Histomorphometric and Vascular Assessment of the Human Appendix Across Different Age Groups: A Post-Mortem Study

International Journal of Anatomy and Physiology | Vol. 15, No. 9, September 2026 | pp. 305–316

DOI: 10.46882/2026/IJAP/000193

Article Type: Original Research Article

Title: Histomorphometric and Vascular Assessment of the Human Appendix Across Different Age Groups: A Post-Mortem Study

Names of Authors: Grace M. Ndlovu¹, Sipho T. Khumalo²

Authors’ Affiliations: ¹Department of Human Anatomy, School of Medicine, University of Pretoria, Pretoria, South Africa; ²Department of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa

Abstract:
The vermiform appendix undergoes significant structural remodeling and lymphoid tissue involution throughout human life, altering its vulnerability to acute inflammation. This post-mortem study quantified the age-related transformations in mucosal thickness, lymphoid follicle density, and microvascular coverage of the human appendix. Fifty-five appendix specimens were collected during autopsies from donors divided into three cohorts: Pediatric (aged 2 to 12 years, n = 15), Young Adult (aged 18 to 35 years, n = 20), and Geriatric (aged 65 to 80 years, n = 20). Sections were stained with Hematoxylin and Eosin (H&E) and CD31 for vascular mapping. The pediatric group demonstrated the highest lymphoid follicle density (4.8 ± 0.6 follicles/mm²), which significantly dropped to 0.8 ± 0.2 follicles/mm² in the geriatric group (p < 0.001), indicating marked immunosenescence. Total mucosal thickness decreased by 42.5% between the young adult and old cohorts (p < 0.01). Furthermore, CD31 immunoreactivity revealed a substantial decline in submucosal microvascular density within the elderly tissues (4.1 ± 0.5% vs 8.6 ± 0.9% in young adults, p < 0.01). These morphological findings illustrate that the aging appendix transforms from a highly vascular, immune-active organ into an atrophic structure with diminished blood supply, explaining the atypical clinical presentations and increased perforation rates observed in elderly acute appendicitis.

Keywords: Appendix, Lymphoid Follicles, Histomorphometry, CD31, Microvascular Density, Post-Mortem

Manuscript Timeline: Received: July 26, 2026; Revised: September 03, 2026; Accepted: September 15, 2026; Published: September 30, 2026

Citation: Ndlovu G.M., & Khumalo S.T. (2026). Histomorphometric and Vascular Assessment of the Human Appendix Across Different Age Groups: A Post-Mortem Study. International Journal of Anatomy and Physiology, 15(9), 305–316. DOI: 10.46882/2026/IJAP/000193

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