Contents of Occipital Triangle
Definition and Boundaries
The occipital triangle is the larger upper subdivision of the posterior triangle, situated above the inferior belly of omohyoid.
| Boundary | Formed By |
|---|---|
| Anterior | Posterior border of SCM |
| Posterior | Anterior border of trapezius |
| Inferior | Inferior belly of omohyoid |
| Roof | Investing layer of deep cervical fascia |
| Floor | Splenius capitis (above), levator scapulae (middle), scalenus medius and posterior (below) |
Contents
Nerve
- Accessory nerve (CN XI): Crosses the triangle obliquely from its entry at Erb’s point to exit under trapezius — most important content
- Cutaneous branches of cervical plexus (emerging at Erb’s point): Lesser occipital, great auricular, transverse cutaneous, supraclavicular nerves
Vessels
- Occipital artery (from external carotid): Crosses the apex of the triangle briefly before entering the scalp
- Transverse cervical artery (from thyrocervical trunk): Passes through the lower part of the triangle
- External jugular vein: Crosses SCM in the roof/superficial fascia at the junction of the upper and lower triangles
Lymph Nodes
- Occipital lymph nodes: Located at the apex near the attachment of trapezius and SCM; drain the back of the scalp
Muscles (of Floor)
- Splenius capitis
- Levator scapulae
- Scalenus medius
Clinical
- Lymphadenopathy of occipital nodes: scalp infections (pediculosis, tinea), rubella (posterior auricular and occipital nodes — classical)
- CN XI injury: most common site of injury for accessory nerve is within the occipital triangle during neck surgery
Posterior Triangle of Neck | Contents of Subclavian Triangle