The Ductless Glands are a number of organs in different parts of the body, which, as their name implies, have no ducts, but pour their "internal secretion" direct into the vascular system. The principal ones are the lymphatic glands, the thyroid gland, suprarenal capsules, and spleen.

Thyroid Gland

The Thyroid Gland is a very vascular structure situated at the upper end of the trachea, and extending upwards on the sides of the larynx. It consists of three parts, two lateral lobes joined in the middle line by the body. It is always relatively larger in the female and child than in the male.

The lateral lobe is triangular in shape, the base extends as far down as the fifth or sixth ring of the trachea, and the apex reaches up to the side of the thyroid cartilage. It is covered by some of the infrahyoid muscles and the sterno-mastoid muscle, and posteriorly it touches the oesophagus and common carotid artery.

The body is a narrow band uniting the lower ends of the lateral lobes and lying on the second and third rings of the trachea.