Dissection of the Auditory Bulla in Postnatal Mice: Isolation of the Middle Ear Bones and Histological Analysis
1Instituto de Investigaciones Biomédicas (IIBm) Alberto Sols CSIC-UAM, 2Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III (ISCIII), 3Instituto de Investigación Sanitaria La Paz (IdiPAZ), 4Facultad de Veterinaria, Universidad Complutense de Madrid, 5Departmento de Otorrino laringología, Hospital Universitario La Paz
1Department of Otolaryngology Head and Neck Surgery, Medical University of South Carolina, 2Department of Pathology and Laboratory Sciences, Medical University of South Carolina, 3Intuitive Surgical, Inc
Source: Richard Glickman-Simon, MD, Assistant Professor, Department of Public Health and Community Medicine, Tufts University School of Medicine, MA
This video describes the examination of the ear, beginning with a review of its surface and interior anatomy (Figure 1). The cartilaginous auricle consists of the helix, antihelix, earlobe, and tragus. The mastoid process is positioned just behind the earlobe. The slightly curving auditory canal ends at the tympanic membrane, which transmits sound waves collected by the external ear to the air-filled middle ear. The Eustachian tube connects to the middle ear with the nasopharynx. Vibrations of the tympanic membrane transmit to the three connected ossicles of the middle ear (the malleus, incus, and stapes). The vibrations are transformed into electrical signals in the inner ear, and then carried to the brain by the cochlear nerve. Hearing, therefore, comprises a conductive phase that involves the external and middle ear, and a sensorineural phase that involves the inner ear and cochlear nerve.
The auditory canal and the tympanic membrane are examined with the otoscope, a handheld instrument with a light source, a magnifier, and a disposable cone-shaped speculum. It is important to be familiar with the tympanic membrane landmarks (
1Department of Otorhinolaryngology, Head and Neck Surgery, Inselspital, Bern University Hospital, University of Bern, 2Department of Otorhinolaryngology, Head & Neck Surgery, University Hospital of Modena, 3Department of Otorhinolaryngology, Head & Neck Surgery, University Hospital of Verona, 4Artificial Hearing Research, Artorg Center for Biomedical Engineering, University of Bern
1Division of Regenerative Medicine, Jikei University School of Medicine, 2Department of Otorhinolaryngology, Jikei University School of Medicine, 3Department of Otorhinolaryngology, Head and Neck Surgery, Keio University School of Medicine, 4Laboratory Animal Facilities, Jikei University School of Medicine