VARIETIES OF THE ANTERIOR TIBIAL ARTERY. 471 



branches. Moreover, from the outermost of these interosseous arteries a small 

 branch is given oif , which gains the outer border of the little toe, and forms its 

 external collateral branch. These arteries communicate with the plantar arch 

 opposite the fore part of the interosseous spaces, by means of the anterior 

 pf/foratiiiff branches, and at the back part of the interosseous spaces, by the 

 jwdcrior i^erf orating branches. 



(«") The dorsal artery of the great toe (dorsalis halliicis) is con- 

 tinued forwards from the dorsal artery of the foot at tlie point where it 

 dips down to the sole. This branch runs along the outer surface of the 

 first metatarsal bone, and furnishes the small dorsal dhjltal A'essels of 

 the great toe and adjacent side of the second toe. 



{(l) The plantar digital branch of the first space is given off 

 from the dorsal artery between the heads of the first interosseous 

 muscle, near the inosculation with the plantar arch, and passing for- 

 wards divides into two smaller branches which proceed along the con- 

 tiguous sides of the first and second toe. 



(e) The plantar digital branch for the inner side of the great 

 toe crosses beneath the first metatarsal bone, and runs along the inner 

 side of the great toe on its plantar surface. 



Varieties of the Anterior Tibial Artery. — Origin. — Incases of early division 

 of the i^opliteal artery, the place of origin of the anterior tibial is necessarily 

 higher up than usual, being sometimes found as high as the bend of the knee- 

 joint. In some of these cases (the posterior tibial artery being small or wanting), 

 the anterior tibial is conjoined with the peroneal artery, '\^^^en the anterior 

 tibial arises higher than usual, the additional upi^er part of the vessel has been 

 seen resting on the posterior surface of the popliteus muscle, and it has been 

 likewise found between that muscle and the bone. 



Course. — The anterior tibial artery, haviag its usual place of origin, has been 

 found to deviate outwards towards the margin of the fibula in its coui'se along the 

 front of the leg, and then to return to its ordinary position iDeneath the annular 

 ligament in front of the ankle-joint. This arteiy has been also noticed by 

 Pelletan and by Velpeau to approach the surface at the middle of the leg, and to 

 continue downwards from that point, covered only by the fascia and integument. 

 Yelpeau states that he found the artery to reach the fore part of the leg by 

 passing round the outer side of the fibula. (Pelletan, " Clinique Chk'urgicale,'" 

 &c., p. 101 : Paris, 1810. Velpeau, " Nouveaux Elemens de Medeciuo Operatoii"e," 

 k,c., t. i., pp. 137 and 537 : Paris, 1837.) 



Size. — This vessel more frequently undergoes a diminution than an increase of 

 size. 



It may be defective in various degrees. Thus the dorsal branch of the foot 

 may fail to give off digital branches to the great and second toes, which may 

 be then derived from the internal plantar division of the i^osterior tiljial. In a 

 farther degree of dimiaution the anterior tibial ends in front of the ankle or at 

 the lower part of the leg ; its place being then taken by the anterior division 

 of the peroneal artery, which supplies the dorsal artery of tlie foot ; the two 

 vessels (anterior tibial and anterior peroneal) being either connected together or 

 separate. 



Two cases are mentioned by Allan Bums, in which the anterior tibial artery 

 was altogether wantuig, its place in the leg being supplied by perforating branches 

 from the posterior tibial arteiy, and on the dorsum of the foot by the anterior 

 peroneal artery. 



The dorsal arteiy of the foot is occasionally larger than usual ; in that case 

 compensating for a defective condition of the internal plantar branch from the 

 posterior tibial artery. 



This artery has been repeatedly found to be ciuwed outwards ]3etween its com- 

 mencement at the lower border of the annular ligament and its termination in 

 the first interosseous space. 



