Iliocostalis

Authors

Affiliations

Nathaniel 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

OIAN

Schematic view of the intermediate intrinsic muscles of the back (Erector spinae)¹

Figure 1: Intermediate intrinsic muscles of the back / Erector spinae (Posterior view)¹

Table 1: Iliocostalis muscles

Muscle	Origin	Insertion	Innervation	Action

Iliocostalis Cervicis

Origin

3rd-7th ribs¹

Insertion

C4-C6 TP¹

Innervation

Spinal nn. C8-L1 (Post rami, lateral branches)¹

Action

Iliocostalis Thoracis

Origin

7-12th ribs¹

Insertion

1st-6th ribs¹

Innervation

Spinal nn. C8-L1 (Post rami, lateral branches)¹

Action

Iliocostalis Lumborum

Origin

Sacrum, iliac crest, lumbar vertebrae SP; lower thoracic vertebrae TP¹

Insertion

6-12th ribs, thoracolumbar fascia (posterior layer), upper lumbar vertebrae (TP)¹

Innervation

Spinal nn. C8-L1 (Post rami, lateral branches)¹

Action

• Bilateral: Extends spine¹
• Unilateral: I/L spine lat-flexion¹

Muscle groups

Iliocostalis is part of the Intermediate intrinsic back muscles (erector spinae)

Palpation

Clinical significance

1.

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