Topography and identification of the parathyroid glands in the calf

There is considerable controversy in the literature concerning the topography of the parathyroid glands in the calf. In the present study, the position of the parathyroids III (external parathyroids) and of the parathyroids IV (internal parathyroids) was examined in 25 young calves, 10 veal calves and 5 adult oxen. Detailed data for the recognition and the collection of these glands are provided. The parathyroids III are well suited for removal in a fresh state, since they can readily be located. They are situated medial to the carotid bifurcation and ventrolateral to the vagus nerve, where the latter gives off the cranial laryngeal nerve. In all young calves and in most veal calves, they lie embedded in the sub-basilar portion of the thymus, from which they can usually be differentiated easily by their color. However, they should not be confused with lymph nodes and hemal nodes, which are located in the neighborhood. Light-microscopical substantiation is therefore advisable. The parathyroids IV are not suited for collection, since they cannot be distinguished macroscopically from the adjacent thyroid gland.