1 62 Anatomy of Skeleton 



Now observe the level of the epiphysial line (Fig. 131) : it lies some distance below 

 the proper capsule, so that the epiphysis includes the fibular facet, the insertion of 

 Semimembranosus, and the extreme upper part of the extensor musculature, as well as 

 all the articular attachments with the exception of the lateral ligaments and a portion 

 of the expansion of Vastus internus, as described later. 



The upper epiphysis is that of the growing end. Observe that the epiphysial line 

 cuts through the adult tubercle : this indicates that the lower part of the tubercle is 

 really a portion of the shaft. A secondary ossification may form a traction epiphysis 

 here, but it is more usual to find an additional centre for the upper part, joined to the 

 upper epiphysis. 



The upper end is cartilaginous at birth, but occasionally the centre, that should 

 appear a few weeks later, is present at birth. The upper end may be somewhat tilted 

 back, a persistence of the state normal in the infant, and a condition found regularly 

 in some of the lower races. 



Other markings, etc., to be found on the upper part of the tibia are shown in 

 Fig. 131. A small smooth area just above the fibular facet is covered by cartilage and 

 supports the bursa round the tendon of Popliteus : this bursa is mainly derived from 

 the infrachondral part of the articulation and may communicate with the upper 

 tibio-fibular joint. The Popliteus is inserted above the oblique line, over the area 

 shown : it may have some tendinous fibres in its structures, and these may cause slight 

 roughnesses on the bone above the oblique line. There is a clear margin of bone above 

 the muscle, which is covered by Semimembranosus internally, but supports the 

 popliteal artery centrally. The insertion of Semimembranosus extends well forward 

 under the internal lateral ligament, with a bursa between them. The ligament 

 makes a marking on the bone, on each side of its edge, a little distance above the oblique 

 line, and inner fibres of the descending expansion from the Semimembranosus tendon 

 reach it here, while the inferior articular vessels and nerve, which pass under the 

 expansion, are thus brought to a deep relation with the ligament : the remainder of 

 the expansion covers the inner part of Popliteus, extending as far out as the vessels 

 lie, and reaches the oblique line. 



The extensor area on the bone reaches up to the margin of the epiphysis. Trace 

 the line of the covering aponeurosis up from the subcutaneous border (Fig. 132) along 

 the outer side of the tubercle. It turns back towards the fibular facet and divides 

 into an upper and lower line a little distance in front of this. The appearance presented 

 varies in individual bones, but comparison between a number will enable one to 

 establish the arrangement shown schematically in Fig. 133. The upper and lower 

 lines mark out a triangular area which is subdivided by a vertical line, and the 

 outer subdivision is for origin of Peroneus longus, the inner for Extensor longus 

 digitorum. Peroneus longus extends from the head of the fibula across the 

 anterior ligaments to the tibia : the vertical line is for the anterior peroneal septum, 

 and the inner part of the lower line is for the septum between the long extensor and 

 Tibialis anticus. 



All these muscles are covered by an aponeurosis into which the Biceps sends an 

 expansion, so that the upper line may be taken to represent part of the insertion of 

 the Biceps. 



Above and in front of this again, forming a rough marking on the bone between 

 the aponeurotic and capsular lines, is the attachment of the strong ilio-tibial band. 



Tibialis anticus arises from the upper half or more of the outer surface : its tendon 

 runs downwards and slightly inwards, so that a large space is left on the widened 



