Longissimus - Podcast Version 0:00 / 0:00 1x 0.25x 0.5x 0.75x 1x 1.25x 1.5x 1.75x 2x The longissimus is a deep muscle of the back. It lies between the iliocostalis and spinalis within the erector spinae complex, and can be divided into three parts – thoracic, cervicis, and capitis. Attachments: Arises from the lower thoracic and lumbar vertebrae, sacrum, posterior aspect of the iliac crest, and the sacroiliac and supraspinous ligaments. It attaches to the lower ribs, the transverse processes of C2 – T12, and the mastoid process of the skull. Actions: Acts unilaterally to laterally flex the vertebral column. Acts bilaterally to extend the vertebral column and head. Innervation: Posterior rami of the spinal nerves. Blood Supply: Longissimus thoracic receives blood supply from the dorsal branches of posterior intercostal and sacral arteries. Longissimus cervicis and capitis receive blood from the transverse cervical, occipital, vertebral, and deep cervical arteries. By TeachMeSeries Ltd (2026) Fig 1The erector spinae. Pro Feature - 3D Model You've Discovered a Pro Feature Access our 3D Model Library Explore, cut, dissect, annotate and manipulate our 3D models to visualise anatomy in a dynamic, interactive way. Learn More Frequent questions What is the longissimus muscle? The longissimus is a deep back muscle that is part of the erector spinae complex, situated between the iliocostalis and spinalis muscles. It consists of three sections: thoracic, cervicis, and capitis. Where does the longissimus muscle attach? The longissimus muscle originates from the lower thoracic and lumbar vertebrae, sacrum, posterior iliac crest, and various ligaments. It inserts into the lower ribs, transverse processes of C2 to T12, and the mastoid process of the skull. What actions does the longissimus muscle perform? The longissimus muscle laterally flexes the vertebral column when acting unilaterally and extends both the vertebral column and head when acting bilaterally. These actions are essential for maintaining posture and facilitating movement. How is the longissimus muscle innervated? The longissimus muscle is innervated by the posterior rami of the spinal nerves. This innervation allows for the muscle's function in movement and stability of the spine. What is the blood supply for the longissimus muscle? The longissimus thoracic receives blood from the dorsal branches of the posterior intercostal and sacral arteries, while the cervicis and capitis parts are supplied by the transverse cervical, occipital, vertebral, and deep cervical arteries. This vascular supply is crucial for muscle health and function. Rate This Article