The occipitomastoid suture is the cranial suture between the occipital bone and the mastoid portion of the temporal bone.
It is continuous with the lambdoid suture.
Mastoid emissary vein is especially important from the neurosurgical point of view, because it is located in variable number in the area of the occipitomastoid suture and it can become a source of significant bleeding in surgical approaches through the mastoid process, especially in retrosigmoid craniotomy,