THE KNEE. 1215 
‘moment of partial flexion. In full flexion almost the whole of the trochlear 
surface of the condyles is exposed to palpation, covered, however, by the stretched 
quadriceps tendon. 
The upper part of the inner surface of the internal condyle is overlapped by the 
muscular prominence of the lower fibres of the vastus internus. Leading upwards 
from the internal condyle is a slight furrow, corresponding to the interval between 
the lower part of the vastus internus and the sartorius; at the bottom of the furrow 
the cord-like tendon of the adductor magnus may readily be felt, and followed down 
to its Insertion into the adductor tubercle; the latter, situated at the junction of the 
internal supracondyloid ridge with the upper and back part of the internal condyle, 
marks the level of the epiphysial cartilage. Anteriorly and posteriorly the epi- 
physial cartilage hes iminediately above the highest part of the articular cartilage. 
Disease of the lower end of the diaphysis of the femur generally invades the trigone of the 
femur and the popliteal space rather than the cavity of the ‘knee-joint. In Macewen’s operation 
for knock-knee, the incision (through which the osteotome is introduced to divide the femur) is 
carried down to the bone through the vastus internus a little above the internal condyle, a finge Ts 
breadth above the summit of the trochlea, to avoid injury to the epiphysial cartilage, and the 
same distance in front of the adductor tendon, to avoid injury to the deep branch of the anasto- 
motic artery. 
Below the internal condyle is the subcutaneous inner tuberosity of the tibia 
across which the tendons of the sartorius, gracilis, and semitendinosus pass to their 
insertion. Between the above tendons and the i inner head of the gastrocnemius is 
a groove which winds downwards and forwards from the popliteal space ; an incision 
along this groove will expose the long saphenous vein and nerve and the superficial 
branch of the anastomotic arter y- 
On the outer side of the knee is the ilio-tibial band, which, after crossing and 
obscuring the line of the joint, is attached to the outer tuberosity of the tibia. By 
semiflexion of the knee the posterior border of the band is thrown into relief, and a 
well-marked furrow intervenes between it and the prominent tendon of the biceps: 
the lower part of the shaft of the femur and the trigone may be reached through 
an incision along this furrow. Under cover of the ilio-tibial band, as it crosses the 
line of the joint, are the external semilunar cartilage, the inferior external articular 
artery, and the external lateral ligament. The head of the fibula, with the tendon of 
the biceps passing to be inserted into it, are rendered distinctly visible by semi- 
flexing the knee; the former lies on a level with the tubercle of the tibia, 14 in. 
behind and a little below the most prominent part of the outer tuberosity 
of the tibia. Immediately below the head of the fibula is the termination of the 
external popliteal nerve, which is lable to be contused from blows, and in 
fractures of the neck of the fibula. 
. The synovial membrane of the knee-joint extends downwards anteriorly as far as the 
level of the upper border of the tibia ; posteriorly, it dips downwards for a short distance 
behind the popliteal notch of the tibia, to form a small cul-de-sac, the close relation of 
~ which to the popliteal artery must be borne in mind in performing the operation of 
excision of the knee. Anteriorly, the synovial cavity extends upwards beneath the quadri- 
__ceps in the form of a pouch, which reaches nearly two inches above the articular surface 
of the femur ; posteriorly, there is no extension of the synovial cavity upwards above the 
condyles ; laterally, the synovial membrane covers the anterior third of the outer surface 
| of each condyle. 
In effusion into the knee-joint the hollows become obliterated, the patella is floated up, and 
fluctuation may be obtained above, below, and to either side of the patella. 
| To pass a tube through the knee-joint for drainage, two short vertical incisions should 
S be made—one on each side of the joint at the level ‘of the upper part of the patella, and 
a finger’s breadth behind its lateral edges. In arthrectomy of the knee for tubercular disease, the 
| subsynovial fat facilitates the separation of the suprapatellar pouch from the lower and anterior 
| part of the shaft of the femur; to expose the pouches behind the condyles, the crucial ligaments 
must be divided. 
THE LEG. 
The inner surface of the tibia is subcutaneous throughout, hence the seat of a 
fracture of the shaft is, as a rule, easily felt, and the lower extremity of the upper 
