Maxillary Artery: Anatomy and Branches

• The maxillary artery is a terminal division of the external carotid artery, along with the superficial temporal artery.
• It enters the infratemporal fossa after branching from the external carotid artery.
• It passes deep to the mandible neck and between the neck and sphenomandibular ligament.
• The auriculotemporal nerve is located superior to the artery, while the maxillary veins are inferior to it.
• The artery typically runs deep relative to the lower head of the lateral pterygoid muscle, often passing between its two heads.
• There are variations in the artery's path around the lateral pterygoid.
• After passing deeply, it enters the pterygomaxillary fissure and the pterygopalatine fossa.
• It is conventionally divided into three parts, relating to the lateral pterygoid muscle: before, on, and beyond.
• Five branches arise from each of the three parts of the maxillary artery but each of the branches have distinct pathways.
• The branches of the first and third parts enter bony foramina, while branches of the second part do not.

First Part Branches

• The first part has five "bony" branches: the inferior alveolar, middle meningeal, accessory meningeal arteries, and two branches to the ear.
• The inferior alveolar and middle meningeal arteries are most important, arising close to each other and passing straight down and up, respectively.
• The inferior alveolar artery descends towards the inferior alveolar nerve, joining it at the mandibular foramen along with a vein.
• Within the mandible, it supplies the dental pulps and the bone.
• Its mental branch exits the mental foramen to supply the lip and skin.
• It atrophies in the edentulous mandibles of the elderly due to alveolar bone resorption.
• The middle meningeal artery ascends to the foramen spinosum
• The auriculotemporal nerve roots embrace it.
• It supplies the skull bone.
• A branch from its sympathetic plexus enters the otic ganglion.
• The accessory meningeal artery passes through the foramen ovale.
• Dura mater of the middle fossa and the trigeminal (Meckel's) cave are supplied by it.
• The main blood supply to the trigeminal ganglion comes from it.
• The remaining two arteries go to the ear, running superficial and deep to the tympanic membrane.
• The deep auricular artery is superficial, supplying the external acoustic meatus between cartilage and bone.
• The anterior tympanic artery runs through the petrotympanic fissure to the middle ear.
• This joins the circular anastomosis around the tympanic membrane.

Second Part Branches

• The second part gives off five branches to soft tissues, including pterygoid muscles, deep temporal branches to temporalis, and branches accompanying the lingual and buccal nerves.

Third Part Branches

• The third part, in the pterygopalatine fossa, gives five branches that accompany nerves. This includes branches of the pterygopalatine ganglion.
• The artery exits the fossa through the sphenopalatine foramen, becoming the sphenopalatine artery, the main artery of the nasal cavity.
• The posterior superior alveolar artery sends branches with corresponding nerves through foramina in the posterior maxilla.
• The greater palatine artery enters the greater palatine foramen to reach the hard palate.
• The pharyngeal artery, which is very small goes into the palatovaginal canal.
• The artery of the pterygoid canal enters its own canal.
• The infraorbital artery passes through the inferior orbital fissure, along the orbit floor and infraorbital canal, emerging with the infraorbital nerve on the face.
• The posterior superior alveolar nerve is a branch of the maxillary nerve in the pterygopalatine fossa.
• It divides into two or three branches that pierce the posterior maxilla, supplying molar teeth and maxillary sinus mucous membrane.
• A gingival branch supplies the gingiva of the vestibule near the molar teeth.
• The buccal branch of the mandibular nerve supplies the adjacent cheek mucous membrane lining the buccinator.
• Posterior superior alveolar nerves can be blocked by injection in the infratemporal fossa.
• The pterygoid venous plexus and vessels are near the needle, posing a risk of puncture and hematoma.

Pterygoid Plexus

• The pterygoid plexus is a network of small veins around and within the lateral pterygoid muscle.
• It is often difficult to demonstrate in dissections as it lies within the muscle.
• In living individuals, these veins are often full and can easily be punctured during anesthetic injections near the posterior superior alveolar nerves.
• Veins draining into it correspond with the maxillary artery branches.
• Blood returns from the periphery via facial, pharyngeal, and diploic veins, and veins draining into the pterygoid plexus.
• The veins draining into it correspond with the maxillary artery branches.
• It also receives drainage from the inferior ophthalmic veins (from the internal carotid artery) via the inferior orbital fissure and the deep facial vein.
• The pterygoid plexus drains into short maxillary veins deep to the mandible neck, which join the superficial temporal vein to form the retromandibular vein.
• The deep facial vein provides an alternate drainage route to the facial vein, if the maxillary vein is blocked.
• The pterygoid plexus serves as a peripheral venous pump, aided by the lateral pterygoid muscle.
• It sucks blood from incompressible areas (face bones, orbit) and pumps it into the maxillary veins.
• This pumping action occurs during active mouth opening (talking or chewing), but not during relaxed mandibular drooping.

Sphenomandibular Ligament

• The sphenomandibular ligament is a fibrous band from the sphenoid spine to the lingula and inferior margin of the mandibular foramen.
• It is the perichondrium of Meckel's cartilage.
• The auriculotemporal nerve, maxillary artery, and vein pass between it and the mandible neck.
• The inferior alveolar vessels and nerve pass between it and the mandibular ramus towards the mandibular foramen.
• The mylohyoid nerve pierces the ligament, branching from the inferior alveolar nerve.
• The small mylohyoid artery, a branch of the inferior alveolar artery, accompanies the nerve and anastomoses with the submental branch of the facial artery.
• The small vein accompanying the mylohyoid artery makes the mylohyoid groove on the mandible.

Exploration of the maxillary artery, a division of the external carotid artery. Includes its path through the infratemporal fossa, its relation to the lateral pterygoid muscle, and its conventional three-part division. Overview of the branches stemming from each part and detailing their respective pathways.