Landmarks Medical and Surgical

by Luther Holden; James Shuter

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.