Tibia

“ 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 foetal tibia has its head slightly bent backward with regard to the shaft, a condition which usually disappears in the adult, but which is shown in the prehistoric tibae found in the cave of Spy. In races that squat on their heels the front margin of the lower end of the tibia is marked by a small articular facet for the neck of the astragalus. ”

“ As the foot, and therefore the tibia also, have a firm position, then the contraction of the muscles named must cause the femur to approach the tibia, whereby the whole body is drawn along with it. This individual act of motion may be well studied in grasshoppers when they are climbing on a twig by stretching out their long fore leg directly forward, and then drawing up the body through the shortening of the tibial flexors until the middle leg also reaches the branch. ”

“ A more serious part of the secondary disease is affection of the deep-seated parts, ligaments, periosteum, and bones. The bones nearest the surface are principally affected: a swelling gradually forms on the tibia or ulna, without discoloration of the integuments, and without pain occurring till after a long time. ”

“ A theory has, however, been advanced to the effect that, since the anterior ridge of the bone represents part of the surface from which the tibialis posticus muscle arises, and since this muscle effects the adduction of the foot, when a person is walking, it is feasible that the altered shape and the increased bulk of the tibia may be due to that factor. ”

“ The anterior tibial nerve lies first on its outer side, then crosses the artery, and eventually reaches its inner side near the foot. Operation.—An incision, at least three inches long, parallel with the outer edge of the tibia, and about three-quarters of an inch from it, exposes the deep fascia. This being divided, the outer edge of the tibialis anticus must be found, and will be the guide to the artery, which, surrounded by its venæ comites, lies very deeply between the muscles. ”

“ The tibia and fibula are separate, and do not otherwise have sufficiently noteworthy characters to call for a special description in this place, except to note an unusual anterior crest on the tibia. To the lower ends of these bones articulate the first row of tarsal elements, the tibiale, intermedium, and fibulare. The tarsus is composed of 9 elements arranged in 3 rows. The proximal row is composed of the tibiale, the intermedium, and the fibulare. On the edge of the tibiale there lies a portion of one of the caudal vertebræ, so that the form of this tarsal element is slightly obscured. ”

“ Chief reliance is to be placed upon the bony points retaining their normal relationships, and upon the fact that the points of maximum tenderness are over the attachments of one or other of the collateral ligaments. As the tibial collateral ligament suffers most frequently, the most tender spot is usually over its attachment to the medial aspect of the head of the tibia—less frequently over the medial condyle of the femur. ”

“ Let us now come, at last, to the mechanical structure of bone, of which we find a well-known and classical illustration in the various bones of the human leg. In the case of the tibia, the bone is somewhat widened out above, and its hollow shaft is capped by an almost flattened roof, on which the weight of the body directly rest. ”

“ A. tibialis anterior.—The anterior tibial artery is the continuation of the popliteal after its passage through the interosseous membrane between tibia and fibula to the dorsal side of the lower leg. Here it passes distad, lying against the interosseous membrane, between the extensor longus digitorum and the tibialis anterior muscle, or partly imbedded in the substance of the latter. It passes, lying beneath the tendons of these muscles, through the transverse ligament proximad of the malleoli, thus reaching the dorsum of the foot. ”

“ In adolescent knock-knee the patient seeks advice because of the deformity or of pain after exertion, especially at the medial side of the epiphysial junctions, of being easily tired, and of incapacity for any occupation involving standing. The bones are coarse and badly formed, and there is frequently a spinous process projecting downwards from the medial side of the tibia about three finger-breadths below the joint. ”

“ This peculiarity of the tibia called platycnemism, is probably a provision of nature, securing a firmer and better defined process upon which the muscles of the leg could fasten themselves, and its prominence among the people of the mounds indicates the possession of great pedestrian powers. ”

“ Flattening of tibia.—In some very ancient human skeletons, there has also been found a lateral flattening of the tibia, which rarely occurs in any existing human beings, but which appears to have been usual among the earliest races of mankind hitherto discovered. ”

“ In superficial bones, such as the tibia, there is enlargement, and it may be possible to recognise egg-shell crackling, or unequal consistence of the bone, which is hard in some parts, and doughy and elastic in others. The disease may pursue an indolent course during months or years until some complication occurs, such as suppuration or fracture. ”

“ Most remarkable of all is the short broad tibia, equipped with four large, hard teeth, which has to perform the digging in the ground after the manner of a spade, while the disproportionately thin and weak tarsal joints, the last of which bears two perfectly straight spines instead of claws, are directed upwards, and do not touch the ground, being no longer used for walking. ”

