A Cadaveric Study on Incidence and Morphology of Psoas Minor Muscle in South Indian Population

Abstract

Introduction: The muscles of posterior abdominal wall on each side of vertebral column include psoas group, quadratus lumborum and iliacus. The psoas muscle group comprises of major, minor and tertius. The psoas major is present in all individuals. Psoas minor is often absent in 40% of the cases. Psoas minor muscle has racial and morphometric variations. Aim: To find the incidence and morphology of psoas minor in south Indian population and discuss its clinical implications. Materials and Methods: The present observational cadaveric study was done on 30 embalmed cadavers for teaching purpose from November 2017 to December 2020 at Karnataka Institute of Medical Sciences, Hubli, Karnataka, India. Cadavers in the study were of the age group between 50-60 years. Out of 30 cadavers, five were females and 25 were males. In cadavers with presence of psoas minor muscle following parameters were photographed and studied: unilateral or bilateral, origin, insertion, nerve supply, total length of musculotendinous unit, length of muscle belly, length of tendon, width and circumference at its widest point. Vernier calipers, measuring tape, scale and inelastic thread were used to note various parameters and were tabulated. Results: Out of 30 cadavers, psoas minor was present in 10 cadavers (two female and eight male), bilateral in five; unilateral in five. The incidence of presence of psoas minor muscle in the present study is 33.33% (two female 6.67% and eight male 26.67%). Conclusion: The psoas minor muscle being vestigial and inconstant, its morphology is highly variable. But the incidence of psoas minor is quiet significant (33.33%). Hence knowledge of psoas minor is important to anatomists for academic purpose and to clinicians for proper diagnosis and treatment.