MORPHOMETRIC  STUDY OF MENISCI OF KNEE JOINTS IN ADULT CADAVERS Rashmi B.N * 1 , Dakshayani K.R 2 , Vadiraja N 3 . *1 Assistant professor, Department of anatomy, Mysore Medical College and Research Institute, Mysore, Karnataka, India. 2  Professor and HOD, Department of anatomy, Mysore Medical College and Research Institute, Mysore, Karnataka, India. 3  Assistant professor, Department of Community Medicine 3 , Mysore Medical College and Research Institute, Mysore, Karnataka, India.    Correspondence   Address:       Dr.   Rashmi   B.N,   Assistant   professor,   Department   of   anatomy,   Mysore   Medical   College   and   Research   Institute,   Mysore,   Karnataka, India.  E-Mail: dr.rashmimanju@gmail.com ABSTRACT Background:    The   menisci   of   knee   joint   are   important   functional   units   able   to   improve   joint   congruence   and   load   distribution   thereby   reducing   the   stress   on the   knee   joint,   a   function   that   is   considered   primordial   to   protect   the   articular   cartilage   and   prevent   osteoarthritis.   Variations   of   form   and   in   particular   of thickness   and   width   of   menisci   can   determine   the   possibility   and   kind   of   injury.   There   are   many   differences   in   the   anatomical   features   and   insertion between   the   lateral   and   medial   menisci   and   also   the   contour   of   the   menisci   changes   from   C-   shaped   to   circular   (discoid)   which   are   important   in   relation   to the   injury   mechanism.   Discoid   meniscus   may   be   unstable   and   therefore   more   susceptible   to   injury.      The   study   of   morphology   of   menisci   of   the   knee   joint will   provide   support   to   meniscal   anatomy   which   is   necessary   for   various   surgical   procedures   and   also   for   arthroscopy   of   the   knee   joint.      The   knowledge   of exact size and shape is essential for meniscal transplantation in meniscal injuries. Materials   and   Methods :   The   study   is   done   on   50   menisci      (32   right   and   18   left   sides)   of   adult   cadavers   preserved   with   formaldehyde   solution   obtained   from department   of   Anatomy,   MMC&RI.   To   measure   the   length   of   each   menisci,   a   cotton   thread   is   place d   across   the   outer   edge   of   the   meniscus    from   the   apex of   the   anterior   horn   to   the   apex   of   the   posterior   horn.   Next   the   thread   length   is   measured   using   vernier   calipers.   Width   is   measured   at   three   points-anterior third,   middle   third   and   posterior   third.   From   each   point,   distance   between   outer   edge   to   inner   edge   is   measured   using   vernier   calipers.   The   thickness   of   the meniscus   is   also   measured   at   three   points-   anterior   third,   middle   third   and   posterior   third.   From   each   point,   the   calipers   is   placed   between   the   top   and bottom edge of the outer circumference to measure the thickness of menisci. The data was  analysed using the student t-test for independent samples. Results :   The   individual   analysis   of   each   meniscus   showed   that   posterior   third   of   medial   meniscus   was   the   widest   part   (16.68±0.60mm)   (p<0.05)   followed   by middle    third    (12.09±0.22mm)    and    anterior    third    (8.88±0.19mm).    Related    to    the    thickness    of    outer    circumference    of    meniscus,    posterior    third (5.90±0.12mm)   of   medial   meniscus   was   the   thickest   part   followed   by   anterior   third   (5.58±0.18mm)   and   middle   third(5.28±0.12mm).   