Moreover, the authors say, "An imbalance in the ocular muscles tone can cause a movement dysfunction at the sphenoid bone, at the maxilla and at the ocular muscle nerves." In addition to muscle contraction, flexibility between the bones in the eye orbit and skull - particularly the phenopetrosal suture, the
occipitomastoid suture, and the lacrimal bone--are key for functional drainage in the head and preventing IOP.
There was also presence of sutural diastasis (12 mm defect of right
occipitomastoid suture) (Figure 4(f)).
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).
According to this method; there was no risk of placement of burrhole at 2 cm inferior to the asterion, 1/3 anterior and 2/3 posterior of occipitomastoid fissure.
Asterion is the meeting point of the lambdoid,
occipitomastoid, and parietomastoid sutures or the point where the temporal, parietal, and occipital bones meet.
These are: (1) the Kerckring ossicle (ko), (2) posterior intraoccipital synchondrosis (pio), (3) anterior intraoccipital synchondrosis (aio), (4) sphenooccipital synchondrosis (sos), (5) petrooccipital fissure (pof) and (6) occipitomastoid suture (oms).
The occipitomastoid suture started showing evidence of progressive fusion by the age of 9 years in 161 cases (80.5%) and reached complete fusion in all cases by the age of 16.5 years.
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 sutures.