Meeting Abstract

P2.51  Friday, Jan. 4  Effects of Parity on Pelvic Shape Dimorphism in Mus DONOVAN, Edward R*; SCHUTZ, Heidi; HAYES, Jack P; Univ, Nevada, Reno; Univ. Colorado, Boulder; Univ. Nevada, Reno edonovan@unr.edu

Studies examining pelvic sexual dimorphism and the effects of parturition on pelvic morphology generally focus on two things: 1) predicting whether a female has given birth and 2) distinguishing males from females. In particular, these studies focus on potential scarring of the cartilaginous joints caused by parturition and identification of characters that differ between males and females. Despite this understanding of pelvic morphology, pelvic shape deformation in response to parity and how such changes affect the degree of pelvic dimorphism have not been examined. In pregnant or lactating females, bone mass and density change due to mobilization of calcium for neonatal skeletal development and milk production. Concurrently, increased mass and size of pregnant females may affect weight bearing by the pelvis and cause associated gait changes. Hence, during pregnancy and lactation the female skeleton must balance the use of mineral resources and maintenance of biomechanical function. The potential tradeoffs induced by this important life-history event may significantly affect pelvic structure. We test the hypothesis that pelvic shape differs significantly between parous and nulliparous females. Specifically we test whether pelvic shape dimorphism is greater between parous females and males than between nulliparous females and males. To test this hypothesis we sample pelves from skeletally mature parous and nulliparous females as well as males. We use landmark-based geometric morphometric techniques to quantify pelvic shape in each of these groups and compare the magnitude of morphological differences between them. We then address the biomechanical implications associated with these structural changes and discuss how locomotion in females might be affected by parity. Supported by NSF IOS 0344994