THE LOWER LIMB 5^5 



thus remain one and a half to be accounted for, namely, both sides 

 of the great toe and the inner side of the second toe. 



Plantar or Perforating Branch of Arteria Dorsalis Pedis. — ^This 

 artery is one of the terminal branches of the arteria dorsalis pedis. 

 Having entered the sole through the proximal part of the first 

 interosseous space, between the two heads of the first dorsal inter- 

 osseous muscl^, it immediately divides into two branches — com- 

 municating and arteria magna or princeps hallucis. 



The communicating branch is a short vessel, which ends by 

 joining the second part of the external plantar artery to complete 

 the plantar arch. 



The arteria magna or princeps hallucis is the fifth plantar 

 digital artery. Commencing at the proximal end of the first inter- 

 osseous space it passes forwards over the plantar aspect of that 

 space and the corresponding dorsal interosseous muscle towards 

 the cleft between the great toe and second toe. In this part of its 

 course it furnishes a single plantar digital artery, which, having 

 crossed the first metatarsal bone, beneath the tendon of the flexor 

 longus hallucis, is distributed to the inner side of the great toe. 

 Near the cleft between the great toe and second toe it receives the 

 innermost superficial digital branch of the internal plantar artery, 

 and then divides into two collateral plantar digital arteries for the 

 supply of the contiguous sides of these two toes. Before dividing, 

 it communicates with the arteria dorsaUs hallucis by an anterior 

 perforating branch, which passes through the distal end of the first 

 interosseous space. 



Varieties — i. Internal Plantar Artery. — This vessel is sometimes very small, 

 and it may then terminate in the flexor brevis hallucis. In other cases it is 

 of fairly large size, and then it may replace the arteria magna or princeps 

 hallucis, and furnish the plantar digital branches for both sides of the great 

 toe and the inner side of the second toe. In very rare cases the internal 

 plantar artery communicates with the external plantar, and so forms a super- 

 ficial plantar arch. In such cases the superficial digital arteries arise from 

 this arch. 



2. External Plantar Artery. — This artery is liable to be diminished in size, 

 and this may occur to such an extent as to exclude it from any share in the 

 plantar arch. Such deficiencies are compensated for by an enlargement of 

 the arteria dorsaUs pedis and its plantar branch. 



The posterior perforating branches of the plantar arch are sometimes of 

 comparatively large size, and then they furnish the dorsal interosseous 

 arteries after they reach the dorsum of the foot. 



For the tendon of the peroneus longus in the sole see p. 516. 



Tendons Involved in Club-loot. 



The chief varieties of club-foot are as follows : talipes equinus, talipes 

 varus, talipes equino-varus, talipes valgus, taUpes calcaneus, and tahpes 

 calcaneo- valgus. 



Talipes Equinus. — In this variety the foot is extended upon the leg, the 

 heel being raised from the ground, so that the person walks upon the toes. 

 The chief tendons involved are (i) the tendo Achillis, and (2) the plantaris 

 tendon. The latter, however, is insignificant. 



Talipes Varus. — In this variety the inner border of the foot is raised so 

 as to invert the sole, and the foot is at the same time slightly extended upon 



