CA Lab 5: Orbit and Ear
The bony orbit forms a four sided
pyramid with the base opening
into the anterior of the face
Foramen Structures that pass through
Optic canal Optic nerve, opthalamic artery,
centeral artery/vein of retina.
Lacrimal Lacrimal gland (secrete the
fossa aqueous-layer of the tear film)
Superior CN III, IV, VI, Frontal, Lacrimal,
orbital Nasociliary branches of V1,
fissure Superior ophthalmic vein
Structure Bones involved
Inferior Maxillary nerve/infraorbital
Superior orbital Frontal bone
orbital nerve; infraorbital vessels
margin
fissure
Medial orbital Frontal process of maxilla
Infraorbital infraorbital VAN
margin
groove and
Inferior orbital Zygomatic process of maxilla +
foramen
margin zygomatic bone
Lateral orbital Frontal process of zygomatic bone
margin + zygomatic process of frontal bone
Roof of bony orbit Orbital plate of frontal bone +
lesser wing of sphenoid
Medial wall of bony Orbital plate of ethmoid bone, Orbital process of
palatine
orbit orbital plate of lacrimal bone,
frontal process of maxilla
Floor of bony orbit Maxilla, palatine, zygomatic bone
Lateral wall of Zygomatic bone (ant), greater wing
bony orbit of sphenoid (post)
, Standing room only =
V1 through foramen
LEVATOR PALPEBRAE
spinosum
SUPERIORIS MUSCLE:
V2 through
Attaches to upper eyelid foramen
Elevates upper rotundun
eyelid
Two parts: V3 through foramen
Skeletal muscleovale
(main) –
innervated by superior division of
oculomotor)
Smooth muscle (deep).
Innervated by sympathetics
Al3(SO)4 LR6
Al = all muscles CNIII
SO4 = Superior Oblique CNIV
LR6 = Lateral Rectus CNVI
Muscle Action Innervation Origin / Insertion
Superior Rectus Elevation, intorsion, assists in 3 (superior Superior part of tendinous ring / su
adduction division) part of sclera in front of the globe
Inferior rectus Depression, extorsion, assists in 3 inferior part of the common tendin
adduction ring/ inferior part of sclera in front
globe
Medial rectus Adduction 3 (inferior Common tendinous ring/medial pa
division) sclera in front of the globe
Lateral rectus Abduction 6 Lateral common tendinous ring / la
ABDUCENS part of sclera in front of the globe
Superior oblique Depression, intorsion, assists in 4 Fibrocartilgenous pulley attaches to
abduction TROCHLEAR frontal bone / outer quadrant of sc
The bony orbit forms a four sided
pyramid with the base opening
into the anterior of the face
Foramen Structures that pass through
Optic canal Optic nerve, opthalamic artery,
centeral artery/vein of retina.
Lacrimal Lacrimal gland (secrete the
fossa aqueous-layer of the tear film)
Superior CN III, IV, VI, Frontal, Lacrimal,
orbital Nasociliary branches of V1,
fissure Superior ophthalmic vein
Structure Bones involved
Inferior Maxillary nerve/infraorbital
Superior orbital Frontal bone
orbital nerve; infraorbital vessels
margin
fissure
Medial orbital Frontal process of maxilla
Infraorbital infraorbital VAN
margin
groove and
Inferior orbital Zygomatic process of maxilla +
foramen
margin zygomatic bone
Lateral orbital Frontal process of zygomatic bone
margin + zygomatic process of frontal bone
Roof of bony orbit Orbital plate of frontal bone +
lesser wing of sphenoid
Medial wall of bony Orbital plate of ethmoid bone, Orbital process of
palatine
orbit orbital plate of lacrimal bone,
frontal process of maxilla
Floor of bony orbit Maxilla, palatine, zygomatic bone
Lateral wall of Zygomatic bone (ant), greater wing
bony orbit of sphenoid (post)
, Standing room only =
V1 through foramen
LEVATOR PALPEBRAE
spinosum
SUPERIORIS MUSCLE:
V2 through
Attaches to upper eyelid foramen
Elevates upper rotundun
eyelid
Two parts: V3 through foramen
Skeletal muscleovale
(main) –
innervated by superior division of
oculomotor)
Smooth muscle (deep).
Innervated by sympathetics
Al3(SO)4 LR6
Al = all muscles CNIII
SO4 = Superior Oblique CNIV
LR6 = Lateral Rectus CNVI
Muscle Action Innervation Origin / Insertion
Superior Rectus Elevation, intorsion, assists in 3 (superior Superior part of tendinous ring / su
adduction division) part of sclera in front of the globe
Inferior rectus Depression, extorsion, assists in 3 inferior part of the common tendin
adduction ring/ inferior part of sclera in front
globe
Medial rectus Adduction 3 (inferior Common tendinous ring/medial pa
division) sclera in front of the globe
Lateral rectus Abduction 6 Lateral common tendinous ring / la
ABDUCENS part of sclera in front of the globe
Superior oblique Depression, intorsion, assists in 4 Fibrocartilgenous pulley attaches to
abduction TROCHLEAR frontal bone / outer quadrant of sc
