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The back of the neck forms the posterior part of the cervical region, extending from the external occipital protuberance and superior nuchal line above to the spine of the seventh cervical vertebra below. It includes a complex of muscles, fasciae, and neurovascular structures that stabilize and move the head and neck.
During dissection:
Make a midline incision from the external occipital protuberance to the spine of C7.
Reflect the skin laterally to expose superficial fascia containing cutaneous nerves and small veins.
The deeper layer reveals trapezius, splenius, semispinalis, and suboccipital muscles.
The greater occipital nerve and occipital artery are key landmarks during dissection.
Posterior primary rami of cervical spinal nerves supply the skin of the back of the neck.
C2 (Greater occipital nerve): supplies skin over occiput up to vertex.
C3 (Third occipital nerve): supplies skin of upper posterior neck.
C4 and below: supply lower cervical and upper thoracic regions.
These nerves pierce trapezius near the midline and travel upwards.
The muscles are arranged in three layers:
Superficial Layer
Trapezius: Elevates, retracts, and rotates scapula.
Latissimus dorsi: Extends, adducts, and medially rotates the humerus.
Intermediate Layer
Levator scapulae: Elevates scapula.
Rhomboideus major and minor: Retract scapula.
Deep (Intrinsic) Layer
Splenius capitis and cervicis: Extend and rotate head and neck.
Semispinalis capitis, multifidus, rotatores: Extend and stabilize vertebral column.
Erector spinae group (spinalis, longissimus, iliocostalis): Maintain posture and extend the spine.
A small, deep compartment below the occipital bone and posterior to atlas and axis.
Boundaries of Suboccipital Triangle:
Medial: Rectus capitis posterior major
Lateral: Obliquus capitis superior
Inferior: Obliquus capitis inferior
Roof: Semispinalis capitis
Floor: Posterior atlanto-occipital membrane and posterior arch of atlas
Contents:
Third part of vertebral artery
Suboccipital nerve (dorsal ramus of C1)
Suboccipital venous plexus
Reflect semispinalis capitis to expose the suboccipital muscles.
Identify the vertebral artery as it curves medially above the posterior arch of atlas.
Locate the suboccipital nerve entering the triangle and the greater occipital nerve emerging below the obliquus capitis inferior.
The suboccipital muscles form a small muscular group deep to semispinalis capitis, situated around the atlas and axis.
Rectus capitis posterior major
Origin: Spinous process of the axis (C2)
Insertion: Lateral part of inferior nuchal line of occipital bone
Nerve supply: Suboccipital nerve (dorsal ramus of C1)
Action: Extension and rotation of head to the same side
Rectus capitis posterior minor
Origin: Posterior tubercle of atlas (C1)
Insertion: Medial part of inferior nuchal line
Nerve supply: Suboccipital nerve
Action: Extension of head
Obliquus capitis superior
Origin: Transverse process of atlas (C1)
Insertion: Between superior and inferior nuchal lines on occipital bone
Nerve supply: Suboccipital nerve
Action: Extension and lateral bending of head
Obliquus capitis inferior
Origin: Spinous process of axis (C2)
Insertion: Transverse process of atlas (C1)
Nerve supply: Suboccipital nerve
Action: Rotation of atlas and head to same side
Medial: Rectus capitis posterior major
Lateral: Obliquus capitis superior
Inferior: Obliquus capitis inferior
Roof: Semispinalis capitis
Floor: Posterior arch of atlas and posterior atlanto-occipital membrane
Third part of vertebral artery
Suboccipital nerve (dorsal ramus of C1)
Suboccipital venous plexus
Reflect semispinalis capitis to reveal suboccipital muscles.
Identify the vertebral artery curving medially above the posterior arch of atlas.
Trace the suboccipital nerve entering the triangle.
Observe the greater occipital nerve emerging below obliquus capitis inferior.
Vertebral artery entrapment:
Excessive rotation or hyperextension of the head may compress the vertebral artery within the suboccipital triangle → dizziness, syncope, or visual disturbances.
Whiplash injury:
Sudden hyperextension of the neck (as in rear-end collisions) can tear suboccipital and deep cervical muscles or strain ligaments of the atlanto-occipital and atlantoaxial joints.
Torticollis (Wry neck):
Due to spasm or shortening of sternocleidomastoid or deep neck muscles including suboccipital group.
