2. SKULL BASE
• From nose to occipital protuberance
Five bones:
• Ethmoid
• Sphenoid
• Occipital
• Temporal
• Frontal
3. Tumors of SKULL BASE
• Primary malignant neoplasms
• CHORDOMA
• CHONDROSARCOMA
• OSTEOGENIC SARCOMA
4. TUMORS OF SKULL BASE
• CHORDOMA
• Bone neoplasm
• Primitive notochord
• Midline mass (clivus, sacrum, vertebrae)
• Predilection for SPHENOOCCIPITAL
SYNCHONDROSIS
5. TUMORS OF SKULL BASE
• CHONDROSARCOMAS
• Malignant
• Cartilage neoplasm
• Parasellar
6. TUMORS OF SKULL BASE
• OSTEOGENIC SARCOMA
• Prior radiation therapy
• Malignant transformation of Paget disease
8. TUMORS OF SKULL BASE
• Lesions of JUGULAR FORAMEN: PARAGANGLIOMAS
– Pulsatile tinnitus
– Conductive hearing loss
– Moth eaten destruction of bone surrounding jugular fossa
– Salt and pepper
• Differentials:
• SCHWANNOMAS
– Arising from CN IX to XI
– Cystic components
• MENINGIOMAS
9. TEMPORAL BONE
• Most common: inflammatory
(CHOLESTEATOMA)
• Common cause of inflammation of middle ear
and mastoid: EUSTACHIAN TUBE
DYSFUNCTION (decreased intratymanic
pressure)
10. TEMPORAL BONE
CHOLESTEATOMA
• Epidermoid cyst
• Desquamating stratified squamous epithelium
• Acquired > congenital
• Soft tissue mass
• middle ear (medial displacement of ossicles)
• with BONY EROSION (scutum)
• Superior portion of tympanic membrane (PARS FLACCIDA)
11. TEMPORAL BONE
• CHOLESTEROL GRANULOMA
• Giant cholesterol cyst
• Petrous apex air cells
• Cholesterol debris and hemorrhagic fluid
14. SUPRAHYOID HEAD AND NECK
• SQUAMOUS CELL CARCINOMA
• Adults
• Multiseptated cystic lesion
• Jugular nodal chain region
• Differential Dx: BRANCHIAL CLEFT CYST
• However, MULTIPLE NODES points to
squamous cell CA
15. SUPRAHYOID HEAD AND NECK
• Oral cavity and oropharynx
Divided by:
• Circumvallate papilae
• Tonsillar pillars
• Soft palate
16. SUPRAHYOID HEAD AND NECK
Spaces divided by DEEP CERVICAL FASCIA
• Superficial mucosa
• PARAPHARYNGEAL
• RETROPHARYNGEAL
• CAROTID
• PAROTID
• Masticator
• Prevertebral
17. SUPERFICIAL MUCOSAL SPACE
Lesions:
• Lateral displacement
• Obliteration of parapharyngeal space
Benign lesions:
TORNWALDT CYSTS
• Midline
• High intensity T2WI
• Notochord remnant
• Aberrantly located in nasopharynx
RETENTION CYSTS
• Obstructed glands
PLEOMORPHIC ADENOMA
• Most common benign
• Mixed cell tumor
18. SUPERFICIAL MUCOSAL SPACE
• Malignant lesions
• SQUAMOUS CELL CARCINOMA most common
• NONHODGKIN LYMPHOMA
• MINOR SALIVARY GLAND CA
• Mass effect
• Lateral compression
• Obliteration of parapharyngeal space
• Invasion of skull base
• Superificial mucosal asymmetry
• Ipsilateral retropharyngeal adenopathy
• Mastoid opacification (EARLY warning sign; dysfunction of eustachian
tube)
19. SUPERFICIAL MUCOSAL SPACE
• ADENOID CYSTIC CARCINOMA
• Perineural spread
• Most common minor salivary gland tumor
• SQUAMOUS CELL CARCINOMA
• Most common malignancy of upper aerodigestive tract
• In the nasopharynx, NASOPHARYNGEAL CA
– EBV
• LYMPHOMA
• Mucosal mass with SUPRACLAVICULAR and MEDIASTINAL
adenopathy
• Splenomegaly
20. PARAPHARYNGEAL SPACE
• Skull base to submandibular region
• Posterior: CAROTID SPACE
• Lateral: PAROTID SPACE
• Anterior:, MASTICATOR SPACE
• Medial: SUPERFICIAL MUCOSAL SPACE
21. CAROTID SPACE
• Anteriorly displace the CAROTID and JUGULAR
VEIN
• Narrows STYLOMANDIBULAR NOTCH
• Note: DEEP PAROTID SPACE lesions WIDENS
stylomandibular notch
22. CAROTID SPACE
• Most tumors: benign
• PARAGANGLIOMAS (most common, frequently multiple)
• SCHWANNOMAS and NEUROFIBROMAS (nerve sheath tumors)
Paragangliomas:
• Vascular tumors
• From carotid bifurcation: CAROTID BODY TUMORS
• From vagus nerve ganglion: GLOMUS VAGALE TUMORS
• From jugular ganglion of CNX: GLOMUS JUGULARE TUMORS
• Around Arnold and Jacobson nerves in middle ear: GLOMUS