“ Afterward the body bends forward over the support, and its weight, pressing from above downward and from before backward, and pressing the articular surfaces of the joint together, forces the head of the tibia backward until the movement is checked by the posterior ligaments. ”

“ Any abnormal laxity of the ligaments of the joint may render the cartilages unduly mobile, so that they are liable to be displaced from comparatively slight causes, and when so displaced it is not uncommon for one or other to be torn by being nipped between the femur and the tibia. ”

“ Musculus plantaris (Fig. 5) .—Small and slender, this muscle lies on the posteromedial surface of the crus, beneath the pars interna of the m. gastrocnemius and originates by fleshy fibers from the posteromedial surface of the proximal end of the tibia immediately distal to the internal articular surface. The belly extends approximately one-sixth of the way down the crus and gives rise to a long, slender tendon that inserts on the proximomedial edge of the tibial cartilage. ”

“ Fracture of the tibia alone, when due to direct violence, is usually transverse, there is little displacement, and as the fibula retains the fragments in position, union usually takes place rapidly and without deformity. Oblique and spiral fractures result from indirect violence. ”

“ If the leg stump is ten centimetres long, if the knee joint is freely mobile and capable of complete, or almost complete, active extension, and if there are no adherent scars around the tuberosities of the tibia, the American apparatus with free knee joint should be adopted. ”

“ The thigh, which is the thickest portion, is grooved on its inner edge, and beset with a double row of strong spines; the tibia is so formed as to close upon it as the blade of a pocket-knife does upon its handle, and being likewise spinous on its interior edge, effectually secures any object that may be within, in a manner somewhat similar to what is practised by that carnivorous vegetable the Dionea muscipula. ”

“ It is obvious that, when the disease has proceeded thus far, the joint must become more or less deformed, and its motions considerably impeded. Accordingly, old men are often seen at work with much rigidity of the joints, particularly of the knee, which is frequently projected inwards, from absorption of the cartilage from the outer condyle of the femur and corresponding part of the tibia, with a thinning and degeneration of the inner-articular cartilage into a tissue resembling the cellular. ”

“ The more or less extensive fusion of the tibia with the fibula and the radius with the ulna in the ungulated mammals, whose habits require only partial rotations of the limbs, is a fact of like meaning. ”

“ The flute, tibia, was originally made of the shin bone, and had a mouth-hole and four finger-holes. Its shape was retained even when, at a later period, it was constructed of other substances than bone. The tibia gingrina consisted of a long and thin tube of reed with a mouth-hole at the side of one end. The tibia obliqua and tibia vasca were provided with mouth-pieces affixed at a right angle to the tube; a contrivance somewhat similar to that on our bassoon. The tibia longa was especially used in religious worship. ”

“ The cartilages enjoy a limited range of movement within the joint, passing backwards during flexion, and forwards again when the limb is extended; under normal conditions the lateral moves more freely than the medial. While the limb is partly flexed, a slight degree of rotation of the leg at the knee is possible, and during this movement the cartilages glide from side to side, and the tibia rotates below them. ”

“ In severe contusions associated with great tension of the skin—for example, over the front of the tibia or around the ankle—blisters often form on the surface and constitute a possible avenue of infection. When deeply situated, the blood tends to spread along the lines of least resistance, partly under the influence of gravity, passing under fasciæ, between muscles, along the sheaths of vessels, or in connective-tissue spaces, so that it may only reach the surface after some time, and at a considerable distance from the seat of injury. ”

“ The individual tarsal bones, especially the talus and calcaneus, are altered in shape as well as in their relations to one another and to the tibio-fibular socket. The navicular and cuboid are rotated medially around the anterior ends of the talus and calcaneus respectively, and the tubercle of the navicular comes to lie close to the medial malleolus. The lower third of the tibia is twisted medially on its vertical axis. ”

“ As the foot enlarges the leg atrophies from disuse; so that in the advanced disease an enormously enlarged and misshapen foot, flexed or extended, is attached to an attenuated leg consisting of little more than skin and bone. In some the tibia, or, if the hand is the seat of invasion, the bones of the forearm become involved; in others the disease at first may be confined to a toe, or a finger, or other limited area. In a very few instances the seat of the disease is the knee, thigh, jaw, or neck. ”

“ The joints of the body always show some changes. The epiphyses are enlarged to a variable degree, resembling the epiphyses typical of human rickets. As in infants, this change is met with most commonly at the wrist joint, involving the ulna and the radius. The knee-joint is likewise often involved, especially the ends of the tibia; the elbow, ankle, and the shoulder may also show an articular swelling of the bones. About these joints hemorrhages in the subcutaneous tissues may be seen, or edema extending along the extremities. ”