Note on some of the motor functions of certain cranial nerves (V, VII, IX, X, XI, XII), and of the three first cervical nerves, in the monkey (Macacus sinicus) / by Charles E. Beevor and Victor Horsley.

  • Beevor, Charles, E. (Charles Edward), 1854-1908.
Date:
[1888]
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Licence: Public Domain Mark

Credit: Note on some of the motor functions of certain cranial nerves (V, VII, IX, X, XI, XII), and of the three first cervical nerves, in the monkey (Macacus sinicus) / by Charles E. Beevor and Victor Horsley. 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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    B. Spinal Division. Our observations of the motor functions of the first three cervical nerves as regards their influence on the hyoidean muscles have been made when the nerves have been excited— (o.) In the spinal canal. (6.) In the neck immediately upon their exit from between the vertebral transverse processes. The nerves in the spinal canal were separated from the spinal cord and thoroughly dried, the efficacy of the precautions taken against spread being evidenced by the difference in result obtained by exciting each root. The effects obtained by the methods a and b were identical. 1st Gervical Nerve. Branch of Union with the Hypoglossal.—In the description of the Xllth cranial nerve, we have stated as the result of our experiments that the depressors of the hyoid bone are not thrown into action when this nerve is stimulated within the skull. On carefully dissecting out the branch from the 1st cervical nerve to the hypoglossal we find on excitation of it that there is no movement in the tongue, but the depressors of the hyoid bone are strongly contracted. Of these muscles the sterno-hyoid and sterno-thyroid were always especially affected, while the omo-hyoid was less frequently seen to contract and in some cases not at all. In the cases where this muscle contracted, in one experiment the anterior belly alone acted, and when both bellies contracted the movement in the anterior was in excess of the posterior. Ilnd Cervical. Branch to the Bescendens Noni.—On stimulating this nerve the depressors of the hyoid were thrown into action, but the muscles involved were not affected in the same way as was the case with the 1st cervical nerve. The muscle which was most constantly set in action by excitation of the Ilnd cervical nerve was the omo-hyoid and especially its posterior belly. The sterno-hyoid and stemo-thyroid also took part in depressing the hyoid bone, but it was especially remarked in half the cases, that their action was notably less powerful than that of the omo-hyoid. In one experiment in which a very weak current was employed, the omo-hyqid was alone seen to contract. We are consequently led to conclude that while the sterno-hyoid, sterno-thyroid, and omo-hyoid muscles are all set in action by excitation of the 1st and Ilnd cervical nerves, the first two muscles are relatively supplied by the former nerves, while the Ilnd nerve is especially connected with the omo-hyoid muscle. Bescendens Noni.—We prefer to mention here the results of exciting this nerve, inasmuch as we regard its motor fibres to be derived entirely from the 1st and Ilnd cervical nerves. This nerve b 2