Foramina Of The Face And Cranium

Question 1

What are the foramina of the anterior part of the cranium?

Answer 1

1 - Cribriform Plate - it’s the roof of the ethmoid bone, permeated with a pepper pot array of tiny holes through which the fibres of the OLFACTORY NERVE (C1) pass up from the nasal cavity.
2 - Optic Canal is located between the body of the sphenoid and the lesser wing of the sphenoid and carries the OPTIC NERVE (C2) travelling from the retina of the eye to the brain, together with the OPHTALMIC ARTERY carrying arterial supply to the orbit

Question 2

What is a fissure?

Answer 2

It’s a narrow elongated slit through which nerves and vessels pass

Question 3

What are the fissures in the back of the orbit?

Answer 3

Superior Orbital Fissure located between the sphenoid lesser wing above and the sphenoid greater wing below
Inferior Orbital Fissure located between the sphenoid greater wing above and the maxilla below

Question 4

What nerves and vessels pass through the Superior Orbital Fissure?

Answer 4

CIII OCULOMOTOR motor nerve
C IV TROCHLEAR motor nerve
C VI ABDUCENT motor nerve
CV OPHTALMIC BRANCH OF THE TRIGEMINAL NERVE sensory nerve from the orbit and the forehead
OPHTALMIC veins carrying venous drainage from the orbit draining into the cavernous sinus

Question 5

What nerves and vessels pass through the Inferior Orbital Fissure?

Answer 5

The Maxillary branch of the Trigeminal nerve CV

Question 6

What are the foramina within the greater wing of the sphenoid?
What nerves pass through them?

Answer 6

Foramen Rotundum - Maxillary branch of the Trigeminal nerve
Foramen Ovale - Mandibular branch of Trigeminal nerve and motor branch of Trigeminal nerve
Foramen Spinosum - Recurrent meningeal branch of the Trigeminal nerve and Middle meningeal artery

Question 7

What are the foramina within the Temporal bone? What are the nerves and vessels passing through them?

Answer 7

Internal auditory meatus is located within the medial wall of the petrous portion of the temporal bone. CVIII (vestibule-cochlear nerve) and CVII (facial nerve)
Stylomastoid foramen is a tiny foramen located between the styloid process and the mastoid portion of the Temporal bone. The motor portion of the facial nerve, after passing through the internal auditory meatus, exits here and turns anteriorly to travel to the face

Question 8

What are the foramina located between two bones?

Answer 8

Jugular foramen - located between the Occipital bone and the mastoid portion of the Temporal bone, on the line of the occipital-mastoid suture.
Foramen Lacerum - located between the body of the sphenoid and the petrous portion of the Temporal bone. In the living skull the foramen lacerum is not a true foramen since its lower portion is filled with cartilage so that nothing can pass through.

Question 9

What nerves and vessels pass through the Jugular Foramen?

Answer 9

Through the Jugular Foramen are passing:
CIX Glosso Pharyngeal Nerve
CX Vagus Nerve
CXI Spinal Accessory Nerve
Internal Jugular Vein - carries almost all the venous drainage from within the cranium

Question 10

What nerves and vessels pass through the Foramen Lacerum?

Answer 10

CAROTID NERVE - is the portion of the sympathetic pathway that travels from the upper thoracic spine T1-T2 via the sympathetic chain in the neck, synapsing at the superior cervical sympathetic ganglion, continuing up through the carotid canal where it also forms the carotid plexus and through the superior part of the foramen lacerum to be distributed through various branches to the cranium and the eyes.
The CAROTID ARTERY travels up the side of the neck in close association with the jugular vein and the vagus nerve within the carotid sheath, it divides in external and internal carotid artery and the internal carotid artery, after passing through the carotid canal, makes an S - shape and emerges superiorly at the foramen lacerum, feeding into the circle of Willis, the arterial ring at the basis of the brain from which branches emerge to supply the brain (anterior, middle and posterior cerebral arteries

Question 11

Where is the mastoid foramen?

Answer 11

It’s a minor foramen in the mastoid process of the Temporal bone arriving the mastoid vein.

Question 12

Where is the Condylar canal?

Answer 12

It’s a small canal within the occiput, posterior and lateral to the condylar processes, lateral to the foramen magnum. Carries the occipital emissary vein.

Question 13

Where is the Foramen Caecum?

Answer 13

It’s a small foramen located at the junction between the frontal bone and the ethmoid. It carries an emissary vein the nose to the superior sagittal sinus. It is significant because it can be a passageway for infection from the nasal cavity into the cranium and the meninges.

Question 14

Where is the incisive fossa?

Answer 14

It’s located close to the anterior end of the intermaxillary suture. It’s the inferior opening of the incisive canal through which the naso-palatine nerve (branch of maxillary branch of CV) passes and receives sensations from the roof of the mouth

Question 15

Where is the supraorbital foramen? Which nerves and vessels pass through it?

Answer 15

It’s a notch located in the superior rim of the orbit. It carries the frontal nerve, a terminal branch of the ophtalmic division of the Trigeminal nerve CV

Question 16

Where is the mental foramen? Which nerves and vessels pass through it?

Answer 16

The mental foramen is located on the anterior surface of the mandible, on each side of the symphysis mentis. The mandibular nerve passes through the foramen ovale and enters the mandible through the mandibular foramen, in the medial wall of the ramus of the mandible, travels inside the mandible giving off alveolar branches to the lower teeth, before emerging to the surface at the mental foramen.

Question 17

Where is the infraorbital foramen? Which nerves and vessels pass through it?

Answer 17

It’s located within the maxilla, just below the inferior rib of the orbit. The maxillary division of the Trigeminal nerve passes through the foramen rotundum, turns forwards to enter the orbit through the inferior orbital fissure , gives off branches to the upper teeth travels along the groove of the floor of the orbit, enters the small canal beneath the inferior rim of the orbit and emerges at the surface at the infraorbital foramen.

Question 18

Where is the mandibular foramen? Which nerves and vessels pass through it?

Answer 18

It’s located in the medial wall of the ramus of the mandible. The mandibular branch of the Trigeminal nerve passes through the foramen ovale, then enters the the jaw at the mandibular foramen and gives alveolar branches to the lower teeth a before emerging to the surface from the mental foramen