General Comments

• The cavernous is a venous blood sinus (not an air sinus) created by divergent layers of endosteal and meningeal dura. It is located in the middle cranial fossa adjacent to the sella turcica. Immediately medial to the thin lateral border of the sella turcica is the sphenoid air sinus. This relationship puts the cavernous sinus at risk during transsphenoidal surgery of the hypophysis. Five of the 12 cranial nerves have components at risk during pathology of the cavernous sinus.

Bones

• Sella turcica -
• Greater wing of the sphenoid bone -
• Lesser wind of the sphenoid bone -
• Apex of the petrous temporal bone
• Anterior and posterior clinoid processes -

Boundaries and external relationships

• Superior -
• Inferior -
• Anterior -
• Posterior -
• Medial -
• Lateral -

Contents, internal relationships, functional components, and expected clinical symptoms

• Internal carotid artery -
• Internal carotid plexus -
• Sympathetic root of the ciliary ganglion -
• Deep petrosal nerve -
• Greater superficial petrosal nerve -
• Nerve of the pterygoid canal (Vidian nerve) -
• Oculomotor nerve (and branches) -
• Trochlear nerve -
• Ophthalmic nerve (V1) and branches -
• Maxillary nerve (V2) -
• Abducens nerve -
• Inferior hypophyseal artery

Vascularization

• Hypophyseal arteries -
• Ophthalmic vein -
• Sphenoparietal sinus -
• Superior petrosal sinus -
• Inferior petrosal sinus -
• Emissary vein to pterygoid venous plexus -
• Intercavernous sinus sinus -

Innervation

• Meningeal branches of maxillary and mandibular nerves -

Routes of Infection

• Face and Orbit -
• Scalp -
• Infratemporal fossa -
• Ischiorectal fossa and internel vertebral venous plexus -
• Base of skull and external vertebral venous plexus -
• Intercavernous sinus -

Bones of the Temporomandibular Joint

• Postglenoid tubercle - posterior margin of mandibular fossa of the temporal bone zygomatic process
• Mandibular fossa - receives the head of the mandible
• Articular eminence of the zygomatic process of the temporal bone - anterior margin of the mandibular fossa
• Coronoid process of the mandible - insertion for temporalis muscle
• Neck of the mandible - insertion for the lateral pterygoid muscle (inferior)
• Lingula - attachment of the sphenomandibular ligament
• Angle of the mandible lateral side - insertion for the masseter muscle
• Angle of the mandible medial side - insertion for the medial pterygoid
• Temporal fossa and superior/inferior temporal lines - origin of the temporalis muscle and fascia
• Lateral and medial surfaces of the the lateral pterygoid plate - origins of the lateral and medial pterygoid muscles
• Infratemporal crest - origin of the superior head of the lateral pterygoid
• Zygomatic arch - origin of the masseter muscle

Articulations of the Temporomandibular Joint

• Mandibular fossa
• Articular disk
• Condyle of the mandible
• Superior and inferior synovial joint cavities
• Posterior, lateral, and anterior joint capsule and ligaments

Muscles and movements

• Masseter - elevation and ipsilateral deviation
• Medial pterygoid - elevation and contralateral deviation
• Superior head lateral pterygoid - depression, protraction, and contralateral deviation
• Inferior head lateral pterygoid - elevation, protraction, and contralateral deviation
• Posterior temporalis - elevation, retraction, and ipsilateral deviation
• Anterior temporatlis - elevation
• Infrahyoid muscles - depression of the mandible

Innervation

• Muscles of mastication - mandibular division of trigeminal
• Strap muscles - ansa cervicalis
• Nerve to mylohyoid, thyrohyoid, and geniohyoid
• Hilton's law for the joint capsule plus the auriculotemporal nerve

Relationships of the Temporomandibular Joint

• Medial - petrotympanic fissure and chorda tympani nerve, styloid process and infratemporal fossa
• Lateral - parotid region, parotid gland, facial nerve,
• Superior - mandibular fossa, temporal fossa
• Inferior - lingula, digastric triangle, maxillary artery
• Anterior - articular tubercle
• Posterior - external auditory meatus, auriculotemporal nerve, parasympathetic communicating branch,

Boundaries of the Infratemporal Fossa

• anterior - posterior aspect of maxilla
• posterior - styloid process
• superior - infratemporal crest
• inferior - body of mandible
• medial - pterygoid plate (pterygo maxillary fissure)
• lateral - ramus of mandible

Bony communications

• Foramen ovale - middle cranial fossa to infratemporal fossa, mandibular nerve (GSA, SVE) and lesser superficial nerve (Preganglionic GVE)
• Foramen spinosum - middle cranial fossa to infratemporal fossa, middle meningeal artery
• Petrotympanic fissure - middle ear to infratemporal fossa, chorda tympani nerve (SVA, preganglionic GVE)
• Inferior orbital fissure - maxillary artery becomes infraorbital artery
• Pterygomaxillary fissure - terminal branches of maxillary artery, posterior superior alveolar nerve (GSA and postganglionic GVE)
• Mandibular foramen - inferior alveolar nerve (GSA) and artery

