196 



THE ARTICULATIONS OF THE HORSE 



the groove on the tuberosity of the tibia, a bursa ])eing interposed between the 

 Hgament and the upper part of the groove. The internal patellar ligament is 

 attached above to the patellar fibro-cartilage, and ends on the tuberosity of the 

 tibia, internally to the groove. It is joined by the common aponeurosis of the 

 gracilis and sartorius. These so-called ligaments are, in reality, the tendons of 

 insertion of tlie quadriceps femoris muscle, and transmit the action of the latter 



to the tibia; they also func- 

 tion similarly for the other 

 muscles attached to them as 

 noted above. 



Posterior crucial 

 ligament 

 Anterior cru- 

 cial ligament 



1 ntcrior ligaments 

 of semilunar car- 

 tilages 



It will be noticed that the 

 upper attachments are further apart 

 than the lower ones, so that the li^:a- 

 ments converge below. The inner 

 ligament is especially obliciue. The 

 middle ligament is more deeply 

 placed than the others, and there- 

 fore cannot usually be felt distinctly 

 in the living animal. 



Fig 



Posterior crucial 

 ligament 



Anterior crucial ligament 



Ligaments of c.r- 

 rnal cartilage 



158. — Semilunar Cartilages and Crucial Ligaments of •t. • i • 



Right Stifle op Horse. The femorO-tibial aitlCU- 



F, Femoral ligament of external cartilage. (After Schmaltz, Atlas latioil (Articulatio fcmorO- 



d. Anat. d. pferdes.) tibialis) is formed between the 



condyles of the femur, the 

 proximal end of the tibia, and the interposed semilunar cartilages. 



Articular Surfaces. — The condyles of the femur are slightly oblique in direc- 

 tion. The articular surface of the outer one is more strongly curved than that of 

 the inner one; the latter is confluent below with the inner ridge of the trochlea, 

 while the narrow ridge which connects the external condyle with the trochlea is 

 usually non-articular. The saddle-shaped surfaces of the condyles of the tibia are 

 not adapted to the femoral condyles, and 

 are in contact with only a small part of 

 them. 



The semilunar cartilages (Meniscus 

 lateralis, medialis) are two C-shaped or 

 crescentic discs of fibro-cartilage which 

 produce congruence in the articular sur- 

 faces. Each has an u])per concave sur- 

 face adapted to the condyle of the femur, 

 and a lower surface which fits the cor- 

 responding condyle of the tibia. The 

 external cartilage does not cover the 

 outer and j^osterior part of the condyle, 

 over which the tendon of origin of the 

 popliteus muscle plays. The peripheral 

 border is thick and convex, the central 

 one very thin and concave. The fibrous 

 ends or cornua are attaclied to the tibia 

 in front of and behind the spine. The 



external cartilage has a third attachment by means of an ol)lique Imnd (Liga- 

 mentuni femorale menisci lat(Talis) which passes from th(^ ]:)osterior cornu to the 

 posterior part of the intercondyloid fossa of the fcniiur. 



The cormia of the internal cartilage (Ligamenta tibia> antorius et posterius menisci medialis) 

 are attached in front of and behind the inner eminence of the spine. The anterior cornu of the 

 external cartilage fLigamentum tibia> anterius menisci lateralis) is attached in front of the outer 

 eminence of the spine. The posterior cornu bifurcates; the lower branch (Ligamentum tibia; 



Head of 



fibula 



Fig. 



150. — Proximal Ends of Right Tuua and 

 l''inuLA OF HonsK, with Skmihtnar Car- 

 tilages and Crucial Ligaments, Exter- 

 nal View. (After Schmaltz, Atlas d. Anat. 

 d. Pferdes.) 



