Report on the progress of human anatomy and physiology in the year 1843-4 / [Sir James Paget].
- James Paget
- Date:
- 1845
Licence: Public Domain Mark
Credit: Report on the progress of human anatomy and physiology in the year 1843-4 / [Sir James Paget]. Source: Wellcome Collection.
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![muscles of the pharynx, but M. Bernard supposes that as the larynx has, in his opinion, both a vocal and a respiratory motor nerve, so also the pharynx has some branches from the pneumo-gastric for the simple movements of deglutition, anti some from the accessory nerves for those movements by which in deglutition the glottis is closed. The conclusion is improbable, and the experiments show that there were difficulties in deglutition, independent of the non-closure of the glottis.] 8th. By the division of the external branch alone of the accessory nerves no effect was produced on the voice or deglutition, but the animal was put into the condition of a short-breathed person; its cries became short and interrupted; it was quickly blown when it made violent muscular efforts, and when the respi¬ ration was hurried ; there was sometimes imperfection in the movements of the fore limbs. Of these effects the shortness of the cry is ascribed, by M. Bernard, to the loss of power in the sterno-mastoid and trapezius muscles, by the contraction of which the descent of the sternum and upper ribs is for a time hindered in healthy vocal expiration. In like manner, the paralysis of these muscles (and of others dependent for fixed points on parts to which they are attached) hinders the fixing of the walls of the chest which is necessary for efforts. 9th. But the paralysis is not complete. M. Bernard relates an experiment in which, after division of the external branches of the right accessory nerve, both sterno-mastoid muscles con¬ tracted with equal force in forcible respiration, but the left alone contracted when the animal cried out.* Hein’s experiments relate almost exclusively to the nerves of the palate. They consisted in irritating the roots of the several nerves within the skull of an animal just beheaded, after removing the brain, so that there was very little danger of a part of one root being mistaken for another. His conclusions regarding the motor fibres of the glosso-pharyngeal are already mentioned. As to those of the pneumo-gastric and accessory nerves, they tend to show that these nerves send branches, through the medium of the pharyngeal branches of the glosso-pharyngeal, to the levator palati, azygos uvulae, and palato pharyngeus. These branches, near their distribution, are almost too minute for dissection; their existence was proved chiefly by the results of the experiments, which at last guided to the detection of them running just under the mucous membrane to the muscles. But he does not pretend to distinguish between the effects (on the muscles of the palate,) of irritating the pneumo-gastric and the accessory ; he believes that their fibres are from the roots mingled, and that they both influence all the muscles supplied from the branches of either. [From all these facts the first conclusion must be, I think, that the precise func¬ tions of these nerves are not yet determined. The most probable account may be— 1. That the glosso-pharyngeal is chiefly the nerve of the sense of taste, and, in a less degree, a nerve of common sensation. 2. That the glosso-pharyngeal is, according to the experiments of Muller and Hein, the motor nerve of the stylo-pharyngeus, and probably, also, of the palato¬ glossus. The branches which it gives to the digastrieus, stylo-hyoideus, and con¬ strictors of the pharynx, appear, according to the experiments, to be sensitive, or else derived from the facial and accessory nerves, with which it has previously united. 3. The pneumogastrie is, from its origin, composed of both sensitive and motor fibres. But it cannot be decided at present, whether it alone supplies any par¬ ticular muscles; or whether, in all its muscular branches, and especially in those given off* above the oesophageal, there are filaments from the accessory as well as from its own roots. 4. The accessory nerve contains in all its lower roots motor fibres alone ; in its upper roots it is not improbable that there are some sensitive fibres also. It is * Hence he supposes that these muscles, and the trapezii, like those of the larynx, have a vocal and a common respiratory function, and a separate nerve for each; so that while they act as common in¬ spiratory muscles under the influence of the cervical nerves, they arrest the respiratory acts when they are under the influence of the accessory nerves. He would, therefore, call these nerves the antago¬ nist rather than the accessory nerves of respiration.](https://iiif.wellcomecollection.org/image/b30385611_0055.jp2/full/800%2C/0/default.jpg)
