318 SPECIAL ANATOMY. 



3. Ramus dorsalis, the termination of art. radialis upon the back of the 

 carpus (see above), gives off: 



a. Transversa carpi dorsalis, passes transversely over the middle of 

 the back of the carpus, inwards, to the rete carpeum dorsale; anas- 

 tomoses with a. ulnaris, and gives off ascending and descending 

 branches. 



b. Interossea IL s. metacarpi dorsalis, passes between the second and 

 third metacarpal bones, passes at the inferior extremity forwards to 

 the arc. volaris sublimis, where two branches are then given off: 



1. Art. dorsalis radialis digiti medii, for the external border of the 

 middle finger. 



2. Art. dors, ulnaris indicis, for the internal border_of the thumb. 



c. 'Interossea 1., passes between the first and second metacarpal bone, 

 and gives off: 



1. Art. dors. rad. indicis for the radial border of index finger. 



2. Art. dors, ulnaris pollicis , for the ulnar border of thumb. 



d. Princeps s. magna pollicis , passes between the muscles of the ball of 

 the thumb and the volar side of the first metacarpal bone to the first 

 phalanx on the radial side. 



Rete articulare cubiti, the anastomosis about the elbow-joint, is 

 formed : 



1. Above by coUateralis radialis, ulnaris superior and inferior. 



2. Below by recurrens radialis , ulnaris, and interossea (which 

 see.) 



II. Ulnaris s. cubitalis, the ulnar artery, 



the internal, larger branch of brachialis, at first slightly curved 

 upwards and backwards, it passes backwards and inwards, then 

 (three lines from the origin) extends downwards on the anterior 

 surface of the Ulna as far as the carpal articulation ; hence, on 

 the outer (radial) side of os pisiforme, above the lig. carpi volar e 

 propr. to the hollow of the hand in the arcus volaris sublimis. 

 Position : at first deep behind mm. pronat. teres,flex. carp, radial, 

 palmar., flex. dig. sublimis, and N. medianus, then superficially, 

 between the tendons of flex, sublim. (outside) and carpi ulnaris 

 (inside) ; upon m. brachial f intern., flex, profund., and pronator 

 quod., the ulna ; on the outer side of Nerv. ulnaris ; at first out- 

 side, then behind, at last inside N. medianus. Branches to the 

 muscles ; also : 



1. Recurrens ulnaris. Origin: from the posterior wall, one inch from the 

 origin of the ulnaris. Course : deeply under the muscles towards the inside, 

 between condyl. internus and olecranon, upwards to the rete articulare cubiti. 



