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Flashcards in Medical imaging of head and neck Deck (11):

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Sphenopalatine fossa
Inferior orbital fissure
Foramen ovale
Foramen spinosum


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The incus and malleus appear as an “ice cream cone” within the temporal bone. The stapes is
not well, if at all, seen on CT. It is important to evaluate the ossicles following temporal bone
trauma as they can become dislocated (“spilled ice
cream cone”).
The vestibule is located immediately posterior to the ossicles.
The semicircular canals are located postero-medial to the ossicles
The tympanic membrane separates the external auditory canal from the middle ear and is not
visualized on this examination


Which suture separates the parietal bone from the occipital bone?



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Explanation:a.The ethmoid air cells are located on either side of the superior nasal septum. They are not visible on this CT slice.b.The frontal sinuses are located in the frontal bones (the sinuses are named for their anatomic location). They are also not visible on this examination. The frontal sinuses are the last of the sinuses to develop, usually in the teen years, and sometimes do not develop at all. In that case, we may say that there is hypoplasia(if they are very small) or aplasia(if they do not develop at all. Alternatively, we can say the frontal sinuses are “non-pneumatized.c.The maxillary sinuses are located within the maxillary bones, on either side of the nose. Of the sinuses, they are the most susceptible to trauma and infection.d.The sphenoid sinuses are located posterior to the maxillary sinuses within the sphenoid bone. e.The mastoid air cells are located within the mastoid processes of the temporal bones. They are seen at the postero-lateral portion of this image.


Which of the extra-ocular muscles may be entrapped in a “blow-out” fracture of the orbit?

a.Superior rectus

b.Superior oblique

c.Lateral rectus

d.Medial rectus

e.Inferior rectus

Correct answer: E


Explanation: A “blow-out” fracture of the orbit occurs as a result of a direct blow to the orbit, often by a fist. This increases the pressure within the orbit and the weakest point, the floor of the orbit/roof of the maxillary sinus often fractures. It is common for a bone fragment to appear displaced into the superior aspect of the maxillary sinus, but sometimes the fracture fragment snaps back up into position. There is usually blood within the maxillary sinus of the affected side and there is often intraorbital fat extending through the defect caused by the fracture. The inferior rectus muscle lies on the floor of the orbit, however, and can sometimes become entrapped by the fracture. If that happens, it results in paralysis of the upward gaze and requires surgery.


The black arrow indicates enlarged adenoids, the yellow arrowindicates enlarged tonsils and the blue arrow indicates the aryepiglottic folds. In which of the pharyngeal compartments are each of these structures located?

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Answers:The adenoids are located in the nasopharynx. In the case of the current study, the adenoids extend into the upper oropharynx, but they originate in the nasopharynx. The nasopharynx extends from the cribiform plate to the hard palate.The tonsils lie within the oropharynx. The oropharynx extends from the hard palate to the level of the hyoid bone.The aryepiglottic folds extend from the arytenoid cartilages to the epiglottis and can become edematous in a case of epiglottitis. These lie within the hypopharynx (laryngopharynx).


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Correct answer: B

Explanation:a.The arytenoid cartilages are calcified on this examination and are present within the inferior hypopharynx, just below the pyriform sinuses. It is very common to have calcification of the arytenoid cartilages and these should not be mistaken for foreignbodies.b.The arrow indicates the epiglottis. The epiglottis is that piece of soft tissue that folds over the airway during swallowing to prevent aspiration. If this becomes inflamed (epiglottitis), it can swell and obscure the airway, causing suffocation. Needless to say, epiglottitis is a medical emergency and, if you suspect it in your patient, you should call an ENT doctor immediately. Patients with epiglottitis appear in distress. They often sit (refusing to lie down), with their head pushed forward to open the airway as much as they can. They classically drool, as they don’t want anything heading down their throat. Their voice is often muffled, referred to as a “hot potato” voice. They are often febrile. If your patient comes in with these symptoms, DO NOT PUT A TONGUE DEPRESSOR IN THEIR MOUTH! This can cause the patient to gag and the swollen epiglottis to spasm, cutting off airflow. Get a STAT lateral x-ray of the soft tissues of the neck and call the ENT.c.The prevertebral soft tissues lie immediately anterior to the vertebrae. The prevertebral soft tissues are abnormally wide in this patient, most likely indicating a retropharyngeal abscess.d.They pyriform sinuses are those air-filled recesses extending inferiorly within the infero-posterior hypopharynx.


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Correct answer: C

Explanation:a.The parotid gland is located at the angle of the mandibleand usually wraps around the angle of the mandible. It normally contains more fat than the submandibular glands and, therefore, appears less “dense”. It is also usually larger than the submandibular gland.b.The right internal jugular vein is located postero-lateral to the submandibular gland and is slightly more dense on this study due to intravenous contrast material.c.This is a typical appearance and location of the submandibular glands.d.Two branches of the common carotid arteries (the internal and external CCAs) are seen on this study. They are located posterior to the submandibular glands and are much whiter on this study due to the presence of iodinated contrast.


Which of the following statements is FALSE?
The banana tree is actually not a tree, but a g
iant herb and the banana is actually its
Face lifts are the most common plastic surgery procedures performed on American
Most of the laugh tracks on television were recorded in the 1950s. Today, most of the
people you hear laughing in situation
comedies are dead.
Mount Everest grows about 2 inches taller every year.
The tongue of a blue whale weighs more than most elephants.

Correct answer: B

Explanation: The most common plastic surgery procedure among American men is a breast reduction



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Correct answer: D

Explanation:a.The esophagus is the rounded structure posterior to the air-filled (black) trachea. In this patient, there is a small finger of thyroid between the trachea and esophagus. That is not common, but as long as there is not thyroidal enlargement (goiter) or mass, it should be of no clinical concern.b.The jugular vein is the larger and more lateral contrast filled structure on either side of the thyroid. The left internal jugular vein is anteriorly displaced and compressed on this study because of the large left low neck mass. Remember, veins are usually larger than the arteries they accompany because their walls are less muscular and rigid.c.We are below the level of the laryngeal cartilage on this patient.d.The thyroid gland lies on either side of the trachea/larynx with a bridging isthmus in front. It is generally as bright as the contrast enhanced vessels as the thyroid takes up iodine in order to make thyroid hormones and the contrast we give is iodinated. In fact, if we were to perform a nuclear medicine radiolabelled thyroid scan or therapy,we would have to wait at least 6 weeks after performing a contrast enhanced CT scan or else there would be too much competitive inhibition caused by the iodinated contrast and the radioiodine would not be taken up well by the thyroid.


Which of the following is NOT a way of differentiating the internal carotid artery from the external carotid artery on imaging studies?
a.The technologist can perform a “temporal tap” on Doppler ultrasound which will transmit waves through the external carotid artery, but not the internal carotid artery.
b.On a CT angiogram, the external carotid artery will have extracranial branches whereas the internal carotid artery will not.c.On a CT angiogram, the external artery will course outward to supply the face, while the internal carotid artery will course inward to supply the brain.d.On Doppler ultrasound, the external carotid artery peak systolic velocity (PSV) will always be higher than that of the internal carotid artery

Correct answer: D

Explanation:a.Because the temporal artery is a branch off the external carotid artery, a temporal tap will transmit waves back into the external carotid artery.b.There are no extracranial branches from the internal carotid arteryc.This is a true statementd.The peak systolic velocity is a measurement of the diameter of artery. It may be higher, lower, or the same in the external carotid artery in comparison to the internal carotid artery, depending on the diameter of each of the arteries and how much stenosis in either artery may be caused by plaque.