Merck Manual

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There are 10 mammary glands in dogs, any of which may be the site of a tumor. Most tumors occur in the 2 sets of glands closest to the hind legs.
There are 10 sets of mammary glands in dogs, any of which may be the site of a tumor. Most tumors occur in the glands closest to the hind legs.
There are 10 mammary glands in dogs, any of which may be the site of a tumor. Most tumors occur in the 2 sets of glands closest to the hind legs.