The varicose distention to which the trunks of the saphena veins in the leg are peculiarly liable, is often found extending to their minute commencing branches on the dorsum of the foot ; so much so that the whole of this region is irregularly distended, and covered with the knots and ramifications of the distended veins. This morbid state is dependent upon the same causes as the varicose affection of the veins of the leg, and can be remedied only by the same means, but with this additional disad vantage, that the mechanical means adopted for their relief by pressure, owing to the more conical form of the foot, can with greater difficulty be retained.
Besides the veins, we find imbedded in this same layer of cellular tissue a number of nervous filaments, which should be remem bered as occasionally interfering with operations on this part. The last portion of the saphenus or long cutaneous nerve runs so near to the saphena major vein that some of its twigs pass in front of and some behind it, and have been occasionally punctured in opening this vein ; but this should form no stronger an objection to this operation than a similar arrangement of the nerves, and a similar accident in bleeding, which occasionallylap pens, should be allowed as an objection to venesection at the bend of the arm.
3. The next layer brought into view by dissection is a thin expansion of fascia, con tinuous with the anterior annular ligament of the ankle, and formed of fibres running in various directions, principally transverse and spreading over the whole of the dorsal region, but principally at the upper part. The ob servations which have been made on this same fascia when covering the ankle may be applied also to the part just described, (see ANKLE JOINT, REGION oF,) with this exception, that as the dorsal fascia is much thinner and more incomplete than that over the ankle, matter would here not be so tightly bound down, nor would it present so strong an obstacle to the pointing of it outward.
4. On removing the layer of aponeurosis a muscular and tendinous stratum is exposed, comprehending the entire muscle of the ex tensor brevis digitorum and the tendons of several of the long muscles situated on the leg. The first of these has a thick fleshy belly, and occupies the outer part of the dorsum of the foot, sending its tendons down, like so many rays, to the bases of the toes. The tendons are spread over the foot in the following order :—on the inner side the tibialis anticus passing to be inserted, by a broad attachment, into the internal cuneiform bone and base of the first metatarsal bone; next the extensor proprius pollicis runs forwards and inwards, along the fibular edge of the first metatarsal bone; then the tendons of the extensor longus digitorum run diverging to wards the bases of the four outer toes, crossing over the tendons of the extensor brevis; and lastly, the tendon of the peroneus tertius, diverging from the extensor longus, sends its small flat tendon to the base of the fifth me tatarsal bone. Each of these tendons runs in its own synovial sheath, and these are, from their superficial situation and from their proximity to the bones over which they pass, peculiarly liable to be affected by pressure, as from tight boots. The consequence of this is not unfrequently seen in a small round swelling, situated generally over the tarsal bones, and upon one of the tendons of the extensor digitorum longus. It is first covered generally by its tenderness, and when this is relieved by taking off the pressure which was its first cause, the swelling itself still remains, soft and elastic to the touch, and having all the characters of an enlarged bursa, and which has received the name of ganglion. The cure may generally be accom
plished easily and expeditiously : a smart blow with some hard body, as • the back of a book, while the swelling is rendered tense by the forcible extension of the foot, will be all that is necessary ; the cyst is thus burst, and its synovial contents, when extravasated among the adjacent cellular tissue, soon become ab sorbed, while the empty cyst itself shrinks and contracts to its natural size. Should, however, this plan not be approved, or, which may happen, not succeed, the introduction of a cataract needle in an oblique direction under the skin, and the puncture of the cyst, will evacuate the fluid into the surrounding cellular tissue, and thus effect a cure.* A tumour is sometimes formed upon the instep, which is also the result of pressure, and which bears a near relation to a corn. It is met with in young men who wear tight boots, and the usual situation of it is over the articulation between the internal cuneiform bone and the metatarsal bone of the great toe. The tumour is under the skin, hard and im movable ; sn that it seems to a superficial observer to be an enlargement of the bone itself. The skin over it is in a natural state, except in cases of long standing, in which the cuticle becomes thickened. This swelling is described by Sir B. Brodie in a clinical lecture in the Medical Gazette, vol. xvii. Ile is uncertain in what precise situation this tumour exists, whether in the ligaments of the joint, or periosteum, or in the ultimate fibres of the tendon of the tibialis anticus muscle, not having had an opportunity of dissecting it.
In this view also are exposed the course and situation of the dorsal artery of the foot. This, which is merely the continuation of the anterior tibial artery, commences its course from the anterior annular ligament of the ankle, a little to the inner side of the middle of the foot; from thence it runs obliquely towards the first interosseal space of the metatarsal bones, at the commencement of which it dips into the sole of the foot, leaving only a branch to continue its course to the great toe. In the course just mentioned this artery rests upon the bones of the tarsus, separated from them and their ligaments only by a small quantity of cellular tissue. It is accompanied by its vein and a branch of a nerve, and will readily be found running along the outer or fibular edge of the tendon of the extensor proprius pollicis, which partly overlaps it. Notwith standing the superficial situation of this artery, its close connexion with the above-mentioned tendon renders it peculiarly ineligible for the application of a ligature, and fortunately it is very rarely that we are called upon to perform an operation upon it ; but its course and situation are important to the surgeon, as afford ing a valuable diagnostic mark, negative at least, if not positive, in the examination of an injury to some of the larger vessels, as the femoral or the anterior tibial. For though, owing to occasional varieties in the course and distribution of the dorsal arteries of the foot, the absence of pugation in the situation of the artcria dorsalis pedis, just indicated, would not be a positive proof of injury to the larger vessels, (though even this might be received valuable corroborative evidence,) vet the clear and full pulsation of this vessel would of course be undoubted evidence that the larger arteries were safe and sound. (See