Surgical Anatomy Part 45

Plate 64,--Figure 1.

Fig. 2, Plate 64.--The prostate is greatly enlarged, and forms a narrow ring around the vesical orifice. Through this an instrument, 12, enters the bladder. The walls of the bladder are thickened and sacculated. On its left side appear numerous sacs, 2, 3, 4, 5, 6, 7, 8, and on the inner surface of its right side appear the orifices of as many more. On its summit another sac is formed. The ureters, 9, are dilated.

[Ill.u.s.tration]

Plate 64,--Figure 2.

FIG. 3, Plate 64.--The prostate is enlarged, its ca.n.a.l is narrowed, and the bladder is thickened and contracted. A calculus, 1, 2, appears occupying nearly the whole vesical interior. The incision in the neck of the bladder in lithotomy must necessarily be extensive, to admit of the extraction of a stone of this size.

[Ill.u.s.tration]

Plate 64,--Figure 3.

FIG. 4, Plate 64.--The prostatic ca.n.a.l is contracted by the lateral lobes, 4, 5; resting upon these, appear three calculi, 1, 2, 3, which nearly fill the bladder. This organ is thickened and fasciculated. In cases of this kind, and that last mentioned, the presence of stone is readily ascertainable by the sound.

[Ill.u.s.tration]

Plate 64,--Figure 4.

FIG. 5, Plate 64.--The three prostatic lobes are enlarged, and appear contracting the vesical orifice. In the walls of the bladder are embedded several small calculi, 2, 2, 2, 2, which, on being struck with the convex side of a sound, might give the impression as though a single stone of large size existed. In performing lithotomy, these calculi would not be within reach of the forceps.

[Ill.u.s.tration]

Plate 64,--Figure 5.

FIG. 6, Plate 64.--Two sacculi, 4, 5, appear projecting at the middle line of the base of the bladder, between the vasa deferentia, 7, 7, and behind the prostate, in the situation where the operation of puncturing the bladder per anum is recommended to be performed in retention of urine.

[Ill.u.s.tration]

Plate 64,--Figure 6.

FIG. 7, Plate 64.--A sac, 4, is situated on the left side of the bladder, 3, 3, immediately above the orifice of the ureter. In the sac was contained a ma.s.s of phosphatic calculus. This substance is said to be secreted by the mucous lining of the bladder, while in a state of chronic inflammation, but there seems nevertheless very good reason for us to believe that it is, like all other calculous matter, a deposit from the urine.

[Ill.u.s.tration]

Plate 64,--Figure 7.

FIG. 8, Plate 64, represents, in section, the relative position of the parts concerned in catheterism. [Footnote] In performing this operation, the patient is to be laid supine; his loins are to be supported on a pillow; and his thighs are to be flexed and drawn apart from each other.

By this means the perinaeum is brought fully into view, and its structures are made to a.s.sume a fixed relative position. The operator, standing on the patient's left side, is now to raise the p.e.n.i.s so as to render the urethra, 8, 8, 8, as straight as possible between the meatus, a, and the bulb, 7. The instrument (the concavity of its curve being turned to the left groin) is now to be inserted into the meatus, and while being gently impelled through the ca.n.a.l, the urethra is to be drawn forwards, by the left hand, over the instrument. By stretching the urethra, we render its sides sufficiently tense for facilitating the pa.s.sage of the instrument, and the orifices of the lacunae become closed. While the instrument is being pa.s.sed along this part of the ca.n.a.l, its point should be directed fairly towards the urethral opening, 6*, of the triangular ligament, which is situated an inch or so below the pubic symphysis, 11. With this object in view, we should avoid depressing its handle as yet, lest its point be prematurely tilted up, and rupture the upper side of the urethra anterior to the ligament. As soon as the instrument has arrived at the bulb, its further progress is liable to be arrested, from these causes:--1st, This portion of the ca.n.a.l is the lowest part of its perinaeal curve, 3, 6, 8, and is closely embraced by the middle fibres of the accelerator urinae muscle. 2nd, It is immediately succeeded by the commencement of the membranous urethra, which, while being naturally narrower than other parts, is also the more usual seat of organic stricture, and is subject to spasmodic constriction by the fibres of the compressor urethrae. 3d, The triangular ligament is behind it, and if the urethral opening of the ligament be not directly entered by the instrument, this will bend the urethra against the front of that dense structure. On ascertaining these to be the causes of resistance, the instrument is to be withdrawn a little in the ca.n.a.l, so as to admit of its being readjusted for engaging precisely the opening in the triangular ligament. As this structure, 6, is attached to the membranous urethra, 6*, which perforates it, both these parts may be rendered tense, by drawing the p.e.n.i.s forwards, and thereby the instrument may be guided towards and through the aperture.

