Tympanic Membrane: Structure, Blood Supply, And Nerve Supply

Tympanic Membrane: Structure, Blood Supply, And Nerve Supply

Question 1. Tympanic membrane
Answer:

• It is thin, translucent partition between the external acoustic meatus and middle ear
• It is placed obliquely at an angle of 55 degrées with the floor of meatus
• It is composed of
  1. Outer cuticular layer of skin
  2. Middle fibrous layer
  3. Inner mucous layer

Tympanic membrane Blood Supply:

• Outer surface deep auricular branch of maxillary artery
• Inner surface anterior tympanic branch of maxillary artery

Tympanic membrane Nerve Supply:

1. Outer surface
   • Anteroinferior part auriculotemporal nerve
   • Posterosuperior part Auricular branch of vagus nerve
2. Inner surface
   • Tympanic branch of glossopharyngeal nerve

Question 2. Development of tympanic membrane
Answer:

• Tubo-tympanic recess develops from the dorsal part of the first pharyngeal pouch
• Tympanic membrane is formed by apposition of this recess and the first ectodermal cleft
• These two forms the inner and outer epithelial linings
• The intervening mesoderm forms the connective tissue basis.

Question 3. Name the muscles of tympanic cavity and their nerve supply.
Answer:

Muscles of tympanic cavity

Question 4. Internal auditory meatus
Answer:

• The internal auditory meatus is a canal within the petrous part of the temporal bone of the skull between the posterior cranial fossa and the inner ear.
• It opens above the anterior part of the jugular foramen
• It is about 1cm long and runs transversely in a lateral direction
  It is closed Laterally by a perforated plate of bone known as lamina cribosa which separates it from the internal ear.
• It transmits the seventh and eighth cranial nerves and the labyrinthine vessels.