Quadrate muscle
Musculus quadratus
Definition
A quadrate muscle (a.k.a. quadrangular muscle) is a type of skeletal muscle characterized by its square or rectangular shape, possessing four relatively equal sides.
Fascicle arrangement
The muscle fibres run parallel to each other between the origin and insertion points. This uniform, parallel arrangement allows the muscle to produce steady and controlled contractions.
Function
Quadrate muscles usually span short distances between adjacent bones or regions. They contribute to joint stability and postural support over a limited range of motion, rather than generating large, sweeping movements.
Examples
The Quadratus Femoris, found in the gluteal region, which acts to laterally rotate and stabilize the hip joint.
The Quadratus Lumborum, located in the posterior abdominal wall, which helps extend and laterally flex the vertebral column
References
Gray, H. (2016) Gray’s anatomy the anatomical basis of clinical practice. 41st edition. Edited by S. Standring. New York: Elsevier.