TYMPANICUM TUMORS
23. CAROTID SPACE
SCHWANNOMAS
• Encapsulated tumors
• From NERVE SHEATH
• Do not infiltrate nerve
• Often from VAGUS NERVE
• Cystic changes and necrosis
NEUROFIBROMAS
• Not encapsulated
• Multiple lesions
• Permeate nerve substance
24. CAROTID SPACE
• LYMPH NODES
• SQUAMOUS CELL NODAL METASTASES:
principal malignancy of carotid space
• DEEP CERVICAL JUGULAR NODAL CHAIN:
within carotid space
– final common EFFERENT pathway of lymphatic
drainage
– Involved in all head and neck pathology
25. PAROTID SPACE
• Lesions from deep lobe of parotid gland
• Deviate parapharyngeal space medially
• WIDENS stylomastoid foramen (unlike carotid
space lesions)
Parotid gland:
• Only one with lymph nodes contained within
its capsule
26. PAROTID SPACE
• Parotid Tumors
• Most are benign mixed cell tumors
(PLEOMORPHIC ADENOMAS)
• Second most common benign salivary gland
tumor: WARTHIN TUMOR
• FACIAL Nerve involvement: suggest
malignancy
27. MASTICATOR SPACE
• Surrounds muscles of mastication and mandible
• From ANGLE OF MANDIBLE superiorly to skull base and
over TEMPORALIS muscle
• Masticators: TEMPORALIS, MEDIAL and LATERAL
PTERYGOIDS, and MASSETER.
• Neuro vascularity: TRIGEMINAL NERVE and INTERNAL
MAXILLARY artery
• Lesions displace parapharyngeal space medially and
posteriorly
28. MASTICATOR SPACE
• Most are infectious in origin
• Muscle asymmetry or unilateral atrophy from compromise of
MANDIBULAR division of 5th CN (neoplasms with perineural
extension along trigeminal nerve)
SQUAMOUS CELL CA
• Extension of oropharyngeal or nasopharyngeal lesions along 3rd
division of CN V
• With ascent to FORAMEN OVALE to the CAVERNOUS SINUS
posteriorly to the brainstem
• Primary CA: Sarcomas, Chondroid, or Nerve Elements, NonHodgkins
lymphoma
29. RETROPHARYNGEAL SPACE
• Posterior to SUPERFICIAL MUCOSAL SPACE and
PHARYNGEAL CONSTRICTOR
• Anterior to PREVERTEBRAL SPACE
• Lesions: posterior displacement of prevertebral muscles
• Most are nodal MALIGNANCY or INFECTION (Lymphoma
and squamous CA)
• CONDUIT for spread of tumor and infection from PHARYNX
to MEDIASTINUM
• “DANGER SPACE”
30. RETROPHARYNGEAL SPACE
• Nodes divided into medial and lateral group
• LATERAL retropharyngeal nodes (NODES OF
ROUVIERE) normal in the young
36. HEAD AND NECK
• SUPERFICIAL head
and neck
• Nasopharynx
• Oropharynx
• Oral cavity
• DEEP head and neck
• Pharyngeal (superficial)
mucosal space
• Parapharyngeal space
• Parotid space
• Carotid space
• Masticator space
• Retropharyngeal space
• Perivertebral space
40. Pharyngeal Mucosal Space
• Most internal compartment
• Closest to the airway
– delineated by middle layer of DEEP CERVICAL
FASCIA
• From BASE OF SKULL to CRICOID
41. Pharyngeal Mucosal Space
• Contents:
• Squamous mucosa
• Lymphoid tissue
• Minor salivary glands
• CARTILAGINOUS PORTION of eustachian tube
• SUPERIOR and MIDDLE pharyngeal constrictor
• Levator palatini
42. PHARYNGEAL MUCOSAL SPACE
• Medial to parapharyngeal space
• Anterior to retropharyngeal space
• Internal to the MIDDLE LAYER OF DEEP
CERVICAL FASCIA
43. PHARYNGEAL MUCOSAL SPACE
PATHOLOGY
• WALDEYER RING
– Ring of lymphoid tissue
– In nasopharynx and oropharynx
– Composed of:
• Palatine tonsils (faucial tonsils)
• Adenoids (nasopharyngeal tonsils
• Lateral bands on lateral walls of oropharynx
• Lingual tonsils at base of tongue
44. Pharyngeal Mucosal Space
Pathology: TORNWALDT CYST
• Benign
• Midline nasopharyngeal mucosal cyst
• Asymptomatic
• If infected:
– Halitosis
– Foul tasting fluid in the mouth
– Otitis media (obstruction of the eustachian tube)
• Retraction of notochord where it contacts the endoderm of primitive
pharynx
• Cystic or crusting
• CT: well circumscribed low (fluid) density and are non enhancing.
