Venous Drainage of
Mouth and Pharynx
As elsewhere in the body, the veins of the face,
oral cavity, and pharynx are more variable than are the arteries. The veins in
this region tend to lie more superficially than the arteries and form plexuses substituting
for single, definite vessels.
The internal jugular vein eventually
receives almost all of the blood derived from the mouth and pharynx. This vein
begins as a continuation of the sigmoid sinus at the jugular foramen and
descends in the neck lateral to the internal and then common carotid
arteries to about the level of the sternoclavicular joint, where it
joins the subclavian vein to form the brachiocephalic vein.
For the most part, the arteries
described in the previous section have veins of the same name accompanying
them, but the veins into which these drain differ in various ways from the
branches of the external carotid artery. The superior thyroid vein does
not differ greatly from the superior thyroid artery, but it does usually empty
directly into the internal jugular vein. Frequently, one encounters a middle
thyroid vein with no corresponding artery that also empties into the
internal jugular vein.
The deep lingual vein, often
more than one channel, accompanies the corresponding artery from the tip of the
tongue to the anterior border of the hyoglossus muscle, where the major vein
receives the sublingual vein and then accompanies the hypoglossal nerve on the
lateral surface of the hyoglossus muscle, as well as a smaller vein(s) that
runs alongside the lingual artery. Near the posterior border of the hyoglossus
muscle, one of these veins receives the dorsal lingual veins, and then
they either join to form a short lingual vein or continue separately to
empty either into the common facial vein or directly into the internal
jugular vein.
The facial vein follows a
not-so-tortuous path (compared with the artery) from the medial angle of the
eye to the lower border of the mandible near the anterior margin of the
masseter muscle. From here it courses posteriorly in the submandibular triangle
(not as sheltered by the mandible as the artery) to join the anterior division
of the retromandibular vein in the formation of a common trunk that
empties into the internal jugular vein. The anterior facial vein receives
tributaries corresponding mostly to the branches of the facial artery but also
some communications from the pterygoid plexus, one of which is often
called the deep facial or external palatine vein.
The maxillary vein is sometimes
a distinct vein with tributaries corresponding to the artery, but more commonly
appears as one or more short veins that drain the pterygoid plexus and
join the superficial temporal vein in the formation of the retromandibular
vein. The pterygoid plexus is partly superficial and partly deep to the lateral pterygoid muscle. The
tributaries are those veins that correspond to the branches of the maxillary
artery, and the plexus communicates with the cavernous sinus by
small veins passing through the foramina in the floor of the middle cranial
fossa and with the pharyngeal plexus, in addition to the other connections
previously mentioned.
The bulk of a pharyngeal plexus of
veins lies superficial to the pharyngeal constrictor muscles. This plexus
communicates in all directions, with connections to the internal and external
jugular veins, pterygoid plexus, common facial vein, lingual vein, superior
thyroid vein, and a submucosal plexus, which is best developed in the lower
part of the posterior pharyngeal wall.
The posterior division of the
retromandibular vein joins the posterior auricular vein to form the external
jugular vein, and an anterior jugular vein begins in the chin
superficial to the mylohyoid muscle and courses inferiorly and then laterally
to empty into the external jugular vein.
