Tendon M. Poplitei

Abstract

The relation of the tendon of the popliteus to meniscus largely depends on the former’s insertion and length as well as the distinctiveness of groove in the lateral condyle of the femur. Short (2,4—2,7 cm.) and long (3,3—3,5 cm.) tendons are in direct contact with meniscus not only during flexion with external rotation but also during extension. A most distinctive impression in the lateral meniscus has been observed in all cases.

In cases with a uniform tendon at both ends (28%), a more or less marked groove has been found present in the lateral condyle of the tibia. As regards the uniform broad tendon (10%), the presence of two grooves has been observed: the one lateral — set obliquely below the upper edge of the lateral condyle — and the other medial, less distinct, in the hind part of the lateral condyle of the tibia. The lateral groove responds to the tendon when the joint is in a position of flexion with external rotation.

In cases with the forking of tendon at the lower end (72%), two grooves have been noticed, the lateral one being broader in most cases (90%). The grooves correspond with the branches of the tendon extending from above and laterally downwards as well as medially.

In cases of m. peroneo-tibialis (18%) as well as those of communication of the bursa of the popliteus with the tibio-fibular joint (34%), the grooves in the lateral condyle have been found placed rather more laterally. The markedness of impression in the lateral meniscus depends on the appearance of the tendon itself, its insertion, length, retinaculum, as well as on the distinctiveness of incisions in the lateral condyle of the femur. Hence, the impression can only be indicated or strongly marked, depending on the tendon and its rate of friction according to different motions of the joint.

The tendon becomes impressed into the groove in the lateral meniscus during flexion with external rotation. During extension, semiflexion and complete flexion, the tendon is not in drirect contact with meniscus. It is only in cases with short and long tendons has been found impressed during extension in the groove of the lateral meniscus.