optician provides answers for CET Module C4823a (November 28)1 Which of the following combinations of bones makes up the medial wall of the orbit? (A) Zygomatic, greater wing of sphenoid; (B) Lacrimal, ethmoid, body of sphenoid; (C) Frontal, lesser wing of sphenoid; (D) Maxilla, zygomatic, palatine.
The correct answer is B: The medial wall is made up from the lacrimal, ethmoid and sphenoid bones.
2 Which thickened fascial sheath links the tarsal plates with the periorbita at the orbital margin? (A) Tenon's capsule; (B) Whitnall's ligament; (C) Septum orbitale; (D) Capsulopalpebral fascia.
The correct answer is C: A thickened fascial sheath, the septum orbitale, is continuous from the periorbita at the orbital margin to the perimeter of the tarsal plates of the eyelids.
3 Which is the largest of the paranasal air sinuses? A Frontal; (B) Maxillary; (C) Sphenoidal; (D) Ethmoidal.
The correct answer is B: The maxillary sinus is the largest.
4 Which of the following extraocular muscles does not originate from the annulus of Zinn? (A) Levator palpebrae superioris; (B) Superior oblique; (C) Inferior oblique; (D) Inferior rectus.
The correct answer is C: The inferior oblique arises in a shallow depression located medially in the floor of the orbit.
5 Which of the following extraocular muscles has the longest course from origin to insertion? (A) Superior rectus; (B) Inferior rectus; (C) Superior oblique; (D) Inferior oblique.
The correct answer is C: The superior oblique has the longest course, being some 32mm to the trochlea and then a further 20mm to insertion.
6 Which of the following nerves runs outside of the annulus of Zinn? (A) Oculomotor; (B) Abducens; (C) Nasociliary; (D) Trochlear.
The correct answer is D: Only the trochlear (fourth) nerve advances external to the common annulus of Zinn.
7 What is the primary function of ocular sympathetic nerves? (A) Vasoconstriction; (B) Vasodilation; (C) Pupil constriction; (D) Secretomotor.
The correct answer is A: Orbital sympathetic nerves are primarily vasoconstrictors.
8 Which of the following is not a branch of the ophthalmic nerve? (A) Infraorbital; B Frontal; (C) Nasociliary; (D) Lacrimal.
The correct answer is A: The infraorbital nerve is a branch of the maxillary nerve.
9 Which of the following arteries anastomoses with the ophthalmic artery and frequently provides an accessory blood supply to the orbit? (A) Frontal; B Supraorbital; (C) Angular; (D) Recurrent meningeal.
The correct answer is D: The recurrent meningeal artery is sometimes called the accessory ophthalmic artery. Its anastomosis with the ophthalmic artery means that sometimes, in cases of internal carotid stenosis or occlusion, it can provide an alternative blood supply.
10 Which of the following is the most common location for a 'blow-out' fracture of the orbit? (A) At the junction of the floor and medial wall; (B) The floor of the orbit in the region of the infraorbital groove; (C) The medial wall at the mid-point of the ethmoid bone; (D) The floor just inside the orbital rim.
The correct answer is B: The most common location for a 'blow-out' fracture is the floor of the orbit in the region of the infraorbital groove.
11 What is the most common cause of orbital cellulitis? (A) Secondary to sinusitis; (B) Direct inoculation of the orbit from trauma; (C) Progression of pre-septal cellulitis; (D) Secondary to infection of the mid-face.
The correct answer is A: Orbital cellulitis is most commonly a result of the spread of infection from the paranasal air sinuses.
12 Which of the following imaging methods provides the clearest visualisation of orbital bones? (A) CT; (B) MRI; (C) Plain radiography; (D) Ultrasonography.
The correct answer is A: Computerised tomography (CT) scans provide the best method for visualising the orbital bones.
1 Which of the following combinations of bones makes up the medial wall of the orbit? (A) Zygomatic, greater wing of sphenoid; (B) Lacrimal, ethmoid, body of sphenoid; (C) Frontal, lesser wing of sphenoid; (D) Maxilla, zygomatic, palatine.
The correct answer is B: The medial wall is made up from the lacrimal, ethmoid and sphenoid bones.
2 Which thickened fascial sheath links the tarsal plates with the periorbita at the orbital margin? (A) Tenon's capsule; (B) Whitnall's ligament; (C) Septum orbitale; (D) Capsulopalpebral fascia.
The correct answer is C: A thickened fascial sheath, the septum orbitale, is continuous from the periorbita at the orbital margin to the perimeter of the tarsal plates of the eyelids.
3 Which is the largest of the paranasal air sinuses? A Frontal; (B) Maxillary; (C) Sphenoidal; (D) Ethmoidal.
The correct answer is B: The maxillary sinus is the largest.
4 Which of the following extraocular muscles does not originate from the annulus of Zinn? (A) Levator palpebrae superioris; (B) Superior oblique; (C) Inferior oblique; (D) Inferior rectus.
The correct answer is C: The inferior oblique arises in a shallow depression located medially in the floor of the orbit.
5 Which of the following extraocular muscles has the longest course from origin to insertion? (A) Superior rectus; (B) Inferior rectus; (C) Superior oblique; (D) Inferior oblique.
The correct answer is C: The superior oblique has the longest course, being some 32mm to the trochlea and then a further 20mm to insertion.
6 Which of the following nerves runs outside of the annulus of Zinn? (A) Oculomotor; (B) Abducens; (C) Nasociliary; (D) Trochlear.
The correct answer is D: Only the trochlear (fourth) nerve advances external to the common annulus of Zinn.