(enhances if fluid is protein rich)
• MGT: Marsupialization transnasally.
• Diff Dx: prominent adenoids, mucous retention cysts, NASOPHARYNGEAL
CARCINOMA (NPC), minor salivary glands, neuroenteric cysts,
meningoceole
46. Pharyngeal Mucosal Space
Pathology: NASOPHARYNGEAL
CARCINOMA• Most common primary malignancy of the nasopharynx
• Assoc with EPSTEIN BARR VIRUS
• Type I: keratinizing squamous cell carcinoma
• Type II: non-keratinizing squamous cell CA
• Type III: undifferentiated
• Nasal obstruction, epistaxis or conductive hearing loss due to eustachian
tube obstruction and middle ear effusion
• Soft tissue masses in LATERAL NASOPHARYNGEAL RECESS (FOSSA OF
ROSENMULLER)
• Bone erosion and Irregular infiltrating margins (aggressive)
47. Pharyngeal Mucosal Space
Pathology: NASOPHARYNGEAL
CARCINOMADifferential for small mass:
• Prominent normal adenoids
• Nasopharyngeal lymphoma
• Low grade primary nasopharyngeal malignancies
Differentials for larger mass (with involvement of base of
skull)
• Mets
• Chordoma
• Chondrosarcoma
• Meningioma
• Pituitary macroadenoma
49. Pharyngeal Mucosal Space
Pathology: ADENOID CYSTIC CA
• Airways, lacrimal glands, breast
• One of the commonest malignancy of salivary
glands
• 2nd most common malignant primary tracheal
neoplasm (after squamous cell CA)
51. Pharyngeal Mucosal Space
Pathology: MINOR SALIVARY GLAND
TUMORS (MSGT)
• Most common site: oral cavity
• Most common histological type: ADENOID
CYSTIC CARCINOMA
52. Pharyngeal Mucosal Space
JUVENILE NASOPHARYNGEAL
ANGIOFIBROMA
• Locally aggressive highly vascular tumour
• Adolescent males
• Most common benign nasopharyngeal neoplasms (however
very rare)
• Epistaxis and chronic otomastoiditis (eustachian tube
obstruction)
• Biopsy is fatal
• Origin: posterior choanal tissues in the SPHENOPALATINE
FORAMEN
53. Pharyngeal Mucosal Space
JUVENILE NASOPHARYNGEAL
ANGIOFIBROMA
• Sizable at diagnosis
• Extension medially into the NASOPHARYNX
• Laterally into PTERYGOPALATINE FOSSA
• Into orbit, paranasal sinuses, intracranial cavity
and infratemporal fossa
• Opacified sphenoid sinus
• HOLMAN MILLER SIGN: anterior bowing of
posterior wall of maxillary antrum
• Erosion of MEDIAL PTERYGOID PLATE
54. Pharyngeal Mucosal Space
JUVENILE NASOPHARYNGEAL
ANGIOFIBROMA
• Lobulated, non-encapsulated soft tissue mass
• In the SPHENOPALATINE FORAMEN
• Blood supply via: external carotid artery
55. Pharyngeal Mucosal Space
PERITONSILLAR ABSCESS (QUINSY)
• Most common deep neck infection
• 2- to 40 years old
• Pus collection between tonsillar capsule and SUPERIOR
PHARYNGEAL CONSTRICTOR muscle
• Complication of tonsillitis
• CT: rim enhancing fluid collection within an enlarged and
inflamed tonsil
• Tx: I and D
57. PARAPHARYNGEAL SPACE
• Boundaries
• Medial to MASTICATOR SPACE
• Lateral to PHARYNGEAL SPACE
• Anterior to PREVERTEBRAL SPACE
• Posterior to MEDIAL PTERYGOID
58. PARAPHARYNGEAL SPACE
• Direct relation with all but one (DANGER
SPACE) other deep compartments of the
head and neck
–Separated by RETROPHARYNGEAL
SPACE
59. PARAPHARYNGEAL SPACE
• Localization of lesions
• PAROTID space displaces the parapharyngeal fat anteromedially
• MASTICATOR space displaces it posteromedially
