Transcript Neck: MRI axial sections

20 Transaxial MRI Images of the Neck
These images start at the maxilla and continue inferiorly to the apices of
the lungs. Like the upper thorax many students find it easier to start at
the bottom and work upward, which is how these images are presented.
There is a good deal of repetition in the neck and not all the anatomy is
repeatedly identified on every image. Nevertheless, be certain you can
identify reoccurring structures on every image.
First page number in parenthesis is Netter’s 3rd edition
Second page number in parenthesis is Netter’s 4th edition
Introduction to the Neck
Another Look
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Although it may look quite different than
the CT study of the thorax, this MRI section
is at a similar cut level to image 2 of the
CT images.
Click for the legend.
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Trachea
Esophagus
Rt & Lt internal jugular veins
Rt & Lt subclavian vein
Rt & Lt subclavian artery
Rt subclavian artery
Lt common carotid artery
Lt subclavian artery
Another Look: Upper Thorax MRI
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MRI study of the Neck
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Images 20 & 19
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Reference
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Trachea
Esophagus*
Rt internal jugular vein
Lt internal jugular vein**
Rt & Lt common carotid arteries
Rt & Lt vertebral arteries
Rt & Lt thyrocervical trunks*** (233, 410)
(237, 427)
8. Rt sternocleidomastoid muscle (23, 24)
(27,28)
9. Rt & Lt external jugular veins
10. Thoracic vertebral body
11. Thoracic nerve root & ganglion (163)(170)
12. Branch of the thyrocervical trunk
13. Lt lobe of thyroid gland. (70, 71)(74,75)
* On this patient the esophagus has
deviated to the Lt side of the trachea
as they approach the thoracic outlet.
** The appearance of the Lt jugular vein in
these images is due to the slow moving
venous blood returning a weak MRI signal.
There is not a thrombus as it might appear.
***These trunk vessels are short, and quickly
branch into cervical and thyroid arteries
as seen in #12.
Images 20-17
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Reference
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1. Rt & Lt external jugular veins* (66) (70)
2. Spinal cord
3. Cerebrospinal fluid in the subarachnoid
space (163) (170)
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4. Rt internal jugular vein
5. Rt common carotid artery
6. Rt. trapezius muscle
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Images 18 & 17
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Reference
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1. Trachea
2. Esophagus
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Lt sternocleidomastoid muscle
Rt internal jugular vein
Rt common carotid artery
Lt lobe of the thyroid gland
Lt vertebral artery* (130) (136)
Spinous process
* Although the transverse processes of C-7 have
foramen through them, the vertebral arteries
do not enter there. They enter at C-6. On
image 16 the vertebral arteries are at the
anterior edge of the vertebral body, and in front
of the transverse processes. On image 15 they
appear to be in the transverse processes, which
is evidence that this is C-6.
See the lizard (bearded dragon) in #15? His eyes are
the vertebral arteries, his tongue is the spinal cord
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Images 16 & 15
Images 16-13
Reference
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Images 14 & 13
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Cricoid cartilage (59, 73) (63, 77)
Lt anterior jugular vein* (27) (31)
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Lt inferior horn of the thyroid cartilage (73) (77)
Lt external jugular vein**
Rt carotid sinus (or bulb)*** (65) (69)
* Look for these bilateral vessels that have been visible
on every image so far.
** The externals have also been visible on every image.
They move laterally as they ascend.
***Netter does not label the carotid sinus (or carotid
bulb, though we can see on plate 65 the widening
of the common carotid as it approaches the
bifurcation of the internal and external arteries,
which typically occurs around the C-4 C-5 interspace.
On image 13 the right sinus is evident. The left is
not as obvious, and the internal and external
carotids are not seen as clearly as the right until
image #10.
Because this area is prone to accumulation of
athromas, referring to it is as the sinus or bulb is
significant to imaging.
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Reference
1. Rt vocal cord (ligament)* (74)
2. Lt. vocal fold** (59, & a plate deleted from the 3rd
and 4th edition which is found 3 slides forward) (63)
3. Glottis***
4. Rt external carotid artery
5. Rt. internal carotid artery
6. Rt internal jugular vein
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7. Submental vein and branches (66) (72)
8. Thyroid cartilage****
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* Not well seen, but we know it is on the edge of the folds
** Tissue lateral to vocal cords
*** Space between cords, covered by the epiglottis
during swallowing
****Not well seen on this or previous image due to the
weighting of these MR images, but there is thyroid
cartilage there
Images 12 & 11
Images 12-9
Reference
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Hyoid bone (59, 61, 64) (63, 65, 66)
Epiglottis (59, 73, 74) (63, 76, 78)
Lt sternocleidomastoid muscle
Lt internal jugular vein
Lt internal carotid artery
Lt external carotid artery
Rt external jugular vein
8. Rt & Lt piriform fossa* (recesses) (62) (66)
9. Tongue
10. Rt submandibular gland** (57, 65) (61, 69)
* Two recessed folds of the laryngopharynx on the lateral
sides of the upper trachea. Often seen on a barium swallow
under fluoroscopy. Though not labeled, they first appear on
image 10.
