Imaging of the Neck Submental Triangle

Traditional Neck Triangles Boundaries:

− Used by clinicians to localize H&N lesions • Inferiorly – Hyoid bone.
2 Major subdivisions • Medially – Imaginary sagittal midline of the
− Anterior triangle neck.
− Posterior triangle • Laterally – Anterior belly of the digastric. 
Anterior Triangle *mylohyoid muscle – forms the base of the submental
Boundaries: triangle
• Superiorly – Inferior border of the mandible Main content:
• Laterally – Medial border of the • Submental lymph nodes
sternocleidomastoid
• Medially – Imaginary sagittal line drawn along Posterior Triangle
the midline of the neck Boundaries:
Subdivisions: • Anterior: Posterior border of the
• Carotid Triangle sterncleidomastoid muscle.
• Muscular Triangle • Posterior: Anterior border of the trapezius
• Submental Triangle muscle.
• Submandibular Triangle • Inferior: Middle 1/3 of the clavicle
Carotid Triangle Subdivisions:
Boundaries: • Occipital Triangle
• Superior: Posterior belly of the digastric muscle. • Supraclavicular Triangle
• Lateral: Medial border of the Contents:
sternocleidomastoid muscle. • Muscles
• Inferior: Superior belly of the omohyoid muscle. – Omohyoid muscle (inferior belly)
Contents : – Vertebral muscles
• Common carotid artery • Splenius capitis 
• Internal jugular vein • Levator scapulae
• Hypoglossal and Vagus nerves • Scalene muscles
Muscular Triangle • Vasculature
Boundaries: – External jugular vein
• Superiorly: Hyoid bone – Transverse cervical artery
• Medially: Imaginary midline of the neck – Subclavian artery and vein
• Supero-laterally: Superior belly of the Contents:
omohyoid muscle • Nerves
• Infero-laterally: Inferior portion of the – Accessory nerve (cranial nerve XI)
sternocleidomastoid muscle – Cervical plexus
Contents: – Phrenic nerve- arises from the anterior
• Infrahyoid strap muscles divisions of spinal nerves C3-C5,
• Pharynx innervate the diaphragms
• Thyroid gland – Brachial plexus
• Parathyroid gland Subdivisions
Submandibular Triangle • Occipital triangle- crossed by the accessory
Boundaries:  nerve
• Superiorly: Body of the mandible • Subclavian triangle- contains the distal portion
• Anteriorly: Anterior belly of the digastric muscle of the subclavian artery
• Posteriorly: Posterior belly of the digastric
muscle Traditional Neck Triangles
Contents: • The traditional compartments are important for
• Submandibular gland describing the spread of superficial and
• Submandibular lymph nodes muscosa-based lesions.
• Facial artery and vein • In contrast to this divisions, multiple facial
planes divide the deep head and neck into
spaces that form true compartments.
 • It is important to realize that these deep spaces Neck Division
are unrelated to the traditional division of the − SHN: Deep facial spaces above hyoid bone
head and neck and traverse the neck without including parapharyngeal (PPS), pharyngeal
regard to the traditional divisions. mucosal space (PMS), masticator (MS), parotid
• Most radiologist have adapted a spatial (PS), carotid (CS), buccal (BS), retropharyngeal
approach to the head and neck, popularized by (RS), danger space (DS), perivertebral space
Dr. Ric Harnsberger. (PVS)

Neck Fasciae − IHN: Spaces predominantly below hyoid bone

• Superficial Cervical Fascia with some continuing into mediastinum or SHN
• Deep Cervical Fascia including visceral space (VS), posterior cervical
– Superficial layer space (PCS), anterior cervical space (ACS), CS,
– Middle layer RPS & PVS.
– Deep layer
SL-DCF NORMAL ANATOMY SHN ANATOMIC SPACES
• SHN: circumscribes MS & PS, contributes to 1. Parapharyngeal space (PPS)
carotid sheath 2. Pharyngeal mucosal space (PMS)
• IHN: “invests” neck by surrounding strap, 3. Carotid space (CS)
Sternomastoid & trapezius muscle; contributes 4. Parotid space (PS)
to carotid sheath 5. Masticator space (MS)
ML-DCF 6. Retropharyngeal space (RPS)
• SHN: Defines PMS deep margin; contributes to 7. Perivertebral space (PVS)
carotid sheath
• IHN: circumbscribes VS; contributes to carotid Posterior Midline
sheath – Retropharyngeal space
DL-DCF • Danger space
• SHN & IHN – surrounds PVS with fascial slip to – Perivertebral space
transverse process dividing PVS into Skull Base Relation
prevertebral and paraspinal components; – Masticator Space
contricutes to carotid sheath. • F. Ovale
• F. Spinosum
Neck Division – Parotid Space
Hyoid Bone/ Cartilage • Stylomastoid foramen
• Suprahyoid Compartment – Carotid Space
• Infrahyoid Compartment • Int Carotid Artery
EXTENT: • Int Jugular Vein
• SHN: neck spaces from skull base to hyoid bone – Pharyngeal Mucosal Space
excluding orbit, sinonasal area and oral cavity • F. Lacerum
(OC) – Parapharyngeal Space
• IHN: Neck spces from hyoid above to – Retropharyngeal Space
cervicothoracic junction below
Hyoid Bone
− U-shape or horse shoe configuration
− Three components
− 2 horns, 1 body
Thyroid Cartilage
− V-shape configuration
− Two components
Cricoid Bone
− Complete cartilagenous ring
− Thicker and taller posteriorlly