Surgical Anatomy Part 33

O. Anterior crural nerve.

P. The hernia within the crural ca.n.a.l.

Q Q. Femoral sheath.

R. Gimbernat's ligament.

FIGURE 2.

The other letters refer to the same parts as seen in Fig. 1.

G. Glands in the neighbourhood of Poupart's ligament.

H. Glands in the neighbourhood of the saphenous opening.

I. The sartorius muscle seen through its fascia.

[Ill.u.s.tration: Abdomen, showing bone, blood vessels and other internal organs.]

PLATE 44.--FIGURE 1, 2.

COMMENTARY ON PLATES 45 & 46.

DEMONSTRATIONS OF THE ORIGIN AND PROGRESS OF FEMORAL HERNIA-- ITS DIAGNOSIS, THE TAXIS, AND THE OPERATION.

PLATE 45, Fig. 1.--The point, 3, from which an external inguinal hernia first progresses, and the part, 5, within which the femoral hernia begins to be formed, are very close to each other. The inguinal hernia, 3, arising above, 5, the crural arch, descends the ca.n.a.l, 3, 3, under cover of the aponeurosis of the external oblique muscle, obliquely downwards and inwards till it gains the external abdominal ring formed in the aponeurosis, and thence descends to the s.c.r.o.t.u.m. The femoral hernia, commencing on a level with, 5, the femoral arch, descends the femoral ca.n.a.l, under cover of the fascia lata, and appears on the upper and forepart of the thigh at the saphenous opening, 6, 7, formed in the fascia lata; and thence, instead of descending to the s.c.r.o.t.u.m, like the inguinal hernia, turns, on the contrary, up over the falciform process, 6, till its fundus rests near, 5, the very place beneath which it originated. Such are the peculiarities in the courses of these two hernial; and they are readily accounted for by the anatomical relations of the parts concerned.

[Ill.u.s.tration: Abdomen, showing bone, blood vessels and other internal organs.]

PLATE 45.--FIGURE 1

PLATE 45, Fig. 2.--There exists a very evident a.n.a.logy between the ca.n.a.ls through which both herniae pa.s.s. The infundibuliform fascia, 3, 3, of the spermatic vessels is like the infundibuliform sheath, 9, 9, of the femoral vessels. Both sheaths are productions of the general fibrous membrane of the abdomen. They originate from nearly the same locality.

The ring of the femoral ca.n.a.l, 12, is situated immediately below, but to the inner side of the internal inguinal ring, 3. The epigastric artery, 1, marks the width of the interval which separates the two rings.

Poupart's ligament, 5, being the line of union between the oblique aponeurosis of the abdominal muscle and the fascia lata, merely overarches the femoral sheath, and does not separate it absolutely from the spermatic sheath.

[Ill.u.s.tration: Abdomen, showing bone, blood vessels and other internal organs.]

PLATE 45.--FIGURE 2

PLATE 45, Fig. 3.--The peritonaeum, 2, 3, closes the femoral ca.n.a.l, 12, at the femoral ring, in the same way as this membrane closes the inguinal ca.n.a.l at the internal inguinal ring, 3, Fig. 2, Plate 45. The epigastric artery always holds an intermediate position between both rings. The spermatic vessels in the inguinal tube, 3, 3, Fig. 2, Plate 45, are represented by the round ligament in the female inguinal ca.n.a.l, Fig. 3, Plate 45. When the bowel is about to protrude at either of the rings, it first dilates the peritonaeum, which covers these openings.

[Ill.u.s.tration: Abdomen, showing bone, blood vessels and other internal organs.]

PLATE 45.--FIGURE 3

PLATE 45, Fig. 4.--The place of election for the formation of any hernia is that which is structurally the weakest. As the s.p.a.ce which the femoral arch spans external to the vessels is fully occupied by the psoas and iliacus muscles, and, moreover, as the abdominal fibrous membrane and its prolongation, the femoral sheath, closely embrace the vessels on their outer anterior and posterior sides, whilst on their inner side the membrane and sheath are removed at a considerable interval from the vessels, it is through this interval (the ca.n.a.l) that the hernia may more readily pa.s.s. The peritonaeum, 2, and crural septum, 13, form at this place the only barrier against the protrusion of the bowel into the ca.n.a.l.

[Ill.u.s.tration: Abdomen, showing bone, blood vessels and other internal organs.]

