Cranio-cerebral topography / by William Anderson and G.H. Makins.

  • Anderson, William, 1842-1900.
Date:
1889
Catalogue details

Licence: Public Domain Mark

Credit: Cranio-cerebral topography / by William Anderson and G.H. Makins. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    and iu any case its position is subject to a variation of an incli in the horizontal and nearly half an inch in the vertical direction.1 The fissure of Rolando in Reid's method is found by two lines running perpendicularly upwards from a base line (which passes through the lower margin of the orbit and the external meatus) at points corresponding to the pre-auricular depression and the posterior border of the mastoid process; but, apart from the practical difficulty of erecting perpendicular lines upon a curved surface, it may be noticed that the posterior border of the mastoid process is seldom well defiued, and that the breadth of the process varies to the extent of fin., and under conditions which bear no reference to cerebral development. In Hare's system, the upper extremity of the fissure is found by a plan almost identical with that previously formulated in the last edition of Quain's Anatomy, and against which no objection can be raised, since it adjusts itself well to the varying size of the brain case. From this point the course of the sulcus is found by a line forming an angle of 67° with the sagittal line, and running downwards and forwards for a distance of 3f in. ;a but it is not very easy to measure angles upon an irregularly curved surface, and the plan is, moreover, open to objection on the score of inelasticity. The external parieto-occipital fissure is placed by most observers beneath or near the apex of the lambdoid suture; but it may be shown that this, as an external landmark, has the same defects as the bregma. Reid, however, while recognising the relation of the sulcus to the suture, prefers to discover the position of the former by prolonging the Sylvian line to the sagittal line—a procedure 1 See Table in Journal of Anatomy and Physiology, 1889, p. 465. - This angle was first estimated by Giacomini, who found it to range between 550 and 650 (U5°-I25° with a vertical line).