Origin and Course
The sphenopalatine artery is a branch of the maxillary artery (a. maxillaris). The maxillary artery itself branches off from the external carotid artery within the substance of the parotid gland, hooks around the neck of the mandible, and divides into three parts.
The sphenopalatine artery arises from the third or pterygopalatine part (pars pterygopalatina), which lies within the pterygopalatine fossa (fossa pterygopalatina). Other branches originating from this part of the maxillary artery include the infraorbital artery, posterior superior alveolar arteries, descending palatine artery, and the artery of the pterygoid canal.
Structures Passing Through the Sphenopalatine Foramen
The sphenopalatine foramen (foramen sphenopalatinum) connects the pterygopalatine fossa to the nasal cavity. The following structures pass through this foramen:
- Sphenopalatine artery (a. sphenopalatina).
- Sphenopalatine veins.
- Posterior superior lateral and medial nasal branches (rr. nasales posteriores superiores laterales et mediales) — branches of the maxillary nerve (n. maxillaris).
Branches and Area of Supply
The sphenopalatine artery gives off the following main branches:
- Posterior lateral nasal branches (rr. nasales posteriores laterales) — course toward the lateral wall of the nasal cavity, nasal conchae, and paranasal sinuses.
- Posterior septal branch (r. septalis posterior) — courses toward the nasal septum.
The anterior and posterior ethmoidal arteries (aa. ethmoidales anterior et posterior) also contribute to the blood supply of the nasal cavity. Venous drainage flows into the pterygoid venous plexus (plexus pterygoideus). Innervation of the posterior nasal cavity is provided by the posterior nasal nerves (nn. nasales posteriores), which are branches of the maxillary nerve traversing the pterygopalatine ganglion (ganglion pterygopalatinum).
Anastomoses and Clinical Significance
The sphenopalatine artery anastomoses with branches of the ophthalmic artery and the greater palatine artery, forming a critical link between the external and internal carotid artery systems.
- Connection with the ophthalmic artery (a. ophthalmica), a branch of the internal carotid artery.
- Connection with the greater palatine artery (a. palatina major). This anastomosis occurs via the incisive canal. The greater palatine artery is a branch of the descending palatine artery (a. palatina descendens), which also originates in the pterygopalatine fossa and courses along the hard palate.