Left lateral exposure of skull bones.  For orientation, anterior is toward the top left corner of the image and superior is toward the right top corner. Flaps of skin and subcutaneous tissue and temporalis muscle have been  reflected to expose lateral skull bones and sutures. The parietal bone joins the squamous portion of the temporal bone at the squamous suture. The mastoid portion of the temporal bone joins the parietal bone at the parietomastoid suture and the occipital bone at the occipitomastoid suture. The parietal bone joins the occipital bone at the lambdoid suture. The asterion is a craniometric point of junction of the parietomastoid, lambdoid, and occipitomastoid sutures. The mastoid foramen located near the occipitomastoid suture transmits an emissary vein to the sigmoid sinus and a small dural branch of occipital artery. (Image courtesy of M Nunez)