Anatomy
In general , neck is the part of a person’s or animal’s body connecting the head to the rest
of the body.
Here, neck is the part extending from the mandible to the thoracic inlet anteriorly and
from the base of the skull to the scapulae posteriorly.
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Clinically, Neck is divided into different areas which are:
Anterior Triangle
Posterior Triangle
Also all triangles mentioned here are paired i.e. they will appear on the left and the right
side of the neck.
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Anterior triangle:
The anterior triangle is situated at the front of the neck.
It is bounded:
Superiorly – Inferior border of the mandible (jawbone)
Laterally – Medial border of the sternocleidomastoid
Medially – Imaginary sagittal line down midline of body
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The muscles in this part of the neck are
divided as to where they lie in relation to
the hyoid bone, which are:
Suprahyoid Muscle:
Stylohyoid
Digastric
Mylohyoid
Geniohyoid
Infrahyoid Muscle:
Omohyoid
Sternohyoid
Sternothyroid
Thyrohyoid
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Anterior triangle is further divided into following parts:
Carotid triangle
Submental triangle
Submandibular triangle
Muscular triangle
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Carotid triangle:
The carotid triangle of the neck has the following
boundaries:
Superior: Posterior belly of the digastric muscle.
Lateral: Medial border of the sternocleidomastoid muscle.
Inferior: Superior belly of the omohyoid muscle.
The main contents of the carotid triangle are the common
carotid artery (which bifurcates within the carotid
triangle into the external and internal carotid arteries),
the internal jugular vein, and the hypoglossal and vagus
nerves.5/15/2017 9
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Submental triangle:
It is bounded:
Inferiorly – Hyoid bone.
Medially – Imaginary sagittal midline of the neck.
Laterally – Anterior belly of the digastric.
The submental triangle is situated underneath the chin.
Its main content is the submental lymph nodes, which
filter lymph draining from the floor of the mouth and
parts of the tongue.
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Submandibular triangle:
The submandibular triangle is located underneath the bodyof the mandible. It contains the submandibular gland(salivary), and lymph nodes. The facial artery and vein alsopass through this area.
The boundaries of the submandibular triangle are:
Superiorly: Body of the mandible.
Anteriorly: Anterior belly of the digastric muscle.
Posteriorly: Posterior belly of the digastric muscle.
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Muscular triangle:
This area actually have four boundaries. It doesn’t contain
vessels, It however contain some muscles and organs – the
infrahyoid muscles, the pharynx, the thyroid and parathyroid
glands.
The boundaries of the muscular triangle are:
Superiorly: The hyoid bone.
Medially: Imaginary midline of the neck.
Supero-laterally: Superior belly of the omohyoid muscle.
Infero-laterally: Inferior portion of the sternocleidomastoid
muscle.5/15/2017 12
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Posterior triangle:
The posterior triangle of the neck is an anatomical
area located in the lateral aspect of the neck.
Its boundaries are as follows:
Anterior: Posterior border of the SCM.
Posterior: Anterior border of the trapezius muscle.
Inferior: Middle 1/3 of the clavicle.
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Structures in posterior triangle are vertebral muscles,
external jugular vein, subclavian vein ,cervical plexus
etc.
Posterior triangle is divided into two divisions by the
omohyoid muscle, which are:
Occipital triangle: the larger, superior part
Subclavian triangle: the inferior part
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For imaging purposes, the boundaries of the neck are
Mandible and the Mylohyoid muscles anterosuperiorly
The base of the skull posterosuperiorly
The scapulae posteroinferiorly, and
The thoracic inlet centrally in the inferior aspect.
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Neck Spaces
Another approach to the anatomy of the neck is the so-called 'spatial approach’.
The ‘neck space’ concept is a commonly used method in radiology in organizing the neck and
establishing appropriate differential diagnosis for pathology discovered within a specific
space of the neck.
The hyoid bone is used as a landmark to divide the neck into the suprahyoid and infrahyoid.
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Suprahyoid neck
parapharyngeal space
parotid space
pharyngeal mucosal space
masticator space
buccal space
danger space
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Infrahyoid neck
anterior cervical space
posterior cervical space
visceral space
Supra and Infrahyoid neck
carotid space
retropharyngeal space
perivertebral space
Subligual space
Submandibular space
Lymph nodes
The neck has an extensive lymphatic network containing
more than one third of the body's total number of lymph
nodes.
