Light micrograph showing a cross-section of the neck. At top is the trachea showing C-shaped tracheal rings of hyaline cartilage. The tracheal mucosa is located inside the cartilage. On both sides, the thyroid can be seen with a striated muscle outside of it. At bottom there is a cross-sectioned oesophagus with a very folded lumen. The spaces among these structures are filled with adipose (fat) tissue.