Manual of practical anatomy / by D.J. Cunningham.

  • Cunningham, D. J. (Daniel John), 1850-1909.
Date:
1907
Catalogue details

Licence: Public Domain Mark

Credit: Manual of practical anatomy / by D.J. Cunningham. Source: Wellcome Collection.

    551/644 (page 527)
    These are prolonged upwards into the medulla, and in the lower part of the posterior area they stand out distinctly, and are separated from each other by a continuation upwards from the cord of the paramedian groove. In the medulla these strands receive different names. The inner one is called the funiculus gracilis, whilst the outer one is designated the fwiiculus cuneatus. Each of these strands, when it reaches the lower part of the floor of the fourth ventricle, ends in a slightly expanded prominence. The swollen extremity of the funiculus gracilis is called the clava; it is thrust aside from its neighbour of the opposite side by the opening up of the medulla to form the floor of the fourth ventricle, and the central canal of the cord opens on the surface in the angle between the two clavae. The thickened end of the cuneate funiculus receives the name of the cuneate tubercle, but it is only in the young brain that it is well marked. In sections through this region of the medulla, it is seen that the prominences produced by these two strands and their enlarged extremities are in a great measure due to the presence of two elongated nuclei or collections of grey matter which lie subjacent to them, and which gradually increase as they are traced upwards. These are termed respectively the gracile and the cuneate nuclei, and it can be easily shown that as the grey matter increases in quantity the fibres of the two corresponding strands diminish in number. Indeed, it is doubtful if any of their fibres are prolonged upwards beyond the level of the nuclei. But a third longitudinal elevation is also apparent in the lower part of the posterior area of the medulla. This is placed on the outer side of the funiculus cuneatus—between it and the posterior row of nerve roots—and it has no counter¬ part in the posterior column of the cord. It is called the funiculus of Rolando, because it is produced by the substantia gelatinosa Rolandi approaching the surface along this line. Extremely narrow below, the funiculus of Rolando widens somewhat as it is traced upwards, and finally ends in an expanded extremity called the tubercle of Rolando. The thin layer of fibres which appear on the surface of the tubercle and funiculus of Rolando and cover the substantia Rolandi in this position belong to the spinal root of the trigeminal nerve. The restiform body forms the upper part of the posterior area. It lies between the lower part of the floor of the fourth