Explains the middle ear cavity boundaries and contents

1. MIDDLE
EAR CAVITY

2. DIMENSIONS
• VERTICAL 15mm
• ANTERO-POSTERIOR 15mm
• Upper 6mm
• Middle 2mm
• Lower 4mm

4. BOUNDARIES
• Anterior Carotid
• Posterior Mastoid
• Roof Tegmen typani
• Floor Jugular
• Lateral Tymanic
• Medial Labrynthine

8. CONTENTS
EAR OSSICLES.
LIGAMENTS.
NERVES – Chorda tympani, Nerve to
stapedius, Nerve to tensor tympani.
BLOOD VESSELS supplying MEC.
MUSCLES – Tensor tympani, Stapedius.

9. AUDITORY TUBE

10. MALLEUS

11. INCUS

12. STAPES

13. BLOOD SUPPLY
• Tympanic br – maxillary artery
• Stylomastoid br. – post. Auricular .a.
• Petrosal br. – middle meningeal .a.
• Sup.tympanic br. ,,
• Tympanic br – ascending pharyngeal.a.
• Tympanic br. – Artery of pterygoid canal
• Tympanic br. - ICA

14. NERVE SUPPLY
• TYMPANIC PLEXUS
– Formed by glossopharyngeal nerve and superior &
inferior caroticotympanic br. Of sympathetic plexus
around ICA.

15. LYMPHATICS
• PAROTID
• DEEP CERVICAL LYMPH NODES.

16. APPLIED ANATOMY
INFECTIONS may spread on to
cranium,
through auditory tube into pharynx,
rupture of tympanic membrane,
pus collection spread onto mastoid antrum,
Compression of facial nerve due to severe
bone diseases.

17. OTITIS MEDIA