Talk:Paper - A double umbilicus (1915)

From Embryology

A double umbilicus

T. B. REEVES Anatomical Laboratory, University of Virginia


After reviewing a considerable literature on anomalies and being imable to find such a case reported, it is deemed worth while to put this specimen on record.

The anomaly here described was found in a colored man, estimated to be about 55 years of age, during our regular class work in anatomy. The surface anatomy of the abdominal wall was normal, except for the presence of a small subcutaneous tumor a short distance above the lunbilicus which was supposed to be a Upoma. On removal of the skin a sharply circumscribed knob of fibrous tissue was found in the subcutaneous tissue 4 cm. above the mnbiUcal fovea and 0.5 cm. to the right of the mid Une (fig. 1). This knob of tissue was 2.5 cm. in diameter and 0.7 cm. thick. It was rather soft in consistency and was definitely surrounded by a thin capsule of connective tissue, except posteriorly where it was continuous with the round ligament of the liver. Superficially it was continuous with the subcutaneous tissue though it separated easily, while its deep surface much more dense merged imperceptibly into the obliterated umbilical vein. The latter entered the abdominal cavity through a foramen in the aponeurotic wall of the abdomen. The foramen had a smooth margin unconnected with the wall of the vein; so that the vein could glide easily backwards and forwards through the foramen. On section the knob mentioned above was somewhat loose in texture and strands of tissue nmning in various directions gave it a lobulated appearance.

On opening the abdomen the urachus and obliterated hypogastric arteries were found extending up on the abdominal wall throwing up their usual folds of peritoneum. The urachus which was apparently single became very small in the region of the umbilicus and seemed to terminate in the lower (true) mnbiUcus. The obliterated hypogastric arteries were of about the normal size and in the mnbiUcal region two or three fibrous cords were given off on each side, which terminated in the lower (true) umbilicus while the remainder passed on to the upper (false) umbihcus (fig. 2).

Fig. 1 F.K., Fibrous Knob; R,S., Rectus Sheath; U.F., Umbilical Fovea; iS., Skin.

The obliterated umbiUcal vein was double, one being attached to the lower umbiUcus while the other was somewhat larger and very firmly attached at the upper umbilicus to the fibrous knob previously described as being outside the rectus sheath in the subcutaneous tissue (fig. 2) . After a very short course, however, the two fused forming the round ligament of the hver which extended upward enclosed in the lower margin of the falciform hgament.

Microscopic examination of the fibrous knob mentioned above revealed it to consist of rather dense connective tissue and a good deal of fat.

Regardless of the apparent weakness of the abdominal wall, it should be noted that there was little possibility of an umbilical hernia. In fact the arrangement was so unique that such could not occur (fig. 3), for the reason that whenever the intraabdominal pressure was increased, the pull of the round ligament on the fibrous knob was in the same proportion, thus ensuring the weak area to be closed at all times.

Fig. 2 F.L., Falciform Ligament; L.T., Ligamentum Teres; U.U,^ Upper Umbilicus; L.t/., Lower Umbilicus; 0./f ., Obliterated Hypogastric; C/., Urachus.

Fig. 3 L,T., Ligamentum Teres; F./^., Fibrous Knob; R.S.^ Rectus Sheath; T.C/., True Umbilicus; S., Skin.

To sum up: There entered the abdomen through the upper navel one umbilical vein and the terminal branches of both hypogastric arteries while the urachus, the other umbilical vein and branches of the hypogastric passed through the lower umbilicus.

When one recalls the changes takmg place on the ventral wall of the embryo in very early embryonic life, it seems reasonable to suppose that such a condition as here described would happen much more frequently than it apparently does. An abnormal growth of tissue across the mid line between the allantois and yolk sac, dividing the single foramen into two, would seem to be the most probable cause of the condition. The anomalous fibrous cords on the posterior wall according to this explanation represent anastomoses between the vitelline and umbiUcal vessels. It is possible that the fibrous knob on the end of the umbiUcal vein represents the remnants of the umbilical vesicle. The fact, however, that its structure is directly continuous with the obUterated vein makes it seem more likely that it was merely a locaUzed hypertrophy on the end of that vessel.