** The sublingual gland is between image 9 & 10, but just does
not show on this exam.
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Images 10 & 9
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Deleted Plate of Laryngopharynx
This plate was deleted from the
3rd edition of the Atlas. It provides an
interesting perspective on the:
Epiglottis
Glottis
Vocal cords (true cords)
Vocal folds (false cords)
Note the triangular shape the vocal cords
form on inspiration. This is the shape
seen on image 12.
Reference
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Lt submandibular gland
Rt sternocleidomastoid muscle
Rt internal jugular vein
Rt internal carotid artery
Rt external carotid artery
Mandibular symphysis (symphysis of the mandible)
Epiglottis
8. Rt & Lt vertebral arteries
9. Lt external jugular vein
10. Body of the Rt mandible
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Images 8 & 7
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Images 8-5
Reference
1. Alveolar process (crest) of the mandible* (13) (15)
2. Gonion (angle) of the Rt mandible**
3. Rt & Lt palatine tonsils (59, 60) (63, 64)
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Rt masseter muscle (50) (54)
Rt parotid (salivary) gland*** (57) (61)
Cerebrospinal fluid (CSF) in the subarachnoid space
Ramus of the Lt mandible
Oropharynx****
* The black holes are sockets with the roots of the teeth in
them, but the ridge of bone the sockets are in is the
alveolar process.
** This is the first image that the most posterior part of the
inferior mandible is clearly seen, making it the gonion
(angle) of the mandible.
***First seen in image 6, the parotid enlarges as images
continue superiorly.
**** Boundaries between the naso, oro, and laryngopharynx
are not distinct, but they are otherwise easy to identify.
In this case the presence of the palatine tonsils, well above
the Images
epiglottis
and below the hard and soft palate place this
6&5
section around the middle of the throat, which is also the
middle of the oropharynx.
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Another Look: Parotid Sialogram
Another Look
Parotid Sialogram
TMJ
Prior to CT and MRI the only way
to investigate the patency of the
salivary ducts, which may be
obstructed by stones, (calculi), was
to inject them with iodinated contrast
and take radiographs. Even in those
days a sialogram was an uncommon
exam.
To localize the parotid papilla, (plate 47)
(51), the patient sucks a lemon wedge,
stimulating salivation. A tiny cannula
is inserted and the duct (57) (61) is
injected.
If you are not familiar with a lateral
radiograph of the skull, see plate 5.
Parotid gland
Parotid duct
Reference
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Rt parotid gland
Uvula (of the soft palate) (48) (52)
Lt masseter muscle
Mandibular molars*
5. Maxillary molars
6. Lt retromandibular vein** (57) (61)
7. Ramus of the Rt mandible
8. Odontoid process (dens) of C2
9. Rt sternocleidomastoid muscle
10. Lt facial artery (56, 65) (60, 69)
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* Image 5 demonstrates the mandibular alveolar process. In
4 and 3 we see teeth: molars are evident. Image 2 again
demonstrates alveolar process, which must be of the
maxilla. Therefore, it is evident that image four is showing
lower teeth, and 3 uppers.
** There is an anterior and posterior retromandibular vein that
penetrates the parotid gland. In image 4 & 3, on the right
side, the pair is seen. For testing purposes either one
can be referred to as simply the retromandibular vein.
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Images 4 & 3
Images 4-1
Reference
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Alveolar process of the maxilla (3, 4)
Rt mastoid process
Lt parotid gland
Rt masseter muscle
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Ramus of the Rt mandible
Incisive canal (6, 33, 35, 36) (6, 37, 39, 40)
Alveolar recess of the Lt maxillary sinus* (44) (48)
Base of occipital bone
Cisterna magna (posterior cerebellomedullary cistern)
(103) (109)
10. Rt vertebral artery** (113) (119)
11. Lobule of Lt auricle (Lt ear lobe) (88) (94)
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* Seen on the left, but due to rotation of the image plane or
asymmetry of patient (either are possible though rotation is
most likely) the right side is demonstrating the bony floor
of the maxillary sinus.
**When the vertebral arteries emerge from the transverse
foramen of C1 they enter the cranium at the anterior margin
of the foramen magnum, in the anterior cerebellomedullary
cistern (cisterna magna).
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Images 2 & 1
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