PLATE 45.--FIGURE 4

PLATE 45, Fig. 5.--The hernia cannot freely enter the compartment, 10, occupied by the artery, neither can it enter the place 11, occupied as it is by the vein. It cannot readily pa.s.s through the inguinal wall at a point internal to, 9, the crural sheath, for here it is opposed by, 4, the conjoined tendon, and by, 8, Gimbernat's ligament. Neither will the hernia force a way at a point external to the femoral vessels in preference to that of the crural ca.n.a.l, which is already prepared to admit it. [Footnote] The bowel, therefore, enters the femoral ca.n.a.l, 9, and herein it lies covered by its peritonaeal sac, derived from that part of the membrane which once masked the crural ring. The septum crurale itself, having been dilated before the sac, of course invests it also. The femoral ca.n.a.l forms now the third covering of the bowel. If in this stage of the hernia it should suffer constriction, Gimbernat's ligament, 8, is the cause of it. An incipient femoral hernia of the size of 2, 12, cannot, in the undissected state of the parts, be detected by manual operation; for, being bound down by the dense fibrous structures which gird the ca.n.a.l, it forms no apparent tumour in the groin.

[Footnote: The mode in which the femoral sheath, continued from the abdominal membrane, becomes simply applied to the sides of the vessels, renders it of course not impossible for a hernia to protrude into the sheath at any point of its abdominal entrance. Mr. Stanley and M.

Cloquet have observed a femoral hernia external to the vessels.

Hesselbach has also met with this variety. A hernia of this nature has come under my own observation. Cloquet has seen the hernia descend the sheath once in front of the vessels, and once behind them. These varieties, however, must be very rare. The external form has never been met with by Hey, Cooper, or Scarpa; whilst no less than six instances of it have come under the notice of Mr. Macilwain, (on Hernia, p. 293.)]

[Ill.u.s.tration: Abdomen, showing bone, blood vessels and other internal organs.]

PLATE 45.--FIGURE 5

PLATE 45, Fig. 6.--The hernia, 2, 12, increasing gradually in size, becomes tightly impacted in the crural ca.n.a.l, and being unable to dilate this tube uniformly to a size corresponding with its own volume, it at length bends towards the saphenous opening, 6, 7, this being the more easy point of egress. Still, the neck of the sac, 2, remains constricted at the ring, whilst the part which occupies the ca.n.a.l is also very much narrowed. The fundus of the sac, 9*, 12, alone expands, as being free of the ca.n.a.l; and covering this part of the hernia may be seen the fascia propria, 9*. This fascia is a production of the inner wall of the ca.n.a.l; and if we trace its sides, we shall find its lower part to be continuous with the femoral sheath, whilst its upper part is still continuous with the fascia transversalis. When the hernia ruptures the saphenous side of the ca.n.a.l, the fascia propria is, of course, absent.

[Ill.u.s.tration: Abdomen, showing bone, blood vessels and other internal organs.]

PLATE 45.--FIGURE 6

PLATE 46, Fig. 1.--The anatomical circ.u.mstances which serve for the diagnosis of a femoral from an inguinal hernia may be best explained by viewing in contrast the respective positions a.s.sumed by both complaints.

The direct hernia, 13, traverses the inguinal wall from behind, at a situation corresponding with the external ring; and from this latter point it descends the s.c.r.o.t.u.m. An oblique external inguinal hernia enters the internal ring, 3, which exists further apart from the general median line, and, in order to gain the external ring, has to take an oblique course from without inwards through the inguinal ca.n.a.l. A femoral hernia enters the crural ring, 2, immediately below, but on the inner side of, the internal inguinal ring, and descends the femoral ca.n.a.l, 12, vertically to where it emerges through, 6, 7, the saphenous opening. The direct inguinal hernia, 13, owing to its form and position, can scarcely ever be mistaken for a femoral hernia. But in consequence of the close relationship between the internal inguinal ring, 3, and the femoral ring, 2, through which their respective herniae pa.s.s, some difficulty in distinguishing between these complaints may occur. An incipient femoral hernia, occupying the crural ca.n.a.l between the points, 2, 12, presents no apparent tumour in the undissected state of the parts; and a bubonocele, or incipient inguinal hernia, occupying the inguinal ca.n.a.l, 3, 3, where it is braced down by the external oblique aponeurosis, will thereby be also obscured in some degree. But, in most instances, the bubonocele distends the inguinal ca.n.a.l somewhat; and the impulse which on coughing is felt at a place above the femoral arch, will serve to indicate, by negative evidence, that it is not a femoral hernia.

[Ill.u.s.tration: Abdomen, showing bone, blood vessels and other internal organs.]

