Important Blood Vessels Of Head And Neck
Veins of head and neck region can be divided into:-
- Extracranial veins - These are:-
- Veins of headandface:-Facial vein, retro mandibular (posterior facial) vein, occipital vein.
- Veins of neck:-Internal jugular vein, external jugular vein, vertebral vein, subclavian vein.
- Intracranial (Dural) venous sinuses :- These are:-
- Paired venous sinus:-Cavernous sinus, superior petrosal sinus, inferior petrosal sinus, transverse sinus, sigmoid sinus, sphenoparietal sinus, petrosquamous sinus, middle meningeal veins (sinus).
- Unpaired venous sinus:-Superior sagittal sinus, inferior sagittal sinus, straight sinus, occipital sinus, anterior and posterior intercavernous sinuses, basilar plexus of veins.
Internal Jugular Vein
- It begins as a continuation of sigmoid sinus in the posterior compartment of jugular foramen. The dilated upper end of vein is known as Superior bulb which is lodged in the jugular fossa of petrous temporal bone. It descends downwards in neck within carotid sheath, along with common and internal carotid arteries and vagus nerve. Behind the sternal end of clavicle, it unites with subclavian vein to form the brachiocephalic vein. Lower end of vein is slightly dilated to form the inferior bulb.
- Its tributaries are: (i) inferior petrosal sinus, (ii) common facial vein, (iii) lingual vein, (iv) pharyngeal veins, (v) superior thyroid vein, and (vi) middle thyroid vein.
- On the left side, the thoracic duct drains into the angle of union ofIJV with subclavian vein and on right side, the right lymphatic duct opens at the same site.
External Jugular Vein
- It is formed by union of posterior auricular vein with posterior division of retro mandibular vein. It ends by opening into subclavian vein. Its tributaries are: (i) posterior external jugular vein, (ii) suprascapular vein, (iii) transverse cervical vein, and (iv) anterior jugular vein.
- Surface anatomy of external jugular vein is marked by a line joining a point behind and below angle of mandible to a point on clavicle just lateral to posterior border of sternocleidomastoid.
- It is the continuation of axillary vein, beginning at the level of outer border of 1strib and ends at the level of medial border of scalenus anterior by joining IN to form brachiocephalic vein. Its tributaries are external jugular and dorsal scapular veins.
Each cavernous sinus is a large venous space situated in the middle cranial fossa on either side of the body of the sphenoid bone. Its interior is divided into a number of trabeculae or caverns. The floor of the sinus is formed by the endosteal dura mater. The lateral wall, roof and medial wall are formed by the meningeal dura mater.
Structures in the lateral wall of the sinus from above downwards:
- Oculomotor nerve
- Trochlear nerve
- Ophthalmic nerve - in the anterior part of the sinus, it divides into the lacrimal, frontal and nasociliary nerves.
- Maxillary nerve - it leaves the sinus by passing through the foramen rotundum on its way to the pterygopalatine fossa.
- Trigeminal ganglion - the ganglion and its dural cave project into the posterior part of the lateral wall of the sinus.
Structures passing through the centre of the sinus:
- Internal carotid artery with the venous and sympathetic plexus around it.
- Abducent nerve, inferolateral to the internal carotid artery.
Tributaries (incoming channels) of cavernous sinus
- Superior ophthalmic vein.
- A branch of inferior ophthalmic vein or sometimes vein itself.
- Central vein of retina (it may also drain into superior ophthalmic vein).
- Superficial middle cerebral vein.
- Inferior cerebral vein.
- Sphenoparietal sinus.
- Frontal trunk of middle meningeal vein (it may also drain into pterygoid plexus or into sphenoparietal sinus).
Draining channels (communications) of cavernous sinus
- Into transverse sinus through superior petrosal sinus.
- Into internal jugular vein through inferior petrosal sinusand through a plexus around the ICA
- Into pterygoid plexus of veinsthrough emissary veins.
- Into facial vein through superior ophthalmic vein.
- Right and left cavernous sinus communicates with each other by anterior and posterior intercavernous sinuses and through basilar plexus of veins.
- Cavernous sinus thrombosis may be caused by infection in dangerous area of face, nasal cavities and paranasal sinuses. It presents as :-
- Nervous symptoms:-Severe pain in the distribution of ophthalmic nerve. Involvement of3rd, 4th and 6thcranial nerves causes paralysis of extraocular muscles with diplopia.
- Venous symptoms: - Edema of eyelids, cornea and root of nose with exophthalmos.
- Communication between cavernous sinus and lCA, after trauma, may cause pulsatile exophthalmos.
Anterior cervical nodes
These nodes lie along anterior jugular vein. They receive afferents from infrahyoid region of neck and drain into (efferent) lower deep cervical lymph nodes.
Superficial cervical nodes
These nodes liesuperficial to sternocleidomastoid along external jugular vein.They receive afferents from lobule of auricle, floor of external acoustic meatus, and skin over angle of mandible and lower part of parotid region. They drain into (efferent) upper and lower deep cervical nodes.
Submental lymph nodes
These lymph nodes lie on the mylohyoid in the submental triangle. The receive afferents from superficial tissue below chin, central part of lowerlip, adjoining gums, anterior part of the floor of the mouthand tip of thetongue. These nodes, themselves, drain into (efferent) into submandibular nodes.
These nodes lie deep to investing layer of deep cervical fascia in submandibular triangle, between the deep fascia and submandibular gland. These nodes receive afferents from centre of forehead; anterior part of nasal cavity; frontal, maxillary and ethmoidal air sinuses; inner canthus (medial angle of eye); whole of upper lip and anterior part of cheek with underlying gum and teeth; outer part of lower lip with lower gums and teeth excluding incisors; anterior two third of tongue-"?" excluding the tip; floor of mouth; and angle of mouth. These nodes also receive efferents of submental nodes. Submandibular nodes drain into (efferent) upper and lower deep cervical nodes. Two of submandibular nodes, one in front and one behind the facial artery, are called lymph gland of stahr.
Deep cervical lymph nodes
These are a vertical chain of lymph nodes. AU lymph nodes draining the superficial and deep tissues of head and neck finally drain into deep cervical group of lymph nodes. These nodes lie deep to sternocleidomastoid.
These are divided into two groups:-
- Upper deep cervical (jugulodigastric) nodes: - These lie along upper part of internal jugular vein in a triangular area bounded by IN, common facial vein and posterior belly of digastric muscle. These nodes receive lymphatics from the palatine tonsil, and posterior and posterior most part of tongue.
- Lower deep cervical (jugular-omohyoid) nodes: - These nodes lie along lower part of internal jugular vein at superior belly of omohyoid. These are mainly concerned with lymphatic drainage of tongue. Some members of lower deep cervical nodes extend laterally into supraclavicular triangle and are known as supraclavicular lymph nodes. One or two lymph nodes lie in front of scalenus anterior and are called scalene lymph nodes.