Imaging of the Suprahyoid

Neck

Benjamin Y. Huang, MD, MPH

Department of Radiology

University of North Carolina School of

Medicine

Neck Overview

• 2 distinct anatomic regions

– Suprahyoid

– Infrahyoid

• Both regions further subdivided into

multiple fascia lined spaces

• Spatial approach is useful for nonmucosal

(deep) H&N lesions

The Deep Cervical Fascia

3 Layers of DCF

• Superficial(investing; SL-DCF)

• Middle(buccopharyngeal; ML-DCF)

• Deep (prevertebral; DL-DCF)

Spaces of the Suprahyoid Neck

• Parapharyngeal (PPS)

• Pharyngeal Mucosal (PMS)

• Masticator (MS)

• Parotid (PS)

• Carotid (CS)

• Retropharyngeal (RPS)

• Perivertebral space (PVS)

Parapharyngeal Space

• Extends from skull base to SMS

• Not truly fascially enclosed

• Borders all three layers of DCF

• Openly communicates with SMS

Parapharyngeal Space

Contents

• Fat

• Minor salivary

glands

• Internal maxillary a.

• Ascending

pharyngeal a.

• Pterygoid venous

plexus

Parapharyngeal Space

PPSPPS

T1W MRICE CT

Parapharyngeal Space

• Primary PPS lesions rare

– BMT

– Minor salivary tumors

– Lipoma

– Atypical branchial cleft cysts

• PPS displacement pattern is key to defining site of origin of other deep neck masses!

Pharyngeal Mucosal Space

• Continuous mucosal sheet from NP to HP (including soft palate)

• Bordered posteriorly and laterally by ML-DCF

• Superiorly bordered by basisphenoid & basiocciput (including foramen lacerum)

Pharyngeal Mucosal Space

Contents

• Pharyngeal mucosa

• Waldeyer’s ring

• Minor salivary glands

• Pharyngobasilar fascia

• Pharyngeal constrictor mm.

• Levator palatini m.

• Torus tubarius

Pharyngeal Mucosal Space

Pharyngeal Mucosal Space

Lesions• PMS lesions push

PPS fat laterally

• DDxMucosa

– SCC

Lymphoid

– NHL

Minor salivary gland

– MSG tumor

Muscle

– Rhabdomyosarcoma

Masticator Space

• Enclosed by SL-DCF

• Extends from high parietal calvarium to mandibular angle

• Abuts skull base (including foramen ovale & spinosum)

Masticator Space

Contents

• Musles of mastication

• CN V3

• Ramus & posterior body of mandible

• Pterygoid venous plexus

Masticator Space

Masticator Space Lesions

• MS lesions push PPS fat posteromedially

• DDxMuscle

– Sarcoma

Mandible

– Sarcoma

– Osteo/chondrosarcoma

– Mets/Myeloma

Nerve

– Nerve sheath tumor

Vascular

– Hemangioma

– Lymphangioma

Other

– Lymphoma/leukemia

– SCC (from the RMT)

Parotid Space

• Enclosed by SL-

DCF

• Extends from skull

base/EAC to below

mandibular angle

Parotid Space

Contents

• Parotid gland/duct

• Facial nerve

• ECA

• Retromandibular v.

• Intraparotid nodes

• Accessory parotid tissue

Parotid Space

Parotid Space Lesions

• PS lesions push PPS fat medially

• DDxParotid

– BMT

– Salivary gland malignancies

– Warthin’s tumors

– Lymphoepithelial cysts

Nerve

– Schwannoma

Lymph Node

– Lymphoma

– Nodal metastases

– Reactive nodes

Vascular

– Hemangioma/Lymphangioma

Other

– 1st branchial cleft cyst

Carotid Space

• Aka post-styloid PPS

• Extends from skull base (jugular foramen & carotid canal) to aortic arch

• All 3 layers of DCF contribute to carotid sheath

Carotid Space

Contents

Suprahyoid

• ICA

• IJV

• CN 9-12

• Sympathetic plexus

• Lymph Nodes

Infrahyoid

• CCA

• IJV

• CN 10

• Lymph Nodes

Carotid Space

Carotid Space Lesions

• CS lesions push PPS fat anteriorly

• DDxNerves/Plexus

– Paraganglioma

– Schwannoma

Vascular

– IJV thrombosis

– CA aneurysm

– CA dissection

Lymph Nodes

Retropharyngeal Space

• Fat filled space posterior posterior to pharynx & trachea

• Enclosed by ML- & DL-DCF

• Separated from DS by slip of DL-DCF

• Extends from skull base to mediastinum (T3)

Retropharyngeal Space

Contents

• Fat

• Lymph nodes (SH

neck only)

– Medial

– Lateral (Rouviere)

Retropharyngeal Space Lesions

• Lateral - displace CS laterally and PPS anterolaterally

• Medial - flatten the prevertebral mm and displace the PMS anteriorly

• DDXNodes

– SCC/NPC mets

– Lymphoma

– Reactive/Suppurative

Fat

– Lipoma

Other

– Abscess/cellulitis

– Effusion/edema

Perivertebral Space

• Space surrounding the

vertebral column

extending from skull

base to upper

mediastinum

• Bounded by DL-DCF

• 2 major components

– Prevertebral

– Paraspinal

Perivertebral Space

Contents

• Prevertebral– Prevertebral mm.

– Scalene mm.

– Brachial plexus roots

– Phrenic nerve

– Vertebral a. & v.

– Vertebral body

• Paraspinal– Posterior elements

– Paraspinal mm.

Perivertebral Space Lesions

• Prevertebral

lesions lift the

prevertebral mm.

off the spine

• Primary paraspinal

masses push the

posterior cervical

fat laterally

Perivertebral Space Lesions

• DDx

Spine– Tumor (Met, sarcoma,

chordoma, B9)

– Discitis/osteomyelitis

Muscle– Sarcoma

– Lymphoma

– Pseudomass (hypertrophy)

Nerve– Schwannoma/NF

Other Spaces

• Buccal space

• Floor of mouth

– Sublingual

space

– Submandibular

space

• Posterior

cervical space

SAMPLE

CASES

SCC – Oropharynx

PMS

High Grade Mucoepidermoid Ca

PS

Ewing Sarcoma

Masticator

Space

Glomus Vagale

CS

Pleomorphic Adenoma

PS

Retropharyngeal

Effusion/Abscess

RPS

Chloroma

MS

Schwannoma

CS

Case courtesy of

Dr. Craig Harr

RP Nodal Met – NP Ca

Summary

• Deep neck can be compartmentalized

based on DCF planes

• Identifying the space of origin can help

pare down DDx

• Look at the PPS displacement to help

identify the space of origin