PLATE 46.--FIGURE 1

PLATE 46, Fig. 2.--When the inguinal and femoral herniae are fully produced, they best explain their distinctive nature. The inguinal hernia, 13, descends the s.c.r.o.t.u.m, whilst the femoral hernia, 9*, turns over the falciform process, 6, and rests upon the fascia lata and femoral arch. Though in this position the fundus of a femoral hernia lies in the neighbourhood of the inguinal ca.n.a.l, 3, yet the swelling can scarcely be mistaken for an inguinal rupture, since, in addition to its being superficial to the aponeurosis which covers the inguinal ca.n.a.l, and also to the femoral arch, it may be withdrawn readily from this place, and its body, 12, traced to where it sinks into the saphenous opening, 6, 7, on the upper part of the thigh. An inguinal hernia manifests its proper character more and more plainly as it advances from its point of origin to its termination in the s.c.r.o.t.u.m. A femoral hernia, on the contrary, masks its proper nature, as well at its point of origin as at its termination. But when a femoral hernia stands midway between these two, points--viz. in the saphenous opening, 6, 7, it best exhibits its special character; for here it exists below the femoral arch, and considerably apart from the external abdominal ring.

[Ill.u.s.tration: Abdomen, showing bone, blood vessels and other internal organs.]

PLATE 46.--FIGURE 2

PLATE 46, Fig. 3.--The neck of the sac of a femoral hernia, 2, lies always close to, 3, the epigastric artery. When the obturator artery is derived from the epigastric, if the former pa.s.s internal to the neck behind, 8, Gimbernat's ligament, it can scarcely escape being wounded when this structure is being severed by the operator's knife. If, on the other hand, the obturator artery descend external to the neck of the sac, the vessel will be comparatively remote from danger while the ligament is being divided. In addition to the fact that the cause of stricture is always on the pubic side, 8, of the neck of the sac, 12, thereby requiring the incision to correspond with this situation only, other circ.u.mstances, such as the constant presence of the femoral vein, 11, and the epigastric artery, 1, determine the avoidance of ever incising the ca.n.a.l on its outer or upper side. And if the obturator artery, [Footnote] by rare occurrence, happen to loop round the inner side of the neck of the sac, supposing this to be the seat of stricture, what amount of anatomical knowledge, at the call of the most dexterous operator, can render the vessel safe from danger?

[Footnote: M. Velpeau (Medecine Operatoire), in reference to the relative frequency of cases in which the obturator artery is derived from the epigastric, remarks, "L'examen que j'ai pu en faire sur plusieurs milliers de cadavres, ne me permet pas de dire qu'elle se rencontre un fois sur trois, ni sur cinq, ni meme sur dix, mais bien seulement sur quinze a vingt." Monro (Obs. on Crural Hernia) states this condition of the obturator artery to be as 1 in 20-30. Mr. Quain (Anatomy of the Arteries) gives, as the result of his observations, the proportion to be as 1 in 3-1/2, and in this estimate he agrees to a great extent with the observations of Cloquet and Hesselbach. Numerical tables have also been drawn up to show the relative frequency in which the obturator descends on the outer and inner borders of the crural ring and neck of the sac. Sir A. Cooper never met with an example where the vessel pa.s.sed on the inner side of the sac, and from this alone it may be inferred that such a position of the vessel is very rare. It is generally admitted that the obturator artery, when derived from the epigastric, pa.s.ses down much more frequently between the iliac vein and outer border of the ring. The researches of anatomists (Monro and others) in reference to this point have given rise to the question, "What determines the position of the obturator artery with respect to the femoral ring?" It appears to me to be one of those questions which do not admit of a precise answer by any mode of mathematical computation; and even if it did, where then is the practical inference?]

The taxis, in a case of crural hernia, should be conducted in accordance with anatomical principles. The fascia lata, Poupart's ligament, and the abdominal aponeurosis, are to be relaxed by bending the thigh inwards to the hypogastrium. By this measure, the falciform process, 6, is also relaxed; but I doubt whether the situation occupied by Gimbernat's ligament allows this part to be influenced by any position of the limb or abdomen. The hernia is then to be drawn from its place above Poupart's ligament, (if it have advanced so far,) and when brought opposite the saphenous opening, gentle pressure made outwards, upwards, and backwards, so as to slip it beneath the margin of the falciform process, will best serve for its reduction. When this cannot be effected by the taxis, and the stricture still remains, the cutting operation is required.

The precise seat of the stricture cannot be known except during the operation. But it is to be presumed that the sac and contained intestine suffer constriction throughout the whole length of the ca.n.a.l. [Footnote]

Previously to the commencement of the operation, the urinary bladder should be emptied; for this organ, in its distended state, rises above the level of the pubic bone, and may thus be endangered by the incision through the stricture--especially if Gimbernat's ligament be the structure which causes it.