A conjoined januceps (janiceps) fetus

Keywords: Mongolia, Richardson, bovine, conjoined, dystocia

A tongue in cheek commentary on an interesting series of images kindly lent to the author by Dr Heather Richardson (heathrichardson@hotmail.com). Dr Richardson spent time performing veterinary services and supporting veterinary education in rural Mongolia. This shows how she delivered a januceps fetus by cesearean section under rather unusual conditions.

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From top L to R and bottom L to R):  A rainstorm threatened to disrupt surgery. Therefore, despite the presence of family treasures and fine carpets, the cow with dystocia was brought into the ger (yurt) for the cesarean section. Dr Richardson commented that it was only the mother of the family who seemed concerned over the fate of their carpets (ringed). The animal was prepared for surgery with resignation on her part.

Fortunately the clouds parted and the cow was led from the ger to the spacious operating room just outside. The final image in the collage shows one of the calve's limbs being exteriorized prior to incising the uterus.

Examination of the calf showed the exact cause of dystocia; a januceps fetus with a single central ear.

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Because of the advanced age of the cow (18 years) and a prolonged struggle to deliver the calf by several people, a guarded prognosis was given for recovery.

In the formation of conjoined twins, division of the embryo into two individuals begins later than in other forms of identical twins and the process of division is never completed. The primitive streak may start to split caudally or cranially. Accordingly, twins may be conjoined either cranially or caudally. When division of the primitive streak begins cranially and does not progress beyond the occipital bones of the skull, the animal develops two incomplete heads. The condition is named for the Roman god Janus who looks both into the past and future. Therefore the name januceps is more appropriate than janiceps, the commonly accepted term.

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Conjoined twins

Keywords: conjoined, fetus, monster, bovine

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The first image shows conjoined Holstein twins. An accurate description of this case would be:  Conjoined, thoraco/omphalocopagus (joined at the thorax and umbilicus), monencephalus (one head) asymmetric (one fetus larger or distinctly different from the other) tetrapus (four feet) twins. Note: [-pus fr. Greek "pous" meaning "foot"].

The breeding date showed that this was a pregnancy approx. 8 months in duration. Yet, the larger of the two fetuses appeared to be about 6.5 months. This suggesting growth retardation of the larger conceptus.

Note: 
Conjoined twins are named according to the section of the body where they are joined. Then the suffix "pagus" (fr. Gk  pagos meaning “fixed”) is added. Parapagus is the most extreme form of conjoining where the notocords (the earlier axial support of the body) develop in close approximation, hence the use of the term  "para" (fr. the same word in Gk  meaning “beside or next to”). Less extreme forms are pygo- (tail), thoraco- , rachi- (fr. Gk  rachis meaning "spine"), omphalo- and ischio- (fr. Gk iskion meaning “hip”). Other terms are added for greater accuracy.

As described in detail elsewhere in LORI, conjoined twins are invariably of the same gender and arise from a late division of a single conceptus, when the primitive streak is already forming. Usually this means that conjoined twins share a single amnion within a single chorion. Unfortunately this interesting phenomenon is seldom recorded in veterinary medicine, probably because the surgeon is preoccupied in delivering the conjoined twins by Cesarean section.  Those who encounter conjoined twins are encouraged to examine and photograph their fetal membranes carefully and to forward those results to this author for possible inclusion in LORI.

Although one would presume that conjoined twins must always delivered by Cesarean section, this is not necessarily so; several cases of vaginal births of live, conjoined twins have been reported in humans and at least one in a grey whale. In quadrupeds like domestic animals, it may be possible for premature conjoined twins to be born per vagina but the author is unaware of natural delivery of conjoined twins at term.

This image below (38 years old!) shows a set of conjoined, thoraco/omphalocopagus twins but unlike those in the first image, these are symmetrical in nature. Read elsewhere in LORI how these twins are usually mirror images of one another, often with situs inversus of the internal organs.

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The fetuses in the image below could be described as bicephalus and bicaudate, parapagus conjoined twins.

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As mentioned in the first paragraph, parapagus is the most extreme form of conjoining where the notocords of each embryo develop in close approximation.

Another entry in LORI illustrates an even more extreme degree of fusion than those shown here: a janusceps (janisceps) fetus.