Anatomical position of the asterion and its underlying structure.

Surface anatomy is important for surgical planning. The asterion has been believed and used for locating the underlying posterior fossa dura. To prove whether this landmark is reliable or not, forty-three fixed heads of cadaver were dissected. A burr hole was made on the asterion and its underlying structure was examined. Seventy-four point four per cent (74.4%) of the asterion on the right side were adjacent to the transverse-sigmoid sinus complex when compared to 58.1 per cent on the left. Twenty-three point three per cent (23.3%) of the asterion on the right side were found over the infratentorial dura while that on the left side were 32.6 per cent. Two point three per cent (2.3%) of the asterion were located over the supratentorial dura on the right and 9.3 per cent on the left side. It is concluded, therefore, that the asterion is not an appropriate landmark to locate the underlying posterior fossa dura.

Anatomical landmark for internal jugular vein catheterization for detection of jugular venous O2 saturation (SjvO2) in Thai people.

Thirty-two (32) cadavers were dissected to find the anatomical landmark for puncturing the internal jugular vein. The point for the right internal jugular vein was 2 cm above and 2.17 cm lateral to the right clavicular head, and that for the left internal jugular vein was 2 cm above and 2.08 cm lateral to the left clavicular head. The right internal jugular vein was found to dominate eighty-eight per cent (88%) of the cadavers. The anatomical point 2 cm above and 2 cm lateral to the head of the clavicle was appropriate for puncturing the internal jugular vein. After puncturing the internal jugular vein, a catheter was inserted ascending to the jugular bulb where jugular venous O2 saturation (Sjv O2) related to the cerebral metabolism was detected.