Contents - ligaments, muscles, movements and limitations of movement

• Temporomandibular joint
• Sphenomandibular ligament
• Pterygomandibular raphe
• Lateral and medial pterygoid muscles - protraction and elevation plus secondary actions

Vasculature and venous communications

• Maxillary artery and branches
• Pterygoid venous plexus - communicates with orbit and face, with retromandibular vein to neck and face, foramen ovale to cavernous sinus

Innervation and functional components

• Mandibular branch of trigeminal nerve - GSA SVE
• Chorda tympani - SVA GVE
• Lesser superficial petrosal nerve - GVE

Lymphatic drainage and significance

• Pathways to deep and superfical cervical nodes
• Muscles of mastication
• Spread of infection to intracranial locations
• Gateway to the pterygopalatine fossa and route for injection to treat trigeminal neuralgia

General Comments

• The sympathetic innervation to the head modulates vascular tone, viscous saliva secretion, sudomotor activity, and pupil dilation. The sympathetic innervation to the neck controls vascular tone and sudomotor activity. The sumpathetic innervation of the thorax and upper limb is derived from cervical sympathetic trunk ganglia. Notably, the brachial plexus receives gray rami from the stellate and middle cervical sympathetic trunk ganglia. These same ganglia provide cardiac nerves the to the mediastinum. The internal and external carotid plexuses of sympathetic fibers are derived from the superior cervical sympathetic ganglion. The vertebral arterial plexus is derived from the vertebral ganglion.

Preganglionic cell bodies

• Intermediolateral cell column of spinal cord levels T1-T4

Postganglionic cell bodies

• For the head - superior cervical sympathetic trunk ganglion
  • postganglionic fibers follow the internal and external carotid arterial distribution
• For the neck, upper limb, and thorax - stellate, vertebral, and middle cervical sympathetic trunk ganglia
  • postganglionic fibers follow cardiac nerves to the thorax, brachial plexus to the upper limb, and cervical arteries

Anatomical pathways

• Stellate ganglion - fused first thoracic and lower cervical sympathetic trunk ganglia
  • located at anterior surface of the neck of the first rib
  • site of postganglionic cell bodies that supply the brachial and cardiac plexuses
• Vertebral ganglion
  • located near the inferior margin of the transverse foramen of the C6 vertebra
  • site of postganglionic cell bodies for the vertebral arterial plexus
• Middle cervical sympathetic trunk ganglion
  • located near the C4 transverse process within the prevertebral space (danger area) immedately anterior longus colli
  • site of postganglionic cell bodies that supply the brachial and cardiac plexuses
• Superior cervical sympathetic trunk ganglion
  • locate near the transverse processes of the atlas and axis at the base of the skull immediately inferior the the carotid canal
  • elaborates internal and external carotid nerves that, in turn, elaborate the internal and external carotid arterial plexuses of sympathetic fibers
  • site of postganlionic cell bodies that supply the head
• Cervical sympathetic trunk
  • begins at stellate ganglion of the anterior surface of the neck of the first rib
  • ascends within the prevertebral space immediately anterior the longus colli and posterior to the carotid sheath and contents
  • superior cervical sympathetic trunk ganglion is immediately anterior to longus capitus
• Ansa subclavia
  • parallel pathway to the cervical sympathetic trunk that passes anterior to the subclavian artery
  • connects the stellate ganglion to either the vertebral or middle cervical sympathetic trunk ganglia or both
  • ascends anterior surface of subclavian artery lateral to the vertebral artery and medial to the internal thoracic artery

Sympathetic Roots of the Parasympathetic Ganglia

• Ciliary ganglion - sympathetic root of the ciliary ganglion derived from the internal carotid plexus within the cavernous sinus
  • pupillary dilator, ciliary muscle (accommodation), and conjuctiva
• Pterygopalatine ganglion - deep petrosal nerve derived from the internal carotid plexus within the cavernous sinus
  • vasculature to the mucosa of the maxillary sinus, nasal cavity, oral cavity, and nasopharynx
  • vasculature of the lacrimal gland
• Otic ganglion - sympathetic root derived from middle meningeal plexus by way of the external carotid plexus
  • vasculature of the parotid region
• Submandibular ganglion - sympathetic root from the facial arterial plexus by way of the external carotid plexus
  • directly activates secretion of viscous saliva from the submandibular gland in response to irritation
  • vasculature in the regions supplied by the lingual nerve - floor of mouth and anterior two-thirds of the tongue

Horner's Syndrome - Sympathetic Denervation of the Head

• Constricted pupil - loss of internal carotid plexus and, thus, sympathetic root of the ciliary ganglion
  • parasympathetic control of pupillary constrictor is unopposed
• Mild ptosis - loss of innervation to the superior tarsal muscle
• Conjunctival injection (red eye) - loss of vascular tone within the conjunctiva
• Flushing of the skin of the face - loss of vascular tone
• Nasal congestion - loss of vascular to the erectile tissues of the nasal cavity
• Runny nose - loss of vascular tone leads to increased fluid stores