William L. Hylander

My current research interests are related to the functional and evolutionary significance of craniofacial form in human and non-human primates, as well as in African bovids. The long-range goal of my research is to gain a better functional understanding of the morphological diversity of the mammalian craniofacial region. As the mammalian face is dominated by the masticatory apparatus, I have concentrated on analyzing, in fully alert primates during mastication and incision, using cinefluorographic, electromyographic, strain gage and force transducer techniques, (1) how internal forces are countered or resisted throughout various facial bones, and (2) the nature of the external forces (jaw-muscle forces and reaction forces along the teeth and temporomandibular joints) associated with these internal forces. These data are then used to test various hypotheses as to the functional and evolutionary significance of craniofacial form in primates.

Selected Publications: Hylander, W.L. The adaptive significance of eskimo craniofacial morphology. 1977. In: Orofacial Growth and Development, A.A. Dahlberg and T.M. Graber (eds.), Mouton. Hylander, W.L. 1985. Mandibular function and biomechanical stress and scaling. Am. Zoologist 25: 315-330. Hylander, W.L., K.R. Johnson and A.W. Crompton. 1987. Loading patterns and jaw movements during mastication in Macaca fascicularis: A bone-strain, electromyographic, and cineradiographic analysis. Am. J. Phys. Anthrop. 72: 287-314. Hylander, W.L., K.R. Johnson. 1997. In vivo bone strain patterns in the zygomatic arch of macaques and the significance of these patterns for functional interpretations of craniofacial form. Am. J. Phys. Anthrop. 102: 203-232. Hylander, W.L. and K.R. Johnson. 1994. Jaw muscle function and wishboning of the mandible during mastication in macaques and baboons. Am. J. Phys. Anthrop. 94: 523-547. Hylander, W.L., Ravosa, M.J., Ross, C.F., and K.R. Johnson. Mandibular corpus strain in Primates: Further evidence for a functional link between symphyseal fusion and jaw-adductor muscle force. Amer. J. Phys. Anthrop., 1998, 107: 257-271. Ravosa, M.J., Johnson, K.R., and W.L. Hylander Strain in the galago facial skull. J. Morph., 2000, 245: 51-66. Hylander, W.L., Ravosa, M.J., Ross, C.F., Wall, C.E., and K.R. Johnson. Symphyseal fusion and jaw-adductor muscle force: An EMG study. Amer. J. Phys. Anthrop., 2000, 112: 469-492.