Enters the orbit through the optic foramen immediately inferior and lateral to the optic n.

Crosses the optic n. to reach the medial part of the orbit

In the orbit, besides other branches including the orbital vessels, it gives rise to 2 major branches that supply the nose:

• ▪

  Dorsal nasal

• ▪

  External nasal from the anterior ethmoidal a.

1 of 2 terminal branches of the ophthalmic a.

Exits the orbit along the superomedial border along with the infratrochlear n.

Supplies the area along the bridge of the nose

A terminal branch of the anterior ethmoid a.

Supplies the area along the external nose at the junction between the nasal bone and the lateral nasal cartilage

Infraorbital is the continuation of the maxillary a.

Arises with the inferior palpebral branch and the superior labial branch

Supplies the lateral aspect of the nose

Passes superiorly immediately deep to the posterior belly of the digastric m. and the stylohyoid m.

Passes along the submandibular gland, giving rise to the submental a., which helps supply the gland

Passes superiorly over the body of the mandible at the masseter, giving rise to the:

• ▪

  Premasseteric a.

Continues anterosuperiorly across the cheek to the angle of the mouth, giving rise to the:

• ▪

  Superior labial a.

• ▪

  Inferior labial a.

Passes superiorly along the side of the nose, giving rise to the:

• ▪

  Lateral nasal a.

Following the last branch, it continues on the side of the nose as the angular a. that terminates along the medial side of the eye

Tortuous, enabling accommodation for mandibular mobility

Begins as the angular v.

Passes inferiorly along the side of the nose, receiving the lateral nasal v.

Continues in a posteroinferior path across the angle of the mouth to the cheek, receiving the superior and inferior labial vv.

While passing toward the mandible, the deep facial v. connects the facial vein to the pterygoid plexus

In the submandibular triangle, the facial v. joins the anterior branch of the retromandibular to form the common facial v.

From the confluence of the supraorbital and supratrochlear vv. along the medial part of the eye

Travels along the lateral side of the nose to become the facial v.

Receives blood from the roof of the orbit and the scalp

Anastomoses with the angular v.

Travels posteriorly to communicate with the pterygoid plexus

Receives blood from the floor of the orbit

Anastomoses with the angular v.

Travels posteriorly with the infraorbital v. that passes through the inferior orbital fissure to communicate with the pterygoid plexus

Arises from the trigeminal in the middle cranial fossa

Passes anteriorly on the lateral wall of the cavernous sinus immediately inferior to the oculomotor and trochlear nn. but superior to the maxillary division of the trigeminal n.

Immediately before entering the orbit, through the superior orbital fissure, the ophthalmic division divides into 3 major branches:

• ▪

  Lacrimal

• ▪

  Frontal

• ▪

  Nasociliary

The nasociliary branch terminates as the:

• ▪

  Anterior ethmoid n.

• ▪

  Infratrochlear n.

Exits between the lateral nasal cartilage and the inferior border of the nasal bone

Supplies the skin of the ala and apex of the nose around the nares

Supplies the skin on the internal surface of the vestibule as the:

• ▪

  Medial internal nasal n.

• ▪

  Lateral internal nasal n.

Passes anteriorly on the superior border of the medial rectus m.

Passes inferiorly to the trochlea toward the medial angle of the eye

Supplies the skin of the bridge of the nose

Also supplies the eyelids, the conjunctiva, and all lacrimal structures

Travels along the lateral wall of the cavernous sinus

Passes from the middle cranial fossa into the pterygopalatine fossa via the foramen rotundum; within the pterygopalatine fossa, it give rise to 4 branches :

• ▪

  Infraorbital—this is the continuation of the maxillary division

• ▪

  Posterior superior alveolar

• ▪

  Zygomatic

• ▪

  Ganglionic (typically 2)

The remaining maxillary branches in the fossa rise directly from the pterygopalatine ganglion

Passes through the inferior orbital fissure to enter the orbit

Passes anteriorly through the infraorbital groove and infraorbital canal and exits onto the face via the infraorbital foramen

Once it exits onto the face, it divides into 3 terminal branches:

• ▪

  Nasal (supplies the ala of the nose)

• ▪

  Inferior palpebral (supplies the skin of the lower eyelid)

• ▪

  Superior labial (supplies the skin of the upper lip)

Enters the orbit through the optic foramen immediately inferior and lateral to the optic n.

