Interspinales Muscle

Authors

Affiliations

Nate Yomogida, B.S., SPT

Doctor of Physical Therapy

B.S. in Kinesiology

Chloë Kerstein, B.S., SPT

Doctor of Physical Therapy

B.A. in Neuroscience

Figure 1: Muscles of the Neck and Back¹

Muscle	Origin	Insertion	Innervation	Action
Interspinales cervicis	C1-C7 SP of superior segment	C1-C7 SP of inferior segment	Spinal nn. Posterior rami	Cervical: Extension Lumbar: Extension
Interspinales lumbora	L1-L5 SP of superior segment	L1-L5 SP of inferior segment	Spinal nn. Posterior rami	Bilateral: Cervical extension and stabilization, lumbar extension and stabilization Unilateral: Cervical extension and ipsilateral sidebend, Lumbar extension and ipsilateral sidebend

Overview

The interspinales muscle exists throughout the spine, but is separated into two sections: interspinalis cervicis and interspinalis lumbora since these two regions are where the muscle is most defined².

Interspinales Cervicis

Origin

C1-C7: SP of inferiorly adjacent vertebrae³

Insertion

C1-C7: SP of superiorly adjacent vertebrae³

Innervation

Spinal nn. (Posterior Rami)³

Action

Extends cervical and Lumbar spines³

Interspinales Lumbora

Origin

L1-L5: SP of inferiorly adjacent vertebrae³

Insertion

L1-L5: SP of superiorly adjacent vertebrae³

Innervation

Spinal nn. (Posterior Rami)³

Action

• BIL: Stabilizes and extends cervical and lumbar vertebrae³
• UNIL: I/L SB cervical and lumbar spines³

Practical function

Since these muscles can act to extend each vertebrae individually and how close they run to the intervertebral joint, these muscles play a role in segmental stabilization of the spine².

References

1.

Betts JG, Blaker W. Anatomy and Physiology. 2nd ed. OpenStax; 2022. https://openstax.org/details/books/anatomy-and-physiology-2e/?Book%20details

2.

Jones B. B Project Foundations. b Project; 2025.

3.

Gilroy AM, MacPherson BR, Wikenheiser JC, Voll MM, Wesker K, Schünke M, eds. Atlas of Anatomy. 4th ed. Thieme; 2020.