There is no doubt that in infancy and early childhood there was no acquired position, and, therefore, neither “front” nor “back” to the band. And later, when, as we have reason to believe, the position of selection was gradually adopted, the terms “front” and “back” were reversible—the “front” meaning that which corresponded to the surface of least thoracic approximation. Thus when the adult condition was fixed, and the “front” answered to the widely separated right side of Eng’s chest and left side of Chang’s chest, the “back” was in relation with the closely approximated left side of Eng’s chest and right side of Chang’s.
To avoid awkward repetition of phrases expressing the facts of the last sentence, the following characters will be employed in describing the “lateral” surfaces of the band.
E. R., C. L. (Eng’s right, Chang’s left) will designate the “anterior” surface of the acquired position. C. R., E. L. (Chang’s right, Eng’s left) will designate the “posterior” surface. Since the right side of Chang’s half of the band merged into the left on Eng’s half, while the right side of Eng’s half, after it passed the middle line, became the left half of Chang’s, we propose using the characters E. L., E. R., and C. R., C. L., which will be understood as signifying left side Eng, right side Eng, etc.
Using the above signs we found that the surface E. R., C. L. was inclined decidedly downward and backward when seen in the congenital position, and was 3 in. high and 2-1/2 in. wide. At E. R., the border answering to the ensiform cartilage was marked by a large rounded tubercle; it was much more pronounced than on the corresponding border of C. L. When seen in the acquired position, E. R., C. L. became “anterior,” when, at its upper margin, C. L. was longer than E. R. by one-half inch. The tubercle on E. R., already noticed, was much more prominent than C. L. The contour of the inferior margin was also different, being more uneven. C. L. was not only longer, but was more obliquely placed downward and outward to the centre of the band than E. R. (See cast in the Mütter Museum.)
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.