872 



THE NERVES. 



descends in the third interosseous space, furnishes a filament to the large cushion of the paw, 

 and divides to form the external palmar collaterals of the index and internal of the medius. 

 Finally, the external branch is placed in the second intermetacarpal space, and gives the 

 following palmar collaterals : the external of the medius and internal of the annularis. 



The ulnar nerve of the Dog, below the elbow, lies beside the ulnar artery to the lower third 

 of that vessel ; there it forms two branches— a dorsal and palmar. The dorsal branch becomes 

 8ubcutaneou8,'pa8ses along the external border of the forearm, metacarpus, and small digit, and 

 constitutes the external dorsal collateral nerve of the latter. 



The palmar branch leaves the carpal sheath, gives oft", at the trapezoides, a ramuscule that 

 passes to the surface of the palmar muscles to form the external collateral palmar of tiie 

 auricularis, and then, at the surface of tl.e deep palmar arch, divides into eight terminal 



Fig. 471. 



THE NERVES OF THE AXILLA. OF MAN. 



1, Scalenus medius; 2. scalenus anticus ; 3, cord formed by 5th and 6th cervical nerves; 4, 7th 

 cervical nerve; 5, superscapular nerve ; 6, subclavian artery (cut) , 7, insertion of subclavius ; 8, 

 cord formed by 8th cervical and 1st dorsal nerves ; 9, pectoralis major (reflected); 10, internal 

 anterior thoracic nerve ; 12, origin of subclavius ; 13, pectoralis minor (reflected) ; 14, internal 

 cutaneous nerve; 15, axillary artery (cut); 16, posterior thoracic nerve; 17, musculo-cutaneous 

 nerve; 18, origin of pectoralis minor; 19, median nerve; 20, nerve of Wrisberg ; 21, coraco- 

 brachialis ; 22, intercosto-humeral nerve ; 23, ulnar nerve ; 24, subscapularis ; 25, brachial 

 artery ; 2 !, lateral cutaneous branch of 3rd intercostal nerve ; 27, middle subscapular nerve ; 28, 

 short subscapular nerve; 29, pectoralis major (cut) ; 31, basilic vein; 32, serratus magnus; 33, 

 latissimus dorsi. 



ramuscules. The smallest of these is expended in the rudimentary muscles of the thumb, the 

 email digit, and interosseous muscles; the largest, three in number, lie on the interosseous 

 arteries, and bifurcate at the digits to form the palmar coUaternls ; the two internal ramuscules 

 are previously confounded with the corresponding branchc s ot the median. From this arrange- 

 ment, it results that the ulnar nerve supplies the palmar surface of all the digits, except the 

 internal border of the index. 



The ulnar of the Cat also dividis into a dorsal and a palmar branch, but the distribution 

 of these is not the same as in the Dog. 



The dorsal branch bifurcates at the carpus : one of the filaments forms the external dorsal 

 collateral of the small digit; the other reaches the first interosseous space, receives a branch 



