1) External ear parts

A. Auricle (pinna)

• Helix
• Antihelix
• Tragus
• Antitragus
• Lobule
• Concha (leads into ear canal)
• Scaphoid fossa, triangular fossa (depressions)

B. External acoustic meatus (external auditory canal)

• Lateral 1/3 cartilaginous
• Medial 2/3 bony
• Ends at tympanic membrane

C. Tympanic membrane (eardrum)

• Pars tensa (large, taut, fibrous)
• Pars flaccida (small, superior, lax)
• Landmarks: handle of malleus, umbo, cone of light

2) Nerve supply

A. External ear (auricle + external canal)

• Auriculotemporal nerve (V3)
  • Anterosuperior auricle, anterior wall/roof of canal
• Great auricular nerve (C2-C3)
  • Most of inferoposterior auricle, lobule
• Lesser occipital nerve (C2)
  • Upper posterior auricle
• Auricular branch of vagus (X) (Arnold nerve)
  • Concha, posteroinferior canal (can cause cough reflex during cleaning)
• Facial nerve (VII) contribution (small sensory component around concha/meatus in some descriptions)

B. Tympanic membrane sensory innervation

• External (lateral) surface: mainly auriculotemporal nerve (V3) + auricular branch of vagus (X)
• Internal (medial) surface: glossopharyngeal nerve (IX) via tympanic plexus

3) Blood supply

A. External ear (auricle)

• Posterior auricular artery
• Superficial temporal artery (anterior auricular branches) (Occipital artery may contribute posteriorly)

B. External auditory canal

• Deep auricular artery (from maxillary artery) is key
• Contributions from posterior auricular/superficial temporal branches

C. Tympanic membrane

• Lateral surface: chiefly deep auricular artery (maxillary)
• Medial surface: vessels from middle ear mucosa, mainly anterior tympanic and related caroticotympanic/stylomastoid contributions (anastomotic network)