However,   in   the   lateral menisci,    middle    third    was    the    thickest    part    (p<0.05)    (table    I).    In    the    present    study,    the    peripheral    length    of    medial    meniscus    (10.38±0.33cm)    was significantly more than the lateral meniscus (9.61±0.2cm).  Discoid medial and lateral menisci were not observed in the present study (0%). Conclusion :   The   morphometric   findings   of   the   meniscus   demonstrate   accordance   with   studies   regarding   the   location   of   meniscal   injuries.   The   anterior   third     of   the   medial   meniscus   presented   smaller   width,   which   explains   the   lower   incidence   of   injuries   at   this   point   of   the   meniscus   due   to   the   weaker   action   of the   femoral   condyles.   Similarly,   measures   of   the   middle   third   confirmed   that   it   is   the   point   of   greatest   tension,   and   also   that   it   is   the   most   frequently   injured region   in   both   menisci.   Thus   the   result   of   this   study   showed   that   there   is   an   important   relationship   between   the   morphometric   data   of   the   menisci   and   the data found in the clinic, which would explain the incidence of injuries in specific points of each meniscus. KEY WORDS: Meniscus, Morphometry, Knee, Discoid meniscus. References 1 . Standring S. Sacrum. In: Standring S, eds. Grays Anatomy. 39th ed. London: Elsevier Churchill Livingstone; 2006;1476-1487. 2 . Moore, K.L., and Dalley, A.F. Anatomiaorientadapara clinica.4.ed. Rio de Janeiro: Guanabara Koogan. 2001. 3 . Kohn,   D.   and   Moreno,   B.   Meniscus   insertion   anatomy   as   a   basic   for   meniscus   replacement:   A   morphological   cadaveric   study.   Arthoscopy.   1995;11:96- 103. 4 . Messner,   K.   and   Gao,   J.   The   menisci   of   the   knee   joint.   Anatomical   and   functional   characteristics   and   a   rationale   for   clinical   treatment.   J.   Anatomy. 1998;193:161-178. 5 . Smillie IS. Injuries of the knee joint. 4 th  ed. London: Living Stone. 1975. 6 . Almeida   S.K.S.,   De   Moraes,   A.S.R.,   Tashimiro,   T.,Neves,   S.E.,   Toscano,   A.E.   and      De   Abreu,   R.R.M.   Morphometric   study   of   the   menisci   of   the   knee   joint. Int. J. Morphol. 2004;22(3): 181-184. 7 . Young   R.   The   external   semilunar   cartilage   as   a   complete   disc.   In:Cleland   J,   Young   R,   eds.   Memoirs   and   Memoranda   in   Anatomy.   London:   Williams   and Norgate, 1889:179. 8 . Smillie IS. The congenital discoid meniscus. J Bone Joint Surg Br 1948;30:671-682. 9 . Kaplan EB. Discoid lateral meniscus of the knee joint. J Bone Joint Surg Am 1957;39A:7787. 1 0 . Braz, P.R.P. and Silva, W.G. Meniscus morphometric study in humans. J Morphol Sci. 2010;27(2):62-66. 1 1 . Testut L, Latarjet A. Tratado de Anatomia Humana. 10 th  ed. Barcelona: Salvat. 1975 1 2 . Cohen,   M.,   Junior,   G.S.M.,   Ejnisman,   B.,   Sexas,   M.R.   and   Vicenze,   V.   Estudo   davascularizacao   domeniscoemhumano.   RevistaBrasileira   de   Ortopedia. 1998;3(4): 264-270. 1 3 . Murlimanju,N.N.,   Shakuntala   R.P.,   Mangala,   M.P.,   Gupta,   C.,   Vishal   kumar.,   and   thejodhar   Pulakunta,   B.V.   Morphometric   analysis   of   the   menisci   of   the knee joint in south Indian human fetuses. J. Morphol. 2010;28(4):1167-1171. 1 4 . Peterson, W. and Tillmann, B. Age related blood and lymph supply of the knee menisci. Acta orthopaedica Scandinavia. 1995;66:308-312. 1 5 . Kelly BT, Green DW. Discoid lateral meniscus in children. Curr Opin Pediatr 2002; 14: 54-61. 16. Rath E Richmond J C. The menisci: basic science and advances in treatment Br J Sports Med. 2000;252-257.