ANATOMICAL STUDY OF THE ACCESSORY HEADS OF THE DEEP FLEXOR MUSCLES OF THE FOREARM (GANTZER MUSCLES) Amal   Yousif   Ahmed   Elhag   Mustafa   *,      Abdullah   Glil   Alkushi,      Wardah   Abdullah   Mohammed   Alasmari,   Ashraf   Mohamed   Elsayed   Ali   Sakran,      Asma Mohammed. Elamin. Department of Human Anatomy, Faculty of Medicine, Umm al Qura University, Makkaha, Saudi Arabia. Correspondence   Address:    Dr.   Amal   Yousif   Ahmed   Elhag   Mustafa,   Department   of   Human   Anatomy,   Faculty   of   Medicine,   Umm   al   Qura   University,   Makkaha, Saudi Arabia. E-Mail:  amaalahmed50@yahoo.com ABSTRACT: Background   and   Objectives:   Proper   knowledge   of   muscular   variations   is   essential   not   only   for   anatomists   but   also   for   surgeons.   Forearm   flexors   are   known to   exhibit   such   variations.   Such   anomalous   muscle   bellies   should   be   kept   in   mind   while   approaching   the   forearm   for   FDS   tendon   transfer   and   other   surgical procedures around it. Materials   and   Methods:    The   present   study   was   consisted   of   20   upper   limbs.   The   dissections   were   carried   out   in   all   the   limbs   on   the   right   and   left   sides.   All the   muscles   were   examined   for   their   presence,   position,   and   their   attachments,   and   then   the   superficial   compartment   was   cut   to   expose   the   deep compartment muscles; If any abnormality was found in the muscular pattern, it was recorded in detail and photographed. Result:   The   incidence   of   the   Gantzer   muscle   was   detected   in   9   (45%)   of   the   20   dissected   forearms,   three   of   these   cases   presented   duplicated   muscle bellies.   It   originated   from   the   medial   epicondyle   in   8(88.9%),   and   from   the   coronoid   process   of   ulna   in   1(11.1%)   of   cases.   It      was   inserted   in   the   flexor pollicis   lungus   in   9(75%)      and   in   the   flexor   digitorum   profundus   in   3   (25%).   In   this   study   the   Gantzer   muscle   was   innervated   by   the   anterior   interosseous nerve which crosses posterior to the muscle in all cases. The muscle was 11.022 cm in length and 0.55 cm in width.  Conclusion: This study will supplement our knowledge on the possible variations of the muscles in this region, which would be useful for hand surgeons. KEY WORDS: Gantzer muscle, anomalous, variations. References 1 . Wood J. Variations in humam myology. Proc R Soc London. 1868;16:483-525. 2 . Le   Double   AF.   Traité   des   variations   du   système   musculaire   de   l'homme   et   de   leur   signification   au   point   de   vue   de   l'anthropologie   zoologique.   Paris: Schleicher Frères; 1897:99-107. 3 . Kaplan EB. Anatomia funcional y quirurgia de la mano. Buenos Aires: Artécnica; 1961:197-250. 4 . Takkallapalli   Anita1,   Sanjay   Kalbande,   Krishnamurthy   Asha,   Dattatray   Dombe   and   Neelee   Jayasree   A   Unique   Variation   of   Flexor   Digitorum   Superficialis Muscle and Its Clinical Significance J Life Sci 2012;4(1):39-43. 5 . Vasavi   Rakesh   G,   Bhagath   Kumar   Potu,   Raghu   Jetti,   Venkata   Ramana   Vollala,   Thejodhar   P   Rare   Origin   of   Two   Accessory   Bellies   from   the   Undersurface of the Flexor Digitorum Superficialis Muscle. Eur J Gen Med 2009; 6, 1, 57-59. Gantzer’s muscle. Chir. Main, 2001;20:241-6. 6 . Spinner, M.; Spencer, P.S. Nerve compression lesions of the upper extremity: a clinical and experimental review. Clin. Orthop., 1974;104:46-67. 7 . Hill, N. A.; Howard, F. M. & Huffer, B.R. The incomplete anterior interosseous nerve syndrome. J. Hand Surg., 1985;10A:4-16. 8 . Proudman,    T.    W.    &    Menz,    P.    J.    An    anomaly    of    the    median    artery    associated    with    the    anterior    interosseous    nerve    syndrome.    J.    Hand    Surg., 1992;17B:507-9. 9 . Mangini U. Flexor pollicis lungus muscle. Its morphology and clinical significance. J Bone Joint Surg Am. 1960;42:467-70. 1 0 . Dellon    AL,    Mackinnon    SE.    Musculoaponeurotic    variations    along    the    course    of    the    median    nerve    in    the    proximal    forearm.    J    Hand    Surg    Br. 1987;12(3):359-63. 1 1 . al-Qattan MM. Gantzer's muscle. An anatomical study of the accessory head of the flexor pollicis longus muscle. J Hand Surg Br. 1996;21(2):269-70. 1 2 . Shirali,   S.;   Hanson,   M.;   Branovacki,   G.;   Gonzalez,   M.   The   flexor   pollicis   longus   and   its   relation   to   the   anterior   and   posterior   interosseus   nerve.   J.   Hand Surg., 1998;23B:170-2. 1 3 . Hemmady   MV,   Subramanya   AV,   Mehta   IM.   The   occasional   head   of   the   flexor   pollicis   longus   muscle:   a   study   on   its   morphology   and   its   clinical significance. JPostgrad Med. 1993;39:14-16. 1 4 . Hollinshead W.H. Anatomy for Surgeons. New York, Harper and Row, 1964;3:412. 1 5 . Jones   M,   Abrahams   PH,   Sanudo   JR,   Campillo   M.   Incidence   and   morphology   of   the   accessory   heads   of   the   flexor   pollicis   longus   and   the   flexor digitorum profundus ( Gantzer’s muscle). j. Anat., 1997;191:451-55. 1 6 . Dykes J, Anison BJ. The accessory tendon of the flexor pollicis longus muscle. Anat Rec. 1944;90:83–87. 1 7 . Malhotra VK, Sing NP, Tewari SP. The accessory head of the flexor pollicis longus muscle and its nerve supply. Anat Anz. 1982;151(5):503-5. 1 8 . Gunnal   SA,   Sidiqui   AU,   Daimi   SR,   Farooki   MS,   Wabalen   RN.   A   Study   on   the   Accessory   Head   of   the   Flexor   Pollicis   Longus   Muscle   (Gantzer's   Muscle).   J Clin Diagn Res. 2013;7(3):418-21. 1 9 . Tamang   BK,   Sinha   P,   Sarda   RK,   Shailo   P,   Murtimanju   BV.   Incidence   and   morphology   of   acessory   head   of   flexor   pollicis   longus   muscle.   An   anatomical study. J Evol Med Dental Sci. 2013;2(36):6800-6. 2 0 . Testut L. Les anomalies musculaires chez l’homme. Paris, Masson. 1884;454–489. 2 1 . Oh   CS,   Chung   IH,   Koh   KS.   Anatomical   study   of   the   accessory   head   of   the   flexor   pollicis   longus   and   the   anterior   interosseous   nerve   in   Asians.   Clin   Anat. 2000;13(6):434-8.