THE ARTICULATIONS. 65 



fiursce in the vicinity of this joint are 5, viz. I under the ligamentum patellae, 1 

 I between the patella and the skin ; I between the internal lateral ligament 

 and the tendons crossing it ; sometimes i replacing the synovial pouch on the 

 anterior surface of the femur ; and occasionally I in the popliteal space re- 

 placing the synovial pouch usually situated therein. 



Describe the Tibio-fibular Articulations. They are 3 in number, as 



follows, viz. 



SUPERIOR TIBIO-FIBULAR ARTICULATION, is an arthrodial joint, formed by 

 the contiguous surfaces of the bones. It has a Synovial Membrane which is 

 sometimes continuous with that of the knee-joint, and 2 ligaments, the 



Anterior and Posterior Superior Tibio-fibular} which connect the head of 

 the fibula with the outer tuberosity of the tibia. 



MIDDLE TIBIO-FIBULAR ARTICULATION. The shafts of these bones do not 

 touch each other, but are connected by the Interosseous Membrane extending 

 between their contiguous borders, and perforated, above for the anterior tibial 

 artery, below for the anterior peroneal vessels. 



INFERIOR TIBIO-FIBULAR ARTICULATION, is an amphi-arthrodial joint, 

 formed by the contiguous rough surfaces on the bones. Its Synovial Mem- 

 brane is derived from that of the ankle-joint, and it has 4 ligaments, viz. 



Inferior Interosseous, continuous with the interosseous membrane. 



Anterior and Posterior Inferior Tibio-fibular, from the margins of the ex- 

 ternal malleolus to the front and back of the tibia. 



Transverse, posteriorly between the 2 malleoli. 



Describe the Ankle-joint. It is a ginglymoid articulation, formed by the 

 lower ends of the tibia and fibula and their malleoli, with the astragalus. Its 

 Synovial Membrane is prolonged upwards between the tibia and fibula for a 

 short distance. Its arteries are derived from the malleolar branches of the 

 anterior tibial and peroneal arteries ; and its Nerves from the anterior tibial 

 nerve. It has 3 ligaments, viz. 



Anterior, connecting the margins of the tibia and astragalus. 



Internal Lateral, or Deltoid Ligament, from the internal malleolus to the 



3 adjacent tarsal bones. 



External Lateral, by anterior posterior and middle fasciculi, from the ex- 

 ternal malleolus to the astragalus and os calcis. 



Describe the Tarsal Articulations. They are in 3 sets, (i) between the 

 bones of the first row, (2) between the bones of the second row, (3) between 

 the 2 rows of bones. 

 (i.) The astragalus and os calcis are united by 3 ligaments. 



External Calcaneo-astragaloid. Interosseous- 



Posterior Calca neo- astragaloid. 

 6* V 



