Longissimus Muscle Anatomy

The longissimus muscle exists as part of the intermediate column of the erector spinae, positioned laterally to the spinalis and medially to the iliocostalis muscles. This muscle demonstrates a complex architectural arrangement, extending from the sacrum to the cranial region.

The intermediate muscles are the erector spinae. They include the longissimus, iliocostalis, and spinalis muscles. Their attachments subdivide these muscles, and they all have a common tendinous origin. They play a role in the movement of the thoracic cage and flexion of the upper vertebral column and head

Longissimus Muscle Anatomy

The Longissimus muscle subdivides into three distinct portions, each serving specific functional roles in spinal biomechanics:

1. Longissimus thoracis,
2. Longissimus cervicis,
3. Longissimus capitis.

Origin & Insertion

The longissimus thoracis originates from the posterior surface of the sacrum, sharing a common tendinous origin with other erector spinae muscles. Its extensive attachments include the transverse processes of all thoracic vertebrae and the lower nine or ten ribs between their tubercles and angles.

The longissimus cervicis spans from the transverse processes of upper thoracic vertebrae (T1-T5) to the posterior tubercles of the transverse processes of C2-C6.

The longissimus capitis extends from the transverse processes of upper thoracic and lower cervical vertebrae (C4-T5) to the mastoid process of the temporal bone.

Neurovascular Supply

The primary innervation of the longissimus muscle derives from the posterior rami of spinal nerves at corresponding segmental levels. This comprehensive innervation pattern ensures precise motor control and proprioceptive feedback. The arterial supply predominantly stems from the posterior branches of intercostal and lumbar arteries, with additional contributions from vertebral arteries in the cervical region.

See Also: Brachial Plexus Anatomy

Function & Action

The longissimus muscle functions bilaterally as a powerful spinal extensor, maintaining erect posture and controlling forward bending through eccentric contraction. When activated on one side, it produces lateral flexion of the spine toward the same side while contributing to contralateral rotation. This muscle’s continuous tonic activity provides essential postural support during both static and dynamic activities.

Regional Actions The longissimus capitis specifically extends and laterally flexes the head, while also assisting in rotational movements. In the cervical region, the longissimus cervicis controls cervical spine positioning and movement. The longissimus thoracis maintains thoracic extension and provides crucial stability to the lumbar spine during functional activities.

Clinical Significance

Understanding the longissimus muscle’s anatomy becomes particularly relevant in various clinical scenarios. Dysfunction of this muscle can manifest as chronic back pain, postural abnormalities, and movement restrictions. Medical professionals should note that the longissimus muscle’s extensive attachment pattern makes it susceptible to various pathological conditions, including myofascial pain syndrome and strain injuries.

References & More

1. Gray’s Anatomy: The Anatomical Basis of Clinical Practice – https://www.elsevier.com/books/grays-anatomy/standring/978-0-7020-7710-5
2. Spine Journal – https://www.thespinejournalonline.com/
3. European Spine Journal – https://www.springer.com/journal/586
4. Clinically Oriented Anatomy – 8th Edition
5. Henson B, Kadiyala B, Edens MA. Anatomy, Back, Muscles. [Updated 2023 Aug 14]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: Pubmed