Crosses the optic n. to reach the medial part of the orbit

In the orbit, besides the orbital branches, it gives rise to 2 major branches that supply the nasal cavity:

• ▪

  Anterior ethmoid

• ▪

  Posterior ethmoid

Travels with the nasociliary n. through the anterior ethmoidal foramen

Enters the anterior cranial fossa, where it gives rise to a meningeal branch

Continues its path to give rise to nasal branches that descend into the nasal cavity:

• ▪

  Lateral branch

• ▪

  Septal branch

Supplies branches to the lateral wall and septum of the nose before giving rise to the external nasal a., which supplies the external nose

Travels through the posterior ethmoidal foramen

Enters the anterior cranial fossa, where it gives rise to a meningeal branch

Continues its path to give rise to nasal branches that descend into the nasal cavity through the cribriform plate:

• ▪

  Lateral branch

• ▪

  Septal branch

Supplies part of the lateral wall near the superior nasal concha and the posterosuperior portion of the nasal septum

Gives rise to a series of branches; 2 provide blood supply to the nasal cavity:

• ▪

  Sphenopalatine

• ▪

  Greater palatine

After passing through the sphenopalatine foramen, enters the nasal cavity, where it gives rise to the posterior nasal branches:

• ▪

  The posterior lateral nasal branch supplies the nasal concha, mucous membranes, and lateral wall

• ▪

  The posterior septal branch continues along the nasal septum to enter the hard palate via the incisive canal

Travels in the palatine canal, where it splits into the lesser palatine a. (supplies the soft palate and palatine tonsil) and greater palatine a., which exits the greater palatine foramen, passes anteriorly toward the incisive foramen (supplies the hard palate gingiva, mucosa, and palatal glands), and anastomoses with the terminal branch of the sphenopalatine a. that exits the incisive foramen

Also provides branches that supply the area of the inferior meatus

Tortuous

Passes superiorly immediately deep to the posterior belly of the digastric and the stylohyoid mm.

Passes along the submandibular gland, giving rise to the submental a. that helps supply the gland

Passes superiorly over the body of the mandible at the masseter m.

Continues anterosuperiorly across the cheek to the angle of the mouth, giving rise to the superior and inferior labial aa.

Passes superiorly along the side of the nose, giving rise to the lateral nasal a.

Continues on the side of the nose as the angular a. that terminates along the medial aspect of the eye

Supplies the upper lip

Gives rise to the septal branch that travels upward to the nasal septum

The major blood supply to the anterior part of the nasal septum

A well-developed plexus lies deep to the mucous membrane

The plexus drains into the following series of veins:

Blood from the venous plexus along the posterior portion of the nasal cavity drains to the sphenopalatine v.

Travels through the sphenopalatine foramen to enter the pterygoid plexus

The olfactory epithelium is found in the roof of the nasal cavity, including the adjacent superior portions of the lateral wall of the nasal cavity and the nasal septum

Roughly 20–25 small olfactory n. fibers, which collectively form the olfactory nerves per side, travel superiorly through the cribriform plate into the anterior cranial fossa to join the olfactory bulb

Sensory

Arises from the main nerve in the middle cranial fossa

Passes anteriorly on the lateral wall of the cavernous sinus immediately inferior to the oculomotor and trochlear nn., but superior to the maxillary division of the trigeminal n.

Immediately before entering the orbit, through the superior orbital fissure, it divides into 3 major branches:

• ▪

  Lacrimal

• ▪

  Frontal

• ▪

  Nasociliary

The nasociliary branch terminates as the:

• ▪

  Anterior ethmoid n.

• ▪

  Infratrochlear n.

Enters the anterior ethmoid foramen and travels through the canal to enter the anterior cranial fossa

While descending toward the nasal cavity, it provides innervation to the anterior parts of the middle and inferior conchae and the region anterior to the nasal concha

Specifically, it supplies the skin on the internal surface of the nasal cavity as the:

• ▪

  Medial internal nasal n.

• ▪

  Lateral internal nasal n.

Sensory

Travels along the lateral wall of the cavernous sinus

Passes from the middle cranial fossa into the pterygopalatine fossa via the foramen rotundum

Within the pterygopalatine fossa, it gives rise to 4 branches:

• ▪

  Infraorbital—this is the continuation of the maxillary

• ▪

  Posterior superior alveolar

• ▪

  Zygomatic

• ▪

  Ganglionic

Passes through the inferior orbital fissure to enter the orbit

Passes anteriorly through the infraorbital groove and infraorbital canal and exits onto the face via the infraorbital foramen

In the infraorbital canal, it gives rise to the:

• ▪

  Anterior superior alveolar n.

The anterior superior alveolar n. has a small branch that supplies the nasal cavity in the region of the inferior meatus and inferior corresponding portion of the nasal septum (in addition to supplying the maxillary sinus; the maxillary central incisor, lateral incisor, and canine teeth; and the gingiva and mucosa alongside these teeth)

Passes through the sphenopalatine foramen to enter the nasal cavity

Passes along the superior portion of the nasal cavity to the nasal septum, where it travels anteroinferiorly to the incisive canal supplying the septum

The greater palatine n. branches from the pterygopalatine ganglion in the pterygopalatine fossa

It descends through the greater palatine canal to enter the hard palate via the greater palatine foramen

While descending in the palatine canal, it gives rise to a:

• ▪

  Posterior inferior lateral nasal branch

Supplies the posterior part of the lateral wall of the nasal cavity in the region of the middle meatus

Passes through the sphenopalatine foramen to enter the nasal cavity and branches into 2 nerves:

• ▪

  Posterior superior medial nasal

• ▪

  Posterior superior lateral nasal