subcostal muscle

sub·cos·tal mus·cle

[TA] one of several inconstant muscles of the posterolateral thoracic wall having the same direction as the internal intercostal muscles but extending across (that is, deep to) one or more ribs. Synonym(s): musculus subcostalis [TA], subcostales [TA], musculus infracostalis

sub·cos·tal mus·cle

(sŭb-kos'tăl mŭs'ĕl) [TA] One of a number of inconstant muscles of the posterolateral thoracic wall having the same direction as the internal intercostal muscles but extending across (deep to) one or more ribs.
Synonym(s): musculus subcostalis [TA] .