Abstract
Background: Aim of present study was to note the frequency of accessory infraorbital foramen in north Indian population and to determine the distance of infraorbital foramen from various anatomical landmarks in adult dry human crania. Methodology: 64 adult north Indian dry human crania of unknown age and gender were analysedfor the presence ofaccessoryinfraorbital foramen and their unilateral or bilateral prevalence was calculated.Shortest distance between the infraorbital foramen from midline, pyriform margin, nasion, infraorbital margin, anterior nasal spine and frontozygomatic suture was measuredon both sides in each craniawith Vernier caliper accurate to 0.1 mm for linear measurement.Observations thus made were compiled and tabulated followed by comparison using appropriate statistical tests. Results: Prevalence of accessory infraorbital foramen is 7.81%, while bilateral prevalence of accessory infraorbital foramen is only 1.56 %, however unilaterally accessory infraorbital foramen is present in 6.25% (2.34 % on right side and 3.9 % on left side). Mean shortest distance of infraorbital foramen from midline was 34.78 ± 3.19mm, while mean shortest distance between the infraorbital foramen to the pyriform margin was 21.26 ± 2.78 mm.Mean shortest distance of infraorbital foramen to the nasion andinfraorbital marginwas 44.95 ± 4.62mm. and 6.58 ± 1.59 mm respectively.Mean shortest distance of infraorbital foramen to the anterior nasal spine and frontozygomatic suture was 36.63 ± 3.16mm.and 35.62 ± 1.98 mm respectively. Conclusion: The knowledge of the distances from surgically encountered anatomic landmarks may be of assistance in locating these important maxillofacial neurologic structures during many procedures. Understanding the location of these foramina will also assist the clinician in performing local anesthetic blocks. [Singh A NJIRM 2015; 6(5):28-33]

Key words: infraorbital foramen, accessory infraorbital foramen, morphometry