| OCR Text |
Show 1890.] HELODERMA SUSPECTUM. 183 each case, that pass downwards and forwards. These appear to be so many separate origins of the obliquus abdominis externus, but they do not properly belong to the series of the intercostals. They pass across to become inserted into the transverse tendinous intersections of the abdominal muscle to which we have referred. Where the external intercostals are covered by the sacro-lumbalis, the two muscles are very intimately fused together, but careful dissection is all that is required to demonstrate their individual independence. 80. Lntemal intercostals.-These are quite as well developed as the external ones, and taken in mid-region they arise and are inserted in the same manner as the more superficial set; but in the present case the fibres pass forwards and downwards, thus leaving contrary- disposed vacuities at the vertebral and free ends of the ribs. With respect to the intersterno-costal spaces, the fibres of the present set of muscles are directed almost entirely inwards and but very slightly forwards. 81. Retrahentes costarum.-A large part of the thoracic parietes and, continuous with it, nearly all of the abdominal parietes are amply lined with strong, oblique muscular fasciculi. The first series of digitations are supplied by the transversalis, and these interdigitate, seriatim, with the fasciculi of the present muscle, and thus together they constitute a thick muscular lining to the internal body-wall. The retrahentes costarum arise, upon either side, from the lateral aspect of the bodies of the vertebrae for nearly the entire length of the spine, from the post-cervical region down nearly to the sacrum, in which latter locality the quadratus lumborum fulfils their part. They pass obliquely forwards and outwards, to become inserted into the middle of the shafts of the ribs upon their internal aspects, inter-digitating, as I have already said, with the fasciculi of the transversalis. Muscles of the Hip-Girdle and of the Pelvic Limb. 82. Iliacus.-A very interesting and broad sheet of muscle that arises from within the pelvis, being attached, for the most part, to the ventral and dorso-ventral surface of the pubis, as well as to the median fibrous band that stands as a raphe between it and the fellow of the opposite side. It may extend also slightly upon the ischium. The fibres converging and passing over the pelvic brim, are inserted into the anterior surface of the proximal extremity of the shaft of the femur of the corresponding side, as well as into its trochanter minor, and into that tendinous band seen to be crossing obliquely the caput femoris, and into the fascia overlying the femoro-pelvic articulation. Mivart, in his work upon the myology of the Iguana, considered the present muscle to represent thepsoas and the iliacus combined, and in describing it divides the same into some four or five parts. In Heloderma I find these several parts more or less distinctly indi- |
