Middle Ear Structures for Extended Matching Questions
Ossicles (Bones)
- Malleus (hammer): Attached to the tympanic membrane; the first bone in the ossicular chain 1, 2
- Incus (anvil): The middle ossicle connecting malleus to stapes 1, 2
- Stapes (stirrup): The smallest bone in the body; articulates with the oval window of the inner ear 1, 2
Membranes and Windows
- Tympanic membrane (eardrum): Thin cone-shaped membrane separating the outer ear from the middle ear cavity 1, 2
- Oval window: Connects the middle ear with the inner ear; receives vibrations from the stapes 2
- Round window: Secondary tympanic membrane that allows fluid movement in the cochlea (general anatomy knowledge)
Muscles
- Tensor tympani muscle: Attaches to the malleus; dampens sound by tensing the tympanic membrane 3
- Stapedius muscle: Attaches to the stapes; the smallest skeletal muscle in the body; dampens excessive sound pressure (general anatomy knowledge)
- Pyramid (pyramidal eminence): Bony prominence housing the stapedius muscle and its tendon (general anatomy knowledge)
Air Spaces and Connections
- Middle ear cavity (tympanic cavity): Air-filled space containing the ossicles 1, 2
- Eustachian tube (auditory tube): Connects the middle ear cavity to the nasopharynx; responsible for pressure equalization and drainage 1, 3
- Mastoid air cells: Posterior extension of the middle ear cavity into the mastoid process 3
- Aditus ad antrum: Opening connecting the epitympanic recess to the mastoid antrum (general anatomy knowledge)
Anatomical Recesses and Landmarks
- Epitympanic recess (attic): Superior portion of the middle ear cavity above the tympanic membrane; contains the head of malleus and body of incus (general anatomy knowledge)
- Mesotympanum: Middle portion of the tympanic cavity at the level of the tympanic membrane (general anatomy knowledge)
- Hypotympanum: Inferior portion of the tympanic cavity below the tympanic membrane (general anatomy knowledge)
- Scutum: Sharp bony spur forming the lateral wall of the epitympanic recess 4
Nerves
- Chorda tympani nerve: Branch of facial nerve (CN VII) that crosses the middle ear medial to the tympanic membrane and malleus; carries taste from anterior 2/3 of tongue (general anatomy knowledge)
- Tympanic plexus: Formed by tympanic branch of glossopharyngeal nerve (Jacobson's nerve); provides sensory innervation to middle ear mucosa (general anatomy knowledge)