Produces characteristic tilt and rotation of head.
Occipital neuralgia:
Irritation of greater occipital nerve (C2) causes pain radiating over the occipital scalp; may result from entrapment as it pierces the semispinalis capitis.
Suboccipital nerve block:
Used for pain relief in occipital neuralgia; anesthetic injected near greater occipital nerve at the superior nuchal line.
Mnemonic:
👉 “ROS Loves India”
R – Rectus capitis posterior major (medial boundary)
O – Obliquus capitis superior (lateral boundary)
S – Obliquus capitis inferior (inferior boundary)
Roof: Semispinalis capitis
Floor: Posterior arch of atlas and posterior atlanto-occipital membrane
Mnemonic:
👉 “Very Strong Vein”
V – Vertebral artery (third part)
S – Suboccipital nerve (dorsal ramus of C1)
V – Suboccipital venous plexus
Mnemonic for Suboccipital Floor:
👉 “MAP”
M – Membrane (posterior atlanto-occipital)
A – Arch (posterior arch of atlas)
P – Parts related (vertebral artery groove)
Mnemonic:
👉 “ROOO” (four O’s)
R – Rectus capitis posterior major
O – Rectus capitis posterior minor
O – Obliquus capitis superior
O – Obliquus capitis inferior
The back of the neck contains deep muscles responsible for extension, rotation, and stabilization of the head and cervical vertebrae.
The suboccipital region is located below the occipital bone and between the atlas and axis vertebrae.
The suboccipital triangle is an important landmark in neurosurgery for exposure of the vertebral artery and posterior arch of atlas.
All suboccipital muscles are supplied by the dorsal ramus of C1 (suboccipital nerve) — unique because it is purely motor.
The greater occipital nerve (C2 dorsal ramus) is sensory to the posterior scalp and does not pass through the triangle.
The vertebral artery forms a loop within the triangle before entering the foramen magnum. This loop allows free head movement but can be compressed in extreme rotation.
The posterior atlanto-occipital membrane forms the floor of the triangle and has a defect where the vertebral artery passes.
Occipital neuralgia can result from irritation of the greater occipital nerve after it pierces semispinalis capitis.
Whiplash injury commonly involves strain or tear of suboccipital muscles and posterior neck ligaments due to sudden hyperextension.
Suboccipital nerve block is used clinically for pain relief in occipital headache or neuralgia.
Occurs due to sudden hyperextension of the neck, often in rear-end automobile collisions.
Causes tearing of suboccipital muscles, ligaments, or joint capsules at the craniovertebral junction.
May result in neck stiffness, pain, and reduced range of motion.
Severe cases can affect spinal cord or brainstem due to instability between atlas and axis.
The third part of the vertebral artery winds around the posterior arch of the atlas.
Excessive rotation or extension of the head can compress this artery.
Results in dizziness, vertigo, blurred vision, or fainting (vertebrobasilar insufficiency).
Clinically important during manipulative therapy or cervical spondylosis.
Characterized by tilting of the head to one side and rotation to the opposite side.
May be due to spasm or fibrosis of sternocleidomastoid or suboccipital muscles.
Can be congenital (due to birth trauma) or acquired (infections, inflammation, trauma).
Caused by irritation of the greater occipital nerve (C2 dorsal ramus).
Pain radiates from upper neck to the posterior scalp.
Often results from entrapment of the nerve as it pierces the semispinalis capitis.
May be relieved by local anesthetic block or physiotherapy.
Seen in trauma, rheumatoid arthritis, Down’s syndrome, or tuberculosis.
Laxity of transverse ligament of the atlas causes anterior displacement of the atlas over the axis.
May compress the spinal cord leading to quadriparesis or even death.
The suboccipital triangle provides a safe surgical approach to the third part of the vertebral artery.
Knowledge of its boundaries and contents is vital during vascular or neurosurgical procedures in this region.
Given for relief of occipital headaches.
Injection is made near the greater occipital nerve at the superior nuchal line, lateral to the external occipital protuberance.
Medial boundary: Rectus capitis posterior major
Lateral boundary: Obliquus capitis superior
Inferior boundary: Obliquus capitis inferior
Floor: Posterior atlanto-occipital membrane and posterior arch of atlas.
Roof: Semispinalis capitis muscle and deep fascia.