The instrument having pa.s.sed the ligament, regard is now to be paid to the direction of the pelvic portion of the ca.n.a.l, which is upwards and backwards to the vesical orifice, 3, d, 3. In order that the point of the instrument may freely traverse the urethra in this direction, its handle, a, requires to be depressed, b c, slowly towards the perinaeum, and at the same time to be impelled steadily back in the line d, d, through the pubic arch, 11. If the third lobe of the prostate happen to be enlarged, the vesical orifice will accordingly be more elevated than usual. In this case, it becomes necessary to depress the instrument to a greater extent than is otherwise required, so that its point may surmount the obstacle. But since the suspensory ligament of the p.e.n.i.s, 10, and the perinaeal structures prevent the handle being depressed beyond a certain degree, which is insufficient for the object to be attained, the instrument should possess the prostatic curve, c c, compared with c b.

[Footnote: It may be necessary for me to state that, with the exception of this figure (which is obviously a plan, but sufficiently accurate for the purposes it is intended to serve) all the others representing pathological conditions and congenital deformities of the urethra, the prostate, and the bladder, have been made by myself from natural specimens in the museums and hospitals of London and Paris.]

[Ill.u.s.tration]

Plate 64,--Figure 8.

In the event of its being impossible to pa.s.s a catheter by the urethra, in cases of retention of urine threatening rupture, the base or the summit of the bladder, according as either part may be reached with the greater safety to the peritonaeal sac, will require to be punctured. If the prostate be greatly and irregularly enlarged, it will be safer to puncture the bladder above the p.u.b.es, and here the position of the organ in regard to the peritonaeum, 1, becomes the chief consideration. The shape of the bladder varies very considerably from its state of collapse, 3, 3, 5, to those of mediate, 3, 3, 2, 1, and extreme distention, 3, 3, 4. This change of form is chiefly effected by the expansive elevation of its upper half, which is invested by the peritonaeum. As the summit of the bladder falls below, and rises above the level of the upper margin of the pubic symphysis, it carries the peritonaeum with it in either direction. While the bladder is fully expanded, 4, there occurs an interval between the margin of the symphysis pubis and the point of reflexion of the peritonaeum, from the recti muscles, to the summit of the viscus. At this interval, close to the p.u.b.es, and in the median line, the trocar may be safely pa.s.sed through the front wall of the bladder. The instrument should, in all cases, be directed downwards and backwards, h, h, in a line pointing to the hollow of the sacrum.

COMMENTARY ON PLATES 65 & 66.

THE SURGICAL DISSECTION OF THE POPLITEAL s.p.a.cE AND THE POSTERIOR CRURAL REGION.

On comparing the bend of the knee with the bend of the elbow, as evident a correspondence can be discerned between these two regions, as exists between the groin and the axilla.

