pyramidalis

noun

py·​ram·​i·​da·​lis pə-ˌram-ə-ˈdā-ləs 

plural pyramidales -(ˌ)lēz  or pyramidalises

: a small triangular muscle of the lower front part of the abdomen that is situated in front of and in the same sheath with the rectus and functions to tense the linea alba