ear

• Pteromastoid segment


  Composite structure formed by the petrous and mastoid parts of the temporal bone, important for housing crucial structures and providing attachment for muscles.
• External Surface of Mastoid Part


  Highly roughened surface due to muscle and blood vessel attachments, giving a rough appearance
• Middle Meningeal Artery


  Artery inside the brain that grows the inside of the skull, supplied by the maxillary artery
• Temporal Fossa


  Space within the temporal bone; below it lies the infratemporal fossa
• Temporal Bone Anatomy


  The study of the structure and composition of the temporal bone, which houses important structures related to hearing and equilibrium
• Ear anatomy


  The external, middle, and inner ear are the three main parts of the ear, each with specific functions related to sound collection, vibration conversion, and sensory reception.
• Temporal Bone Landmarks


  Distinct features of the temporal bone include the squamous, tympanic, styloid, and petrous parts, each playing a role in the overall topographic anatomy
• Mastoid Process


  Part of the temporal bone forming the mastoid portion, separate from the petrous part structurally
• Muscles Attaching to Mastoid


  Include digastric muscle, longus capitis muscle, and sternocleidomastoid muscle, contributing to the rough exterior surface.
• Jugular Fossa


  The impression for the jugular vein on the inferior surface of the petrous bone.
• Bony Labyrinth


  Interconnected cavities within the petrous part of the temporal bone lined by periosteum and filled with perilymphatic fluid
• Endolymphatic fluid


  Fluid found within the membranous labyrinth of the inner ear, with a similar concentration to cytosol.
• Hypotympanum


  The region below the level of the inferior margin of the eardrum.
• Zygomatic Process


  Anterior projection from the squamous part, consisting of posterior and anterior roots.
• Ear Ossicles


  The three smallest bones in the human body (malleus, incus, stapes) located in the middle ear that amplify sound vibrations from the eardrum to the inner ear.
• Temporal Lobe


  Part of the brain housing the temporal lobe which usually rests here.
• Tympanic Bone


  Curved bone forming most of the auditory canal's margins and the posterior wall of the tympanic cavity.
• Ear

  The organ of hearing and equilibrium (balance)
• Parts of the ear

  • External ear
  • Middle ear
  • Internal ear

  
• External ear and middle ear

  • Mainly concerned with the transfer of sound to the internal ear

  
• Internal ear

  • Contains the organ for equilibrium as well as for hearing

  
• Tympanic membrane

  Separates the external ear from the middle ear

  
• Pharyngotympanic tube

  Joins the middle ear to the nasopharynx

  
• External ear

  • Composed of the auricle (pinna) and the external acoustic meatus

  
• Auricle

  Shell-like structure that collects sound
• Parts of the auricle

  • Concha
  • Helix
  • Lobule
  • Tragus
• Lobule

  Non-cartilaginous part consisting of fibrous tissue, fat, and blood vessels
• Tragus

  Tongue-like projection overlapping the opening of the external acoustic meatus
• Arterial supply to the auricle

  • Derived mainly from the posterior auricular and superficial temporal arteries
• Nerves to the skin of the auricle

  • Great auricular and auriculotemporal nerves
• Great auricular nerve

  Supplies the cranial (medial) surface and the posterior part of the lateral surface of the auricle
• Auriculotemporal nerve

  Supplies the skin of the auricle anterior to the external acoustic meatus
• Lymphatic drainage of the auricle

  • Lateral surface of superior half drains to superficial parotid lymph nodes
  • Cranial surface of superior half drains to mastoid and deep cervical lymph nodes
  • Remainder of auricle, including lobule, drains to superficial cervical lymph nodes
• External acoustic meatus

  Ear canal that leads inward through the tympanic part of the temporal bone from the auricle to the tympanic membrane

  
• External acoustic meatus

  • Lateral third is cartilaginous and lined with skin continuous with auricular skin
  • Medial two thirds is bony and lined with thin skin continuous with external layer of tympanic membrane
• Cerumen

  Earwax produced by ceruminous and sebaceous glands in the subcutaneous tissue of the cartilaginous part of the meatus

  
• Tympanic membrane

  Thin, oval semitransparent membrane at the medial end of the external acoustic meatus
• Tympanic membrane

  • Covered with thin skin externally and mucous membrane of the middle ear internally
  • Has a concavity toward the external acoustic meatus with a shallow, cone-like central depression called the umbo
  • Oriented like a mini radar or satellite dish positioned to receive signals coming from the ground in front and to the side of the head

  
• Parts of the tympanic membrane

  • Pars flaccida (thin, lacks radial and circular fibers)
  • Pars tensa (remainder of membrane with radial and circular fibers)
• Tympanic membrane

  Moves in response to air vibrations that pass to it through the external acoustic meatus