Surface landmarks for suboccipital craniotomy

Surface anatomic landmarks of the skull are important to ensure proper surgical planning and approaches. Localization of internal cranial anatomic features based on such landmarks is essential for identifying and avoiding important anatomic structures, minimizing complications and decreasing surgical morbidity. Twenty-five adult dry Anatolian skulls of unknown age and sex from the collection of the Department of Anatomy, Faculty of Medicine, Cukurova University were examined to determine the relationships between specific landmarks. Mean distances and associated SDs for the right and left sides for each of the following were: asterion to the root of the zygoma 53.03 +/- 3.53 and 50.46 +/- 4.97 mm, asterion to the tip of the mastoid process 49.71 +/- 3.92 and 49.17 +/- 4.16 mm, asterion to the digastric point 29.32 +/- 7.09 and 28.78 +/- 4.89 mm, digastric point to the occipitomastoid suture 6.89 +/- 4.21 and 6.95 +/- 4.02 mm, digastric point to the jugular point 25.14 +/- 5.15 and 25.29 +/- 5.38 mm, jugular point to the stylomastoid foramen 8.08 +/- 1.95 and 6.81 +/- 1.47 mm, stylomastoid foramen to the jugular foramen 6.11 +/- 2.33 and 7.08 +/- 1.90 mm, and projection of the digastric point to the border of the sigmoid sinus 3.20 +/- 1.62 and 3.09 +/- 1.92 mm. In addition, the presence of a septum associated with the jugular foramen was noted as a no septum (62.5% and 70.8%), incomplete (29.2% and 16.7%), and complete (8.3% and 12.5%) on the right and left sides, respectively. These distances will aid neurosurgeons in safely placing burr holes for suboccipital craniotomy.