A text-book on anatomy, physiology, and hygiene, for the use of schools and colleges / by John C. Draper.

  • Draper, John C. (John Christopher), 1835-1885.
Date:
[1894], ©1894
Catalogue details

Licence: Public Domain Mark

Credit: A text-book on anatomy, physiology, and hygiene, for the use of schools and colleges / by John C. Draper. Source: Wellcome Collection.

Provider: This material has been provided by the Francis A. Countway Library of Medicine, through the Medical Heritage Library. The original may be consulted at the Francis A. Countway Library of Medicine, Harvard Medical School.

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    Sections of Spinal Cord. Fi&127- middle, and posterior col- umn on each side. These inclose a certain portion of gray substance, which occupies the central re- gions of the cord. The proportion of gray mate- rial varies, as is shown in the sections in Fig. 127. Exteriorly the spinal cord is covered by a series of membranes similar to those of the brain, and of which they may be re- garded as continuations. The first membrane is composed of the blood- vessels which nourish the organ; the second affords protection; and the third is analogous to the dura mater. From the anterior and posterior columns of the cord the nerves of the body take their origin; they are all formed of white nervous substance, and convey impressions to and from the nervous centres or ganglia. The nerves of the head are derived directly from the base of the brain. Many of them are engaged.in special functions, as the optic, olfactory, and auditory, while others are distrib- uted to the muscles and skin of this region. The nerve which supplies the facial muscles is called the facial; it passes over the masseter muscle, and is the chief nerve of expression, as is demonstrated by the blank, expressionless appearance of one side of the face when the facial nerve of that side is injured. The nerves of the trunk, upper and lower extremities, are de- rived from the spinal cord. They originate in the anterior and posterior columns of the cord, and pass out through foram- ina between the vertebrae. In Fig. 128, a is the cervical por- tion, with its nerves; Z>, the dorsal portion and nerves; c, the lumbar portion and nerves; <?, the pons varolii. In the neck the first four spinal nerves unite soon after emerging from the vertebral column, and form a plexus, from What are the membranes of the cord? From what parts of the cord do the nerves take their origin ? Describe the facial nerve. Describe the cervical plexus.