Splenic anatomy is more relevant then you might know. “Why does my side hurt when i run?” It seems that the spleen can contract to enlarge the available blood supply during childhood [1].
Ref 1 [ Lodin-Sundström, Angelica; Schagatay, Erika (June 2010). “Spleen contraction during 20 min normobaric hypoxia and 2 min apnea in humans”. Aviation, Space, and Environmental Medicine. 8 (6): 545–49. doi:10.3357/ASEM.2682.2010. PMID20540444.]