L1: Organisation of the head and neck Flashcards
What are the 2 divisions of the cranium?
- neurocranium (bones of the skull that completely encase the brain and its associated structures)
- viscerocranium (facial skeleton which is suspended beneath the neurocranium, it contains the mandible)
What are the connections b/w the bones that form the neurocranium called?
Sutures
Where is the scalp?
Extends from just above the eyebrow/above temples to the occipital region (bony protuberance at base of skull)
Where is the face?
From the eyebrows to the lower part of the chin. (however the forehead can be described as part of the face or the scalp)
What are the 2 divisions of muscles in the head?
- muscles of facial expression
- muscles of mastication (muscles responsible for moving the mandible/jaw)
What is the definition of mastication?
Chewing
What are 2 key nerves of the face?
-facial nerve: 7th cranial nerve (supply facial expression muscles)
-trigeminal nerve: 5th cranial nerve (supply muscles of mastication)
These are both types of cranial nerves
What are the key blood vessels that supply the head?
-facial artery and vein (obliquely travel up the face)
Where are sphincters found?
Muscles that are circularly arranged around orifices of the skull. (when they contract they close off the orifice)
What are the two types of muscles in the muscles of facial expression?
-sphincters
-dilators
They attach to the bones of the skull/skin/fascia/other muscles
Where are dilators found?
Linearly arranged muscles that stretch/open the structures around an orifice
What is the function of muscles of mastication?
They act on the temporomandibular joint to open or close the jaw
How many cranial nerves are there?
12
Where is the facial nerve?
Comes from the brain stem inside the skull, then exits base of skull and runs through the parotid gland (superficially)
-therefore they are vulnerable to damage in facial injuries/disease and surgery of the parotid gland
Within the paroti gland it splits into 5 extracranial key terminal branches
What are the 5 extra-cranial branches of the facial nerve?
Temporal Branch (first branch up to temporal region of face) Zygomatic Branch (runs along bone called zygoma) Buccal Branch (runs along the cheek) Marginal Mandibular Branch (runs along the margin of the mandible) Cervical Branch (runs down into the neck) These are all motor nerves, they have no sensory functions. They only supply the muscles.
Why does the eye go red if the orbicularis oculi is paralysed?
Because it is the sphincter muscle around the eye, and helps to keep it shut, so if it is paralysed then the eye drys out/becomes injured and becomes red.
What is the function of the trigeminal nerve?
Key sensory nerve of the face and scalp
What are the 3 keys branches of the trigeminal nerve?
-opthalmic division: forehead/scalp/tip of nose/eyes (Va)
-maxillary division: central face (Vb)
-mandibular division: jaw line up to temporal area (Vc)
Carry sensory information from the dermatome of the face/scalp
How are cranial nerves found?
In pairs. e.g. left trigeminal nerve & right trigeminal nerve
What type of nerves are the opthalmic and maxillary divisions of the trigeminal nerve?
Only sensory
What type of nerve is the mandibular division of the trigeminal nerve?
Both sensory and motor, as it carries motor fibres to the muscles of mastication
What are the 3 branches of the aorta?
- brachiocephalic trunk (branches into right subclavian artery which goes into right upper limb & the right common carotid artery)
- left common carotid artery
- left subclavian artery (runs into left upper limb)
Where are the R/L common carotid arteries found?
Both run up the length of the neck, to a point at whcih they terminate by splitting into two branches: internal and external carotid arteries.
They bifuracte at the 4th cervical vertebral level, just below the hyoid bone.
Where is the internal carotid artery found?
They continue to run up through the rest of the neck without giving off any branches, then run through base of skull and innervate inside the neurocranium.
