Posted on Jul 27th, 2020 / Published in: Thoracic Spine
The longissimus muscles are long intrinsic muscles in the back and form the erector spinae together with the spinalis and iliocostalis. Longissimus thoracis is the longest, thickest, and most central of the erector spinae muscle group.
The longest muscle of the thorax.
This muscle is divided into a lumbar and thoracic portion. However, there is some dispute in the literature whether the lumbar section of the longissimus thoracis is a separate longissimus, namely the longissimus lumborum, or whether it is all part of the longissimus thoracis.
Lumbar part - Lumbar intermuscular aponeurosis, anteromedial aspect of ilium, Posterior sacroiliac ligament.
Thoracic part - Spinous and transverse processes of vertebrae L1-L5, median sacral crest, posterior surface of sacrum and posterior iliac crest.
Lumbar part - Accessory and transverse processes of vertebrae L1-L5.
Thoracic part - Transverse process of vertebrae T1-T12, Angles of ribs 7-12.
Bilateral contraction - extension of spine.
Unilateral contraction - lateral flexion of spine (ipsilateral).
Lateral branches of posterior rami of spinal nerves.
Superior intercostal, posterior intercostal and subcostal arteries; lateral sacral and median sacral arteries.
In runners, the longissimus thoracis was a significant compensator for 4 out of 5 weakness conditions. Therefore, insufficient strength of the deep core musculature may increase a runner's risk of developing lower back pain.
Raabe, M. E., & Chaudhari, A. (2018). Biomechanical consequences of running with deep core muscle weakness. Journal of biomechanics, 67, 98–105.
Longissimus thoracis exercises
Back extension medium
Lie on your front, resting on the forearms. Place your arms at a 90-degree angle, as shown, and hold.