Page 318 - Clinical Anatomy

ECA5 7/18/06 6:51 PM Page 303

The veins of the head and neck 303

uncus of the temporal lobe of the cerebrum and the internal carotid artery,
which first pierces the roof of the sinus then doubles back to lie against it.
The ophthalmic veins drain into the anterior aspect of the cavernous
sinus which also links up, through these veins, with the pterygoid venous
plexus and the anterior facial vein. The cavernous sinus also receives
venous drainage from the brain (the superficial middle cerebral vein) and from
the dura (the sphenoparietal sinus).
Posteriorly, the superior and inferior petrosal sinuses drain the cavernous
sinus into the sigmoid sinus and into the commencement of the internal
jugular vein respectively.

Clinical features

1◊◊The cavernous sinus is liable to sepsis and thrombosis as a result of
spread of superficial infection from the lips and face via the anterior facial
and ophthalmic veins, or from deep infections of the face via the pterygoid
venous plexus around the pterygoid muscles, or from suppuration in the
orbit or accessory nasal sinuses along the ophthalmic vein and its tribu-
taries. A characteristic picture results—blockage of the venous drainage of
the orbit causes oedema of the conjunctiva and eyelids and marked exoph-
thalmos, which demonstrates transmitted pulsations from the internal
carotid artery. Pressure on the contained cranial nerves results in ophthal-
moplegia. Examination of the fundus shows papilloedema, venous
engorgement and retinal haemorrhages, all resulting from the acutely
obstructed venous drainage.
2◊◊Fractures of the skull or penetrating injuries of the skull base may
rupture the internal carotid artery within the cavernous sinus. A carotico-
cavernous arteriovenous fistula results with pulsating exophthalmos, a
loud bruit easily heard over the eye and, again, ophthalmoplegia and
marked orbital and conjunctival oedema due to the venous pressure within
the sinus being raised to arterial level.
3◊◊The sigmoid and transverse sinuses are often together termed the lateral
sinus by clinicians. Close relationship to the mastoid and middle ear renders
these sinuses liable to infective thrombosis secondary to otitis media.
Spread of infection or thrombosis from the lateral sinus to the sagittal
sinus may cause impaired C.S.F. drainage into the latter and therefore the
development of a hydrocephalus—this syndrome of raised C.S.F. pressure
associated with sinus thrombosis following ear infection is termed otitic
hydrocephalus.
It is also possible for sagittal sinus thrombosis to follow infections of the
skull, nose, face or scalp because of its diploic and emissary vein connec-
tions; if there were no emissary veins, infections of the face and scalp would
never have achieved their sinister reputation.

The internal jugular vein

The internal jugular vein runs from its origin at the jugular foramen (where