Behind the knee-joint, the muscles which connect the leg with the thigh enclose the s.p.a.ce named popliteal. When the integuments and subcutaneous substance are removed from this place, the dense fascia lata may be seen binding these muscles so closely together as to leave but a very narrow interval between them at the mesial line. On removing this fascia, B B M M, Plate 65, the muscles part asunder, and the popliteal s.p.a.ce as usually described is thereby formed. This region now presents of a lozenge-shaped form, B J D K, of which the widest diameter, D J, is opposite the knee-joint. The flexor muscles, C D J, in diverging from each other as they pa.s.s down from the sides of the thigh to those of the upper part of the leg, form the upper angle of this s.p.a.ce; whilst its lower angle is described by the two heads of the gastrocnemius muscle, E E, arising inside the flexors, from the condyles of the femur. The popliteal s.p.a.ce is filled with adipose substance, in which are embedded several lymphatic bodies and through which pa.s.s the princ.i.p.al vessels and nerves to the leg.

In the dissection of the popliteal s.p.a.ce, the more important parts first met with are the branches of the great sciatic nerve. In the upper angle of the s.p.a.ce, this nerve will be found dividing into the peronaeal, I, and posterior tibial branches, H K. The peronaeal nerve descends close to the inner margin of the tendon, J, of the biceps muscle; and, having reached the outer side of the knee, I*, Plate 66, below the insertion of the tendon into the head of the fibula, winds round the neck of this bone under cover of the peronaeus longus muscle, S, to join the anterior tibial artery. The posterior tibial nerve, H K, Plate 65, descends the popliteal s.p.a.ce midway to the cleft between the heads of the gastrocnemius; and, after pa.s.sing beneath this muscle, to gain the inner side of the vessels, H*, Plate 66, it then accompanies the posterior tibial artery. On the same plane with and close to the posterior tibial nerve in the popliteal s.p.a.ce, will be seen the terminal branch of the lesser sciatic nerve, together with a small artery and vein destined for distribution to the skin and other superficial parts on the back of the knee. Opposite the heads of the gastrocnemius, the peronaeal and posterior tibial nerves give off each a branch, both of which descend along the mesial line of the calf, and joining near the upper end of the tendo Achillis, the single nerve here, N, Plate 65, becomes superficial to the fascia, and thence descends behind the outer ankle to gain the external border of the foot, where it divides into cutaneous branches and others to be distributed to the three or four outer toes. In company with this nerve will be seen the posterior saphena vein, L, which, commencing behind the outer ankle, ascends the mesial line of the calf to join the popliteal vein, G, in the cleft between the heads of the gastrocnemius.

On removing next the adipose substance and lymphatic glands, we expose the popliteal vein and artery. The relative position of these vessels and the posterior tibial nerve, may now be seen. Between the heads of the gastrocnemius, the nerve, H, giving off large branches to this muscle, lies upon the popliteal vein, G, where this is joined by the posterior saphena vein. Beneath the veins lies the popliteal artery, F.

On tracing the vessels and nerve from this point upwards through the popliteal s.p.a.ce, we find the nerve occupying a comparatively superficial position at the mesial line, while the vessels are directed upwards, forwards, and inwards, pa.s.sing deeply, as they become covered by the inner flexor muscles, C D, to the place where they perforate the tendon of the adductor magnus on the inner side of the lower third of the femur.

The popliteal artery, F, Plate 66, being the continuation of the femoral, extends from the opening in the great adductor tendon at the junction of the middle and lower third of the thigh, to the point where it divides, in the upper, and back part of the leg, at the lower border of the popliteus muscle, L, into the anterior and posterior tibial branches. In order to expose the vessel through this extent, we have to divide and reflect the heads of the gastrocnemius muscle, E E, and to retract the inner flexors. The popliteal artery will now be seen lying obliquely over the middle of the back of the joint. It is deeply placed in its whole course. Its upper and lower thirds are covered by large muscles; whilst the fascia and a quant.i.ty of adipose tissue overlies its middle. The upper part of the artery rests upon the femur, its middle part upon the posterior ligament of the joint, and its lower part upon the popliteus muscle. The popliteal vein, G; adheres to the artery in its whole course, being situated on its outer side above, and posterior to it below. The vein is not unfrequently found to be double; one vein lying to either side of the artery, and both having branches of communication with each other, which cross behind the artery. In some instances the posterior saphena vein, instead of joining the popliteal vein, ascends superficially to terminate in some of the large veins of the thigh. Numerous lymphatic vessels accompany the superficial and deep veins into the popliteal s.p.a.ce, where they join the lymphatic bodies, which here lie in the course of the artery.

