Deep muscles of the back
After completing this study unit you will be able to:
- Identify and group the deep muscles of the back.
- Understand and memorize their attachments and functions.
- Learn innervation and blood supply patterns of each muscle group.
The deep (intrinsic) muscles of the back extend along the length of either side of the vertebral column, deep to the thoracolumbar fascia, all the way from the skull to the pelvis. Their main functions include maintaining the body posture as well as facilitating the movements of the vertebral column.
They can be subdivided into four groups, or layers:
- Superficial layer: Splenii muscles
- Intermediate layer: Erector spinae muscles
- Deep layer: Transversospinal muscles
- Deepest layer: Segmental muscles
The majority of the deep back muscles are innervated by the segmental branches of the posterior rami of spinal nerves. The blood supply comes from branches of the occipital, deep and transverse cervical, vertebral, posterior intercostal, subcostal, lumbar and lateral sacral arteries.
So much information can surely sound overwhelming but don’t worry as in the following video tutorial we made sure to explain the anatomy of this complex muscle group in an easy-to-digest way.
Take a quiz
Ready to sum up all the information you've gathered? You can do so with our quiz below.
Ready to test your knowledge on a wider range of topics? Try out this quiz about all the muscles of the back.
Do you enjoy exploring these muscles through layers? Take a look at our gallery and revise muscle by muscle.
Erector spinae muscle:
Iliocostalis (cervicis, thoracis, lumborum)
Longissimus (capitis, cervicis, thoracis)
Spinalis (capitis, cervicis, thoracis)
Semispinalis (capitis, cervicis, thoracis)
Multifidus (cervicis, thoracis, lumborum)
Rotatores (breves, longi)
|Deepest layer (intrinsic)||Levatores costarum (longi, breves)
Interspinales (cervicis, thoracis, lumborum)
Intertransversarii (anterior and posterior cervical, medial, lateral lumbar)
|Innervation||Posterior rami of spinal nerves except for the intertransversarii muscles (anterior and posterior rami of spinal nerves)|
|Blood supply||Vertebral artery, deep cervical, transverse cervical, occipital, posterior intercostal, subcostal, lumbar and lateral sacral arteries|