Typically, as many as 75 lymph nodes are located on each side
of the neck
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Lymph nodes
They are classified into following groups according to its location:
Level I:Submental & Submandibular nodes
Level II: Upper Internal Jugular Vein nodes
Level III: Middle Internal Jugular Vein nodes
Level IV: Lower internal Jugular Vein nodes
Level V: Posterior Triangle nodes(Spinal accessory, Transverse cervical,
Supraclavicular)
Level VI: Anterior Triangle nodes(Paratracheal, Pretrachial, Visceral)
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Indications
Inflammatory, nodal and tumoral diseases including lymphoma and metastases.
Thyroid diseases
Pharyngeal lesions
Salivary glands pathologies
Detection /confirmation of lesions
Follow-ups
Baseline scans
Trauma
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Contra-indications
Hypersensitivity to iodinated contrast media
Pregnancy(relative)
Renal diseases
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Patient Preparation
Clear history should be taken along with reports of previous investigations.
Pregnancy needs to be ruled out.
Radiopaque materials should be removed from FOV.
Proper information and instruction about the procedure.
NPO for 4-5 hours prior to procedure for CECT.
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Patient Preparation
Blood creatinine levels should be in its normal limit (M=0.6 to 1.5,F=0.5-1.2 mg/dl) and
Blood urea level should range between 9 to 42 mg/dl
Signed informed consent from patient or his/her close relatives.
Irritable/uncooperative and Pediatric patients should be sedated.
Neck should be in neutral position.
The patient should be instructed to avoid swallowing movements.
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Routine Neck protocol
Patient positioning
Head first, supine with arms by the sides of the trunk with hands tucked under the hips.
Head rest/support can be applied to restrict the neck movement.
Topogram position/Landmark: lateral; level of forehead
Mode of scanning: Helical with single breath-hold technique
Scan orientation
Cranio-caudal
Starting location:Base of the skull
End location :Arch of the aorta
Cranio-caudal orientation reduces artifacts at the level of the thoracic inlet caused by
the beam-hardening effects of the contrast agent.5/15/2017 39
Routine Neck protocol
FOV: Just fitting the ROI.
Gantry tilt
To make the plane of the scanning parallel to the hard palate or
perpendicular to the plane of larynx.
Contrast administration: Intravenous and monophasic
Volume of contrast: 80-100 ml
Rate of injection of contrast: 2-3 ml/sec
Scan delay: 30-40 sec 5/15/2017 40
Routine Neck protocol
Slice thickness in reconstruction
3-5 mm
Slice interval in reconstruction
1.5-2.5 mm
Reconstruction algorithm/kernel
Medium smooth for soft tissue.
Sharp for cartilage, bone and lung parenchyma in the scan range.
3D-Reconstructions
MPR
MIP5/15/2017 41
Routine Neck TUTH Protocol
Patient positioning : Head first, supine with arms by the sides of the trunk, Head rest preferred
Topogram position/Landmark: lateral; level of forehead
Mode of scanning: Helical
Scan orientation
Cranio-caudal
Starting location: Base of the skull
End location :Arch of the aorta
Slice Acquisition: 0.6x128
Recon Slice Thickness: 0.75mm
Recon Interval:0.7mm5/15/2017 42
Routine neck TUTH Protocol
FOV: Just fitting the ROI.
Gantry tilt: Nil
Volume of contrast: 80-100 ml
Rate of injection of contrast: 2-3 ml/sec
Scan delay:35-40 sec
Recon Algorithm: b31s medium smooth
3D recon: MPR
Window Setting: W/L: 250/50
Filming: 3mmx3mm Axial: Plane + Contrast film
Coronal and Sag MPR film 5/15/2017 43
Protocol for Larynx and Hypopharynx
Indications
Screening for inflammatory or tumoral diseases of the larynx and hypopharynx.
Preoperative baseline scan
Post-surgery or post-chemotherapy follow-ups.
Patient positioning
Head first, supine with arms by the sides of the trunk with hands tucked under the
hips.
