AnatomySpine and backBackInterspinales muscles

AnatomySpine and backBackInterspinales muscles

Interspinales muscles

Author: Gordana Sendić, MD • Reviewer: Nicola McLaren, MSc
Last reviewed: October 30, 2023
Reading time: 5 minutes

Interspinales muscles (Musculi interspinales)

Interspinales muscles are short, paired muscles that belong to the deepest layer of the intrinsic muscles of the back. They extend between adjacent spinous processes of the vertebral column.

Even though they span the entire length of the vertebral column, they are only properly developed in the cervical and lumbar spine, whereas in the thoracic spine they are underdeveloped or often completely absent.

Interspinales muscles serve to aid other intrinsic muscles of the back to extend the spine. However, it’s more important role is to stabilize the spine during movement and maintain normal posture of the body.

This article will discuss the anatomy and functions of the interspinales muscles.

Key facts about the interspinales muscles
Origin	Interspinales cervicis: Superior aspect of spinous processes of vertebrae C3-T1 Interspinales thoracis: Superior aspect of spinous process of vertebrae T2, T11 & T12 (variable) Interspinales lumborum: Superior aspects of spinous processes of vertebrae L2-L5
Insertion	Interspinales cervicis: Inferior aspect of spinous processes of vertebrae C2-C7 Interspinales thoracis: Inferior aspect of spinous processes of vertebrae T1, T10 & T11 Interspinales lumborum: Inferior aspects of spinous processes of vertebrae L1-L4
Function	Extension of cervical and lumbar spine
Innervation	Posterior rami of spinal nerves
Blood supply	Interspinales cervicis: vertebral artery, deep cervical artery, occipital artery, transverse cervical artery Interspinales thoracis: superior intercostal artery, posterior intercostal arteries, subcostal artery Interspinales lumborum: lumbar arteries

Contents

Origin and insertion
Relations
Innervation
Blood supply
Functions
Sources

+ Show all

Origin and insertion

The interspinales muscles are small muscles that connect the spinous processes of adjacent spinal vertebrae. They are comprised of paired muscle fascicles, one on each side of the interspinous ligament. The interspinales muscles are divided based on the region of the vertebral column into:

Interspinales cervicis: consists of six pairs of muscles that originate at the superior aspect of the spinous processes of vertebrae C3-T1, and insert at the inferior aspect of the spinous processes of the cranially adjacent vertebrae C2-C7, respectively.
Intererspinales thoracis: these muscles are generally underdeveloped or even absent, with only some segments having distinct muscle fascicles. Usually they consist of three pairs of muscles that originate at the superior aspect of spinous processes of vertebrae T2, T11 and T12, and insert at the inferior aspect of the spinous processes of the cranially adjacent vertebrae T1, T10 and T11, respectively.
Interspinales lumborum: consists of four pairs of muscles that originate at the superior aspects of spinous processes of vertebrae L2-L5, and insert at the inferior aspect of the spinous processes of the cranially adjacent vertebra L1-L4, respectively.

Relations

Interspinales comprise the deep layer of the intrinsic muscles of the back. They are found lateral to the interspinous ligament, passing inferiorly on each side of the ligament, and are located medial and deep to the attachments of the multifidus and rotatores muscles, which also belong to the deepest layer of the intrinsic muscles.

Innervation

Like the other intrinsic muscles of the back, interspinales muscles are innervated by the posterior rami of the respective spinal nerves.

Blood supply

The interspinal muscles are supplied by the dorsal branches of the respective segmentally extending arteries. The supplying arteries are prone to variation, but generally they include:

Interspinales cervicis: branches of the vertebral artery, deep cervical artery, occipital artery and transverse cervical artery.
Interspinales thoracis: branches of the superior and posterior intercostal arteries and subcostal artery.
Interspinales lumborum: branches of the lumbar arteries.

Venous drainage of the interspinales muscles occurs via the corresponding veins of the aforementioned arteries.

Functions

The actions of interspinales are not well established. Most authors consider these muscles incapable of generating enough force to produce significant movement of the vertebral column. However, they are thought to assist with extension in the cervical and lumbar spine, and they are best developed in these regions.

Interspinales muscles have a pronounced density of muscle spindles, which are proprioceptors that monitor and adjust muscle tension and posture. Thus they provide stability to the spine, controlling the position of the vertebral column.

To learn more about the anatomy of the dorsal trunk, check out the following resources:

Sources

All content published on Kenhub is reviewed by medical and anatomy experts. The information we provide is grounded on academic literature and peer-reviewed research. Kenhub does not provide medical advice. You can learn more about our content creation and review standards by reading our content quality guidelines.

References:

Moore, K. L., Dalley, A. F., & Agur, A. M. R. (2014). Clinically Oriented Anatomy (7th ed.). Philadelphia, PA: Lippincott Williams & Wilkins.
Palastanga, N., & Soames, R. (2012). Anatomy and human movement: structure and function (6th ed.). Edinburgh: Churchill Livingstone.
Standring, S. (2016). Gray's Anatomy (41st ed.). Edinburgh: Elsevier Churchill Livingstone.

Layout:

Abdulmalek Albakkar

Illustrators:

Interspinales muscles (Musculi interspinales) - Yousun Koh

Interspinales muscles: want to learn more about it?

Our engaging videos, interactive quizzes, in-depth articles and HD atlas are here to get you top results faster.

What do you prefer to learn with?

Videos Quizzes Both

“I would honestly say that Kenhub cut my study time in half.” – Read more.

Kim Bengochea, Regis University, Denver

© Unless stated otherwise, all content, including illustrations are exclusive property of Kenhub GmbH, and are protected by German and international copyright laws. All rights reserved.

Register now and grab your free ultimate anatomy study guide!