Iliocostalis

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The Iliocostalis is a member of the Erector Spinae (Paraspinal*) group, composed of:

• Iliocostalis
• Longissimus
• Spinalis

*The term paraspinal usually denotes the muscles of the erector spinae group as well as the muscles of the transversospinalis group.

The Iliocostalis has three parts: Iliocostalis Lumborum, Iliocostalis Thoracis, Iliocostalis Cervicis.

ATTACHMENTS:

• Sacrum and iliac crest to ribs to C4.
  • Sacrum, iliac crest, and ribs #3-12 to ribs #1-12 and transverse processes of C4-C7.

ACTIONS:

• Extends the neck and trunk at the spinal joints.
• Laterally flexes the neck and trunk at the spinal joints.
• Ipsilaterally rotates the neck and trunk at the spinal joints.
• Anteriorly tilts the pelvis at the lumbosacral joint.
• Ipsilaterally elevates the pelvis at the lumbosacral joint.

NOTES:

1. The iliocostalis is the most lateral of the three subgroups of the erector spinae group.
2. The name iliocostalis tells us that this muscle group attaches from the ilium to the ribs (cost means ribs).
3. Some sources call the iliocostalis the iliocostocervicalis, indicating that this muscle group extends up into the cervical spine.