Head rest/support can be applied to restrict the neck movement.
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Protocol for Larynx and Hypopharynx
Topogram position/Landmark
lateral; level of forehead
Mode of scanning
Helical with single breath-hold technique
Scan orientation
Cranio-caudal
Starting location: Base of the skull
End location : Arch of the aorta
FOV
Just fitting the ROI.5/15/2017 45
Protocol for Larynx and Hypopharynx
Gantry tilt: To make the plane of the scanning parallel to the hard palate or
perpendicular to the plane of larynx.
Contrast administration: Intravenous , monophasic
Volume of contrast: 80-100 ml
Rate of injection of contrast: 2-3 ml/sec
Scan delay: 30-40 sec
Slice thickness in reconstruction : 3-5 mm
Slice interval in reconstruction : 1.5-2.5 mm5/15/2017 46
Protocol for Larynx and Hypopharynx
Reconstruction algorithm/kernel
Medium smooth for soft tissue.
Sharp for cartilage, bone and lung parenchyma in the scan range.
3D-Reconstructions
MPR
MIP
Virtual endoscopy
Dynamic maneuvers
phonation (for a better visualization of the laryngeal ventricle)
modified Valsalva (for a better visualization of the pyriform sinuses and upper airway).
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CT Carotid Angiography
Indications
Suspected occlusion of the carotid arteries, their aneurisms, dissections.
Preoperatively for head /neck tumors to detect the origin of their feeding vessels for the purpose ofligation.
The goals of CTA for cervicocranial vascular evaluation can be summarized as follows:
to accurately measure stenosis of the carotid and vertebral arteries and their branches
to evaluate the circle of Willis for completeness using three-dimensional reformationsof cerebral vasculature in relation to other structures, and
to detect other vascular lesions, such as dissections or occlusions.
Patient positioning
Head first, supine with arms by the sides of the trunk with hands tucked under the hips.
Head rest/support can be applied to restrict the neck movement.5/15/2017 48
CT Carotid Angiography
Topogram position/Landmark: lateral; level of forehead
Mode of scanning: Helical with single breath-hold technique
Scan orientation :Caudo-Cranial
Starting location: Arch of the aorta
End location : 2-3 cm above the sella
FOV: Just fitting the ROI.
Gantry tilt: Nil
Contrast administration: Intravenous , monophasic, Saline chasing(half the volume of NS
w.r.t the volume of contrast administration is given immediately after contrast
administration, which reduces contrast volume, streak artifact and gives better and
consistent enhancement)5/15/2017 49
CT Carotid Angiography
Volume of contrast: 80-100ml
Rate of injection of contrast: 4-5 ml/sec
Scan delay: 10-15 sec
Slice thickness in reconstruction : 1.0-1.5 mm
Slice interval in reconstruction : 0.5-0.75 mm
Reconstruction algorithm/kernel: smooth
3D-Reconstructions
MIP
VRT (preferably after bone subtraction) 5/15/2017 50
Carotid Angio TUTH Protocol
Patient positioning : Head first, supine with arms by the sides of the trunk, Head
rest preferred
Topogram position/Landmark:lateral; level of forehead
Mode of scanning: Helical
Scan orientation: Caudo-Cranial
Starting location: Base of the skull
End location :2-3 cm above the sella
Slice Acquisition: 0.6x128
Recon Slice Thickness: 0.75mm
Recon Interval:0.7mm5/15/2017 51
FOV: Just fitting the ROI.
Gantry tilt: Nil
Volume of contrast: 80-100 ml
Rate of injection of contrast: 4-5ml/sec
Bolus Tracking(ROI: Arch of aorta), Post Threshold Delay:5 sec
Window Setting: W/L: 800/90
Recon Algorithm: b30f medium smooth
3D recon: MIP, VRT(with subtraction) 5/15/2017 52
Carotid angio TUTH Protocol
References
CT and MRI protocol- a practical approach, Satish K Bhargava.
CT and MRI of whole body, Fifth edition, Johan R. Hagga.
Anatomy for Diagnostic Imaging, second edition
Sectional Anatomy for Imaging Professionals, ed 2, LORRIE L. KELLEY
www.radiologyassistant.nl
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