M. supracoracoideus:

Deep to the ori­gins of M. pectoralis, M. supracoracoideus is attached to the sternocoracoclavicular membrane, sternum (Osteo. Annot. 153) and coracoid (Osteo. Annot. 174) resulting in the formation of discrete linear scars on the bones. The tendon lies in Sulcus supracoracoideus (Annot. 172) on the base of the Proc. procoracoideus and traverses the Canalis triosseus (Osteo. Annot. 177). Insertion is on Tuberculum dorsale of the humerus (Osteo. Annot. 182, 183). N. supracoracoideus perforates Memb. sternocoracoclavicularis (Arthr. Annot. 86, 88) or the body of the coracoid (Osteo. Annot. 172), entering the deep face of the muscle. 

Synonyms: "deep head" of M. supracoracoideus. This muscle is most probably a derivative of deltoideus minor (Annot. 80) as originally suggest by Furbringer (1902; M. deltoideus minor, pars ventralis) and substantiated by Sullivan (1962; "coracobrachialis anterior, pars ventralis") 

Variations: