Part 5

‘Nélaton’s line,’ as it is termed, theoretically holds good. But in stout persons it is not always easy to feel these bony points so as to draw the line with precision. A surgeon must, after all, in many cases trust to measurement by his eyes and his flat hands--his best guides. Thus, let the thumbs be placed firmly on the spines of the ilia, while the fingers grasp the trochanters on each side. Having the sound side as a standard of comparison, the hand will easily detect any displacement on the injured side. Hippocrates bids us compare the sound parts with the parts affected (in fractures) and observe the inequalities.

The top of the great trochanter is the guide in an operation recently introduced by Mr. Adams, namely, the ‘subcutaneous section of the neck of the femur.’ ‘The puncture should be made one inch above and nearly one inch in front of the top of the trochanter. The neck of the bone is to be sawn through at right angles to its axis, the saw working parallel to Poupart’s ligament, and about one inch below it.’

=Spine of the ilium.=--The anterior superior spine of the ilium is the point from which we measure the length of the lower limb. By looking at the spines of opposite sides we can detect any slant in the pelvis. By pressure on both spines simultaneously we examine if there be a fracture of the pelvis, or disease at the sacro-iliac joint.

100. ‘In reducing a dislocation of the hip by manipulation it is important to bear in mind that, in every position, the head of the femur faces nearly in the direction of the inner aspect of its internal condyle.’[8]

101. =Compression of femoral artery.=--About a point midway between the spine of the ilium and the symphysis pubis, the femoral artery can be felt beating, and effectually compressed, against the pubes. How should the pressure be applied when the patient lies on the back? In accordance with the slope of the bone--that is, with a slight inclination upwards. A want of attention to this point is the reason why so many fail when they undertake to command the circulation through the femoral artery in an amputation, or to cure an aneurysm by digital compression.

If the Italian tourniquet be used, we should be careful to adjust the counter-pad well under the tuberosity of the ischium. If digital pressure be used, it is easy to command the femoral by slight pressure of the thumb, provided the fingers have a firm hold on the great trochanter.

102. =Sartorius.=--The sartorius is the great fleshy landmark of the thigh, as the biceps is of the arm, and the sterno-cleido-mastoideus of the neck. Its direction and borders may easily be traced by asking the patient to raise his leg, a movement which puts the muscle in action. The same action defines the boundaries of the triangle (of Scarpa) formed by Poupart’s ligament, the adductor longus and sartorius.

=Line of femoral artery.=--To define the course of the femoral artery, draw a line from midway between the anterior superior spine of the ilium and the symphysis pubis to the (spur-like) tubercle for the adductor magnus on the inner side of the knee. The femoral artery lies under the upper 2/3 of this line.

The sartorius begins to cross the artery, as a rule, from three to four inches below Poupart’s ligament. The point at which the profunda artery arises is about one and a half or two inches below the ligament. Therefore the incision for tying the femoral in Scarpa’s triangle should commence about a hand’s breadth below Poupart’s ligament, and be continued for three inches in the line of the artery.

To command the femoral in Scarpa’s triangle, the pad of the tourniquet should be placed at the apex, and the direction of the pressure should be, not backwards, but outwards, so that the artery may be compressed against the femur.

In the middle third of the thigh the femoral artery lies in Hunter’s canal, overlapped by the sartorius. About the commencement of the lower third the artery leaves the canal through the oval opening in the adductor magnus, and, under the name of popliteal, enters the popliteal space. The line for finding the artery in Hunter’s canal has been already traced (102). The incision to reach the artery in this part of its course would fall in with the outer border of the sartorius.

To command the femoral artery in Hunter’s canal, the pressure should be directed outwardly, so as to press the vessel against the bone.

_THE BUTTOCKS._

103. =Buttocks.--Bony landmarks.=--The bony landmarks of the buttocks which can be distinctly felt are: 1, the posterior superior spines of the ilia; 2, the spines of the sacral vertebræ; 3, the two tubercles of the last sacral vertebra; 4, the apex of the coccyx in the deep groove leading to the anus; 5, the tuberosities of the ischia on each side of the anus.

