RadioAnat Flashcards
Orbital bones: medial wall of the orbit
Ethmoid Bone
Orbital bone: Entire roof of the orbit
Frontal Bone
Orbital bone: medial wall and floor of the orbit
Maxilla Bone
Orbital bone: medial wall
Lacrimal bone
Orbital bone: lateral margin and floor of the orbit
Zygomatic Bone
Orbital bone: forms the apex
Sphenoid bone
MAXILLARY BONE
LACRIMAL BONE
ETHMOID BONE
BODY OF SPHENOID BONE
Median orbital wall
smallest bones, anterior part of the medial wall of orbits; in between ethmoid and maxilla
LACRIMAL BONE
MAXILLARY BONE
ZYGOMATIC BONE
PALATINE BONE
FLOOR OF ORBITAL BONE
ZYGOMATIC BONE
GREATER WING OF THE SPHENOID BONE
LATERAL WALL OF ORBITAL BONE
Frontal
Maxillary
Ethmoid
Sphenoid
Paranasal Sinuses
Excellent view for
Maxilla, Maxillary sinuses, Zygoma, Zygomatic arches, Rims of orbits (floor) and Nasal bones
Water’s View
Excellent view for
Entire rim of orbit - superomedial rim, Ethmoid sinus, Floor of orbit may be well seen in petrous bone are projected below the inferior orbital rim
Caldwell’s View
Key structures: Frontal sinus, Maxillary sinus, Frontal process of Zygoma, Body of Zygoma (malar eminence), Temporal process of Zygoma
Rule: smooth, non-disturpted, same contour on both sides
Water’s View
Key structures: Ethmoid sinuses and Orbit
Rule: Ethmoid sinuses density should be equal of darker than the orbit, smooth non-disrupted orbital walls
Caldwell’s View
Most comprehensive single projection display
Water’s view
Excellent view for
Maxillary Sinus: Posterolateral Wall
Zygomatic arch
Towne’s View
Key structures: Frontal sinus, Maxillary Sinus, Sphenoid Sinus, Hard Palate, Anterior wall of temporal fossa, Pterygoid plate
Towne’s View
Retrobulbar Fat, EOMS, Optic Nerve
Orbital Tissue
Superior, Inferior, Medial and Lateral
Recti Muscles
Superior and Inferior Oblique
Oblique Muscle
is a ring of fibrous tissue that surrounds the optic nerve at its entrance at the apex of the orbit.
Annulus of Zinn
Annulus of Zinn is the origin of these muscles except:
a. Superior Rectus
b. Inferior Rectus
c. Lateral Rectus
d. Superior Oblique
d. Superior Oblique
Pulley for the Superior Oblique Muscle
Trochlea
Water: Bright
Fat: Dark
Air/Bone: Dark
T2
Water: Dark
Fat: Bright
Air/Bone: Dark
T1
15-30 mm from the orbital rim
ANTERIOR ETHMOIDAL FORAMEN
20-40 mm from the orbital rim
POSTERIOR ETHMOIDAL FORAMEN
T1WI & T2WI: medium to low signal intensity
CORNEA/ SCLERA
T1W1: low T2WI: high
ANTERIOR EYE CHAMBER
98% water and less than 2% collagen
POSTERIOR EYE CHAMBER
65% water and 35% protein
T1WI: intermediate T2WI: low
LENS
Demarcates the anterior and posterior ethmoid air cells
Middle Turbinate
All the paranasal sinuses drain into the middle meatus, EXCEPT
a. posterior ethmoid and sphenoid sinuses
b. ethmoid bulla and maxillary sinus
c. frontal sinus and maxillary sinus
a.posterior ethmoid and sphenoid sinuses
Tympanic Membrane
Outer cartilagenous portions
Bony or osseous portion
Squamous epithelium
Parts of External Auditory Canal
Flexible part of Tympanic Membrane
Par flaccida
Tense part of Tympanic Membrane
Pars tensa
Middle Ear Space: Superior to annulus
body of incus and head of malleus
Epitympanum (Attic)
Middle Ear Space: on level with the TM (oval and round windows, long process of process of incus, articulation with stapes, facial nerve in bony canal)
Mesotympanum
Below annulus (jugular bulb)
Hypotympanum
In anterior recess of middle ear (eustachian tube)
Protympanum
Posterior to annulus (sinus, tympani, facial recess)
Retrotympanum
Spur - shaped bony projection top of tympanic membrane
Scutum
anterior recess of TM, between neck of malleus and pars flaccida of tympanic membrane
Prussak’s space
most common site of acquired attic cholesteatoma
Prussak’s space
Head
Manubrium or handle
Malleus (Hammer)
Long process
Short process
Lenticular process
Incus
Foot plate
Capitulum
Ctus
Stapes
- arises form cartilaginous and bony margins of eustachian tube
- inserts on handle of malleus
- dampens ossicular chain
Tensor tympani membrane
- opening between middle and inner ear, associated with scala tympani
- below oval window
Round window
Medial wall of tympanic cavity formed by basal turn of cochlea
Promotory
- channel through which the tympanic cavity communicates with the nasopharynx.
- approximately 36 mm in length and is directed downward, forward, and medialy, forming an angle of about 45 degrees with the sagittal plane
Eustachian Canal
- SEMICIRCULAR CANALS
- COCHLEA
- VESTIBULE
- VESTIBULAR AQUEDUCT
Bony Labyrinth
- UTRICLE AND SACCULE
- COCHLEAR DUCT
- ENDOLYMPHATIC DUCT AND SAC
Membranous Labyrinth
3 parts of semicircular canal
- Superior semicircular canal (SSC)
- Posterior semicircular canal (PSC)
- Horizontal or Lateral semicircular canal
(LSC)
Axial: apical, middle, and basal turns (NORMAL)
Hamburger Sign
2 parts of Aqueducts
Cochlear Aqueduct
Vestibular Aqueduct
- Bony canal that passes to posterior fossa dura
- Opens lateral to IAM
- transmits endolymphatic duct and 2 blood vessels into blind sac (reservoir for excess endolymph)
Vestibular aqueduct
Common crus of vestibular aqueduct
union of superior and posterior SC duct
Neurovascular Space
Facial nerve canal, Carotid Canal, Jugular Fossa
- taste fibers to anterior 2/3 tongue
- preganglionic parasympathetic to submandibular and sublingual glands
- Courses between incus and handle of melees
Chorda tympani