Iliocostalis Cervicis: Origin, Insertion, Action & Neck Pain

The Iliocostalis Cervicis is the uppermost portion of the Iliocostalis muscle, which is the most lateral column of the Erector Spinae group. Located in the lower neck and upper back, it extends from the ribs to the neck vertebrae, playing a crucial role in posture and neck mobility.

[Image of Iliocostalis Cervicis anatomy]

Quick Anatomy Snapshot

Group	Erector Spinae (Lateral Column).
Origin (Proximal)	Angles of Ribs 3-6.
Insertion (Distal)	Posterior tubercles of the Transverse Processes of C4-C6.
Nerve Supply	Lateral branches of the Posterior Rami of cervical spinal nerves.
Primary Actions	Bilateral: Extension of the neck. Unilateral: Lateral flexion (side bending) and Rotation of the neck to the same side.

Deep Dive: The Lateral Column

To understand the Iliocostalis Cervicis, you must visualize the Erector Spinae group. It is divided into three parallel columns running up the back. The mnemonic is "I Like Standing" (Lateral to Medial):

• Iliocostalis (Lateral column - attaches to ribs)
• Longissimus (Intermediate column - attaches to TPs)
• Spinalis (Medial column - attaches to SPs)

The Iliocostalis column is further divided into three vertical segments: Lumborum (lower back), Thoracis (mid-back), and Cervicis (neck). The Cervicis portion creates a bridge between the upper ribs and the cervical spine.

Physio Corner: Clinical Relevance

💪 Functional Fact: This muscle is often overworked in people with Forward Head Posture (e.g., looking at smartphones or computers). As the head drifts forward, the posterior neck extensors must contract isometrically all day to prevent the head from dropping, leading to chronic tension.

Palpation

The Iliocostalis Cervicis is deep to the Trapezius and Rhomboids but superficial to the deep suboccipital muscles. Palpate lateral to the spinous processes in the lower cervical/upper thoracic region. It is felt as a thin cord-like muscle running vertically along the angles of the upper ribs.

⚠️ Clinical Pathology: Mechanical Neck Pain
Trigger points in the Iliocostalis Cervicis can refer pain upward to the neck and shoulder blade region. It is a common culprit in "wry neck" (torticollis) or general stiffness prohibiting rotation.

Manual Muscle Testing (MMT)

We test the cervical extensors as a group.

Testing Tip: Ensure the patient extends the neck (looking up) rather than just the head (chin lift). Stabilize the upper back to prevent thoracic extension compensation.

Step-by-Step Procedure (Oxford Scale)

Grade	Patient Action & Resistance
Grade 3, 4, 5 (Against Gravity)	Position: Prone (face down), head off the edge of the table or on the table. Action: Patient extends the neck (lifts head to look at wall). Resistance: Applied to the occiput (back of head), pushing down into flexion. Grade 3: Full range against gravity. Grade 4/5: Holds against resistance.
Grade 0, 1 (Palpation)	Action: Palpate the paravertebral muscles in the neck. Cue: "Try to lift your head." Grade 1: Muscle hardening felt. Grade 0: No activity.

Frequently Asked Questions

Does it attach to the skull?

No. The Iliocostalis Cervicis stops at the transverse processes of C4-C6. The muscles that extend to the skull are the Longissimus Capitis and Spinalis Capitis.

What is the difference between Longissimus and Iliocostalis?

Iliocostalis is the lateral column and primarily attaches to Ribs. Longissimus is the intermediate column and primarily attaches to Transverse Processes.

Is it a respiratory muscle?

Indirectly. By stabilizing the ribs (origin) during forced inspiration or extension, it provides a stable base for other respiratory muscles to work, but it is not a primary breathing muscle.

Test Your Knowledge: Iliocostalis Cervicis Quiz

1. To which group does the Iliocostalis Cervicis belong?

2. Where does the Iliocostalis Cervicis insert?

3. What is the primary bilateral action of this muscle?

4. The Iliocostalis is which column of the Erector Spinae?

5. Where does the Iliocostalis Cervicis originate?

6. Which nerve supplies this muscle?

7. Unilateral contraction causes rotation to which side?

8. Forward Head Posture affects this muscle by:

9. Which muscle is an antagonist to the Iliocostalis Cervicis (for extension)?

10. True or False: Iliocostalis Cervicis attaches to the Cranium.

References

• Moore, K. L., Dalley, A. F., & Agur, A. M. R. (2018). Clinically Oriented Anatomy. 8th ed. Philadelphia: Wolters Kluwer.
• Standring, S. (2016). Gray's Anatomy: The Anatomical Basis of Clinical Practice. 41st ed. Elsevier.
• Kendall, F. P. (2005). Muscles: Testing and Function, with Posture and Pain. 5th ed. Lippincott Williams & Wilkins.