The posterior spines of the ilia are about the level of the second sacral spine, and correspond with the middle of the sacro-iliac symphysis.

The third sacral spine marks the lowest level to which the membranes of the cord and the cerebro-spinal fluid descend in the spinal canal.

The tuberosities of the ischia, in the erect position, are covered by the gluteus maximus. In the sitting position they support the weight of the body, and are only covered by a thick pad of coarse fat. Between this pad and the bones there is a bursa, which becomes occasionally enlarged and inflamed in coachmen.

The prominence of the nates is one of the characteristics of man in connection with his erect attitude. ‘Les fesses n’appartiennent qu’à l’espèce humaine.’ They are formed of an accumulation of fat over the great muscle of the buttock (gluteus maximus). From their appearance we may gather some indication of the state of the constitution. They are firm and globose in the vigorous; loose and flaccid in the infirm. Wasting and flattening of one, compared with the other, is an early symptom of disease in the hip.

104. =Fold of the buttock.=--The deep furrow, termed ‘the fold of the buttock,’ which separates the nates from the back of the thigh, corresponds with the lower border of the gluteus maximus. Its altered direction in disease of the hip is very characteristic. This is the best place to feel for the great ischiatic nerve. We find it by pressing deeply between the trochanter and the tuber ischii, rather nearer to the latter. When we sit upright, the nerve is not liable to pressure; but it becomes numbed when we sit long sideways.

105. =Gluteal artery.=--To find at what point the gluteal artery comes out of the pelvis, draw a line from the posterior superior spine of the ilium to the top of the trochanter major, rotated inwards. The junction of the inner with the middle third of this line lies over the artery as it emerges from the upper border of the great ischiatic notch.

The point of exit of the ischiatic artery from the pelvis is about half an inch lower than that of the gluteal.

106. =Pudic artery.=--The pudic artery crosses the spine of the ischium. To find it, draw a line from the outer side of the tuber ischii to the posterior superior spine of the ilium. The junction of the lower with the middle third gives the position of the artery. The ischiatic artery lies close to it, but nearer the middle line.

Looking at the course of these arteries it appears that when we sit on hard seats the pressure is sustained by the bones; when we recline on soft seats the pressure is sustained more by the soft parts, and reaches the arteries; hence the tendency of modern modes of reposing to drive the blood into the interior of the pelvis and favour the production of piles and uterine disorders. A celebrated French accoucheur used to say that the fashion of high waists, tight lacing, and easy chairs brought him many thousands a year.

_THE KNEE._

107. =Bony points.=--The patella; the tuberosities of the two condyles; the tubercle of the tibia for the attachment of the ligamentum patellæ; another (the lateral) tubercle, on the outer side of the head of the tibia; and the head of the fibula are the chief bony landmarks of the knee.

Observe that the head of the fibula lies at the outer and back part of the tibia, and that it is pretty nearly on a level with the tubercle for the attachment of the ligamentum patellæ.

We can also feel the adductor tubercle or spur-like projection of bone above the internal condyle which gives attachment to the tendon of the adductor magnus. This spur-like projection corresponds with the level of the epiphysis of the lower end of the femur, and also with the level of the highest part of the trochlea for the patella: facts worth notice in performing excision of the knee.

‘In reducing a dislocation of the hip, it is important to bear in mind that the inner aspect of the internal condyle in every position of the limb faces nearly in the direction of the head of the femur.’ (100)

The tubercle on the outer side of the head of the tibia gives attachment to the broad and strong aponeurosis (tendon of the tensor fasciæ), which, acting like a brace for the support of the pelvis, is well seen in emaciated persons down the outer side of the thigh. This tubercle indicates the level to which the condyles of the femur descend, and the lower level of the synovial membrane.

The patella, in extension of the knee, is nearly all above the condyles; in flexion, it lies in the inter-condyloid fossa (more on the external condyle), and thus protects the joint in kneeling. Its inner border is thicker and more prominent than the outer, which slopes down towards its condyle.

