L'U THE ANATOMY OF THE HORSE. 



1-adial vessels and the median nerve may be felt as they lie on the bone 

 under cover of the posterior supei-ficial pectoral, and they may be made 

 to roll under the finger. This should be practised, as the posterior 

 radial artery is a convenient vessel at which to feel the pulse. The 

 internal subcutaneous vein crosses the inner ftice of the fore -arm 

 obliquely upwards and forwards ; and in the living animal, pressure at 

 the upper part Avill distend the vessel and bring it into view. At the 

 outer side of the carpus the prominence foi*med by the pisiform bone 

 may be seen and felt. On the inner surface of the fore-arm, at its lower 

 third, the skin presents an oval-shaped, horny callosity, vulgarly termed 

 the chestnut. This is largest in coarse-bred animals. 



Directions. — The skin is now to be carefully removed from the 

 fore -arm and carpus, and the cutaneous nerves and vessels are to be 

 sought. 



Cutaneous Nerves. (1) At the front of the elbow -joint (Plate 8) the 

 cutaneous division of the musculo-cutaneous branch of the median appears 

 from beneath the biceps, and splits into two branches, one accompanying 

 the anterior, the other the internal, subcutaneous vein ; (2) a little way 

 below the elbow, on its inner aspect, the cutaneous branch of the ulnar 

 (Plate 5) appears from beneath the insertion of the posterior superficial 

 pectoral, and divides for the supply of the skin of the back of the fore-arm 

 on both its outer and its inner side ; (3) perforating the caput medium, 

 or emerging at its lower edge, are some twigs from the musculo-spiral 

 nerve, which are distributed to the skin of the outer side of the fore-arm 

 beneath the elbow ; (4) on the outer side of the carpus (Plate 8) are the 

 ramifications of a cutaneous branch of the ulnar, which comes out be- 

 tween the tendons of the external and oblique flexors of the metacarpus. 



Subcutaneous Veins. — 1. The Median or Internal subcutaneous vein 

 begins at the inner side of the carpus, where it continues upwards the 

 internal metacarpal vein. It crosses the fore -arm obliquely upwards 

 and forwards, in company with a cutaneous nei've already described, 

 and divides into the cephalic and basilic veins. The Cephalic vein has 

 already been seen ascending in the groove between the mastoido- 

 humeralis and the anterior superficial pectoral to terminate in the 

 jugular. The Basilic vein pierces the posterior superficial pectoral 

 to concur in forming the brachial vein. 



2. The Anterior subcutaneous or radial vein is much smaller than the 

 preceding vessel. It begins at the front of the carpus, and, ascending 

 on the middle line of the fore-arm, it empties itself into the cephalic or 

 the median vein. 



Directions. — The thin superficial fascia in which these nerves and 

 vessels are distributed should be removed to show the deep fascia. 



Deep Fascia of the fore-arm. — This is spread in the form of a close- 

 fitting fibrous envelope around the fore -arm. Above it receives an 



