Metacarpophalangeal joint loads during bonobo locomotion: model predictions versus proxies. Issue 164 (25th March 2020)

• Record Type: Journal Article
• Authors: Synek, Alexander; Lu, Szu-Ching; Nauwelaerts, Sandra; Pahr, Dieter H.; Kivell, Tracy L.
• Is Part Of: Journal of the Royal Society interface. Volume 17:Issue 164(2020)
• Publication Date: 2020-03-25
• Subjects: musculoskeletal -- joint load -- bone -- primate -- hand -- metacarpal; Physical sciences -- Research -- Periodicals; Life sciences -- Research -- Periodicals; Interdisciplinary research -- Periodicals; 570.5
• DOI: 10.1098/rsif.2020.0032
• Languages: English
• ISSNs: 1742-5689

Abstract

Abstract : The analysis of internal trabecular and cortical bone has been an informative tool for drawing inferences about behaviour in extant and fossil primate taxa. Within the hand, metacarpal bone architecture has been shown to correlate well with primate locomotion; however, the extent of morphological differences across taxa is unexpectedly small given the variability in hand use. One explanation for this observation is that the activity-related differences in the joint loads acting on the bone are simply smaller than estimated based on commonly used proxies (i.e. external loading and joint posture), which neglect the influence of muscle forces. In this study, experimental data and a musculoskeletal finger model are used to test this hypothesis by comparing differences between climbing and knuckle-walking locomotion of captive bonobos ( Pan paniscus ) based on (i) joint load magnitude and direction predicted by the models and (ii) proxy estimations. The results showed that the activity-related differences in predicted joint loads are indeed much smaller than the proxies would suggest, with joint load magnitudes being almost identical between the two locomotor modes. Differences in joint load directions were smaller but still evident, indicating that joint load directions might be a more robust indicator of variation in hand use than joint load magnitudes. Overall, this study emphasizes the importance of including muscular forces in the interpretation of skeletal remains and promotes the use of musculoskeletal models for correct functional interpretations.