Session 6: Anatomy of the Orbit Flashcards Preview

Y2 LCRS 2 - HNS Anatomy - Laz > Session 6: Anatomy of the Orbit > Flashcards

Flashcards in Session 6: Anatomy of the Orbit Deck (36)
Loading flashcards...
1

Which bones make up the roof, floor and lateral wall of the orbit?

Roof – orbital plate of frontal bone
Floor – orbital plate of maxillary bone
Lateral wall – greater wing of the sphenoid bone + zygomatic bone

2

Which bones make up the medial wall of the orbit?

Lacrimal bone
Orbital plate of ethmoid
Frontal process of maxilla
Lesser wing of sphenoid

3

Which structures pass through the optic canal?

Optic nerve
Ophthalmic artery

4

Which structures pass through the inferior orbital fissure?

Zygomatic branch of the maxillary division (V2) of trigeminal nerve
Infraorbital vessels

5

Which structures pass through the superior orbital fissure?

Oculomotor
Trochlear
Ophthalmic division (V1) of trigeminal
Abducens
Ophthalmic veins (superior and inferior)
Sympathetic fibres

6

Name the 4 recti muscles and state their origin and insertion.

Superior Rectus, Inferior Rectus, Lateral Rectus, Medial Rectus
Origin: common tendinous ring at the back of the eye
Insertion: 5 mm behind the corneal margin (onto the sclera)

7

State the innervation of the 6 extrinsic eye muscles?

Lateral Rectus = Abducens (CN 6)
Superior Oblique = Trochlear (CN 4)
Medial Rectus, Superior Rectus, Inferior Rectus,
Inferior Oblique = Oculomotor (CN 3)

8

State the origin and insertion of the inferior oblique.

Origin: orbital surface of maxilla
Insertion: postero-lateral inferior quadrant of the globe

9

State the origin and insertion of the superior oblique.

Origin: body of sphenoid
Insertion: via the trochlea to the postero-lateral superior quadrant of the globe

10

Which muscle is responsible for elevating the eyelid?

Levator palpebrae superioris

11

Where is the origin and insertion of this muscle?

Origin: lesser wing of sphenoid
Insertion: superior tarsal plate and skin of the eyelid

12

Describe the innervation of this muscle.

Oculomotor and sympathetic to smooth muscle

13

Describe the isolated muscle action of the oblique muscles.

Superior oblique = depresses AND abducts
Inferior oblique = elevates AND abducts

14

Describe the isolated muscle action of the superior and inferior recti.

Superior rectus = elevates AND adducts
Inferior rectus = depresses AND adducts

15

Describe how you would test the muscle actions of superior rectus and inferior rectus.

Superior rectus = make the patient abduct their eye and then elevate it
Inferior rectus = make the patient abduct their eye and then depress it

16

Describe how you would test the muscle actions of superior oblique and inferior oblique.

Superior oblique = make the patient adduct their eye and then depress it
Inferior oblique = make the patient adduct their eye and then elevate it

17

Which nerve axons make up the optic nerve?

Retinal ganglion cell axons

18

What types of fibres are found within the oculomotor nerve?

Motor fibres to MR, SR, IR, IO and LPS
Parasympathetic fibres
The oculomotor nerve has two rami

19

What are the branches of the ophthalmic division of the trigeminal nerve? Which branch is biggest?

Nasociliary
Lacrimal
Frontal – this is the largest

20

What structure do the cranial nerves pass through before reaching the superior orbital fissure?

Cavernous sinus

21

Which of the nerves passing through the cavernous sinus, passesthrough the middle of it rather than passing through the walls?

Abducens (CN 6)

22

What are the branches of the branches of the ophthalmic division of the trigeminal nerve?

Lacrimal – no branches
Nasociliary
 Branch to ciliary ganglion
 Ethmoidal
 Infratrochlear
Frontal
 Supratrochlear
 Supraorbital

23

What limb of the autonomic nervous system is the ciliary ganglioninvolved in?

PARASYMPATHETIC

24

Which fibres enter the ciliary ganglion and which fibres leave the ciliary ganglion?

Fibres entering the ciliary ganglion: preganglionic fibres in the inferior ramus of the oculomotor nerve
Fibres leaving the ciliary ganglion: postganglionic fibres in the short ciliary nerves

25

What do the fibres leaving the ciliary ganglion innervate?

Sphincter pupillae
Ciliary muscle

26

What are the SIX branches of the ophthalmic artery?

Supratrochlear
Supraorbital
Lacrimal
Ciliary
Muscular branches
Central artery of the retina

27

Name the two ophthalmic veins and state where they drain.

Superior ophthalmic vein = cavernous sinus
Inferior ophthalmic vein = pterygoid plexus

28

Describe the location of the lacrimal glands.

Anterolateral superior orbit

29

Describe the innervation of the lacrimal glands.

Parasympathetic secretomotor fibres of Facial Nerve (CN 7) from the pterygopalatine ganglion via the zygomaticotemporal and, finally, lacrimal nerves

30

Where do the tears initially drain?

Lacrimal Sac