108. =Ligamentum patellæ.=--The line of the ligamentum patellæ is vertical. Hence any deviation from this line, one way or the other, indicates more or less dislocation of the tibia. There is a pellet of fat under the ligament, which answers a ‘packing’ purpose--sinking in when the knee is bent; rising when the knee is extended, and bulging on either side of the tendon, almost enough to give the feel of fluctuation.

In a well-formed leg the ligamentum patellæ, the tubercle of the tibia, and the middle of the ankle should be in the same straight line. A useful point in the adjustment of fractures.

Behind the upper half of the ligamentum patellæ is the synovial membrane of the knee-joint; behind the lower half is a synovial bursa and a pad of fat. It is well to remember this in cases of injury to the ligamentum patellæ.

109. =Patellar bursa.=--The patellar or housemaids’ bursa is situated not only over the patella, but over the upper part of the ligament. This is plain enough when the bursa becomes enlarged. There is another subcutaneous bursa over the insertion of the ligament into the tubercle of the tibia. This is quite independent of the deep bursa between the tendon and the bone.

110. =Synovial membrane of knee.=--The synovial membrane of the knee, when the joint is extended, rises like a cul-de-sac above the upper border of the patella about two inches. It ascends, too, a little higher under the vastus internus than the vastus externus--a fact very manifest when the joint is distended. When the knee is bent this cul-de-sac is drawn down--hence the rule of bending the knee in operations near the lower end of the femur.

The lower level of the synovial membrane of the knee is just above the level of the upper part of the head of the fibula. The tibio-fibular synovial membrane is, with rare exceptions, independent of that of the knee.

111. =Popliteal tendons.=--The tendons forming the boundaries of the popliteal space can be distinctly felt when the muscles which bend the knee are acting. On the outer side, we have the biceps running down to the head of the fibula. On the inner side we feel three tendons, disposed as follows:--nearest to the middle of the popliteal space is the semitendinosus, very salient and traceable high up the thigh; next comes the thick round tendon of the semimembranosus; still more internally is the gracilis. The sartorius, which forms a graceful muscular prominence on the inner side of the knee, does not become tendinous until it gets below it.

112. =Popliteal bursa.=--The precise position of the bursa in the popliteal space, which sometimes enlarges to the size of a hen’s egg, is between the tendon of the inner head of the gastrocnemius and the tendon of the semimembranosus, just where they rub one against the other. The bursa is from one and a half to two inches long. When enlarged, it makes a swelling on the inner side of the popliteal space, which bulges and becomes tense when the knee is extended, and _vice versâ_. I examined 150 bodies with a view to ascertain how often this bursa communicates with the synovial membrane of the knee. There was a communication about once in five instances. This should make us cautious in interfering too roughly with the bursa when enlarged.

113. =Popliteal artery.=--The popliteal artery can be felt beating and can be compressed against the back of the femur, close to which it lies. But pressure, sufficient to stop the blood, should be firm, and should be made against the bone nearer to the inner than the outer hamstrings. The line of the artery corresponds with the middle of the ham. It lies under cover of the fleshy belly of the semimembranosus, and the outer border of this muscle is the guide to it. An incision down the middle of the ham would fall in with the vessel just above the condyles.

114. =Peroneal nerve.=--The peroneal nerve runs parallel with and close to the inner border of the tendon of the biceps. It can be felt in thin persons. There is a risk of dividing it in tenotomy of the biceps, unless the knife be carefully introduced from within outwards. Below the knee the nerve can be felt close to the fibula just below the head, and when pressed upon in this situation causes a sensation to run down its branches to the foot.

_THE LEG AND ANKLE._

115. =Bony points.=--The tubercle of the tibia (for the attachment of the ligamentum patellæ), the sharp front edge called the shin, and the broad flat subcutaneous surface of the bone can be felt all the way down. The inner edge can be felt too, but not so plainly. The lower third is the narrowest part of the bone and the most frequent seat of fracture.

The head of the fibula is a good landmark on the outer side of the leg, about one inch below the top of the tibia and nearly on a level with the tubercle. Observe that it is placed well back, and that it forms no part of the knee-joint, and takes no share in supporting the weight.

