The =lateral lobes= of the thyroid gland are long and narrow, and have a
flattened, ellipsoidal form; they are placed on the lateral surfaces of
the trachea near the larynx. The extremities are small, the posterior
one often being pointed. The =isthmus= is inconstant and variable; in
large dogs it usually has the form of a glandular band which may be
nearly half an inch (ca. 1 cm.) wide; in small dogs it is usually
absent.
=Accessory thyroids= are frequently present; three or four may be found
on either side, as well as a median one near the hyoid bone.
The =parathyroids=, about the size of millet or hemp seed, are four in
number usually. Two are placed on the deep face of the thyroid lobes;
the others are placed laterally near the anterior extremity of the
thyroid.