Morphological Study of Psoas Minor Muscles with Embryological Basis and Clinical Insights

The psoas group of muscles belongs to the posterior abdominal wall. The psoas minor is an inconstant, vestigial, fusiform, slender muscle. Researchers have frequently paid attention to the anatomy, morphology, frequency, of this muscle and its clinical, racial, ethnic correlation. Aim: To investigate and study the psoas minor muscle, with regard to its frequency, agenesis, origin, insertion, morphological variations, its embryological basis and clinical significance. Materials and Methods: The present observational study was conducted at Lady Hardinge Medical College, New Delhi, between December 2018 to May 2019 in the Department of Anatomy. Nine cadavers were studied during routine dissection of the posterior abdominal wall (three females and six males). The prevalence, morphology, morphometry, laterality, sexual dimorphism for psoas minor muscle was assessed. The mean, standard deviation and coefficient of variation of the morphometric parameters were also evaluated. Results: Psoas minor muscle was present in 55.55% (5/9) cadavers. The muscle was bilateral in 22.22% (2/9) cases and unilateral in 33.33% (3/9) cases. In all the cases, the muscle took origin from the T12-L1 vertebra and the intervertebral disc. However, the muscle showed a variation in its distal attachment in one of the cadavers. The muscle was unilateral in both the female cadavers and bilateral in two male cadavers. Conclusion: The prevalence was found to be 55.55%. Knowledge about the incidence of psoas minor muscle is of significant academic interest to anatomists as well as clinicians, for diagnostic purposes (particularly in abdominal pain) and during radiographic imaging.