FORAMEN.pptx

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 2 nd largest foramen in the body(1 st 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

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