Some parietomastoid sutures bifurcate into two branches before they join the squamosal sutures.
On the 80 skull sides, 11 (13.8%) parietomastoid sutures bifurcated into two branches before they joined to the squamosal sutures.
First, about 14% of the parietomastoid sutures separated into two branches before concatenating squamosal sutures, leading to an uncertainty of confirming the definite SP.
The asterion, one of the important surface landmark for approaches of the posterior cranial basis is defined as the junction point of parietomastoid
and occipitomastoid sutures "Lambdoid", which coincides with the site of the posterolateral fontanella, in the neonatal skull which closes during the second year (Avci et al.; Bonilla et al., 2012; Brockmeyer et al.; Day & Tschabitscher; Lang & Samii; Mwachaka et al., 2010; Rhoton, 1996; da Silva et al., 2010; Sripairojkul & Adultrakoon; Standring, 2008).
Asterion is the meeting point of the lambdoid, occipitomastoid, and parietomastoid
sutures or the point where the temporal, parietal, and occipital bones meet.
On the skull projection with the 35 [degrees] caudal angulation, the midlamboid, occipitomastoid and parietomastoid
sutures lacked closure, their greatest separation occurring at the asterion.
Asterion (As): the meeting point of the lambdoid, occipitomastoid, and parietomastoid