Author: Dr Peter de Souza
Last modified: 23 November 2023

The longissimus muscle is one of the three groups of muscles which make up the erector spinae lying either side of the spinous processes of the vertebral column, and forming the largest group of intrinsic back muscles. The iliocostalis is the outermost erector spinae muscle, the longissimus lies in the middle, and the spinalis lies most medially.

Each of the three erector spinae muscles originates from a broad tendon which is attached to the sacrum, spinous processes of the lower thoracic and lumbar vertebrae (T11-L5), thoracolumbar fascia and the iliac crest. In the upper lumbar region, each of the iliocostalis, longissimus and spinalis divide into three columns of muscle, which are then further subdivided into three components. The longissimus divides into the longissimus thoracis, longissimus cervicis and the longissimus capitis.

The erector spinae are covered by the thoracolumbar fascia, lying deep to the rhomboid, splenius and serratus posterior inferior muscles.


  • longissimus thoracis: blends with iliocostalis in lumbar region, transverse processes of L1-5
  • longissimus cervicis: transverse processes of T1-5
  • longissimus capitis: transverse processes of T1-4, articular processes of C4-C7


  • longissimus thoracis:transverse processes of T1-12, tubercles of ribs 2-12
  • longissimus cervicis:transverse processes of C2-6
  • longissimus capitis: posterior aspect of the mastoid process


  • Extension of vertebral column


  • Lateral branches of dorsal rami of the cervical, thoracic and lumbar spinal nerves