Basic Cranial Approaches

Retrosigmoid craniotomy

Retrosigmoid craniotomy simulation
This is a simulation of a retrosigmoid craniectomy. The lateral cerebellar surface is exposed as well as transverse and sigmoid sinus.
1. Soft tissue dissection
Left sided retrosigmoid craniotomy. Soft tissue dissection exposing the initial muscular layer.
2. Occipital artery and mastoid emissary vein
Deep soft tissue dissection exposing the occipital artery in its second segment running above the longissimus muscle. The mastoid emissary vein is also preserved and presented.
3. Asterion
The bone landmarks for retrosigmoid craniectomy. The asterion is formed by the junction of the occipitomastoid, parietomastoid and lambdoid sutures. It usually marks the lower end of the sigmoid transverse junction.
4. Craniotomy
5. Cerebellopontine angle exposure
A retractor is placed on the latera cerebellar hemisphere exposing the neurovascular structures within the cerebellopontine angle.