• CAROTID space displaces it anteriorly
• PHARYNGEAL MUCOSAL SPACE displaces it posterolaterally
• RETROPHARYNGEAL space and DANGER space displaces is
anterolaterally
60. PARAPHARYNGEAL SPACE
• Lesions (SLAT) arising in parapharyngeal
space displaces the CAROTID SPACE
posteriorly
• Salivary gland tumours
• Lipoma
• Parapharyngeal cellulitis / abscess
• Trigeminal schwannoma
61. PAROTID SPACE
• Most lateral of the major spaces of UPPER
SUPRAHYOID NECK
• CERVICAL FASCIA overlying the superficial lobe of
parotid gland
• Traversed by
• EXTERNAL CAROTID ARTERY (ECA)
• RETROMANDIBULAR VEIN
• FACIAL NERVE
62. PAROTID SPACE
• Contains:
• Parotid glands
• Intraparotid lymph nodes
– Drains the EXTERNAL EAR and LATERAL SCALP
• Intraparotid FACIAL NERVE (VII)
• ECA
• RETROMANDIBULAR VEIN
• Low attenuation: fat and glandular tissue
63. PAROTID SPACE
• Deep parotid lobe mass:
– Displaces fat medially in the parapharyngeal space and cause
– POSTEROMEDIAL displacement of posterior belly of DIGASTRIC
muscle and CAROTID space
– Associated widening of the STYLOMANDIBULAR notch
65. CAROTID SPACE
• Three layers of deep cervical fascia (CAROTID SHEATH)
• Bifurcation of common carotid artery: between
SUPRAHYOID and INFRAHYOID spaces
• Common carotid a. (inferiorly)
• Internal carotid a. (superiorly)
• CN IX, X, XI, XII (9-12)
• Sympathetic nerves
• Deep cervical lymph node chain
66. CAROTID SPACE
• Origin of internal and external carotid a.
obscured by MASTOID PROCESS
• First immediate branch of external carotid:
SUPERIOR THYROID ARTERY
• Intramural metastatic nodal invasion of the
carotid artery: relative contraindication for
surgical tumor resection
67. MASTICATOR SPACE
• Muscles of mastication
– Temporalis (close)
– Masseter (close)
– Medial pterygoid (close)
– Lateral pterygoid (open)
• Mandible
• Inferior alveolar nerve, vein and artery
• Mandibular division of the TRIGEMINAL nerve
(CNV3) (FORAMEN OVALE)
68. MASTICATOR SPACE
Boundaries:
• Buccal space anteriorly
• Parotid space posterolaterally
• Parapharyngeal space medially
• Malignacy spread perineurally (CNV3) into MIDDLE
CRANIAL FOSSA
• Schwannoma: well-circumscribed high-attenuating
contrast-enhancing FUSIFORM mass extending through
FORAMEN OVALE
69. Retropharyngeal Space
• From base of skull to T1-T6
• AREOLAR FAT : main component
• Anterior to danger space
• Posterior to pharyngeal mucosal space
• Anteromedial to carotid space
• Posteromedial to parapharyngeal space
• ALAR FASCIA separates retropharyngeal from danger
space
70. Perivertebral Space
• Posterior to retropharyngeal and danger space
• Distance between the anterior border of the vertebral body and the
posterior border of the trachea
• <7mm C2
• <22mm at C6/7
• Children <14mm C6
• Mass in prevertebral portion: anterior displacement of the muscles
• Mass in retropharyngeal space: flattening of prevertebral muscles
71. Perivertebral Space
• Paraspinal mass displaces paraspinal muscles and posterior
cervical space fat AWAY from spine.
• Extension of lesions into EPIDURAL SPACE from
perivertebral space
• LONGUS COLLI TENDINITIS: soft tissue swellingin
preverterbal portion anterior to C2-C3 with calcification of
the tendon
• CHORDOMAS: rare and aggressive tumors from notochord.