Third part of vertebral artery
Suboccipital nerve (dorsal ramus of C1)
Suboccipital venous plexus
Suboccipital nerve (dorsal ramus of C1) supplies all the four suboccipital muscles:
Rectus capitis posterior major
Rectus capitis posterior minor
Obliquus capitis superior
Obliquus capitis inferior
It provides surgical access to the third part of the vertebral artery.
Important in angiography and vascular surgeries near the craniovertebral junction.
Pain in the posterior scalp due to irritation of the greater occipital nerve (C2 dorsal ramus).
The nerve gets compressed while piercing the semispinalis capitis, causing sharp or throbbing pain.
Excessive rotation or extension of the neck can compress the artery, leading to:
Vertigo
Visual disturbances
Loss of balance or syncope
Suboccipital nerve (C1): Purely motor; supplies suboccipital muscles; lies inside the triangle.
Greater occipital nerve (C2): Purely sensory; supplies posterior scalp; lies outside the triangle.
Abnormal tilt and rotation of the head caused by spasm or fibrosis of sternocleidomastoid or suboccipital muscles.
May be congenital (birth injury) or acquired (infections or trauma).
The loop in the third part of vertebral artery allows head movement without stretching the vessel.
Prevents ischemia during normal motion but may compress in extreme rotation.
These questions are frequently asked in both theory viva and practical examinations to assess understanding of the suboccipital region anatomy and its clinical relevance
1. The suboccipital triangle is located between which two vertebrae?
A. C1 and C2
B. C2 and C3
C. C3 and C4
D. C4 and C5
✅ Answer: A. C1 and C2
Explanation: The triangle lies between the atlas (C1) and axis (C2), deep to semispinalis capitis.
2. The nerve supply of suboccipital muscles is derived from —
A. Dorsal ramus of C1
B. Dorsal ramus of C2
C. Ventral ramus of C1
D. Ventral ramus of C2
✅ Answer: A. Dorsal ramus of C1
Explanation: The suboccipital nerve (C1) is purely motor and supplies all four suboccipital muscles.
3. The greater occipital nerve is —
A. Dorsal ramus of C1
B. Ventral ramus of C1
C. Dorsal ramus of C2
D. Ventral ramus of C2
✅ Answer: C. Dorsal ramus of C2
Explanation: It is the dorsal ramus of the second cervical nerve and supplies the posterior scalp.
4. The floor of the suboccipital triangle is formed by —
A. Semispinalis capitis
B. Posterior arch of atlas and posterior atlanto-occipital membrane
C. Rectus capitis posterior major
D. Obliquus capitis inferior
✅ Answer: B. Posterior arch of atlas and posterior atlanto-occipital membrane
5. The roof of the suboccipital triangle is formed by —
A. Semispinalis capitis
B. Trapezius
C. Splenius capitis
D. Sternocleidomastoid
✅ Answer: A. Semispinalis capitis
6. The contents of the suboccipital triangle include all except —
A. Third part of vertebral artery
B. Suboccipital nerve
C. Suboccipital venous plexus
D. Greater occipital nerve
✅ Answer: D. Greater occipital nerve
Explanation: Greater occipital nerve lies below the triangle, not within it.
7. The vertebral artery enters the cranial cavity through —
A. Foramen lacerum
B. Foramen magnum
C. Jugular foramen
D. Foramen ovale
✅ Answer: B. Foramen magnum
8. The vertebral artery is a branch of —
A. Common carotid artery
B. Internal carotid artery
C. Subclavian artery
D. External carotid artery
✅ Answer: C. Subclavian artery
9. Which muscle rotates the atlas and head to the same side?
A. Rectus capitis posterior minor
B. Obliquus capitis superior
C. Obliquus capitis inferior
D. Splenius capitis
✅ Answer: C. Obliquus capitis inferior
Explanation: It acts on the atlantoaxial joint to rotate the head to the same side.
10. Which of the following is purely motor?
A. Greater occipital nerve
B. Lesser occipital nerve
C. Suboccipital nerve
D. Transverse cervical nerve
✅ Answer: C. Suboccipital nerve
11. Pain radiating from the neck to the back of the scalp is due to involvement of —
A. Suboccipital nerve
B. Greater occipital nerve
C. Lesser occipital nerve
D. Accessory nerve
✅ Answer: B. Greater occipital nerve
Explanation: It supplies sensory fibers to the posterior scalp and is responsible for occipital neuralgia.
