Cranial nerves: These are so called because they emerge through the foramina or fissures in the cranium and are covered by tubular sheaths derived from the cranial meninges.
The cranial nerves are bundles or sensory (or) motor fibers that inervate muscles (or) glands, carry impulses from sensory receptors, (or) show a combination of both motor and sensory functions.
The 12 cranial nervers:
- Olfactory Nerve
- Optic Nerve
- Oculomotor Nerve
- Trochlear Nerve
- Trigeminal Nerve
- Abducent Nerve
- Facial Nerve
- Vestibulocochlear Nerve
- Glossopharyngeal Nerve
- Vagus Nerve
- Spinal Accessory Nerve
- Hypoglossal Nerve
Mnemonic for 12 Cranial nerves:
These are sentences which can help in remembering the order of the cranial nerves, it is very useful to keep these in mind and we can easily recollect the correct order of Cranial nerves.
“Oh, Oh, Oh, To Take A Family Vacation! Go Vegas And Hardees”
“One Of Our Telugu Teacher Ask For Very Good Vada And Halwa” – For Indians
“Oh, Oh, Oh, Truly There Are Five Very Gorgeous Vixen Awaiting Him”
These are a couple of sentences which have helped me and many others during viva or examinations, do let us know if you have your own Mnemonic to remember Cranial nerves.
To Know the Function and origin of these Cranial Nerves see: Detailed Description of 12 Cranial Nerves
14 Important facts and points about Cranial Nerves:
- Largest Cranial Nerve – Trigeminal nerve (5th Cranial nerve)
- Smallest cranial nerve – Trochlear Nerve (4th Cranial nerve)
- Most Slender Cranial Nerve – Trochlear nerve (4th Cranial nerve)
- Longest Cranial Nerve – Vagus Nerve (10th cranial nerve)
- Longest intracranial course – Trochlear nerve (4th Cranial nerve)
- Most frequently paralized cranial nerve – Facial Nerve
- Vagus Nerve is with Vague or Extensive Distribution
- Smallest branch of Trigeminal nerve is the Opthalmic branch
- Largest branch of Trigeminal nerve is Mandibular branch
- Buccal nerve is the only Sensory branch of anterior division of the Mandibular Nerve
- Trigeminal Ganglion is the only sensory ganglia which lies outside the cranial cavity
- Smallest of 3 terminal branches of opthalmic nerve is lacrimal nerve and frontal nerve is the largest terminal branch of opthalmic nerve
- Posterior Ethmoidal is the branch of Nasociliary which is frequently absent.
- Posterior Superior alveolar nerve is the branch of maxillary nerve in Pterygopalatine fossa
- Nerve to the stylopharyngeus is the only motor nerve among all the sensory branches of the glossopharyngeal nerve.
- Middle superior alveolar nerve is present in only 28% of the individuals
- Greater palatine nerve = Anterior palatine nerve
- Lesser Palatine Nerve = Middle and Posterior palatine branches
- Nervus Intermedius is Sensory branch of facial nerve
Mnemonic for Function of Cranial Nerves – Motor or sensory:
Note: S= Sensory, M= Motor and B= both motor and sensory
“Some Say Marry Money But My Brother Says Big Brain Matter Most“
So from this Mnemonic we can see that the 1st, 2nd and 8th cranial nerves are sensory, 3rd, 4th, 6th, 11th and 12th cranial nerves are only motor while 5th, 7th, 9th and 10th cranial nerves are both motor and sensory.
Remembering these cranial nerves is a must for any medical/dental student, and that too in order is a must, and knowing them in detail is also necessary so i am going to describe the functions of each of these nerves in detail in my future posts.