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Sexual Dimorphism and the Scaling of Intrinsic Thumb Muscle Physiological Cross‐Sectional Area and Trapeziometacarpal Joint Size
Author(s) -
Kashyap Ritesh,
Orr Caley
Publication year - 2019
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2019.33.1_supplement.616.30
Subject(s) - thumb , sexual dimorphism , joint (building) , osteoarthritis , cadaveric spasm , medicine , wrist , anatomy , structural engineering , pathology , alternative medicine , engineering
The thumb is a common site for the development of osteoarthritis (OA) and studies show that there is greater prevalence of OA of the thumb joint in women. While a number of explanations have been proposed, the mechanism underlying the sex distribution of OA remains unknown. One possible contributing factor is the generally smaller size of females. Given constraints on size at the trapeziometacarpal (TMC) joint (which is locked into the wrist complex), it is possible that stress (force per unit area) tends to be greater in smaller individuals. This may lead to quicker progression of the degenerative processes characteristic of OA. However, increased stress requires a similar muscle force acting on a relatively smaller joint, and this might be the case if females must maintain a minimum level of grip strength for day‐to‐day function. Thus, we hypothesize that females have higher TMC joint stress due to scaling constraints (small joint surfaces with relatively large muscles). To test this hypothesis, cadaveric samples from the University of Colorado School of Medicine were used to measure the physiological cross‐sectional area (PCSA) of intrinsic thumb muscles and scaled against the surface area of the TMC joint. Preliminary data suggest that females tend to have a higher total intrinsic thumb muscle PCSA compared to males, but a clear scaling pattern between the variables was not evident. This suggests a more complicated relationship between joint size and thumb muscle force potential. However, further data and analysis might reveal muscle and joint scaling patterns that could provide an explanatory mechanism for the higher prevalence of OA in women than men. In turn, this could provide a background for future research into methods of preventing OA. Support or Funding Information Modern Human Anatomy Program This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .