Anatomy Atlas

Suboccipital triangle

Trigonum suboccipitale
Space / regiondraftMSK

Small triangle deep in the back of the neck, bounded by three suboccipital muscles. It contains the vertebral artery and the suboccipital nerve, and the greater occipital nerve emerges just below it.

Core anatomy

Location

Deep posterior neck just below the occiput, beneath trapezius and semispinalis capitis.

Boundaries
superomedial
Rectus capitis posterior major
superolateral
Obliquus capitis superior
inferolateral
Obliquus capitis inferior
roof
Semispinalis capitis (deep to trapezius and splenius capitis)
floor
Posterior atlanto-occipital membrane and posterior arch of the atlas (C1)
Contents
  • Vertebral artery (3rd part, V3), running in the groove on the posterior arch of the atlas
  • Suboccipital nerve (dorsal ramus of C1): motor to the suboccipital muscles; usually no cutaneous branch
Communications

The vertebral artery passes from the triangle through the posterior atlanto-occipital membrane into the vertebral canal and foramen magnum.

Notes

The greater occipital nerve (dorsal ramus of C2) emerges below obliquus capitis inferior and ascends superficial to the triangle; it is not a content of the triangle itself. The suboccipital muscles (rectus capitis posterior major and minor, obliquus superior and inferior) fine-tune head posture and are rich in proprioceptors.

Mentioned in

Generated automatically from links in other entries.

Suboccipital triangle (posterior view)Posterior view of the upper neck with the superficial muscles removed. On each side, rectus capitis posterior major runs from the spinous process of the axis up to the occipital bone, obliquus capitis inferior runs from the spinous process of the axis out to the transverse process of the atlas, and obliquus capitis superior runs from the transverse process of the atlas up to the occipital bone. These three muscles bound the suboccipital triangle. Rectus capitis posterior minor lies medially, from the posterior tubercle of the atlas to the occiput. In the floor of the triangle, the vertebral artery runs medially along the posterior arch of the atlas, with the suboccipital nerve emerging between them. The greater occipital nerve winds around the lower border of obliquus capitis inferior and ascends medial to the triangle.Occipital boneObliquus capitis superiorSuboccipital triangleVertebral artery (V3)Suboccipital nerve(C1 dorsal ramus)Transverse process of atlasObliquus capitis inferiorGreater occipital nerve(C2 dorsal ramus)Spinous process of axis (C2)Rectus capitis posterior minorMastoid processRectus capitis posterior majorPosterior arch of atlasLamina of axisPosterior view · trapezius,splenius and semispinaliscapitis (roof) removedNot to scale

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Suboccipital triangle. Posterior view with the superficial muscles removed. Rectus capitis posterior major, obliquus capitis superior and obliquus capitis inferior bound the triangle; the vertebral artery and suboccipital nerve (C1) lie in its floor on the posterior arch of the atlas. The greater occipital nerve (C2) emerges below obliquus capitis inferior and is not a content of the triangle.
Original schematic, created for this atlas.

Clinical correlations

Vertebral artery exposure and injury

Mechanism / lesion

The artery lies relatively superficially on the posterior arch of C1 here; it is at risk in posterior C1–C2 surgery and in some upper cervical injuries.

Classic presentation

Bleeding at surgery or posterior circulation ischemia (see vertebral artery).

Cervicogenic headache

Mechanism / lesion

Pain referred from upper cervical structures (C1–C3 joints and muscles) through convergence with the trigeminal nucleus.

Classic presentation

Unilateral occipital headache spreading forward, provoked by neck movement or pressure on the suboccipital region, with reduced neck range of motion.

High-yield PANCE pearls

  • Suboccipital triangle contents: vertebral artery (V3) + suboccipital nerve (C1).
  • Greater occipital nerve (C2) emerges below obliquus capitis inferior → occipital neuralgia.

Imaging anatomy

CT

CT angiography shows the V3 segment looping over the posterior arch of C1.

MRI

Suboccipital soft tissues, craniovertebral junction (e.g. Chiari malformation).

Ultrasound

Used to guide greater occipital nerve blocks at the level of obliquus capitis inferior.

Key views & landmarks
  • CT angiography of the neck (vertebral artery)

Physical exam

Surface landmarks

Just below the external occipital protuberance and superior nuchal line, deep to the palpable trapezius and semispinalis.

Palpation

Deep suboccipital tenderness in cervicogenic headache; tenderness over the greater occipital nerve (about a third of the way from the occipital protuberance to the mastoid) in occipital neuralgia.

Self-quiz

Q1.

Which structure is contained in the suboccipital triangle?

Show answer

B

The vertebral artery (and the suboccipital nerve, C1) lie in the triangle. The greater occipital nerve emerges below obliquus capitis inferior, superficial to it.

Q2.

Which muscle forms the inferior boundary of the suboccipital triangle?

Show answer

C

Obliquus capitis inferior forms the inferolateral boundary; rectus capitis posterior major and obliquus capitis superior form the upper sides.

Q3.

The suboccipital nerve is the dorsal ramus of which spinal nerve?

Show answer

A

The suboccipital nerve is the dorsal ramus of C1 and is mainly motor. The greater occipital nerve is the dorsal ramus of C2.

Flashcards

See also