Anatomical and functional study of the musculus psoas major and nervus femoralis in correlation with pelvic diameters

Background/Aim. The iliopsoas muscle [musculus (m.) iliopsoas] originates from the Greek word psóa, which means loin and represents the only muscle in the body with anatomical preconditions to simultaneously and directly contribute to the stability and movement of the trunk, pelvis, and legs. M. iliopsoas belongs to the inner thigh muscle group and forms part of the posterior abdominal wall. This muscle is the major flexor of the hip joint, and it is functionally essential for proper posture, walking, running, and other physical activities. The aim of this study was to determine the relationship between the anatomical parameters of the pelvis and nervus (n.) femoralis, as well as the relationship between the same pelvic parameters and m. psoas major. Methods. The study was conducted at the Faculty of Medicine, University of Belgrade, on cadaveric material of the Institute of Anatomy “Niko Miljanić”. For measurement purposes, 14 cadavers were used, seven of which were male and seven female, aged 67–79 years. The measuring instruments used in this study were a ruler and an electronic digital caliper (measuring range 0–500 mm, resolution 0.01 mm). Statistical data processing was performed in the SPSS 11.0 program using the Mann-Whitney U test. Results. The results of this study indicate a significant statistical difference in pelvic width between male and female cadavers, which was observed in the reduction of the bituberal line in females, while the parameters of the bispinal line showed no significant difference between the two genders. The decrease of the bituberal line in females was followed by an increase in the width of the proximal origin with a statistically significant decrease in the length of the proximal origin of the m. psoas major. Furthermore, the vertical distance of n. femoralis from the exit point of the muscle to the bispinal line was significantly reduced in the male cadavers. Conclusion. Based on our results, we can assume that, in most cases, due to the smaller bituberal and bispinal line or narrower pelvis, a shorter proximal attachment of the m. psoas major will occur with greater width (L2–L5 level) in the female than in the male gender, resulting in a longer vertical distance of n. femoralis. Such results indicate a close correlation between the anatomical parameters of the m. psoas major, which may affect the distance of n. femoralis exit from the muscle.