Portal de Periódicos da CAPES

In vivo and in vitro bone strain in the owl monkey circumorbital region and the function of the postorbital septum

1996; Wiley; Volume: 101; Issue: 2 Linguagem: Inglês

10.1002/(sici)1096-8644(199610)101

1096-8644

Callum F. Ross, William L. Hylander,

Primate Behavior and Ecology

American Journal of Physical AnthropologyVolume 101, Issue 2 p. 183-215 Full Access In vivo and in vitro bone strain in the owl monkey circumorbital region and the function of the postorbital septum Callum F. Ross, Corresponding Author Callum F. Ross Department of Anatomical Sciences, Health Sciences Center, State University of New York at Stony Brook, Stony Brook, New York 11794-8081Department of Anatomical Sciences, Health Sciences Center, SUNY Stony Brook, Stony Brook, NY 11794-8081Search for more papers by this authorWilliam L. Hylander, William L. Hylander Department of Biological Anthropology and Anatomy, Duke University Medical Center, Duke University, Durham, North Carolina 27706Search for more papers by this author Callum F. Ross, Corresponding Author Callum F. Ross Department of Anatomical Sciences, Health Sciences Center, State University of New York at Stony Brook, Stony Brook, New York 11794-8081Department of Anatomical Sciences, Health Sciences Center, SUNY Stony Brook, Stony Brook, NY 11794-8081Search for more papers by this authorWilliam L. Hylander, William L. Hylander Department of Biological Anthropology and Anatomy, Duke University Medical Center, Duke University, Durham, North Carolina 27706Search for more papers by this author First published: October 1996 https://doi.org/10.1002/(SICI)1096-8644(199610)101:2 3.0.CO;2-3Citations: 95AboutReferencesRelatedInformationPDFPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessClose modalShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Abstract Anthropoids and tarsiers are the only vertebrates possessing a postorbital septum. This septum, formed by the frontal, alisphenoid, and zygomatic bones, separates the orbital contents from the temporal muscles. Three hypotheses suggest that the postorbital septum evolved to resist stresses acting on the skull during mastication or incision. The facial-torsion hypothesis posits that the septum resists twisting of the face about a rostrocaudal axis during unilateral mastication; the transverse-bending hypothesis argues that the septum resists caudally directed forces acting at the lateral orbital margin during mastication or incision; and the tension hypothesis suggests that the septum resists ventrally directed components of masseter muscle force during mastication and incision. This study evaluates these hypotheses using in vitro and in vivo bone strain data recorded from the circumorbital region of owl monkeys. Incisor loading of an owl monkey skull in vitro bends the face upward in the sagittal plane, compressing the interorbital region rostrocaudally and "buckling" the lateral orbital walls. Unilateral loading of the toothrow in vitro also bends the face in the sagittal plane, compressing the interorbital region rostrocaudally and buckling the working side lateral orbital wall. When the lateral orbital wall is partially cut, so as to reduce the width of its attachment to the braincase, the following changes in circumorbital bone strain patterns occur. During loading of the incisors, lower bone strain magnitudes are recorded in the interorbital region and lateral orbital walls. In contrast, during unilateral loading of the P3, higher bone strain magnitudes are observed in the interorbital region, and generally lower bone strain magnitudes are observed in the lateral orbital walls. During unilateral loading of the M2, higher bone strain magnitudes are observed in both the interorbital region and in the lateral orbital wall ipsilateral to the loaded molar. Comparisons of the in vitro results with data gathered in vivo suggest that, during incision and unilateral mastication, the face is subjected to upward bending in the sagittal plane resulting in rostrocaudal compression of the interorbital region. Modeling the lateral orbital walls as curved plates suggests that during mastication the working side wall is buckled due to the dorsally directed component of the maxillary force which causes upward bending of the face in the sagittal plane. The balancing side lateral orbital wall may also be buckled due to upward bending of the face in the sagittal plane as well as being twisted by the caudoventrally directed components of the superficial masseter muscle force. The in vivo data do not exclude the possibility that the postorbital septum functions to improve the structural integrity of the postorbital bar during mastication. However, there is no reason to believe that a more robust postorbital bar could not also perform this function. Hypotheses stating that the postorbital septum originally evolved to reinforce the skull against routine masticatory loads must explain why, rather than evolving a postorbital septum, the stem anthropoids did not simply enlarge their postorbital bars. © 1996 Wiley-Liss, Inc. Literature Cited Cachel S (1979) A functional analysis of the primate masticatory system and the origin of the anthropoid post-orbital septum. Am. J. Phys. Anthropol. 