Report of an autopsy on the bodies of Chang and Eng Bunker, commonly known as the Siamese twins

by Harrison Allen

III. Coverings of the Band.

In front (E. R., C. L.) the superficies could not be well examined owing to the restrictions imposed by the families. A view of it from within can be obtained in Figs. [8], [9], q. v. Permission having been granted to make an incision “behind,” at C. R., E. L., a modified letter-H incision was employed, thus—

Turning the skin flaps here indicated upwards and downwards, and the lateral triangles outwards, there was found beneath, a layer of superficial fatty connective tissue, with a well-defined layer of fat on either side, but with an intermediate portion which was free from fat, and of greater thickness.

The skin could with some little trouble be raised over the dorsal or upper surface, showing here entire absence of fat. A very delicate artery was found running across the middle, from Eng to Chang.

The lower portion of the surface C. R., E. L. was inseparably connected with the umbilicus. It was also united to the superficial fascia on C. L., about 1-¹/₂ inches from the umbilicus; this did not have any connection with the deeper parts. The process of fibrous tissue which had been felt through the skin was conspicuous on this surface of the band, and was covered by a delicate non-fatty layer of connective tissue. Towards the lower part of the surface were seen several diverging lines of fibrous tissue, which were lost within the integument about the umbilical scar, at the lower surface of the band. They were exceedingly thin, and at one point lay directly over the posterior and inferior wall of the umbilical pouch of Chang.

Fig. 3. The surface, C. R., E. L., exposed by removal of skin and superficial fascia to display the tendons of the external oblique muscles and adjacent parts. A. The superficial fascia—lost over the position of Chang’s umbilical pouch. B, C. Supplemental layers of fibrous tissue of Eng not seen in Chang; B is a continuation toward Eng of aponeurotic fibres having a source from the linea alba of Chang; C is independent of the former, and is continuous with the deep pectoral fascia. D. The interlacing of fibres on tendon of external oblique muscle of Chang. E. The linea alba of Chang, beginning at C. R. F. Its continuation to E. L., and insertion upon the ensiform cartilage.

Turning down the superficial layer, the aponeurosis of the external oblique muscle was exposed (Fig. [3]). A marked contrast was exhibited in the two sides of the band. In Chang the parts were normal so far as they were exposed—the characteristic apertures for the escape of small vessels being abundant and conspicuous. In turning down the superficial fascia in Eng (Fig. [3], A), it was found to be continuous at its lower portion with an aponeurotic layer (Fig. [3], B), which extended toward the median line, where it was continuous with the linea alba of Chang. In addition to this, a second layer (Fig. [3], C), analogous in position to a deep layer of the superficial fascia, which was entirely independent of Chang, extended over nearly the whole of Eng’s division, and was particularly well defined over the fibres of origin of the external oblique muscle. This was continuous with the deep layer of the superficial fascia which passed over the entire side of Eng’s thorax.

Toward the middle of the band this layer gradually lost its distinctive features, and was firmly incorporated with the tendon of the external oblique muscle. A number of fibres corresponding to it extended in inseparable intimacy with this tendon. These were gradually lost as they approached the linea alba of Chang, and the parts being in position these fibres were at their lower portion covered in by the aponeurotic extension of the linea alba already mentioned.

On Chang’s side, as we have seen, the parts comparable to these accessory layers were absent. There was no line of demarcation between the tendon of the oblique and the aponeurotic attachment of the pectoralis. The tendon of the external oblique presented a different appearance from the normal one in a more extensive interlacing of fibres of the linea alba with the tendon.

The part termed above the linea alba of Chang (Fig. [3], E), has already been indicated through skin and superficial fascia. As can be seen, this band of fibres, having its origin from the middle line of the abdomen of Chang, was found to be a direct continuation of the linea alba. It was remarkable in not being inserted into the ensiform process of Chang, but into that of Eng, and in giving off the aponeurotic outshoot B, already noticed, as well as in having a diffused point of insertion into Eng’s tissue as in the ensiform cartilage (F). In a word, the linea alba approaches the surface C. R., E. L. from C. R. below, and is inserted into E. L. above.