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Ear, Nose, and Paranasal Sinus
Published in Swati Goyal, Neuroradiology, 2020
The external auditory canal (EAC), with lateral one-third cartilaginous and medial two-thirds bony composition, extends from the auricle to the tympanic membrane. The middle ear cavity is within the petrous portion of the temporal bone and consists of the tympanic cavity (containing the ossicles, namely the malleus, incus, and stapes) and the antrum. The mastoid antrum communicates with the epitympanum via aditus ad antrum. The middle ear also contains muscles (tensor tympani and stapedius), the round and oval windows, and the chorda tympani nerve. The inner ear consists of the osseous labyrinth (cochlea, vestibule, and the three semicircular canals, namely the superior, posterior, and lateral canals) and the membranous labyrinth (the cochlear duct, utricle, saccule, semicircular ducts, endolymphatic duct, and endolymphatic sac). The membranous labyrinth contains endolymph, surrounded by perilymph, and is enclosed within the bony labyrinth. The internal auditory canal (IAC) is located in the petrous bone and transmits facial and vestibulocochlear nerves along with the labyrinthine artery. The pars flaccida is the upper delicate part that is associated with Eustachian tube dysfunction and cholesteatoma. The pars tensa is larger and more robust, and associated with perforations.
Special Senses
Published in Pritam S. Sahota, James A. Popp, Jerry F. Hardisty, Chirukandath Gopinath, Page R. Bouchard, Toxicologic Pathology, 2018
Kenneth A. Schafer, Oliver C. Turner, Richard A. Altschuler
The middle ear contains an air-filled space within the temporal bone (tympanic cavity) delineated laterally by the tympanic membrane at the end of the external auditory meatus and medially by the inner ear. The Eustachian (auditory) tube extends anteriorly from the tympanic cavity to connect with the nasal pharynx, and the mucous membranes lining these structures are similar. The auditory tube allows for equilibration of sound pressure to the air-filled middle ear space, provides drainage of fluids, but may also be a route of infection for the middle ear. The inner aspect of the tympanic membrane is covered by a mucous membrane of the middle ear, and the outer aspect is covered by mucosa of the external auditory meatus.
Anatomy and Embryology of the External and Middle Ear
Published in John C Watkinson, Raymond W Clarke, Christopher P Aldren, Doris-Eva Bamiou, Raymond W Clarke, Richard M Irving, Haytham Kubba, Shakeel R Saeed, Paediatrics, The Ear, Skull Base, 2018
The tympanic membrane lies at the medial end of the external auditory meatus and forms the majority of the lateral wall of the tympanic cavity. It is slightly oval in shape, being broader above than below, forming an angle of about 55° with the floor of the meatus. Its longest diameter from posterosuperior to anteroinferior is 9–10 mm, while perpendicular to this the shortest diameter is 8–9 mm. Most of the circumference is thickened to form a fibrocartilaginous ring, the tympanic annulus, which sits in a groove in the tympanic bone, the tympanic sulcus. The sulcus does not extend into the notch of Rivinus at the roof of the canal, which is formed by part of the squama of the temporal bone. From the superior limits of the sulcus, the annulus becomes a fibrous band which runs centrally as anterior and posterior malleolar folds to the lateral process of the malleus, the handle of which is clearly visible within the tympanic membrane. This leaves a small, triangular region of tympanic membrane above the malleolar folds within the notch of Rivinus, called the pars flaccida, which does not have a tympanic annulus at its margins. The pars tensa forms the rest of the tympanic membrane and is concave towards the ear canal but each segment is slightly convex between the lateral attachment of the annulus and the centre of the membrane where the tip of the malleus handle is attached at the umbo (Figure 46.4).
Transcanal endoscopic management of isolated congenital middle ear malformations
Published in Acta Oto-Laryngologica, 2023
Licai Shi, Shuainan Chen, Rujie Li, Yideng Huang
All operations in this study were performed by the same experienced ear surgeon (Yideng Huang) by exclusively transcanal endoscopic tympanoplasty surgery. Each patient received general anesthesia. After creating a tympanomeatal flap and removing a small part of the bone in the upper wall of the external auditory canal, the tympanic cavity and ossicular chain can be explored. The ways of hearing reconstruction were mentioned as follows. (1) Malleus-incus complex (MIC) anomalies with normal and mobile stapes. After removing the deformed auditory ossicles, the hearing was reconstructed with partial auditory ossicle prosthesis (PORP) (Figure 1). (2) Abnormal stapes suprastructure with a mobile stapes footplate: after removing the deformed superstructure of stapes and other malformed auditory ossicles, the hearing was reconstructed with complete auditory ossicular prosthesis (TORP) (Figure 2). (3) Stapes footplate fixation or oval window bony atresia/aplasia, with or without other parts of ossicular chain anomalies. Vestibulotomy with piston insertion was performed to establish a connection between the vestibule and the handle of the malleus or the long process of the incus (Figures 3–5).
Transcanal endoscopic ear surgery for management of ossicular malformation: clinical outcomes of 17 cases
Published in Acta Oto-Laryngologica, 2022
Alyssa Yoshida, Makoto Hosoya, Sho Kanzaki, Masato Fujioka, Hiroyuki Ozawa
In cases in which the lesion was located near the stapes, it was possible to perform a stapes surgery. However, four patients required the assistance of the microscope. In these cases, a narrowed external ear canal was observed. For these cases, we curved the external ear canal with microscopic assistance using powered devices. In cases that needed to enlarge the external ear canal, it was considered necessary for the observation of the tympanic cavity. In some cases of ossicular malformation, malformation of the ear canal is accompanied. Patients with a narrowed ear canal require a different approach using TEES; however, in some cases, it can be performed using powered devices. Ito et al. [16] reported that TEES was successfully performed in all 31 pediatric patients without resorting to a retroauricular incision by using a rigid endoscope with a 2.7 mm outer diameter. Transcanal atticotomy was performed in 7 of 31 (23%) patients, and transcanal atticoantrotomy followed by cartilage scutumplasty was required in 4 of 31 (13%) patients. Therefore, by using powered devices, TEES can be safely performed even in narrowed external ear canal cases.
Comparison of clinical outcome between endoscopic and postauricular incision microscopic type-1 tympanoplasty
Published in Acta Oto-Laryngologica, 2021
Yonglan Zhang, Wei Wang, Kaixu Xu, Ming Hu, Yuanxu Ma, Peng Lin
The affected ear was lifted upwards. An incision (∼1 cm) was made in the longitudinal direction at the inner edge of the tragus. The medial perichondrium of the tragus (about 1.5 cm × 1.0 cm) was excised. The incision in the tragus was sutured. Under the otoscope, a graft bed was made at the border of the perforating hole of the TM. Local anesthesia was induced at the junction of the bone and cartilage of the posterior wall of the ear canal. At 3–4 mm from the TM ring, a circular knife was used to cut the EAC skin in a U-shape. The tympanomeatal flap was elevated. The TM was separated from the surface of the handle of the malleus if the perforation was at the front or if the perforation was large. The tympanic cavity, eustachian ostium, and ossicular chain were explored. The perichondrium of the tragus was placed under the perforation margin of the TM through the TM. The perichondrium of the tragus was placed between the handle of the malleus and the TM if the perforation was at the front or if the perforation was large. The TM was filled with gelatin sponge for support. The tympanomeatal flap of the auditory canal was restored. The lateral auditory canal was filled with NasoPore bioresorbable dressing (Stryker, Kalamazoo, MI).