Table 2.

Pinned cranial bone in the different approaches

Approach	Cranial bone pinned by the single pin	Cranial bone pinned by the pins of the two pin side
Bifrontal	Parietal: superior and posterior to the external auditory meatus (EAMa)	Parietal: superior and toward the midline Temporal: mastoid process
Pterional	Frontal: anterosuperior to the pterion	Occipital: superior and lateral to the occipital protuberance Temporal: mastoid process
Middle Fossa	Frontal: superolateral to the nasion	Occipital: superior and lateral to the occipital protuberance
Prone/ventral position	Parietal: superior to the EAM	Parietal: superior and posterior of the EAM, superior and anterior of the EAM

^aExternal auditory meatus