12. The vertebral artery is liable to compression during —
A. Flexion of the neck
B. Rotation or extension of the neck
C. Inspiration
D. Swallowing
✅ Answer: B. Rotation or extension of the neck
13. The muscle forming the medial boundary of suboccipital triangle is —
A. Obliquus capitis inferior
B. Rectus capitis posterior major
C. Rectus capitis posterior minor
D. Obliquus capitis superior
✅ Answer: B. Rectus capitis posterior major
14. The nerve emerging below obliquus capitis inferior is —
A. Suboccipital nerve
B. Accessory nerve
C. Greater occipital nerve
D. Lesser occipital nerve
✅ Answer: C. Greater occipital nerve
15. The suboccipital triangle is an important landmark because —
A. It contains the accessory nerve
B. It contains the third part of the vertebral artery
C. It contains the brachial plexus
D. It contains the hypoglossal nerve
✅ Answer: B. It contains the third part of the vertebral artery
Q1. What forms the posterior boundary of the neck?
The external occipital protuberance and superior nuchal line above, and the spine of C7 vertebra below, form the posterior boundary.
Q2. What are the main layers of muscles in the back of the neck?
Superficial layer: Trapezius
Intermediate layer: Splenius capitis and splenius cervicis
Deep layer: Semispinalis capitis and suboccipital muscles
Q3. Name the suboccipital muscles.
Rectus capitis posterior major, rectus capitis posterior minor, obliquus capitis superior, and obliquus capitis inferior.
Q4. Which nerve supplies all suboccipital muscles?
The suboccipital nerve (dorsal ramus of C1).
Q5. What are the boundaries of the suboccipital triangle?
Medial: Rectus capitis posterior major
Lateral: Obliquus capitis superior
Inferior: Obliquus capitis inferior
Q6. What forms the floor and roof of the suboccipital triangle?
Floor: Posterior arch of atlas and posterior atlanto-occipital membrane
Roof: Semispinalis capitis muscle
Q7. What are the contents of the suboccipital triangle?
Third part of the vertebral artery
Suboccipital nerve (C1 dorsal ramus)
Suboccipital venous plexus
Q8. Which nerve is purely motor in this region?
The suboccipital nerve (C1 dorsal ramus).
Q9. Which nerve is purely sensory in the same region?
The greater occipital nerve (C2 dorsal ramus).
Q10. What is the difference between the suboccipital and greater occipital nerves?
Suboccipital nerve: Motor; lies within the triangle; supplies muscles.
Greater occipital nerve: Sensory; lies below the triangle; supplies posterior scalp.
Q11. Which muscle rotates the head to the same side?
Obliquus capitis inferior.
Q12. What is the action of rectus capitis posterior major?
Extension and rotation of the head to the same side.
Q13. What is the action of obliquus capitis superior?
Extension and lateral flexion of the head.
Q14. What artery passes through the suboccipital triangle?
The third part of the vertebral artery.
Q15. The vertebral artery is a branch of which vessel?
The subclavian artery.
Q16. Through which foramen does the vertebral artery enter the cranial cavity?
Through the foramen magnum.
Q17. Why does the vertebral artery form a loop before entering the skull?
To allow free rotation of the head without stretching or compressing the artery.
Q18. What is the clinical importance of the suboccipital triangle?
It is the surgical landmark for exposing the third part of vertebral artery.
Site for vertebral angiography and nerve blocks.
Q19. What is occipital neuralgia?
Pain over the posterior scalp due to irritation of the greater occipital nerve (C2 dorsal ramus), often from entrapment in semispinalis capitis.
Q20. What is the cause of dizziness during neck rotation?
Compression of the vertebral artery within the suboccipital triangle.
Q21. What is whiplash injury?
A hyperextension injury of the neck, commonly from rear-end car collisions, leading to strain or tear of suboccipital muscles and ligaments.
Q22. Which muscle overlies the suboccipital triangle?
Semispinalis capitis forms its roof.
Q23. What structure lies deep to the posterior atlanto-occipital membrane?
The dura mater and spinal cord.
Q24. Which nerve emerges below the obliquus capitis inferior muscle?
The greater occipital nerve.
Q25. What movements occur at the atlanto-occipital and atlantoaxial joints?
Atlanto-occipital joint: Flexion and extension (“yes” movement).
Atlantoaxial joint: Rotation (“no” movement).
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