![]() These cells convert the vibrations to nerve signals, which are then transported to the brain. It is filled with fluid and lined with very fine hairs (hair cells). The sound waves are amplified by this transfer and then enter the cochlea. The malleus is attached to the eardrum, picking up its vibrations and passing them on to the inner ear via the incus and the stapes. It is the ear bones that are important for hearing: the malleus, the incus and the stapes. But germs can also enter the middle ear through the Eustachian tube from the upper throat. A rare, otorhinolaryngological malformation characterized by failure in development of the external ear canal. Air moves in and out to accommodate different pressures in the outside environment. External auditory canal aplasia/hypoplasia. It is connected to the upper throat by the Eustachian tube. The middle ear is an air-filled cavity also referred to as the tympanic cavity. First cartilage and then further on bone help to keep this passageway open so that the sound waves can reach the eardrum without being affected. Like a satellite dish, it captures sound waves and passes them on to the outer ear canal. The lymphatic drainage of the external ear is to the superficial parotid, mastoid, upper deep cervical and superficial cervical nodes.The outer ear is made up of skin and cartilage. Some individuals can complain of an involuntary cough when cleaning their ears - this is due to stimulation of the auricular branch of the vagus nerve (the vagus nerve is also responsible for the cough reflex). Branches of the facial and vagus nerves - innervates the deeper aspect of the auricle and external auditory meatus. ![]() Auriculotemporal nerve (branch of the mandibular nerve) - innervates the skin of the auricle and external auditory meatus.Lesser occipital nerve (branch of the cervical plexus) - innervates the skin of the auricle.Greater auricular nerve (branch of the cervical plexus) - innervates the skin of the auricle.The sensory innervation to the skin of the auricle comes from numerous nerves: Venous drainage is via veins following the arteries listed above. Maxillary artery (deep auricular branch) - supplies the deep aspect of the external acoustic meatus and tympanic membrane only.The external ear is supplied by branches of the external carotid artery: The parts of the tympanic membrane moving away from the lateral process are called the anterior and posterior malleolar folds. The handle of malleus continues superiorly, and at its highest point, a small projection called the lateral process of the malleus can be seen. On the inner surface of the membrane, the handle of malleus attaches to the tympanic membrane, at a point called the umbo of tympanic membrane. The translucency of the tympanic membrane allows the structures within the middle ear to be observed during otoscopy. The membrane is connected to the surrounding temporal bone by a fibrocartilaginous ring. It is a connective tissue structure, covered with skin on the outside and a mucous membrane on the inside. The tympanic membrane lies at the distal end of the external acoustic meatus. It ends by running in an inferoanterior direction.The external auditory canal’s function is to transmit sound from the pinna to the eardrum. In then turns slightly to move superoposteriorly. Once the sound waves have passed the pinna, they move two to three centimetres into the auditory canal before hitting the eardrum, also known as the tympanic membrane.Initially it travels in a superoanterior direction.The external acoustic meatus does not have a straight path, and instead travels in an S-shaped curve as follows: The walls of the external 1/3 are formed by cartilage, whereas the inner 2/3 are formed by the temporal bone. The external acoustic meatus is a sigmoid shaped tube that extends from the deep part of the concha to the tympanic membrane.
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