A description of the distribution of the nerves of the human body; with elementary physiological and surgical observations: including Mr. Brookes's nomenclature of the nervous system ... / by G.D. Dermott.

  • Dermott, G. D. (George Darby), 1802-1847.
Date:
1830
Catalogue details

Licence: Public Domain Mark

Credit: A description of the distribution of the nerves of the human body; with elementary physiological and surgical observations: including Mr. Brookes's nomenclature of the nervous system ... / by G.D. Dermott. Source: Wellcome Collection.

    37/48 (page 35)
    Tile Obturator Nerve, Arises from the Second, Third, and Fourth Lumbar Nerves; emerges from behind the internal or Pelvic side of the Psoas Magnus, and then from beneath the forking of the Common Iliac Artery; it afterwards courses forwards through the side of the Pelvis, in correspondence with the Linea Ilio-Pec- tinea, in the cellular hollow beneath the Psoas Magnus Muscle and External Iliac Vessels, but excluded from the Serous Ca¬ vity of the Pelvis by the Peritoneum which lines the side of the Pelvis : this part of the Peritoneum is to be cut through inferiorly to the position of the Psoas Mag¬ nus Muscle and Iliac Vessels, then the nerve will be found, coursing forwards, suspended in cellular membrane and some fat; it emerges from the Pelvis through the Sinus Obturatorius or upper part of the Foramen Thyroideum, superiorly to the Obturator Ligament and origins of the Obturator Muscles; it afterwards de¬ scends, in diverging filaments, between the anterior surface of the Obturator Externus and posterior surface of the Pectenalis Muscle, and for the most part is given to the Pectenalis and substance of the three portions of the Triceps Adductor Femo- ris : but one brunch, longer than the rest, emerges from between the portions of the Triceps, perforates the Fascia Lata, and descends in the substance of the Fascia Superficialis, like the Ramus Cutaneus Internus, supplying the integuments of the internal and lower part of the thigh, as low as the inner side of the knee. The Ischiatic Nerve, Arises from the two Inferior Lumbar, and three Superior Sacral Nerves,—which descend obliquely in front of the Pyrifor- mis Muscle, gradually converging, so as to unite into the commencement of this nerve—as it is about to emerge from the Pelvis through the lower part of the great Ischiatic Notch, and from beneath the un¬ derside of the Pyriformis Muscle: it next descends in the space between the Tube¬ rosity of the Ischium and Trochanter Ma¬ jor; but somewhat nearer the Tuberosity than the Trochanter, being supported, in regular succession, upon the Geminus Su¬ perior, Obturatur Internus, Geminus In¬ ferior and Quadratus Femoris; and is co¬ vered by the thick substance of the lower or Ischiatic-half of the Gluteus Maximus Muscle; it subsequently descends into the upper part of the back of the thigh, becom¬ ing immediately covered by the superior part of the long head of the Biceps Flexor Cruris, before it gets from beneath the lowest part of the Gluteus Maximus: it is then continued downwards through the posterior part of the thigh, between the posterior surface of the Triceps Adductor Magnus (anteriorly), and the long head of the Biceps Flexor Cruris (posteriorly), of course ranging in its descent more in¬ wardly, and more perpendicularly, than the Shaft of the Os Femoris; till by the latter inclining inwards, it afterwards comes, somewhat distantly, behind the lower part of the Shaft of the Os Femoris, gets into the upper part of the ham behind the com¬ mencement of the Popliteal Artery and upper part of the Popliteal Vein; and as it is here immersed in the Fat of the Ham, and between the position of the Semi- Membranosus and the Biceps Muscles, bi¬ furcates into—the Posterior Tibia/, the more internal, perpendicular, and larger, —and the Peroneal Nerve, the more ex¬ ternal, and lesser one. Observe, then, that the Ischiatic Nerve is protected between two great prc*ni- nenees of bone, the Tuberosity of the Is¬ chium, and Trochanter Major of the Os Femoris, but is nearest to the least move- able of these, or the one that can afford to it most protection from external pressure in the sitting position, viz. the Tuberosity of the Ischium; and that it is also encu- shioned here on the Rotator Muscles; and thickly covered by the Gluteus Maximus: that it subsequently descends, amidst an immense mass of flesh, which constitutes the internal part of the Thigh; and ranges more internally than the position of the Os Femoris; so that it is not subjected to be compressed between the Os Femoris and the seat, in the ordinary mode of sit¬ ting. Sometimes the Ischiatic Nerve is double from its very commencement, part perfo¬ rating the Pyriformis Muscle and splitting it into two, and the other part emerging from the under side of the Pyriformis Muscle in the usual manner, and the two subsequently descending through the back of the Thigh, as a double Ischiatic Nerve, one portion becomes the Posterior Tibial, and the other the Peroneal Nerve. Sometimes the high bifurcation of the Is¬ chiatic Nerve into these two latter nerves, is in the posterior part of the Thigh, and, in fact, when the Ischiatic Nerve bifurcates in the Ham, the fasciculi constituting the Posterior Tibial Nerve and the fasciculi constituting the Peroneal can be easily separated as high up as the Great Ischia¬ tic Notch. If the dissector wishes to expose the Great Ischiatic Nerve in the highest part of the back of the Thigh, he must make an incision through the Common Integu¬ ments obliquely across the lower edge of