OCR Text |
Show 338 MR. J. B. SUTTON ON THE INTERVERTEBRAL [June 29, in a paper published in the ' Journal of Anatomy and Physiology ' January of the present year. The object of this paper was to draw attention to the circumstance that if a section be carried vertically through the long axis of the second vertebra in an adult there will be found in the majority of cases a small strip of cartilage occupying the position indicated in the drawing (fig. 1). Prof. Cunningham states that whilst engaged in an investigation into the curves of the spinal column in M a n and the Apes he made mesial sections of a large number of frozen human spines. His Fig. 1. A vertical section through the body of the axis to show the lenticular-shaped piece of cartilage, c. attention was attracted to a small lenticular-shaped plate of cartilage, which seemed in almost every case to be interposed between the os odontoideum and the body of the axis vertebra; on all sides it was surrounded by bone, so that it could only be brought into view by means of sections. The observations were made on eighteen axis vertebrae, but three were eliminated on account of difficulty in ascertaining the age of the subjects. The fifteen remaining specimens were divided into three groups according to their age. The first group comprised six axes, two from females and four from males, varying in age from twenty-four to fifty. In all the cartilage was present, measuring 4 m m . in length and 2 m m . in thickness. The second set comprised three specimens from females, varying in age from fifty to sixty years. The cartilage was present, and of the same dimensions as in the younger bones in the previous set. The third group consisted of six examples, two males and four females, the limits of age being from sixty to seventy. In four of the axes the lenticular disk was present, and measured in length 3 m m . and in width 1| m m . In the two oldest examples the disk was absent. The cartilage in the youngest specimen, a girl aged twenty-four years, was found to be of the hyaline type, with evidence in some of the sections of a sluggish ossific process around the margin ; but remains of the notochord could not be detected. |