The shaft of the fibula arches backwards, the reverse of the shaft of the tibia. The fact of the bones not being on the same plane should be remembered in flap amputations. The shaft of the fibula is so buried amongst the muscles, that the only part to be distinctly felt is the lower fourth. Here there is a flat triangular subcutaneous surface, between the peroneus tertius in front, and the two peronei (longus and brevis) behind. Here is the most frequent seat of fracture.

116. =Malleoli.=--The shape and relative position of the malleoli should be carefully studied, as the great landmarks of the ankle. The inner malleolus does not descend so low as the outer, and advances more to the front: at the same time, owing to its greater antero-posterior depth, it is on the same plane as the outer behind. The lower border of the inner malleolus is somewhat rounded, and the slight notch in it for the attachment of the lateral ligament can be felt. The outer malleolus descends lower than the inner, thus effectually locking the joint on the outer side. Its shape is not unlike the head of a serpent. Viewed in profile, it lies just in the middle of the joint.

In Syme’s amputation of the foot at the ankle, the line of the incision should run from the apex of the outer malleolus, under the sole to the centre of the inner.

In a well-formed leg, the inner edge of the patella, the inner ankle, and the inner side of the great toe, should be in the same vertical plane. Look to these landmarks in adjusting a fracture or dislocation, keeping at the same time an eye upon the conformation of the opposite limb.

There are several strong tendons to be seen and felt about the ankle.

117. =Tendo Achillis.=--Behind is the tendo Achillis. It forms a high relief, with a shallow gutter on each side of it. The narrowest part of the tendon, where it should be divided in tenotomy, is about the level of the inner ankle; below this it expands again to be attached to the lower and back part of the os calcis. Seen in profile, the tendon is not straight,but slightly concave--being drawn in by an aponeurosis which forms a sort of girdle round it. This girdle proceeds from the posterior ligament of the ankle; and, though most of its fibres encircle the tendon, some of them adhere to and draw in its sides. All this disappears when the tendon is laid bare by dissection.

118. =Tendons behind inner ankle.=--Above and behind the malleolus internus we can feel the broad flat tendon of the tibialis posticus and upon it that of the flexor longus digitorum. The tendon of the tibialis posticus lies nearest to the bone and comes well up in relief in adduction of the foot. It lies close to, and parallel with, the inner edge of the tibia, so that this edge is the best guide to it. Therefore in tenotomy the knife should be introduced first perpendicularly between the tendon and the bone, and then turned at right angles to cut the tendon. The tendon has a separate sheath and synovial membrane, which commences about one inch and a half above the apex of the malleolus, and is continued to its insertion into the tubercle of the scaphoid bone. The proper place, then, for division of the tendon, is about two inches above the end of the malleolus.

In a young and fat child, where the inner edge of the tibia cannot be distinctly felt, the best guide to the tendon is a point midway between the front and the back of the ankle. An incision in front of this point might injure the internal saphena vein; behind this point, the posterior tibial artery.

119. =Tendons behind outer ankle.=--Behind the malleolus externus we feel the two peroneal (long and short) tendons. They lie close to the edge of the fibula, the short one nearer to the bone. In dividing these tendons, the knife should be introduced perpendicularly to the surface, and about two inches above the apex of the ankle, so as to be above the synovial sheaths of the tendons.

=Tendons in front of ankle.=--Over the front of the ankle, when the muscles are in action, we can see and feel, beginning on the inner side, the tendons of the tibialis anticus, the extensor longus pollicis, the extensor longus digitorum, and the peroneus tertius. They start up like cords when the foot is raised, and are kept in their proper relative position by strong pulleys formed by the anterior annular ligament. Of these pulleys the strongest is that of the extensor communis digitorum. When the ankle is sprained, the pain and swelling arise from a stretching of these pulleys and effusion into their synovial sheaths. A laceration of one of the pulleys and escape of the tendon is extremely rare.

