Can fetal ossicles be used as prosthesis in adults? A morphometric study

Objectives: The tympanic cavity contains 3 small immovable bones, the malleus, incus and stapes. Extensive studies have been carried out on the morphometry of the ossicles. According to some scientists, in human beings the auditory ossicles reach there definitive size and shape in fetal periods and postnatal modifications are minimal, while there are certain studies which their contradict this claim. These contradictory claims prompted us to make an endeavor to find out the growth pattern of the ear ossicles and comparing the data with adults.Methods: Twenty-two fetal cadavers of either sex, ranging in gestational ages between 24-40 weeks, were collected from local hospitals and 15 adult formalin-fixed cadavers in age groups of 20-30 years were taken. For the study, the fetuses were kept in 2 Groups of 24-28 weeks and 36-40 weeks. From the data obtained, the mean, standard deviation and percentage gain from one group to another in different dimensions of various parts of each ossicle was calculated.Results: The age periods between 40 weeks (full term fetuses) and adults, revealed spurt in the growth of diameter of head of malleus (3%), width of short process of incus (2.7%), width of footplate (5.2%) and height of stapes (13%). These changes were insignificant in terms of acoustic transmission.Conclusion: It is concluded that by the end of gestation, the ear ossicles develop morphometric features comparable to adults with no appreciable changes in the post natal period. Hence, they can be used as prosthesis in adults suffering from ossicular chain malformations and can be an easy and cheap method for treatment of this type of patients. 

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  • Williams PL, Bannister LH, Berry MM, et al. (eds.) Gray's Anatomy. 38th ed. Edinburgh: Churchill Livingstone; 1999. p. 355
  • Unur E, Ulger H, Ekinci N. Morphometrical and morphological variations of middle ear ossicles in the newborn. Erciyes Medical Journal 2002;24:57-63.
  • Arensburg B, Nathan H. Observations on a notch in the short (superior or posterior) process of the incus. Acta Anat (Basel) 1971;78:84-90.
  • Sarrat R, Torres A, Guzman AG, Lostalé F, Whyte J. Functional structure of human auditory ossicles. Acta Anat (Basel) 1992;144: 189
  • Aycan K, Unur E, Bozkır MG. Anatomical study of malleus. Journal of Health Sciences 1990;1:152-8.
  • Hough JV. Congenital malformations of the middle ear. Arch Otolaryngol 1963;78:335-43.
  • Harada O, Ishii H. The condition of the auditory ossicles in micro- tia: findings in 57 middle ear operations. Plast Reconst Surg 1972;50:48-53.
  • Nomura Y, Nagao Y, Fukaya T. Anomalies of the middle ear. Laryngoscope 1988; 98:390-3.
  • Causins VC, Milton CM. Congenital ossicular abnormalities: a review of 68 cases. Am J Otol 1988;9:76-80.
  • Siegert R, Weerda H, Mayer T, Brückmann H. High resolution computerized tomography of middle ear abnormalities. [Article in German] Laryngorhinootologie 1996;75:187-94.
  • Louryan S. Development of auditory ossicles in the human embryo: correlations with data obtained in mice. [Article in French] Bull AssocAnat (Nancy) 1993;77:29-32.
  • Sarrat R, García Guzmán A, Torres A.. Morphological variations of human ossicula tympani. Acta Anat (Basel) 1988;131:146-9.
  • Huttenbrik KB. The mechanics and function of the middle ear. Part 1: The ossicular chain and middle ear muscles. [Article in German] Laryngorhinootologie 1992;71:545-51.
  • Beer HJ, Bornitz M, Hardtke HJ, et al. Modeling of components of the middle ear and simulation of their dynamic behavior. Audiol Neurotol 1999;4:156-62.
  • ApoorvaModi, Parikh. Essentials of Forensic Medicine. 3rd ed. 19 p. 80-2. Lasky LE, Williams AL. Development of auditory system from conception to term. NeoReviews 2005;6:141-52.
  • Anson BJ, Bast TM. The temporal bone and the ear. Charles. C. Thomas, Springfield: 1949. p. 26-38.
  • Ham AW. Hams Histology. 7th ed. Lippincott; 1974. p. 700.
  • Olszewski J. The morphometry of ear ossicles in human during development. [Article in German] Anat Anz 1990;171:187-91.
  • Barut C, Ertilav H. Guidelines for standard photography in gross and clinical anatomy. Anat Sci Educ 2011; 4:348-56.
  • Ulijaszek SJ, Lourie JA. Anthropometry in health assessment: the importance of measurement error. Coll Antropol 1997;21:429-38.
  • Goto R, Mascie-Taylor CG. Precision of measurement as a com- ponent of human variation. J Physiol Anthropol 2007;26:253-6.
  • Weinberg SM, Scott NM, Neiswanger K, Marazita M. Intraobserver error associated with measurements of the hand. Am J Hum Biol 2005;17:368-71. Unur et al., 1993 2002 1968 1972 1972 1981 1990 Malleus Length of ossicle Length of handle Diameter of head 86 53 34 - - - - - - - - Incus Length of ossicle
  • Total width of ossicle Length of long process 23 53 55 - - - - - - - - Stapes Height of ossicle Length of base of footplate Width of base of footplate 81 86 52 3 - - - - 3 -