There was a junction between the manubrium of each.
"Anomalies and Curiosities of Medicine" by George M. Gould
The sternum consists of segments, the sternebrae (st.); anteriorly there is a bony manubrium (mb.
"Text Book of Biology, Part 1: Vertebrata" by H. G. Wells
The sternum is much wider than long, and no specimens give evidence of a manubrium.
"Dragons of the Air" by H. G. Seeley
In the Pig the precise reverse is seen, the manubrium being narrower than the rest of the sternal bonelets.
"The Cambridge Natural History, Vol X., Mammalia" by Frank Evers Beddard
The stomach may be drawn out into the manubrium, forming a proboscis ("Magenstiel") of considerable length.
"Encyclopaedia Britannica, 11th Edition, Volume 14, Slice 2" by Various