mastoids and organs of hearing
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Mastoids and Organs of Hearing. Fall 2011 FINAL. Ear. http://www.squidoo.com/otosclerosis. Temporal Bone. Temporal Bones. Situated on each side of cranial base between ____________and occipital bone Form large part of ______ cranial fossa and a small part of ________ cranial fossa.

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temporal bones
Temporal Bones
  • Situated on each side of cranial base between ____________and occipital bone
  • Form large part of ______ cranial fossa and a small part of ________ cranial fossa
temporal bones1
Temporal Bones
  • Consist of
    • Squamous portion
    • Tympanic portion
    • Styloid process
    • Zygomatic process
    • Petromastoid portion

a) contains the organs for ___________________

temporal bones2
Temporal Bones
  • Tympanic portion = located below squama and in front of petromastoid portion
    • Forms anterior wall, inferior wall and part of posterior walls of the EAM
  • Styloid process = slender, pointed bone projecting inferiorly, anteriorly, and slightly medially from inferior surface of tympanic portion
temporal bones3
Temporal Bones
  • Petromastoid portion combines petrous and mastoid portions
    • Forms the inferior, posterior part of the temporal bone
    • Articulates with parietal bone at its superior border and with occipital bone at its posterior border
    • Usually contains air cells, which vary greatly in size, number, and pneumatization
temporal bones4
Temporal Bones
  • Mastoid process = conical process projecting from mastoid portion
  • Petrous portion projects medially and anteriorly between greater wing of sphenoid and occipital bone
    • Also called petrous pyramid
    • Conical or pyramidal in shape
    • Thickest and densest portion of cranium
    • Contains the organs of hearing and balance
temporal bones5
Temporal Bones
  • Auditory ossicles = bones of middle ear

1.

2.

3.

  • Temporal bone articulates with the parietal, occipital, sphenoid, zygoma, and mandible
temporal bone pathology
Temporal Bone Pathology
  • Mastoiditis
  • Neoplasms
    • Acoustic neuroma
    • Cholesteatoma
    • Polyp
  • Otosclerosis
essential projections temporal bone
Essential Projections: Temporal Bone
  • Axiolateral oblique (Modified Law)
  • Axiolateral oblique (Stenvers)
  • Axiolateral oblique (Arcelin)
axiolateral oblique modified law
Axiolateral Oblique (Modified Law)
  • IOML ______with IR
  • IPL _________ to IR
  • MSP angled 15 degrees toward IR
axiolateral oblique modified law1
Axiolateral Oblique (Modified Law)
  • CR
    • Angled 15 degrees caudad to midpoint of IR
    • Exits mastoid tip closer to IR about 1 (2.5 cm) posterior to EAM
    • Enters 2 (5 cm) posterior to and superior to upper EAM
axiolateral oblique temporal bone modified law
Axiolateral Oblique Temporal Bone (Modified Law)
  • Mastoid process closer to IR
  • Air cells centered to IR
  • Opposite mastoid process inferior and anterior mastoid of interest
  • Auricle of ear not superimposing mastoid
  • Superimposition of IAM and EAM
  • TMJ visible anterior to mastoid process
  • Close beam restriction
axiolateral oblique stenvers
Axiolateral Oblique (Stenvers)
  • IOML ________with transverse axis of IR
  • MSP at ________angle from IR
axiolateral oblique stenvers1
Axiolateral Oblique (Stenvers)
  • CR
    • Angled 12 degrees cephalad
    • Enters about 3 to 4 (7.6 to 10 cm) posterior and ½ (1.3 cm) inferior to upside EAM
    • Exits 1 (2.5 cm) anterior to downside EAM
    • IR and CR centered
axiolateral oblique temporal bone stenvers
Axiolateral Oblique Temporal Bone (Stenvers)
  • Petromastoid portion in profile
  • Lateral border of skull to lateral border of orbit
  • Petrous ridge extended to a point about two thirds up lateral border of orbit Mastoid process in profile below cranium
  • Posterior margin of mandibular ramus superimposing lateral border of C-spine
  • Mandibular condyle projecting over atlas near petrosa
  • Close beam restriction
axiolateral oblique temporal bone arcelin
Axiolateral Oblique Temporal Bone (Arcelin)
  • Rotate face away from side of interest to place MSP at 45-degree angle with plane of IR
  • IOML perpendicular to IR
axiolateral oblique temporal bone arcelin1
Axiolateral Oblique Temporal Bone (Arcelin)
  • CR
    • Angled 10 degrees caudad
    • Enters temporal area at 1 (2.5 cm) anterior to EAM and ¾ (1.9) cm above it
    • Center IR and CR
axiolateral oblique temporal bone arcelin2
Axiolateral Oblique Temporal Bone (Arcelin)
  • Petromastoid portion in profile
  • Lateral border of skull to lateral border of orbit
  • Petrous ridge lying horizontal about two thirds up lateral border of orbit Mastoid process in profile below cranium
  • Posterior margin of mandibular ramus superimposing lateral border of C-spine
  • Mandibular condyle projecting over atlas near petrosa
  • Close beam restriction
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