! B. ANOMALIES DUE TO DISEASE OF THE PELVIC BONES. C. ANOMALIES IN THE CONJUNCTION OF THE PELVIC BONES. (a) Too firm union (synostosis). Apt to be found in elderly primiparæ, particularly at the sacro-coccygeal joint. (1) Of symphysis. (2) Of one or both sacro-iliac synchondroses. (b) Too loose a union or separation of the joints. (1) Relaxation and rupture. (2) Luxation of the coccyx. D. ANOMALIES DUE TO DISEASE OF THE SUPERIMPOSED (2) Luxation of One Femur (3) Luxation of Both Femora. (4) Unilateral or Bilateral Club-foot. (5) Absence or Bowing of One or Both Lower Extremities. The simple flat pelvis is the most frequent variety in this country. The contraction is at the conjugate diameter of the inlet. The narrow, funnel-shaped pelvis occurs in those whose bony development has ceased or in those who never have walked. In the latter the three developmental factors which produce the normal adult pelvis have been inoperative. In the split pelvis This the deformity is at the symphysis and is associated with extrophy of the bladder. The characteristics of the rachitic pelvis are: excessive rotation of the sacrum on its transverse axis, resulting in an abnormal projection of the promontory and increased sacral curve; decrease in depth of pelvic cavity; the curve of the iliac bones is exagerated and their anterior spines more widely separated. This form and the generally contracted are next in frequency to the simple flat in this country. The greatest contraction is in the conjugate at the brim. Osteomalacia is very rare in this country. It gives rise to the "beak-like" projection at the symphysis. The new growths causing deformity may be any of the tumors that can develop from bone. Small nodules on the promontory or spines of ischia may lacerate the soft parts or puncture the child's head. When the pelvic joints are too firmly united the physiological loosening which happens during the latter months of pregnancy cannot occur. Anchylosis of the sacro-coccygeal joint is not infrequent in old primiparæ. Spondylolisthesis is a slipping down of the last lumbar vertebra into the pelvic cavity. The finger in the vagina can often feel the bifurcation of the aorta. In kyphosis the weight of the body is from above downward and from before backward. The sacrum is thus pushed backward, is narrowed, tuberosities of the ischia approach each other, increasing the diameters of the inlet but diminishing the outlet, particularly in its transverse diameter. The distortion resulting from scoliosis is a lateral displacement of the promontory giving rise to an oblique deformity. Lordosis is the compensatory curve associated with kyphosis. Pelvimetry. TABLE OF MEASUREMENTS. Pelvis. Iliac spines, 26 cm. Iliac crests, 29 cm. External conjug., 20 cm. Internal conjug., diagonal, 123 cm. |