EEGIONAL ANATOMY 27 



{a) The Solar Plexus. — The veins of this plexus dis- 

 charge themselves in two directions : (1) Bii a central canal 

 or canals running along the bottom of the lateral lacunae 

 of the plantar cushion to gain the deep layer of the 

 coronary plexus. (2) By the Circumfiex or Peripheral Vein 

 of the Toe, a canal formed by ramifications from the solar 

 and the podophyllous plexuses, and following the direction 

 of the artery of the same name. The circumflex vein 

 terminates by forwarding branches to concur in the forma- 

 tion of the superficial coronary plexus. 



ih) The Podojjhijllous or Laminal Plexus. — The jiodo- 

 phyllous veins anastomose below with the circumflex vein 

 of the solar plexus, and above with the veins of the 

 coronary plexus. 



(c) The Coronary Plexus.- — -This proceeds from the podo- 

 phyllous, the intra-osseous, and the solar networks, and 

 consists of a central and two lateral parts. 



The central portion lies between the lateral cartilages 

 and immediately under the coronary cushion. The lateral 

 portions are ramifications on both surfaces of the lateral 

 cartilages. The ramifications on the lateral cartilages 

 may be again distinguished as superficial and deep. The 

 superficial layer is distributed over the external face of the 

 cartilage, forming thereon a dense network, and finally 

 converges towards the superior limit of the plexus to form 

 ten or twelve principal branches, which again unite to 

 form two large vessels. These vessels, by their final fusion 

 at the lower end of the first phalanx, constitute the digital 

 vein. The deep layer is formed, as before described, by 

 ascending branches from the posterior parts of the podo- 

 phyllous and solar plexuses, and by branches from the 

 intra-osseous system of the pedal bone. The veins of this 

 deep layer finally drain into the two vessels proceeding 

 from the superficial layer, which go to the formation of the 

 digital vein. 



The Digital Veins — These arise from the network 

 formed on the surfaces of the lateral cartilages, and ascend 

 in front of the digital arteries to unite above the fetlock, 



