THE KNEE-JOINT. 291 
the tibia above the groove for the semi-membranosus tendon. The long or anterior 
portion inclines somewhat forwards, and descending superficially to the tendon of 
the semi-membranosus, it is continued downwards, to be attached to the upper part of 
the inner surface of the shaft of the tibia below the level of the anterior tuberosity. 
On its superficial aspect the internal lateral ligament is augmented by prolonga- 
tions from the tendons of the semi-membranosus and sartorius muscles, but is 
separated by a bursa from the tendons of gracilis, semi-tendinosus and sartorius. 
Its deep surface is adherent to the convex edge of the internal semilunar cartilage, 
but lower down the inferior 
internal articular vessels inter- 
vene between the igament and 
the shaft of the tibia. 
The external lateral ligament 
a ; ais Inner head 
(lig. collaterale fibulare, Fig. of gastroc. 
223), sometimes called the aa 
ligamentum laterale externum 
loneum, is a distinct rounded 
5 ap : e External lateral__ [Be 
band which is under cover of ligament (long) Epes 
‘the ordinary capsule, and yet External lateral (Winslow) 
well separated from the joint- 
cavity by intervening objects. 
It is attached superiorly to a 
tubercle on the outer surface 
ligament (short) 
Posterior superior 
tibio-fibular Q : 
ligament Tendon of 
- semi-mem-- 
branosus 
of the external condyle, im- 
mediately above the groove 
occupied by the tendon of the 
popliteus muscle, superficial to 
which the ligament descends. 
By its lower end it is attached 
to the outer side of the head 
of the fibula, in front of the 
styloid process. In its course vertically downwards it splits the tendon of inser- 
tion of the biceps flexor cruris (Fig. 223), the portions of which are fixed to the 
head of the fibula on either side “of. the ligament, and a bursa may intervene 
between the tendon and the ligament. The inferior external articular vessels pass 
forwards subjacent to this ligament and above the head of the fibula. Unlike 
the internal ligament, it is not attached to the corresponding semilunar cartilage. 
The ligamentum laterale externum breve seu posticum (lig. 224) is an inconstant structure 
which is attached by its upper end immediately behind the preceding, and subjacent to the 
~ outer head of the gastrocnemius muscle. It likewise descends superficial to the popliteal tendon 
and is affixed inferiorly into the styloid process of the fibula. 
The intra-articular structures of the knee-joint are more important and more 
numerous than in any other joint of the body. 
; The crucial ligaments (ligamenta cruciata genu) are two strong, rounded, tendinous 
- bands which extend from the non-articular area on the upper surface of the head 
of the tibia to the non-articular sides of the intercondyloid notch of the femur 
These interarticular ligaments are distinguished from each other as the anterior or 
external and the posterior or internal. They cross each other like the limbs of 
an X, yet they remain distinct throughout, and each has its own partial synovial 
covering. They le within the capsule of the joint, and extend between non- 
articular surfaces in relation to the longitudinal axis of the limb. 
The ligamentum cruciatum anterius (Figs. 223 and 225) is attached inferiorly” 
to the inner part of the rough depressed area in front of and close to the spine of 
the tibia. It passes obliquely upwards, outwards, and backwards to the inner: 
non-articular surface of the external condyle, where it finds attachment far back in 
the posterior part of the intercondyloid notch. This ligament is tense in the position 
of extension, and therefore it assists in maintaining the erect attitude. 
The ligamentum cruciatum posterius (Figs. 223 and 225) is somewhat shorter 
than the preceding. It is attached inferiorly to the hinder part of the depressed. 
Internal lateral | 
ligament 
Aperture for tendon 
of popliteus muscle} Interosseus 
membrane 
Fic, 224.—DIssEcTION OF KNEE-JOINT FROM BEHINIx. 
