Review article
Composition of the psoas major muscle regarding its complex function
Juraj Arbanas
; Zavod za anatomiju, Medicinski fakultet Sveučilišta u Rijeci, Rijeka
Gordana Starčević-Klasan
; Zavod za anatomiju, Medicinski fakultet Sveučilišta u Rijeci, Rijeka
Daniela Malnar
; Zavod za anatomiju, Medicinski fakultet Sveučilišta u Rijeci, Rijeka
Abstract
Psoas major is a muscle of the posterior abdominal wall. The name psoas comes from the Greek word psoa meaning the “loin region”. Its linear origin is complex and includes the vertebral bodies and associated intervertebral discs from twelfth thoracic to fourth or fifth lumbar vertebrae and of the costal processes of all the lumbar vertebrae. Psoas major together with iliacus muscle inserts on the lesser trochanter of the femur. The degree of unification of the psoas and iliacus muscle can vary (m. iliopsoas), and rarely, its proximal attachments can show atypical anatomical variations. Moreover, composition of the psoas major muscle can differ regarding sex and race. Psoas major muscle is composed of all three muscle fibre types. Since it is dynamic as well as postural muscle it shows equal distribution of fast and slow muscle fibres. Regarding its dynamic function psoas major muscle is designated as the main flexor of the hip joint. Its rotational action as well as the actions of the abduction or adduction is minimal. In addition, psoas major muscle can produce ventral and lateral flexion of the vertebral column. Regarding its postural function psoas major muscle maintains lumbar lordosis and stabilizes lumbar spine, sacroiliac joint and hip joint during sitting as well as standing, walking or running.
Keywords
anatomical variations; composition; function; psoas major muscle
Hrčak ID:
84186
URI
Publication date:
4.6.2012.
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