The branches derived from the popliteal artery are the muscular and the articular. The former spring from the vessel opposite those parts of the several muscles which lie in contact with it; the latter are generally five in number--two superior, two inferior, and one median. The two superior articular branches arise from either side of the artery, and pa.s.s, the one beneath the outer, the other beneath the inner flexors, above the knee-joint; and the two inferior pa.s.s off from it, the one internally, the other externally, beneath the heads of the gastrocnemius below the joint; while the middle articular enters the joint through the posterior ligament. The two superior and inferior articular branches anastomose freely around the knee behind, laterally, and in front, where they are joined by the terminal branches of the anastomotic, from the femoral, and by those of the recurrent, from the anterior tibial. The main vessel, having arrived at the lower border of the popliteus muscle, divides into two branches, of which one pa.s.ses through the interosseous ligament to become the anterior tibial; while the other, after descending a short way between the bones of the leg, separates into the peronaeal and posterior tibial arteries. In some rare instances the popliteal artery is found to divide above the popliteus muscle into the anterior, or the posterior tibial, or the peronaeal.

The two large muscles, (gastrocnemius and soleus,) forming the calf of the leg, have to be removed together with the deep fascia in order to expose the posterior tibial, and peronaeal vessels and nerves. The fascia forms a sheath for the vessels, and binds them close to the deep layer of muscles in their whole course down the back of the leg. The point at which the main artery, F, Plate 66, gives off the anterior tibial, is at the lower border of the popliteus muscle, on a level with N, the neck of the fibula; that at which the artery again subdivides into the peronaeal, P, and posterior tibial branches, O, is in the mesial line of the leg, and generally on a level with the junction of its upper and middle thirds. From this place the two arteries diverge in their descent; the peronaeal being directed along the inner border of the fibula towards the back of the outer ankle; while the posterior tibial, approaching the inner side of the tibia, courses towards the back of the inner ankle. The gastrocnemius and soleus muscles overlie both arteries in their upper two thirds; but as these muscles taper towards the mesial line where they end in the tendo Achillis, V V, Plate 65, they leave the posterior tibial artery, O, with its accompanying nerve and vein, uncovered in the lower part of the leg, except by the skin and the superficial and deep layers of fasciae. The peronaeal artery is deeply situated in its whole course. Soon after its origin, it pa.s.ses under cover of the flexor longus pollicis, R, a muscle of large size arising from the lower three fourths of the fibula, N, and will be found overlapped by this muscle on the outer border of the tendo Achillis, as low down as the outer ankle. The two arteries are accompanied by venae comites, which, with the short saphena vein, form the popliteal vein. The posterior tibial artery is closely followed by the posterior tibial nerve. In the popliteal s.p.a.ce, this nerve crosses to the inner side of the posterior tibial artery, where both are about to pa.s.s under the gastrocnemius muscle, to which they give large branches. Near the middle of the leg, the nerve recrosses the artery to its outer side and in this relative position both descend to a point about midway between the inner ankle and calcaneum, where they appear having the tendons of the tibialis posticus and flexor longus digitorum to their inner side and the tendon of the flexor longus pollicis on their outer side. Numerous branches are given off from the nerve and artery to the neighbouring parts in their course.

The varieties of the posterior crural arteries are these--the tibial vessel, in some instances, is larger than usual, while the peronaeal is small, or absent; and, in others, the peronaeal supplies the place of the posterior tibial, when the latter is diminished in size. The peronaeal has been known to take the position of the posterior tibial in the lower part of the leg, and to supply the plantar arteries. In whatever condition the two vessels may be found, there will always be seen ramifying around the ankle-joint, articular branches, which anastomose freely with each other and with those of the anterior tibial.

