Orbit Practice Questions Flashcards
Which of the following bones does not contribute to the orbit?
A. Maxilla B. Frontal C. Sphenoid D. Temporal E. Palatine
D. Temporal
The temporal bone does not contribute to the osteology of the orbit. The maxilla contributes to the floor and medial wall, the frontal bone to the roof, the sphenoid bone to the roof and medial wall, and the palatine bone to the floor.
To test the integrity of the superior rectus muscle of the left orbit, in which direction would you ask the patient to look?
A. Left and up
B. Left and down
C. Right and up
D. Right and down
A.
To isolate the superior rectus muscle, you would first ask the patient to look out (abduct the eye) then look up (elevate the eye.
Which of the following muscles is capable of performing elevation, abduction, and extorsion movements of the eyeball?
A. Superior rectus B. Inferior rectus C. Medial rectus D. Lateral rectus E. Superior oblique F. Inferior oblique
F.
The inferior oblique performs the three movements: extorsion, abduction, and elevation of the eyeball.
The dilator pupillae receives what type of innervation and through which terminal nerve?
A. Motor – long ciliary nerves
B. Motor – short ciliary nerves
C. Sympathetic – long ciliary nerves
D. Parasympathetic – long ciliary nerves
E. Parasympathetic – short ciliary nerves
C.
The dilator pupillae receives sympathetic fibers from the long ciliary nerve fibers. These fibers travel from the superior sympathetic cervical ganglion, along the nerve to the internal carotid artery, where the sympathetic fibers form the internal carotid plexus. The fibers follow branches of the internal carotid artery to the orbit where they are located on the ophthalmic artery. From the ophthalmic artery, these fibers travel onto the ophthalmic division of the trigeminal nerve, specifically the nasociliary nerve, which gives the long ciliary nerves.
From which of the following nerves does the supratrochlear nerve branch?
A. Nasociliary B. Frontal C. Lacrimal D. Optic E. Lacrimal
B
The frontal nerve divides into two branches: the supratrochlear and the supra- orbital. The smaller, more medial branch is the supratrochlear, and the larger, more lateral branch is the supraorbital branch.
What is the motor innervation of the levator palpebrae muscle?
A. CN III (oculomotor nerve)
B. CN IV (trochlear nerve)
C. CN V1 (ophthalmic division of the trigeminal nerve)
D. CN VI (abducent Nerve)
A.
The levator palpebrae superioris is innervated by the superior division of the oculomotor nerve from the inferior surface. Once the muscle is cut and reflected back, the nerve can be seen on the inferior aspect of the muscle.
When the eye is adducted, what is the action of the inferior rectus muscle?
A. Depression
B. Elevation
C. Intorsion
D. Extorsion
D.
When the eye is adducted, the inferior rectus muscle will can cause an extorsion movement of the eyeball.
A physician asks a patient to look to the right, and then gaze down. Which muscle and nerve is being tested in the left eye?
A. Superior rectus – CN III B. Inferior rectus – CN III C. Superior oblique – CN III D. Superior rectus – CN IV E. Inferior rectus – CN IV F. Superior oblique – CN IV
F.
When the patient is asked to look to the right and down, the left eye is being adducted and then depressed. This is isolating and testing the superior oblique muscle.
The parasympathetic innervation of the lacrimal gland originates from which cranial nerve?
A. Oculomotor B. Trochlear C. Trigeminal D. Abducent E. Facial
E.
The parasympathetic innervation to the lacrimal gland arises in the facial nerve [CN VII], travels along the greater petrosal nerve, which is a branch of the facial nerve. The greater petrosal nerve joins with the deep petrosal nerve (sympathetic) to form the nerve of the pterygoid canal. The parasympathetic fibres synapse in the pterygopalatine ganglion, before the postsynaptic fibres leave the ganglion with the zygomatic branch of the maxillary Nerve [CN V2]. These fibres then transfer via branches of the zygomatic nerve to the Lacrimal nerve [CN V1] to reach the lacrimal gland.
Through which space does the ophthalmic artery enter the orbit?
A. Optic canal B. Superior orbital fissure C. Inferior orbital fissure D. Supraorbital foramen E. Infraorbital foramen
A.
The ophthalmic artery accompanies the optic nerve through the optic canal to access the orbit.
