The trachea, larynx, lower pharynx and esophagus all lie behind the thyroid. In the pharynx, the pharyngeal glands secrete mucus. Obstruction of the airway can occur at the level of the pharynx or the trachea. Abnormalities of the pharynx and/or oral cavity may lead to oropharyngeal dysphagia. The foregut comprises the sucking pharynx and the oesophagus. It connects the inferior part of the pharynx (hypopharynx) with the trachea. Muscles in the pharynx push the food into the esophagus. Epiglottal consonants are made with the epiglottis and the back wall of the pharynx. The excretory bladder extends from the posterior end to the pharynx. Beneath this ganglion lies an exocrine gland that empties into the pharynx. The tonsils are a compact mass which point away from the lumen of the pharynx. Underdevelopment of the pharynx can also narrow the airway. The digestive system consists of a mouth, pharynx, and a gastrovascular cavity. Upper gastrointestinal bleeding is from a source between the pharynx and the ligament of Treitz. The mouth opens into a flattened pharynx.