The popliteal artery is unfavourably circ.u.mstanced for the application of a ligature. It is very deeply situated, and the vein adheres closely to its posterior surface. Numerous branches (articular and muscular) arise from it at short intervals; and these, besides being a source of disturbance to a ligature, are liable to be injured in the operation, in which case the collateral circulation cannot be maintained after the main vessel is tied. There is a danger, too, of injuring the middle branch of the sciatic nerve, in the incisions required to reach the artery; and, lastly, there is a possibility of this vessel dividing higher up than usual. Considering these facts in reference to those cases in which it might be supposed necessary to tie the popliteal artery--such cases, for example, as aneurism of either of the crural arteries, or secondary haemorrhages occurring after amputations of the leg at a time when the healing process was far advanced and the bleeding vessels inaccessible,--it becomes a question whether it would not be preferable to tie the femoral, rather than the popliteal artery. But when the popliteal artery itself becomes affected with aneurism, and when, in addition to the anatomical circ.u.mstances which forbid the application of a ligature to this vessel, we consider those which are pathological,--such as the coats of the artery being here diseased, the relative position of the neighbouring parts being disturbed by the tumour, and the large irregular wound which would be required to isolate the disease, at the risk of danger to the health from profuse suppuration, to the limb from destruction of the collateral branches, or to the joint from cicatrization, rendering it permanently bent,--we must acknowledge at once the necessity for tying the femoral part of the main vessel.

When the popliteal artery happens to be divided in a wound, it will be required to expose its bleeding orifices, and tie both these in the wound. For this purpose, the following operation usually recommended for reaching the vessel may be necessary. The skin and fascia lata are to be incised in a direction corresponding to that of the vessel. The extent of the incision must be considerable, (about three inches,) so as the more conveniently to expose the artery in its deep situation. On laying bare the outer margin of the semi-membranosus muscle, while the knee is straight, it now becomes necessary to flex the joint, in order that this muscle may admit of being pressed inwards from over the vessel. The external margin of the wound, including the middle branch of the sciatic nerve, should be retracted outwards, so as to ensure the safety of that nerve, while room is gained for making the deeper incisions. The adipose substance, which is here generally abundant, should now be divided, between the mesial line and the semimembranosus, till the sheath of the vessels be exposed. The sheath should be incised at its inner side, to avoid wounding the popliteal vein. The pulsation of the artery will now indicate its exact position. As the vein adheres firmly to the coats of the artery, some care is required to separate the two vessels, so as to pa.s.s the ligature around each end of the artery from without inwards, while excluding the vein. While this operation is being performed in a case of wound of the popliteal artery, the haemorrhage may be arrested by compressing the femoral vessel, either against the femur or the os pubis.

In the operation for tying the posterior tibial artery near its middle, an incision of three or four inches in extent is to be made through the skin and fascia, in a line corresponding with the inner posterior margin of the tibia and the great muscles of the calf. The long saphena vein should be here avoided. The origins of the gastrocnemius and soleus muscles require to be detached from the tibia, and then the knee is to be flexed and the foot extended, so as to allow these muscles to be retracted from the plane of the vessels. This being done, the deep fascia which covers the artery and its accompanying nerve is next to be divided. The artery will now appear pulsating at a situation an inch from the edge of the tibia. While the ligature is being pa.s.sed around the artery, due care should be taken to exclude the venae comites and the nerve.

DESCRIPTION OF PLATES 65 & 66.

PLATE 65.

A. Tendon of the gracilis muscle.

B B. The fascia lata.

C C. Tendon of the semimembranosus muscle.

D. Tendon of the semitendinosus muscle.

E E. The two heads of the gastrocnemius muscle.

F. The popliteal artery.