Changes

The '''thoracic and cranial abdominal mammary glands '''drain via '''cranial superficial epigastric veins''' into the '''internal thoracic vein'''. '''Caudal abdominal and inguinal mammary glands '''drain via '''caudal superficial epigastric veins''' into the '''external pudendal vein'''.  

The '''thoracic and cranial abdominal mammary glands '''drain via '''cranial superficial epigastric veins''' into the '''internal thoracic vein'''. '''Caudal abdominal and inguinal mammary glands '''drain via '''caudal superficial epigastric veins''' into the '''external pudendal vein'''.  

===Lymphatics===

===Lymphatics===

The more caudal mammary glands drain to the  '''superficial inguinal lymph node''' and the more cranial mammary glands to the axillary or sternal lymph nodes.  

The more caudal mammary glands drain to the '''superficial inguinal lymph node''' and the more cranial mammary glands to the '''axillary or '''sternal''' lymph nodes.  

===Innervation===

===Innervation===

Somatic innervation is via the ventral rami of the spinal nerves.  Mammary branches of the '''pudendal nerve''' supply the caudal aspect of the udder. There is sympathetic innervation to the blood vessels and teat sphincter smooth muscle. Mammary glands also have major influence from endocrine hormones.

Somatic innervation is via the ventral rami of the spinal nerves.  Mammary branches of the '''pudendal nerve''' supply the caudal aspect of the udder. There is sympathetic innervation to the blood vessels and teat sphincter smooth muscle. Mammary glands also have major influence from endocrine hormones.