Xiphisternum

1887, "Skeleton", entry in The Encyclopædia Britannica, Volume 22, 9th Edition, page 113, The xiphisternum may assume various forms, but attains its maximum development in Birds, where it forms the part of the sternum posterior to the attachment of the ribs, and may consist of a median and four lateral processes, as in the Fowl. It bears the greater part of the keel.

Hence the spaces between the forks of the hyposternum and between the hypo- and xiphisternums are relatively much smaller, and the external process of the hyposternum is twice as broad as in the common Cock.

Unfixed cartilage was studied. It was isolated from the xiphisterna of female Sprague-Dawley rats (150-200 g body weight) killed by cervical fracture. The xiphisternum was removed immediately at its point of attachment to the sternal column.

Again, the distance between the umbilicus and the xiphisternum is divided into three equal parts, corresponding to 28, 32, and 36 weeks. At 36 weeks, the fundus is at the level of the xiphisternum.