Homogeneous hypodense or isodense (T1) and
hyperintense (T2)
72. Perivertebral Space
• VERTEBRAL OSTEOMYELITIS presents with BONE
MARROW EDEMA (signal changes with low signal
intensity on T1 and high signal intensity on T2)
• Vertebral LYMPHOMA : WRAP AROUND signal
(tumor in bone marrow and paraspinal tissues
without alteration in normal vertebral shape
• BONE METS and MYELOMA: destruction of bony
cortex and bulging contour
73. DANGER SPACE
• Potential space
• Behind retropharyngeal space
• Connects DEEP CERVICAL SPACE to MEDIASTINUM
Boundaries:
• Anterior: alar fascia
• Posterior: prevertebral fascia
• Superior: clivus
• Inferior: posterior mediatinum (level of diaphragm)
• Path for spread of infxn from pharynx to mediastinum
80. OSTEOMEATAL COMPLEX
• Channel that links FRONTAL sinus, ANTERIOR and MIDDLE ETHMOID
sinuses, MAXILLARY sinus to the MIDDLE MEATUS
Five structures:
• Maxillary ostium: drains maxillary
• Infundibulum: drains maxillary and ethmoid to HIATUS SEMILUNARIS
• Ethmoidal bulla: single air cell
• Uncinate process: hook like process from posteromedial aspect of
NASOLACRIMAL DUCT (anterior boundary of hiatus semilunaris
• Hiatus semilunaris: FINAL DRAINAGE PASSAGE
82. Paranasal Sinuses: Maxillary
• Drains into MIDDLE MEATUS of the nose
• Present at birth
• Develops until 14 years old
RETENTION CYSTS
• Mucosal and cortical integrity is preserved.
• Radiopaque dome shaped structures with rounded edge on the
FLOOR of maxillary sinus
PARANASAL SINUS MUCOCOELE
• Complete opacification of one or more paranasal sinuses
• Associated boney expansion
83. Paranasal Sinuses Mucocoele
• Distort local anatomy
• Exert pressure on adjacent structures
• Frontal sinus: front of orbit mass
• Posterior ethmoid: compression of orbital apex
• Sphenoidal mucocoele: compress PITUITARY and BRAINSTEM
• Maxillary mucocoele: elevate orbital floor; proptosis
• If it becomes infected, acute sinusitis
• Potential extension of infection into adjacent spaces
– Intracranial SUBDURAL EMPYEMA, MENINGITIS, CEREBRAL ABSCESS
– Orbit: SUBPERIOSTEAL ABSCESS
– Subcutaneous: POTT’S PUFFY TUMOR
84. Paranasal Sinuses Mucocoele
• Frontal sinus: most prone to mucocoeles
• Cystic fibrosis: most common association
• Water rich content: low T1, high T2 signal
• Protein rich content: high T1, low T2 signal
89. Haller Cells
• AKA infraorbital ethmoidal air cells or
maxilloethmoidal cells
• Extramural ethmoidal cells that extend into
inferomedial orbital floor
• Infection extension to orbits
96. Cavernous Sinus Thrombosis
• Contiguous spread of infection from the
• Sinuses
• MIDDLE THIRD OF THE FACE
• Dental abscess
• Orbital cellulitis
• Staph aureus
• MRI with contrast
98. Parotid Glands
• Largest
• Around the MANDIBULAR RAMUS
• Anterior and inferior to the ear: PAROTID FACIAL SPACE
• Passes through parotid gland:
• Facial nerve
• External carotid artery (ECA)
– Forms 2 terminal branches within the parotid gland
– MAXILLARY A.
– SUPERFICIAL TEMPORAL A.
99. Parotid Glands
• Arterial supply:
• ECA and Transverse Facial A.
• Venous drainage: Internal Jugular V.
• Malignancy: high vascularity by UTZ
101. Note Worthy
• Abscess: fluid collection with peripheral rim
enhancement
• Phlegmon: low density edematous tissue
without peripheral enhancement
102. ANTERIOR JUGULAR VEIN
• Paired tributary of the external jugular vein
• Originates at level of HYOID bone or
SUPRAHYOID neck
• Medial border of SCM
• Connected to contralateral anterior jugular
vein via JUGULAR ARCH
103. ARTERIAL SUPPLY
• COMMON CAROTID A.
– External CA
– Internal CA
• Cervical a.
• Petrous a.
• Cavernous / ophthalmic a.
• Willis / Cerebral
• SUBCLAVIAN A.
– Vertebral a.
– Thyrocervical trunk
– Costocervical trunk
104. ASCENDING PHARYNGEAL ARTERY
• Smallest branch of EXTERNAL CAROTID A.
• Course: vertically with ICA, side of the PHARYNX
• Supplies: base of the skull
– Anastomose with ANTERIOR and POSTERIOR
CEREBRAL circulation
• Terminates at BASE OF SKULL
