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

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.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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$TuE Obturator Nerve, Arises from the Second, Third, and FouvUi Lumbar Nerves; emerges from behmd the internal or Pelvic side of the Psoas Magnus, and Uien from beneath the forking of the Common Ihac 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 iVessels, 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, isuspended in cellular membrane and some fat; it emerges from the Pelvis through the Sinus Obturatorius or upper part of |lhe Foramen Thyroideum, superiorly to '.he (Obturator Ligament and origins of I'Jie Obturator Muscles; it afterwards de- jjcends, in diverging filaments, between the nterior surface of the Obturator Externus .nd posterior surface of the Pectenalis iVIuscle, and for the most part is given to he Pectenalis and substance of the three jortions of the Triceps Adductor Femo- :is: but one branch, longer than the rest, imerges from between the portions of the Triceps, perforates the Fascia Lata, and lescends in the substance of the Fascia Juperficialis, like the Ramus Cutaneus nternus, supplying the integuments of the nternal and lower part of the thigh, as low s the inner side of the knee. TuE IscuiATic Nerve, Ibises from the two Inferior Lumbar, Ind three Superior Sacral Nerves,—which Vescend obliquely in front of the Pyrifor- lais Muscle, gradually converging, so as I) unite into the commencement of this lerve—as it is about to emerge from the yelvis through the lower part of the great \schiatk Notch, and from beneath the un- Krside of the Fyriformis Muscle: it next ascends in the space between the Tube- ksity of the Ischium and Trochanter Ma- Yv; but somewhat nearer the Tuberosity lan the Troclvantcr, being supported, in gular succession, upon the Geminus Su Ijrior, Obturatur Internus, Geminus In- |rior and Quadratus Femoris; and is co •red by the thick substance of the lower Ischiatic-half of the Gluteus Maximus [luscle; it subsequently descends into the ijper part of the back of tiie thigh, becom- Ig immediately covered by the superior irt of the long head of the Biceps Flexor ',e''«ruris, before it gels from hencalli tiic ij'iBwest part of the Gluteus Maximus: it is then continued dowmoards 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 comesj; somewhat distantly, behind the lower part of the Shaft of the Os Femoris, gets into the tipper part of the ham behind the co)7i-r mencement of the Popliteal Artery and upper part of the Popliteal Vein; and as it is here immersed in the Fat of tlie.Hum<, and between the position of the Semi-- Membranosus and the Biceps Muscles, bi- furcates into—the Posterior Tibial, the more internal, perpendicular, and largeF, —and the Peroneal Nerve, the more ex- ternal, and lesser one. . 'i I- Observe, then, that the Ischiatic Nerve is protected between two great prwuii- nences 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, yiz. 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 Pyriforniis Muscle and splitting- it into two, and the other part emerging from the under side of the Fyriformis Muscle in the usual manner, and the two subsequently descending through the back of the Thigli, as a double Ischiatic Nerve, one portion becomes the Posterior Tibial, and the oliier 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, tlie fasciculi constituting the Posterior Tibial Nerve and the fasciculi constituting the I'eroneal can be easily separated as high up as the Great Ischia- tic Notch. 1 If die dissector wishes to expose tlie Great Ischiatic Nerve in the highest part of the back of the Thigh, he must riiake an incision through the Common IntCga- ments obliquely across the lower cdac of$