Morphology and Morphometric Analysis of the Psoas Minor Muscle in Adult Human Cadavers at a Tertiary-Care Institution in Western India

Introduction: The psoas minor is a slender, inconstantly present vestigial muscle of the posterior abdominal wall. Classical texts report its presence in 40-50% of individuals. Still, considerable ethnic and geographic variation has been documented, and morphometric data from Western Indian cadaveric populations remain scarce despite their growing relevance to retroperitoneal surgery, abdominopelvic imaging, and lumbopelvic physiotherapy. Aim: This study aims to determine the observed frequency and document the morphology and morphometric characteristics of the psoas minor muscle in adult human cadavers available for routine dissection at a single tertiary-care institution in Vadodara, Gujarat (Western India). Materials and methods: This cross-sectional observational cadaveric study was conducted in the Department of Anatomy, Smt. B.K. Shah Medical Institute and Research Centre, Sumandeep Vidyapeeth, Vadodara, on cadavers dissected during routine undergraduate teaching between January 2022 and January 2026; institutional ethics committee approval was obtained for the retrospective analysis and reporting of these pre-existing dissection findings. Thirty adult formalin-embalmed cadavers (60 sides) allocated for routine undergraduate dissection across three consecutive MBBS batches were systematically examined. The posterior abdominal wall was exposed, and the psoas major was reflected medially to inspect for the psoas minor. When identified, origin, insertion, number of bellies, belly length, tendon length, total length, and maximum belly diameter were recorded using a digital caliper and non-elastic thread. Descriptive statistics were computed using SPSS Statistics version 26.0 (IBM Corp. Released 2019. IBM SPSS Statistics for Windows, Version 26.0. Armonk, NY: IBM Corp.). Results: The psoas minor was identified in two of 30 cadavers (6.67%; exact binomial 95% CI 0.8-22.1%), corresponding to three of 60 sides (5.00%; 95% CI 1.0-13.9%). One cadaver exhibited a bilateral psoas minor, and one showed a unilateral left-sided muscle. All three muscles originated from the lateral aspect of the bodies of T12 and L1 and inserted, via a long, slender tendon, into the pecten pubis and iliopubic eminence, with the tendon also blending laterally with the iliac fascia. The mean belly length was 4.57 ± 0.46 cm, the mean tendon length was 17.17 ± 0.85 cm, the mean total length was 21.73 ± 0.45 cm, and the mean belly diameter was 0.60 ± 0.05 cm. Conclusions: The observed frequency of the psoas minor in this single-institution cadaveric sample from Vadodara, Gujarat (6.67%) is considerably lower than the classically reported prevalence of 40-50%, consistent with growing evidence of regional and ethnic variation. Awareness of its infrequent presence and morphometric profile is clinically relevant during retroperitoneal surgery, radiological interpretation, psoas compartment block, and physiotherapeutic management of lumbopelvic dysfunction.