Light micrograph showing a cross-section of the neck. At the top and sides are the striated muscles of the neck. Beneath the muscle, the largest cartilage is the thyroid cartilage. At centre is the trachea, showing C-shaped tracheal rings of hyaline cartilage. The tracheal mucosa is located inside the cartilage. On the sides, behind the muscles are two thyroid lobules. The right thyroid lobule shows a small parathyroid gland. At bottom there is a cross-sectioned oesophagus with a folded lumen. The spaces among these structures are filled with adipose (fat) tissue.