86 OUTLINES OF EQUINE ANATOMY. 



centrally is rounded, but superiorly becomes flattened from 

 behind forwards. It consists of a sliaft and two extremi- 

 ties. Tlie shaft presents four surfaces. The anterior 

 surface is in all parts convex and rounded, though in blend- 

 ing with the upper extremity it is inclined to become flat. 

 It is directly continuous with the inner and outer surfaces. 

 The inner surface is rounded. Supero-posteriorly it pre- 

 sents a roughened prominence, elongated from above down- 

 wards, continuous by two roughened sharp lines with the 

 head. The anterior of these sharp lines marks out the 

 attachment of vastus iuternus. This prominence is tro- 

 chanter minor internus. To it are attached psoas 

 magnus and iliacus. Below it the surface is roughened 

 for attachment of pectineus and of one head of biceps 

 adductor femoris ; still lower down is an oblique smooth 

 surface, extending from above downwards and backwards 

 for passage of the femoral artery and vein, at the upper 

 part of which, opposite the centre of the bone postero- 

 internally is the medullary foramen. Still lower down this 

 surface is very rough for attachment of the other head of 

 biceps adductor femoris. The jjosterior surface of the bone 

 superiorly is very wide, j^resenting a fiat surface between 

 the two small trochanters. Slightly inclined to the outer' 

 side of the centre of this part is a roughened surface for 

 attachment of ischio-femoralis and a portion of triceps 

 abductor femoris. From the upper part of trochanter 

 minor externus a thick ridge runs upwards towards the 

 posterior part of trochanter major; this forms the outer 

 boundary of the trochanteric fossa, a deep depression on 

 the supero-posterior and external part of the bone, into which 

 are inserted the two obturator muscles and pyriformis, 

 with gemini or ischio-trochanterius. The middle third 

 of this surface is roughened and continuous with that on 

 the inner surf ace for pectineus and biceps adductor femoris ; 

 below this, separated by the smooth oblique groove for the 

 femoral artery, is a triangular space extending as far as 

 the outer condyle for attachment of the lower head of 

 biceps adductor femoris. The external surface presents 

 superiorly the ridge running from trochanter major to 

 trochanter minor externus, to which the posterior head of 

 gluteus maximus is attached. This culminates in a long 

 process flattened from before backwards, curled forwards, 

 and tuberous at its free margin, trochanter minor externus, 



