Semispinalis Cervicis: Origin, Insertion, Nerve, Action & Neck Stability

The Semispinalis Cervicis is a deep muscle of the posterior neck, belonging to the Transversospinalis group. While it is completely covered by the larger Semispinalis Capitis, it plays a critical role in stabilizing the cervical vertebrae and maintaining the natural curve (lordosis) of the neck.

[Image of Longissimus Cervicis anatomy]

Quick Anatomy Snapshot

Group	Transversospinalis (Deep Back Muscles).
Origin (Proximal)	Transverse Processes of the upper 5 or 6 Thoracic Vertebrae (T1-T6).
Insertion (Distal)	Spinous Processes of the Cervical Vertebrae (C2-C5).
Nerve Supply	Posterior (Dorsal) Rami of cervical spinal nerves.
Primary Actions	Bilateral: Extension of the neck (and spinal stabilization). Unilateral: Rotation of the neck to the Opposite (Contralateral) side.

Deep Dive: The "Hidden" Stabilizer

To understand the Semispinalis Cervicis, you must distinguish it from its superficial partner, the Semispinalis Capitis.

1. Vertebrae vs. Skull

The key difference lies in the insertion:
• Semispinalis Capitis: Inserts onto the Occipital Bone (Skull).
• Semispinalis Cervicis: Inserts onto the Spinous Processes of the Neck (C2-C5).
This means the Cervicis muscle acts specifically on the spinal column segments, making it a primary stabilizer of the cervical curve.

2. The "Axis" Anchor

The thickest fascicle of this muscle inserts onto the massive spinous process of the Axis (C2). This provides a strong anchor point for rotation of the upper neck.

Physio Corner: Clinical Relevance

💪 Functional Fact: In patients with chronic neck pain, MRI studies often show fatty infiltration (atrophy) in the Semispinalis Cervicis. This suggests that deep muscle weakness contributes to spinal instability, forcing superficial muscles (Trapezius) to become tight and painful.

Palpation

Palpation is difficult because it is covered by the Semispinalis Capitis.
Technique: Locate the spinous process of C2. Move laterally about 1-2 cm into the laminar groove. Deep pressure here accesses the Semispinalis Cervicis. Tenderness in this specific groove is very common in "Text Neck" sufferers.

⚠️ Clinical Pathology: Loss of Lordosis
The Semispinalis Cervicis acts as a bowstring to maintain the C-shaped curve of the neck. When this muscle becomes weak or inhibited (due to whiplash or poor posture), the neck can straighten (Military Neck) or even reverse its curve (Kyphosis), accelerating disc degeneration.

Manual Muscle Testing (MMT)

It is tested as part of the deep neck extensor group.

Testing Tip: To bias the Semispinalis Cervicis over the Capitis, focus on extending the lower neck while keeping the chin slightly tucked (preventing upper cervical hyperextension).

Step-by-Step Procedure (Oxford Scale)

Grade	Patient Action & Resistance
Grade 3, 4, 5 (Against Gravity)	Position: Prone (face down), chest supported, head off the table. Action: Patient extends the neck to look at the floor (maintaining a long neck). Resistance: Applied to the posterior head/upper neck, pushing down. Grade 3: Holds head against gravity. Grade 4/5: Holds against resistance.
Grade 0, 1 (Palpation)	Action: Palpate deep in the paravertebral gutter next to the spinous processes. Cue: "Try to lift the back of your neck." Grade 1: Deep tension felt. Grade 0: No activity.

Frequently Asked Questions

Does it attach to the skull?

No. The Semispinalis Cervicis stops at C2. The Semispinalis Capitis continues past it to attach to the skull.

Which rotation does it perform?

Contralateral Rotation (Opposite side). Because its fibers run Up and In (Transverse Process to Spinous Process), contraction pulls the spinous process toward the transverse process, turning the front of the vertebrae to the opposite side.

What covers this muscle?

It is immediately covered by the Semispinalis Capitis. Superficial to that are the Splenius muscles and the Trapezius.

Test Your Knowledge: Semispinalis Cervicis Quiz

1. Where does Semispinalis Cervicis insert?

2. Which muscle lies immediately superficial to the Semispinalis Cervicis?

3. What is the unilateral action of this muscle?

4. Which group does this muscle belong to?

5. Where does Semispinalis Cervicis originate?

6. Which nerve supplies this muscle?

7. Atrophy of the Semispinalis Cervicis is associated with:

8. The largest fascicle of this muscle attaches to which specific vertebra?

9. What is the fiber direction of the Semispinalis group?

10. True or False: Semispinalis Cervicis crosses more vertebral segments than Multifidus.

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.
• Jull, G. A., et al. (2008). Whiplash, Headache, and Neck Pain. Elsevier.