7 What is the primary function of ocular sympathetic nerves? (A) Vasoconstriction; (B) Vasodilation; (C) Pupil constriction; (D) Secretomotor.
The correct answer is A: Orbital sympathetic nerves are primarily vasoconstrictors.
8 Which of the following is not a branch of the ophthalmic nerve? (A) Infraorbital; B Frontal; (C) Nasociliary; (D) Lacrimal.
The correct answer is A: The infraorbital nerve is a branch of the maxillary nerve.
9 Which of the following arteries anastomoses with the ophthalmic artery and frequently provides an accessory blood supply to the orbit? (A) Frontal; B Supraorbital; (C) Angular; (D) Recurrent meningeal.
The correct answer is D: The recurrent meningeal artery is sometimes called the accessory ophthalmic artery. Its anastomosis with the ophthalmic artery means that sometimes, in cases of internal carotid stenosis or occlusion, it can provide an alternative blood supply.
10 Which of the following is the most common location for a 'blow-out' fracture of the orbit? (A) At the junction of the floor and medial wall; (B) The floor of the orbit in the region of the infraorbital groove; (C) The medial wall at the mid-point of the ethmoid bone; (D) The floor just inside the orbital rim.
The correct answer is B: The most common location for a 'blow-out' fracture is the floor of the orbit in the region of the infraorbital groove.
11 What is the most common cause of orbital cellulitis? (A) Secondary to sinusitis; (B) Direct inoculation of the orbit from trauma; (C) Progression of pre-septal cellulitis; (D) Secondary to infection of the mid-face.
The correct answer is A: Orbital cellulitis is most commonly a result of the spread of infection from the paranasal air sinuses.
12 Which of the following imaging methods provides the clearest visualisation of orbital bones? (A) CT; (B) MRI; (C) Plain radiography; (D) Ultrasonography.
The correct answer is A: Computerised tomography (CT) scans provide the best method for visualising the orbital bones.
1 Which of the following combinations of bones makes up the medial wall of the orbit? (A) Zygomatic, greater wing of sphenoid; (B) Lacrimal, ethmoid, body of sphenoid; (C) Frontal, lesser wing of sphenoid; (D) Maxilla, zygomatic, palatine.
The correct answer is B: The medial wall is made up from the lacrimal, ethmoid and sphenoid bones.
2 Which thickened fascial sheath links the tarsal plates with the periorbita at the orbital margin? (A) Tenon's capsule; (B) Whitnall's ligament; (C) Septum orbitale; (D) Capsulopalpebral fascia.
The correct answer is C: A thickened fascial sheath, the septum orbitale, is continuous from the periorbita at the orbital margin to the perimeter of the tarsal plates of the eyelids.
3 Which is the largest of the paranasal air sinuses? A Frontal; (B) Maxillary; (C) Sphenoidal; (D) Ethmoidal.
The correct answer is B: The maxillary sinus is the largest.
4 Which of the following extraocular muscles does not originate from the annulus of Zinn? (A) Levator palpebrae superioris; (B) Superior oblique; (C) Inferior oblique; (D) Inferior rectus.
The correct answer is C: The inferior oblique arises in a shallow depression located medially in the floor of the orbit.
5 Which of the following extraocular muscles has the longest course from origin to insertion? (A) Superior rectus; (B) Inferior rectus; (C) Superior oblique; (D) Inferior oblique.
The correct answer is C: The superior oblique has the longest course, being some 32mm to the trochlea and then a further 20mm to insertion.
6 Which of the following nerves runs outside of the annulus of Zinn? (A) Oculomotor; (B) Abducens; (C) Nasociliary; (D) Trochlear.
The correct answer is D: Only the trochlear (fourth) nerve advances external to the common annulus of Zinn.
7 What is the primary function of ocular sympathetic nerves? (A) Vasoconstriction; (B) Vasodilation; (C) Pupil constriction; (D) Secretomotor.
The correct answer is A: Orbital sympathetic nerves are primarily vasoconstrictors.
8 Which of the following is not a branch of the ophthalmic nerve? (A) Infraorbital; B Frontal; (C) Nasociliary; (D) Lacrimal.
The correct answer is A: The infraorbital nerve is a branch of the maxillary nerve.
9 Which of the following arteries anastomoses with the ophthalmic artery and frequently provides an accessory blood supply to the orbit? (A) Frontal; B Supraorbital; (C) Angular; (D) Recurrent meningeal.
The correct answer is D: The recurrent meningeal artery is sometimes called the accessory ophthalmic artery. Its anastomosis with the ophthalmic artery means that sometimes, in cases of internal carotid stenosis or occlusion, it can provide an alternative blood supply.
10 Which of the following is the most common location for a 'blow-out' fracture of the orbit? (A) At the junction of the floor and medial wall; (B) The floor of the orbit in the region of the infraorbital groove; (C) The medial wall at the mid-point of the ethmoid bone; (D) The floor just inside the orbital rim.
The correct answer is B: The most common location for a 'blow-out' fracture is the floor of the orbit in the region of the infraorbital groove.
11 What is the most common cause of orbital cellulitis? (A) Secondary to sinusitis; (B) Direct inoculation of the orbit from trauma; (C) Progression of pre-septal cellulitis; (D) Secondary to infection of the mid-face.
The correct answer is A: Orbital cellulitis is most commonly a result of the spread of infection from the paranasal air sinuses.
12 Which of the following imaging methods provides the clearest visualisation of orbital bones? (A) CT; (B) MRI; (C) Plain radiography; (D) Ultrasonography.
The correct answer is A: Computerised tomography (CT) scans provide the best method for visualising the orbital bones.
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