained with Hematoxylin and Eosin (H&E), Periodic Acid-Schiff (PAS), and Masson’s trichrome for quantitative microstructural profiling. The high-sodium group displayed severe architectural disruption within the inner medulla and papilla, characterized by lumen dilation of the collecting ducts and flattening of the principal epithelial cell height (6.10 ± 0.45 μm vs 9.85 ± 0.65 μm in controls, p < 0.01). Masson's trichrome staining demonstrated a 3.4-fold expansion of interstitial extracellular matrix deposition in the medullary space, indicating focal interstitial fibrosis. PAS staining revealed localized basement membrane splitting along the thin limbs of Henle’s loop. These histological alterations demonstrate that chronic high-sodium loading alters the specialized cell structural integrity of the renal medulla and induces tubulointerstitial remodeling, shedding light on the morphological pathways underpinning sodium-dependent renal concentrating defects.

Keywords: Renal Medulla, High-Sodium Diet, Collecting Ducts, Histological Damage, Interstitial Fibrosis, Wistar Rats

Manuscript Timeline: Received: August 24, 2026; Revised: September 19, 2026; Accepted: September 27, 2026; Published: September 30, 2026

Citation: Al-Zahrani F.H., & Al-Hassan M.A. (2026). Histological Changes in the Renal Medulla and Papilla of Adult Wistar Rats Following Chronic Intake of High-Sodium Drinking Solutions. International Journal of Anatomy and Physiology, 15(9), 473–484. DOI: 10.46882/2026/IJAP/000207

International Journal of Anatomy and Physiology | Vol. 15, No. 9, September 2026 | pp. 461–472

DOI: 10.46882/2026/IJAP/000206

Article Type: Original Research Article

Title: Variations in the Anatomy of the Dorsalis Pedis Artery and its Branching Patterns: A High-Resolution Color Doppler Ultrasonography Study

Names of Authors: Min-Seok Choi¹, Sun-Young Park²

Authors’ Affiliations: ¹Department of Anatomy, Seoul National University College of Medicine, Seoul, South Korea; ²Department of Radiology, Samsung Medical Center, Seoul, South Korea

Abstract:
The dorsalis pedis artery (DPA) is the primary source of arterial blood supply to the dorsum of the foot, serving as a key landmark for peripheral pulse evaluations, microvascular micro-surgical flaps, and distal arterial cannulations. This study utilized high-resolution color Doppler ultrasonography to comprehensively map the course, diameter variations, and terminal branching patterns of the DPA relative to bony soft-tissue axes. One hundred limbs from fifty healthy adult volunteers (25 males, 25 females; mean age 24.5 ± 3.2 years) were scanned using a 12-MHz linear array transducer. The classic linear continuation of the anterior tibial artery across the midpoint of the bimalleolar line was observed in 81.0% of limbs (n = 81). Variational configurations were documented in 19.0% of the cases. The most frequent variant involved a lateral deviation of the main DPA trunk toward the second intermetatarsal space (11.0%). Complete absence or severe hypoplasia of the DPA, where the dorsum of the foot was supplied by the perforating branch of the peroneal artery, was identified in 5.0% of limbs. The mean diameter of the DPA trunk at the ankle joint level was 2.14 ± 0.28 mm in males and 1.82 ± 0.21 mm in females (p < 0.05). These ultrasonic measurements offer specific anatomical margins, providing critical guidance for clinicians executing foot reconstructive flap adjustments or catheterization entries.

Keywords: Dorsalis Pedis Artery, Color Doppler Ultrasonography, Anatomical Variations, Foot Anatomy, Peripheral Vascular Examination

Manuscript Timeline: Received: August 23, 2026; Revised: September 18, 2026; Accepted: September 27, 2026; Published: September 30, 2026

Citation: Choi M.S., & Park S.Y. (2026). Variations in the Anatomy of the Dorsalis Pedis Artery and its Branching Patterns: A High-Resolution Color Doppler Ultrasonography Study. International Journal of Anatomy and Physiology, 15(9), 461–472. DOI: 10.46882/2026/IJAP/000206

International Journal of Anatomy and Physiology | Vol. 15, No. 9, September 2026 | pp. 449–460

DOI: 10.46882/2026/IJAP/000205

Article Type: Original Research Article

Title: Histomorphometric and Vascular Assessment of the Human Epiglottis Across Different Decades of Adult Life

Names of Authors: Lars M. Ericsson¹, Sven O. Lindstrom²

Authors’ Affiliations: ¹Department of Anatomy, Histology and Embryology, Karolinska Institutet, Stockholm, Sweden; ²Department of Physiology, Faculty of Medicine, Uppsala University, Uppsala, Sweden

Abstract:
The epiglottis undergoes continuous mechanical displacement during deglutition, requiring optimal elasticity and microvascular perfusion to preserve structural resilience. This post-mortem study quantified the age-related alterations occurring within the extracellular matrix, elastic cartilage layer, and microvascular network density of the human epiglottis. Forty-five epiglottic tissue samples were collected during medico-legal autopsies from adult donors categorized into three groups: Early Adulthood (aged 20 to 35 years, n = 15), Middle Age (aged 45 to 55 years, n = 15), and Advanced Age (aged 70 to 85 years, n = 15). Transverse sections from the lingual and laryngeal aspects were processed and stained with Verhoeff's Van Gieson (VVG) and CD31 for vascular mapping. The advanced age cohort demonstrated a significant 38.5% reduction in elastic fiber content within the perichondrium (p < 0.001), accompanied by widespread fiber fragmentation. The mean thickness of the central elastic cartilage layer decreased from 1.15 ± 0.12 mm in early adulthood to 0.78 ± 0.08 mm in the advanced age group (p < 0.01), coupled with focal chondrocyte hypertrophy and matrix calcification. Furthermore, CD31 immunoreactivity revealed a 42.1% drop in mucosal microvascular density within aging specimens. These quantitative metrics reveal a clear structural decline, demonstrating that the aging epiglottis undergoes significant fibroelastic degradation and vascular involution, which can alter its biomechanical protection of the airway during swallowing.

Keywords: Epiglottis, Histomorphometry, Elastic Cartilage, CD31, Microvascular Density, Aging

Manuscript Timeline: Received: August 22, 2026; Revised: September 17, 2026; Accepted: September 26, 2026; Published: September 30, 2026

Citation: Ericsson L.M., & Lindstrom S.O. (2026). Histomorphometric and Vascular Assessment of the Human Epiglottis Across Different Decades of Adult Life. International Journal of Anatomy and Physiology, 15(9), 449–460. DOI: 10.46882/2026/IJAP/000205