Manual of general, descriptive, and pathological anatomy (Volume 3).

  • Meckel, J. F. (Johann Friedrich), 1781-1833.
Date:
1832
Catalogue details

Licence: Public Domain Mark

Credit: Manual of general, descriptive, and pathological anatomy (Volume 3). Source: Wellcome Collection.

Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)

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    The arrangement of these filaments is not always exactly the same ; we usually see a filament which goes a little obliquely upward and outward from the internal extremity of the upper edge of the lower nerve, towards the external extremity of the lower edge of the upper nerve. But sometimes this filament descends directly from the lower edge of the upper nerve, to the upper edge of the lower nerve. Between this arrangement and the preceding is one which is inter- mediate, where the most superior fasciculus of the lower nerve divides at its centre into two parts, the upper of which goes to the upper nerve in the first of the two modes mentioned above, while the lower proceeds in the direction of the fasciculus, forming the most upper part of the lower nerve. Sometimes one or two thin fasciculi are found between two pairs of nerves, and usually a little nearer the lower than the upper. When there is only one fasciculus, this divides into two ; when two, they arise immediately one at the side of the other. In both cases either the fasciculi primitively distinct, or the two branches of the single fasciculus separate from below upward immediately after arising, and form, one the most inferior fasciculus, the other the most superior of the pairs between which they are situated. Sometimes they are united together by superior and inferior fasciculi, and after- ward by a transverse filament. The first arrangement usually exists between the inferior cervical nerves, the third between the middle, the second between the superior, and the fourth between the first two, counting from above downward. The cervical nerves may be divided into twro groups ; the first com- prises the four lower pairs, the other the four upper pairs, for the first differ much from the second, as they enlarge to give origin to the nerves of the upper extremities. A. INFERIOR CERVICAL NERVES AND FIRST DORSAL NERVE, OR NERVES OF THE UPPER EXTREMITIES. § 1831. The nerves of the upper extremities (JV. brachiales, s. ex- tremitath superior!*)(I) arise from the first dorsal and the four in- ferior cervical nerves, which unite at some distance from their foramina to form the brachial plexus, so that a greater number of trunks comes afterward from the latter, each of which is formed from the fasciculi coming from several of the carrying nerves. The first dorsal nerve emerges below the first dorsal vertebra, the eighth cervical below the seventh cervical vertebra, the seventh below the sixth, the sixth below the fifth, and the fifth below the fourth. That nerve which usually occupies the centre of the group, that is the seventh cervical nerve is the largest: the first dorsal and the fifth cervical nerves are the smallest: the fifth cervical nerve is smaller than the first dorsal and the sixth and eighth dorsal are about the same size. ' (1) J. J. Klint, De ncrvis brachii, Gottiagen .1784.—P. Carrmer n*™ , pathol.tli. Amsterdam, 1760. tamper, Dcmonst. anal.