Paraspinal Musculature: The Perils of Cricket

Attaching inferiorly to the fibers of the iliolumbar ligament, superiorly to the lowest rib, and medially to the transverse processes of the L1-L4 vertebral bodies, the quadratus lumborum muscle is visible in virtually all MRI studies of the lumbar spine... at least the axial sequences.  The QL is also visible in virtually every abdominal/pelvis CT, too.

Since the anterior surface of the muscle forms the front of the thoracolumbar fascia, it remains relatively sequestered from abdominal processes that affect its anterior neighbors: the kidney and psoas muscle.

Most of the interest in the world today in the quadratus lumborum muscle comes from Australia, where there is concern that fast-bowl cricket is leading to injury of the L4 pars interarticularis injury (an injury also commonly seen in tennis players).  Radiologists there determined that an enlarged quadratus lumborum is associated with an ipsilateral L4 pars fracture, however, there is debate whether the asymmetry of the muscle is a source of stress on the vertebral body or may be just a defensive adapatation to stress on the vertebral body.

Incidentally, the QL is the muscle that allows to hold our body horizontally on one elbow (as below).

1. McGill S, Juker D, Kropf P. "Quantitative intramuscular myoelectric activity of quadratus lumborum during a wide variety of tasks" Clinical Biomechanics 11:3, 170-172 (April 2011).

2. Engstrom, C. M., Walker, D., Kippers, V. and Buckley, R.  "Quadratus lumborum asymmetry and pars interatricularis injury in cricket fast bowlers: A prospective MRI examination" (2000). Quadratus lumborum asymmetry and pars interatricularis injury in cricket fast bowlers: A prospective MRI examination. In: , 2000 Pre-Olympic Congress Book of Abstracts. International Congress on Sport Science, Sports Medicine and Physical Education, Brisbane, (191-192). 7-12 September 2000.