The lymph from the auditory tube is drained into the deep cervical lymph nodes. The venous blood is drained from the auditory tube via the pterygoid plexus of veins in the infratemporal fossa. Artery of the pterygoid canal (a branch of the maxillary artery).Middle meningeal artery (a branch of the maxillary artery ).Ascending pharyngeal artery (a branch of the external carotid artery ).The blood supply to the auditory tube is provided by the following arteries: Vasculature and innervation of the auditory tube Blood supply and venous drainage It assists in allowing air pressure to equalize between the tympanic cavity and the external ear during swallowing. Tensor veli palatini - this muscle tenses the soft palatine and assists levator veli palatini.The tightening stops the vibration from disturbing the perilymph. Contractions pull the manubrium of the malleus inwards and tighten it. The reflex contracts the muscles of the middle ear. Tensor tympani - it allows involuntary control known as a tympanic reflex.During swallowing, this muscle opens the pharyngeal orifice of the auditory tube and allows the equalization of pressure. Salpingopharyngeus - it starts from the superior margin of the medial cartilage of the auditory tube.This muscle is the elevator muscle of the soft palate.
This connection between the middle ear and the nasopharynx serves primarily to equalize the pressure. The air pressure in the external ear and the nasopharynx is equal to open-air pressure. The auditory tube is lined with mucosa that is the continuation of the pharynx mucosa. On the border between both of the parts of the auditory tube is the narrowest place called isthmus tubae auditivae. The auditory tube has two openings - the pharyngeal orifice of the auditory tube in the lateral wall of the pharynx and the tympanic orifice of the auditory tube that opens in the tympanic cavity anterior wall. The groove ends opposite the middle of the medial pterygoid plate. The cartilage lies in a groove between the petrous part of the temporal bone and the great wing of the sphenoid. Its apex is attached to the superior margin of the medial end of the bony part, but its base lies directly under the mucous membrane of the nasal part of the pharynx. The cartilaginous part of the auditory tube is formed of a triangular plate of elastic fibrocartilage. The opening of the bony part of the auditory tube is clearly visible on the inferior surface of the skull at the junction between the squamous and petrous parts of the temporal bone, immediately posterior to the foramen ovale and foramen spinosum. The bony part starts in the anterior wall of the tympanic cavity and is gradually getting narrower. Cartilaginous part (the remaining two-thirds).Bony part (the one-third nearest the middle ear).Protection from the influences of the nasopharyngeal environment and loud sounds.Pressure equalization on both aspects of the tympanic membrane.The main functions of the auditory tube are as following: The tube is shorter and straighter in children than in adults, so middle ear infections are more common in children. From here, the auditory tube extends forward, medially, and downward to enter the nasopharynx, opening in the lateral wall of the nasopharynx just posterior to the inferior meatus of the nasal cavity.īy joining the two structures, the auditory tube acts as a pathway for upper respiratory infection to spread into the middle ear. The opening of the auditory tube in the middle ear is located in its anterior wall. The auditory tube is 3,5-4 cm long and around 2 mm in diameter. The auditory tube (also known as the pharyngotympanic tube, Eustachian tube, Latin: tuba auditiva) is a tunnel that connects the tympanic cavity to the nasopharynx and equalizes pressure on both sides of the tympanic membrane.
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