Blood supply to oro-dental tissuesAshok K Ramadorai BDS FDS RCSEd FFDRCSIre( Oral surg)

Maxillary arteryFirst part- between the neck of the condyle and sphenomandibular ligament,deep to the lower head of lateral pterygoidBranches- IA, Middle meningeal, accessory meningeal, deep auricular, anterior tympanic.DAMAI to remember!

SECOND PART between the two heads of the lateral pterygoidBranches to masseter, pterygoids and deep temoral to temporalis.

THIRD PART- in the pterygopalatine fossa .The third part passes through the sphenopalatine foramen to change its name to sphenopalatine artery- main for nasal cavityBranches of third part- PSA, Greater palatine, pharyngeal, artery of pterygoid canal, Infra orbital artery.

Mandibular teeth & PeriodontiumThe Inferior Alveolar artery which supplies the mandibular teeth is derived from the maxillary artery before it crosses the lateral pterygoid muscle.A mylohoid branch is given off before the IA artery enters the mandibular foramen to enter the Mandibular canal and terminates as mental and incisive arteries .

Posteriorly , the buccal gingiva is supplied by the buccal artery ( a branch of maxillary artery as it crosses the lateral pterygoid muscle) and by perforating branches from IA artery.Anteriorly, the labial gingiva ia supplied by the mental artery and perforating branches of incisive artery.Lingual gingiva- perforating branches of artery and lingual artery

Maxilary teeth and PeriodontiumThe Posterior superior alveolar artery arises from the maxillary artery in the ptergopalatine fossa.It courses torturously over the maxillary tuberosity before entering the bony canals to supply molar and premolar teethAlso gives a branch to buccal gingiva, maxillary sinus and cheek

The middle superior alveolar artery when present arises from the infra orbital artery( which itself is a branch third part of maxillary artery in the pterygopalatine fossa)The MSA artery runs in the lateral wall of the maxillary sinus terminating near the canine tooth where it anastomoses with the ASA and PSA arteries.

The ASAartery also arises from the infra orbital artery and runs downwards in the anterior wall of the maxillary sinus to supply the anterior teeth.Like the superior alveolar nerves, the superior alveolar arteries form plexusesBuccal gingiva around the maxillary molars- gingival and perforating branches from the posterior superior aleveolar artery and by the buccal artery.

Labial gingiva of anterior teeth- labial branches of infra orbital artery and perforating branches of ASA artery.Palatal Gingiva- Greater palatine artery.Cheek- Buccal branch of maxillary artery.Tongue- Lingual arteryLip- Superior and inferior branches of facial artery.

Venous drainageFacial v- main vein draining the faceBegins in the medial corner of the eye by confluence of supra orbital and supra trochlear vein, passes across the face behind the facial artery, below the mandible it joins the anterior branch of retromandibular v to form common facial v.

Branches from the ST v and Maxillary v join to form the retromandibular vein within the substance of the parotid gland.The ant branch of the RM v joins the facial v which empties into the IJV, the post branch pierces the investing layer of deep fascia and is joined by post auricular v to form Ext jugular vein .

The EJV lies deep to the platysma and on superficial fascia over the SM muscle , pierces the investing layer of deep fascia a finger breadth above the midpoint of the clavicle. and finally empties into subclavian vein.

Deep vein anastomosesThe facial v communicates with the cavernous sinus.1. At the medial canthus there is a communication with the sup opthalmic vein which drains directly into the sinus.Blood from the forehead normally flows via the facial vein; if the latter is blocked/ thrombosis blood above the obstruction will flow through the orbit into the Cavernous sinus.

2. Deep facial vein between the facial vein and the pterygoid plexus.The plexus receives a vein from the cavernous sinus through foramen ovale or Vesalius( medial to foramen ovale)Danger area of the face- lies between the angular and deep facial veins.

Cavernous sinus thrombosisThe cavernous sinus is in venous connection with the skin part of the face where infection may produce thrombosis.By the superficial middle cerebral vein such thrombosis can spread through the hemisphere. The danger area of the face lies above the level of the deep facial vein; it comprises the upper lip and medial part of the cheek.

It is significant that it lies between the two veins of communication between face skin and cavernous sinus, namelyThe angular vein via Superior opthalmic vein directly into the cavernous sinus.2. Deep facial vein via pterygoid plexus and the communicating veins in the foramen ovale and venous foramen.

Thrombosis of the cavernous sinus produces opthalmoplegia from occular nerve interruption. Retrograde thrombosis of inferior pertrosal sinus and medullar veins is usually very fatal.