SYNDESMOU 



be subdivided into three sets: (1) those of the Tibiofibular articulation; (2) the 

 interosseous membrane; (3) those of the Tibiofibular syndesmosis. 



Tibiofibular Articulation (articulatio libiofibularis; superior tibiofibular articula- 

 tion). This articulation is an arthrodial joint between the lateral condyle of the 

 tibia and the head of the fibula. The contiguous surfaces of the bones present 

 flat, oval facets covered with cartilage and connected together by an articular 

 capsule and by anterior and posterior ligaments. 



The Articular Capsule (capsula articularis; capsular ligament). The articular 

 capsule surrounds the articulation, being attached around the margins of the 

 articular facets on the tibia and fibula; it is much thicker in front than 

 behind. 



The Anterior Ligament (anterior superior ligament). The anterior ligament of 

 the head of the fibula (Fig. 347) consists of two or three broad and flat bands, 

 which pass obliquely upward from the front of the head of the fibula to the front 

 of the lateral condyle of the tibia. 



The Posterior Ligament (posterior superior ligament). The posterior ligament of 

 the head of the fibula (Fig. 348) is a single thick and broad band, which passes 

 obliquely upward from the back of the head of the fibula to the back of the lateral 

 condyle of the tibia. It is covered by the tendon of the Popliteus. 



Synovial Membrane. A synovial membrane lines the capsule; it is continuous with that of 

 the knee-joint in occasional cases when the two joints communicate. 



Interosseous Membrane (membrana interossea cruris; middle tibiofibular liga- 

 ment). An interosseous membrane extends between the interosseous crests of the 

 tibia and fibula, and separates the muscles on the front from those on the back 

 of the leg. It consists of a thin, aponeurotic lamina composed of oblique fibers, 

 which for the most part run downward and lateralward ; some few fibers, however, 

 pass in the opposite direction. It is broader above than below. Its upper margin 

 does not quite reach the tibiofibular joint, but presents a free concave border, 

 above which is a large, oval aperture for the passage of the anterior tibial vessels 

 to the front of the leg. In its lower part is an opening for the passage of the anterior 

 peroneal vessels. It is continuous below with the interosseous ligament of the tibio- 

 fibular syndesmosis, and presents numerous perforations for the passage of small 

 vessels. It is in relation, in front, with the Tibialis anterior, Extensor digitorum 

 longus, Extensor hallucis proprius, Peronseus tertius, and the anterior tibial 

 vessels and deep peroneal nerve; behind, with the Tibialis posterior and Flexor 

 hallucis longus. 



Tibiofibular Syndesmosis (syndesmosis tibiofibularis; inferior tibiofibular articu- 

 lation). This syndesmosis is formed by the rough, convex surface of the medial 

 side of the lower end of the fibula, and a rough concave surface on the lateral side 

 of the tibia. Below, to the extent of about 4 mm. these surfaces are smooth, and 

 covered with cartilage, which is continuous with that of the ankle-joint. The 

 ligaments are: anterior, posterior, inferior transverse, and interosseous. 



The Anterior Ligament (ligamentum malleoli lateralis anterius; anterior inferior 

 ligament). The anterior ligament of the lateral malleolus (Fig. 355) is a flat, 

 triangular band of fibers, broader below than above, which extends obliquely 

 downward and lateralward between the adjacent margins of the tibia and fibula, 

 on the front aspect of the syndesmosis. It is in relation, in front, with the Peronseus 

 tertius, the aponeurosis of the leg, and the integument; behind, with the interosseous 

 ligament; and lies in contact with the cartilage covering the talus. 



The Posterior Ligament (ligamentum malleoli lateralis posterius; posterior inferior 

 ligament). The posterior ligament of the lateral malleolus (Fig. 355), smaller 

 than the preceding, is disposed in a similar manner on the posterior surface of 

 the syndesmosis. 