50: 1– 18. Cartmill M (1980) Morphology, function and evolution of the anthropoid postorbital septum. In RL Ciochon and AB Chiarelli (eds.): Evolutionary Biology of the New World Monkeys and Continental Drift. New York: Plenum, pp. 243– 274. Connolly R, and Quimby FW (1978) Acepromazine-keta-mine anesthesia in the rhesus monkey (Macaca mulatto). Lab. Anim. Sci. 28: 72– 74. Covey DS, and Greaves WS (1994) Jaw dimensions and torsion resistance during canine biting in the Carnivora. Can. J. Zool. 72: 1055– 1060. Dally JW, and Riley WF (1965) Experimental Stress Analysis. New York: McGraw-Hill. Dechow P, Nail GA, Schwartz-Dabney CL, and Ashman RB (1993) Elastic properties of human supraorbital and mandibular bone. Am. J. Phys. Anthropol. 90: 291– 306. Greaves WS (1985) The mammalian postorbital bar as a torsion-resisting helical strut. J. Zool. Soc. (Lond.) 207: 125– 136. Greaves WS (1995) Functional predictions from theoretical models of the skull and jaws in reptiles and mammals. In JJ Thomason (ed.): Functional Morphology in Vertebrate Paleontology. New York: Cambridge University Press, pp. 99– 115. Herring SW, and Mucci RJ (1991) In vivo strain in cranial sutures: The zygomatic arch. J. Morphol. 207: 225– 239. Hylander WL (1981) Patterns of stress and strain in the macaque mandible. In DS Arlson (ed.): Craniofacial Biology. Monograph 10. Craniofacial Growth Series. Center for Human Growth and Development. Ann Arbor: University of Michigan, pp. 1– 37. Hylander WL (1984) Stress and strain in the mandibular symphysis of primates: A test of competing hypotheses. Am. J. Phys. Anthropol. 64: 1– 46. Hylander WL, and Johnson KR (submitted) 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. Anthropol. Hylander WL, Picq PG, and Johnson KR (1991) Masticatory-stress hypotheses and the supraorbital region of primates. Am. J. Phys. Anthropol. 86: 1– 36. Hylander WL, Johnson KR, and Crompton AW (1992) Muscle force recruitment and biomechanical modeling: An analysis of masseter muscle function during mastication in Macaca fascicularis. Am. J. Phys. Anthropol. 88: 365– 387. Jaslow CR (1990) Mechanical properties of cranial sutures. J. Biomech. 23: 313– 321. Preuschoft H, Demes B, Meyer M, and Bar HF (1986) The biomechanical principles realised in the upper jaw of long-snouted primates. In JG Else and PC Lee (eds.): Primate Evolution. Cambridge: Cambridge University Press, pp. 249– 264. Rosenberger AL (1986) Platyrrhines, catarrhines and the anthropoid transition. In BA Wood, L. Martin, and P Andrews (eds.): Major Topics in Primate and Human Evolution. Cambridge: Cambridge University Press, pp. 66– 88. Ross CF (1993) The functions of the postorbital septum and anthropoid origins. Ph. D. Dissertation. Duke University. Ann Arbor: UMI Dissertation Services. Ross CF (1995) Muscular and osseous anatomy of the primate anterior temporal fossa and the functions of the postorbital septem. Am. J. Phys. Anthropol. 98: 275– 306. Ross CF (1996) An adaptive explanation for the origins of the Anthropoidea (Primates). Am. J. Primatol. (in press). Citing Literature Citation StatementsbetaSmart citations by scite.ai include citation statements extracted from the full text of the citing article. The number of the statements may be higher than the number of citations provided by Wiley Online Library if one paper cites another multiple times or lower if scite has not yet processed some of the citing articles.SupportingSupporting9MentioningMentioning91ContrastingContrasting1Explore this article's citation statements on scite.aipowered by Volume101, Issue2October 1996Pages 183-215 Citation StatementsbetaSmart citations by scite.ai include citation statements extracted from the full text of the citing article. The number of the statements may be higher than the number of citations provided by Wiley Online Library if one paper cites another multiple times or lower if scite has not yet processed some of the citing articles.SupportingSupporting9MentioningMentioning91ContrastingContrasting1Explore this article's citation statements on scite.aipowered by ReferencesRelatedInformation RecommendedElectromyography of the anterior temporalis and masseter muscles of owl monkeys (Aotus trivirgatus) and the function of the postorbital septumCallum F. Ross, William L. Hylander, American Journal of Physical AnthropologyMuscular and osseous anatomy of the primate anterior temporal fossa and the functions of the postorbital septumCallum Ross, American Journal of Physical AnthropologyIn vivo bone strain and finite-element modeling of the craniofacial haft in catarrhine primatesCallum F. Ross, Michael A. Berthaume, Paul C. Dechow, Jose Iriarte-Diaz, Laura B. Porro, Brian G. Richmond, Mark Spencer, David Strait, Journal of AnatomyAt Birth, Tarsiers Lack a Postorbital Bar or SeptumTimothy D. Smith, Valerie B. Deleon, Alfred L. Rosenberger, The Anatomical Record