The place for the division of the tendon of the tibialis anticus, so as to divide it below its synovial sheath, is about one inch before its insertion into the cuneiform bone. The knife should be introduced on the outer side, so as to avoid the dorsal artery of the foot.

Now trace the lines of the arteries, and the landmarks near which they divide.

120. =Popliteal artery.=--About one inch and a quarter below the head of the fibula, or say one inch below the tubercle of the tibia, the popliteal artery divides into the anterior and posterior tibial. The peroneal comes off from the posterior tibial about three inches below the head of the fibula.

Consequently we may lay down, as a general rule, that, in amputations one inch below the head of the fibula, only one main artery, the popliteal, is divided. In amputations two inches below the head of the fibula, two main arteries, the anterior and posterior tibial, are divided. In amputations three inches below the head, three main arteries, the two tibials and the peroneal, are divided.

121. =Anterior tibial artery.=--The anterior tibial artery comes in front of the interosseous membrane, one inch and a quarter below the head of the fibula, and here lies close to this bone. Its subsequent course is defined by a line drawn from the front of the head of the fibula to the middle of the front of the ankle. This line corresponds pretty nearly with the outer border of the tibialis anticus all the way down. If this muscle be put in action, its outer border (the intermuscular line) is plainly seen, and the incision for the ligature of the artery in any part of its course may be defined with the greatest precision. The artery can be felt beating and can be compressed where it crosses the front of the tibia and ankle.

122. =Posterior tibial artery.=--The posterior tibial commences about one inch and a quarter below the head of the fibula. Its subsequent course corresponds with a line drawn from the middle of the upper part of the calf to the hollow behind the inner ankle, where it can be felt beating distinctly about half an inch behind the edge of the tibia. A vertical incision down the middle of the calf would reach the artery under cover of the gastrocnemius and soleus. A vertical incision along the middle third of the leg, about half an inch from the inner edge of the tibia, would enable the operator to reach the artery sideways, by detaching from the bone the tibial origin of the soleus.

123. =Saphena veins.=--The subcutaneous veins on the dorsum of the foot form an arch convex towards the toes (as on the back of the hand), from which issue the two main subcutaneous trunks of the lower limb, the internal and external saphena veins. The internal saphena vein can be always plainly seen over the front of the inner ankle. Its further course up the inner side of the leg, knee, and thigh to its termination in the femoral is not in all persons manifest.

The external saphena vein runs behind the outer ankle and up the middle of the calf to empty itself (generally) into the popliteal vein.

_THE FOOT._

What are the bony landmarks which guide us in the surgery of the foot?

124. =Points of bone.=--Along the inner side of the foot, beginning from behind, we can feel--1, the tuberosity of the os calcis; 2, the projection of the internal malleolus; 3, the projection of the os calcis, termed ‘sustentaculum tali,’ about one full inch below the malleolus; 4, about one inch in front of the malleolus internus, and a little lower, is the tubercle of the scaphoid bone; the gap between it and the sustentaculum tali being filled by the calcaneo-scaphoid ligament and the tendon of the tibialis posticus, in which there is often a sesamoid bone; 5, the internal cuneiform bone; 6, the projection of the first metatarsal bone; 7, the sesamoid bones of the great toe.

Along the outer side of the foot we can feel--1, the external tuberosity of the os calcis; 2, the external malleolus; 3, the peroneal tubercle of the os calcis, one inch below the malleolus, with the long peroneal tendon below it, and the short one above it; 4, the projection of the base of the fifth metatarsal bone.

125. =Lines of joints.=--In fat persons the following rules for finding the joints may be of service as regards the surgery of the foot:--

The level of the ankle joint lies about half an inch above the end of the inner malleolus. This is worth remembering in performing ‘Syme’s’ amputation.

The tubercle of the scaphoid bone is the best guide to the astragalo-scaphoid joint which lies immediately behind it; and the plane of this joint is in the same line as that of the calcaneo-cuboid. Thus a line drawn transversely over the dorsum of the foot, behind the tubercle of the scaphoid, would strike both the joints opened in ‘Chopart’s’ operation.