foramen of the skull and its embedded structures

1. FORAMEN

2. FORAMEN
• Foramen is an opening inside the body that allows key
structures to connect one part of the body to another.
• We have foramens in various bones of the body such as
vertebral column and pelvis but predominantly there are
more foramen in skull.

3. FORAMEN OF THE
SKULL
There are around 21 foramen in the
human skull. Skull bones in which
foramen is embedded are
• Frontal
• Ethmoid
• Sphenoid
• Maxilla
• Palatine
• Temporal
• occipital

4. FRONTAL BONE
• SUPRA ORBITAL FORAMEN
- A small groove at superior and
medial margin of the orbit in the
frontal bone.
- supra orbital nerve which is the
terminal branch of frontal nerve
passes through this foramen

5. • FORAMEN OF CECUM
- Located anterior to the cribriform
plate.
- Transmits the emissary vein from
the nose to the superior sagittal
sinus

6. ETHMOID BONE
• FORAMEN OF CRIBRIFORM PLATE
OR OLFACTORY FORAMEN
- The cribriform plate forms the roof
of nasal cavity and olfactory
foramen are in two depressions
lateral to median blade of cribriform
plate
- This allows olfactory nerve(CN I) to
pass through .

7. • Anterior and posterior ethmoidal
foramen
- Situated lateral to olfactory foramen
- Anterior foramen transmits ant.
Ethmoidal artery, vein and nerve.
- Posterior foramen transmits
posterior vessels and nerve.

8. SPHENOID BONE
• SUPERIOR ORBITAL FISSURE
- Situated in between lesser and greater wings of
sphenoid bone.
- Gives passage to multiple structures including
Oculomotor nerve
Trochlear nerve
Ophthalmic nerve
Abducens nerve
Ophthalmic veins
Sympathetic fibers from cavernous plexus

9. Since multiple structures
pass thro this foramen, can
be damaged in orbital
trauma particularly blowout
fractures.

10. • INFERIOR ORBITAL FISSURE
- Formed by both sphenoid and maxilla
- Located along the boundary of floor and lateral
wall of orbit.
- Transmits
Zygomatic nerve branches of maxillary nerve
Infraorbital nerve
Infra orbital vessels
Inferior division of ophthalmic nerve

11. • OPTIC CANAL
- Located in sphenoid bone bounded medially by
body of sphenoid and laterally by lesser wing of
sphenoid.
- Transmits optic nerve and ophthalmic artery into
the orbital cavity.

12. • FORAMEN ROTUNDUM
- Located inferomedial to the superior fissure at
the base of greater wing of sphenoid bone
- Allows passage of maxillary nerve , a branch of
trigeminal nerve.

13. • FORAMEN OVALE
- Opening in the greater wing of sphenoid
- Posterolateral to foramen of rotundum
- Transmits
mandibular nerve, a branch of trigeminal nerve
Accessory meningeal artery
Lesser petrosal nerve
Emissary vein

14. • FORAMEN SPINOSUM
- Opening in the greater wing of sphenoid.
- Posterolateral to foramen ovale.
- Allows passage of middle meningeal artery, vein
and meningeal branch of mandibular nerve.
- clinical significance- used as an anatomical
landmark during nerve surgery.
- Also be relevant in achieving hemostasis during
surgery by ligation of middle meningeal artery.

15. • FORAMEN LACERUM
- Triangular hole in the base of the skull.
- Located between 3 bones
Sphenoid bone – anterior border
Apex of petrous part of temporal bone –
posterolateral border
Basilar part of occipital bone - posteromedial
border
- Transmits many structures including
Greater and deep petrosal nerve – which merge to
form nerve of pterygoid canal
Artery of pterygoid canal

16. • FORAMEN LACERUM
- Clinical significance: portal entry for removal of
tumors such as nasopharyngeal carcinoma, adenoid
cystic tumor, juvenile angiofibroma.

17. • FORAMEN LACERUM
- Clinical significance: portal entry for removal of
tumors such as nasopharyngeal carcinoma, adenoid
cystic tumor, juvenile angiofibroma.

18. MAXILLA
• INFERIOR ORBITAL FISSURE
• INCISIVE FORAMEN
- Opening of incisive canals on the hard palate
behind the incisor teeth.
- Situated within incisive fossa of maxilla.
- Structures passing through
Pterygopalatine nerves
Nasopalatine nerve
Infra trochlear nerve, a branch of ophthalmic nerve
Sphenopalatine artery and vein

19. • INCISIVE FORAMEN
- Clinical significance: used as a landmark when
describing cleft lip and cleft palate which can
extend either in front of or behind the foramen.
- As many nerves exit this foramen, it may also used
for injection of local anesthetic in dental surgeries.

20. PALATINE
• GREATER PALATINE FORAMEN
- Greater palatine nerves and vessels
• LESSER PALATINE FORAMEN
- Lesser palatine nerve
• SPHENOPALATINE FORAMEN
- Connects nasal cavity with pterygopalatine fossa.
- Formed by both sphenoid and palatine bone
- Transmits
sphenopalatine artery and vein
Posterior superior lateral nasal nerves

21. TEMPORAL BONE
• CAROTID CANAL
- Located at the petrous part of temporal bone in
middle cranial fossa.
- Allows internal carotid artery to enter middle
cranial fossa from neck.
- Both internal and external openings of the canal
are located anterior to jugular foramen.

22. • JUGULAR FORAMEN
- Located behind the carotid canal
- One of the large foramen in base of the skull.
- Formed in front by petrous part of temporal bone,
behind by occipital bone.
- Subdivided into three compartments
Anterior- inferior petrosal sinus
Intermediate – glossopharyngeal nerve, vagus nerve
and accessory nerve.
Posterior- internal jugular vein, ascending pharyngeal
artery, meningeal branches of occipital artery.

23. • INTERNAL AUDITORY MEATUS/CANAL
- canal within petrous part of temporal bone of skull.
- Between posterior cranial fossa and inner ear.
- Provides passage to
vestibulocochlear nerve
Facial nerve
Labryinth artery

24. • STYLOMASTOID FORAMEN
- foramen between styloid and mastoid process of
temporal bone.
Transmits
facial nerve
Stylomastoid artery
- Inflammation of facial nerve in this foramen cause
bell’s palsy.

25. OCCIPITAL BONE
• FORAMEN MAGNUM
- Large oval shaped opening in occipital bone of
skull.
- Important structure in bipedal mammals
- 2nd largest foramen in the body(1st one is obturator
foramen in pelvis)
- The alar ligament attached on each side to tubercle
of occipital condyle divides the foramen into
anterior smaller and posterior larger compartment.
- Transmits a number of important structures
between neck and neurocranium.

26. Anterior comp.- apical ligament and tip of dens.
cruciate ligament of atlas
membrane tectoria
Posterior comp. – lower end of medulla oblangata
the spinal cord
vertebral artery
accessory nerve
anterior and posterior spinal arteries
tonsil of cerebellum

27. • HYPOGLOSSAL CANAL
- HIDDEN MEDIALLY AND SUPERIOR TO EACH
OCCIPITAL CONDYLE.
- TRANSMITS HYPOGLOSSAL NERVE.
• CONDYLAR CANAL
-present in lateral part of occipital bone behind the
occipital condyle

28. THANK YOU