MORPHOMETRY OF ANTERIOR CLINOID PROCESS: A CADAVERIC STUDY  Mangesh Lone * 1 , Lakshmi Rajgopal 2 ,Anjali Telang  3 . *1 Assistant Professor, Department of Anatomy, LTMMC & GH, Sion, Mumbai, Maharashtra, India. 2 Professor (Additional), Department of Anatomy, Seth GS Medical College, Mumbai, Maharashtra, India. 3 Assistant Professor, Department of Anatomy, Seth GS Medical College, Mumbai, Maharashtra, India. Address   for   Correspondence:   Dr.   Mangesh   Lone,   Department   of   Anatomy,   Third   floor,   Lokmanya   Tilak   Municipal   Medical   College   &   General   Hospital,   Sion, Mumbai 400022, Maharashtra, India. Mailing address: Phone no:   Landline (022)24063214, 9773788335 E-Mail:  mangeshc2500@gmail.com ABSTRACT Introduction :   Surgeries   in   the   paraclinoid   region   for   the   clinoid   segment   of   internal   carotid   artery,   periclinoid   tumours,   lesions   of   anterior   part   of   cavernous sinus   and   traumatic   optic   neuropathy   require   the   removal   of   anterior   clinoid   process   to   increase   the   accessibility   to   the   important   structures   in   the   region. Anterior   clinoidectomy   is   a   critical   and   important   procedure   and   requires   utmost   knowledge   of   the   morphometry   of   anterior   clinoid   process.   So,   this   study was undertaken to record the morphometry of anterior clinoid process (ACP). Materials   and   Methods:    Fifty   formalin-fixed   cadavers   were   utilized   from   a   medical   college   in   Mumbai,   Maharashtra.   The   measurements   were   done bilaterally   after   removal   of   the   brain   and   meticulous   dissection   of   cranial   fossae   was   done   to   reflect   the   duramater,   nerves,   vessels   and   other   structures from the field of measurement. Results :   The   mean   distance   between   the   tip   of   ACP   and   medial   margin   of   the   optic   canal   on   the   right   side   was   11.5   mm   and   on   the   left   side   was   11.6   mm; the   mean   distance   between   the   tip   of   ACP   and   lateral   margin   of   the   optic   canal   on   the   right   side   was   5.4   mm   and   on   the   left   side   was   5.4   mm;   the   mean distance   between   medial   margin   of   the   optic   canal   and   the   lateral   edge   of   ACP   on   the   right   side   was   14.3   mm   and   on   the   left   side   was   14.2   mm;   the   mean distance   between   the   lateral   margin   of   the   optic   canal   and   the   lateral   edge   of   ACP   on   the   right   side   was   3.3   mm   and   on   the   left   side   was   3.4   mm;   the   mean distance   between   the   tip   of   ACP   and   the   tip   of   posterior   clinoid   process   (PCP)   on   the   right   side   was   4.2   mm   and   on   the   left   side   was   4.3   mm;   the   mean distance   between   the   tips   of   ACP   was   22.8   mm;   the   mean   distance   between   the   ACPs   at   the   level   of   lateral   margin   of   the   optic   canal   was   23.9   mm;   the mean   distance   between   the   ACPs   at   the   level   of   medial   margin   of   the   optic   canal   was   12.3   mm   and   mean   vertical   dimension   of   the   ACP   at   the   level   of lateral   margin   of   optic   canal   was   2.4   mm.   Conclusion :   The   findings   of   the   present   study   will   help   the   surgeons   in   surgeries   of   the   cavernous   sinus   and paraclinoid region requiring anterior clinoidectomy. 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