The internal surface of the cranial base can be divided into 3 cranial fossae, the anterior, middle, and posterior. The anterior and middle fossae are separated by the lesser wing of sphenoid bone, and the middle and posterior fossae are separated by petrous part of temporal bone.
Various structures (nerves, arteries, veins) passing through various foramina of skull are listed below:
Foramen Ovale:
Mnemonic: MALE
1. Mandibular Nerve (CN V3)
2. Accessory meningeal nerve
3. Lesser petrosal nerve
4. Emissary vein (Cavernous sinus to pterygoid plexus)
5. Occasionally anterior trunk of middle meningeal artery
Foramen Spinosum
Mnemonic: MEN
1. Middle meningeal artery and vein (posterior trunk)
2. Emissay vein
3. Nervus spinosus (Meningeal branch of mandibular nerve)
Foramen Lacerum:
Mnemonic: MEIG
Structures passing whole length:
1. Meningeal branch of Ascending pharyngeal artery
2. Emissary vein
Other structures partially traversing:
3. Internal carotid artery
4. Greater petrosal nerve
Carotid Canal:
Internal carotid artery (ICA) and venous and sympathetic plexus around it
Foramen Rotundum:
Maxillary nerve (CN V2)
Stylomastoid Foramen:
1. Facial nerve (CN VII)
2. Posterior Auricular artery (Stylomastoid branch)
Internal Acoustic Meatus:
1. Facial nerve (CN VII)
2. Vestibulo-cochlear nerve (CN VIII)
3. Nerves intermedius or pars intermedia of wrisberg
4. Labyrinthe vessels
Hypoglossal canal:
1. Hypoglossal nerve
2. Meningeal branch of Hypoglossal nerve
3. Meningeal branch of Ascending Pharyngeal artery
4. Emissary vein (Sigmoid sinus to internal jugular vein)
Jugular Foramen:
1. Anterior part: Inferior Petrosal Sinus
2. Middle part: 9,10,11 MAP
a. CN IX (Glossopharyngeal nerve)
b. CN X (Vagus nerve)
c. CN XI (Accesory nerve)
d. Meningeal branch of Ascending Pharyngeal Artery
3. Posterior part:
a. Internal Jugular vein (IJV) – Sigmoid sinus junction
b. Emissary vein (Sigmoid sinus to occipital vein)
c. Occipital artery
Mastoid canaliculus (entry) and Tympanomastoid fissure (exit):
Auricular branch of vagus nerve
Tympanic Canaliculus
Tympanic branch of CN IX (Glossopharyngeal nerve)
Incisive Foramen
1. Greater palatine vessels
2. Nasopalatine nerves
Greater Palatine Foramen:
Mnemonic: GAP (Greater and Anterior Palatine Vessels)
1. Greater Palatine vessels
2. Anterior Palatine vessels
Lesser Palatine Foramen:
Middle and Posterior Palatine nerve
Superior Orbital Fissure
1. Lacrimal nerve
2. Frontal nerve
3. Trochlear nerve
4. Occulomotor nerve
5. Nasociliary nerve
6. Abducent nerve
7. Superior ophthalmic vein
Foramen magnum
Mnemonic: MAVer
1. Medulla oblongata
2. Ascending parts of spinal accessory nerves
3. Vertebral arteries
Tags: carotid canal, cranial fossa, foramina of skull, jugular foramen
Source :: Medchrome
