Head and neck Flashcards
How many cranial bones are there
8
How many facial bones are there
14
Name the cranial bones
- ethmoid
- frontal
- occipital
- parietal
- sphenoid
- temporal
Name the three fontanelles in the skull and describe their location
Coronal - front of skull
Sagittal - middle
Lambdoid - back of skull
What is the purpose of fontanelles in the skull
Fontanelles are not solid bone, they are cartilage and they can overlap during the birthing process, they shut over after about a year to a year and a half
What is the cranial base made up of
Ethmoid bone
Frontal bone
Occipital bone
Sphenoid bone
Temporal bone
What is the cranial base
The bottom of the skull, the brain sits on top of this base
What bone lies in the front-middle of the skull and is a butterfly shape
Sphenoid bone
What is the foramen magnum
A hole in the skull that sits in the middle of the cranial bones
Functions as a passage of the CNS through the skull connecting the brain with the spinal cord
Describe the facial bones that sit in the middle of the face
Maxilla - directly in the middle of the face / top jaw
Zygoma - on the outside of the maxilla
Why is the sphenoid bone placed quite far back in the skull
So that it allows for better peripheral vision
What is the weakest part of the skull
The Pterion
What is the relevance of the squamous part of the temporal bone
This is the weakest part of the skull and can be very sensitive, if an artery is damaged here it is very serious
What is the cranial vault
The top of the skull
Includes the frontal bone, occipital bone, parietal bone, squamous part of temporal bone
What is the thinnest bone in the body
The lacrimal bone in the thinnest bone in the body, any trauma around here is very serious
Sits beside the eye
What is the intraorbital foramen
A small hole in the skull at the bottom of the eye, contains some sensory nerves
What is contained within the Cribiform plate
This is the portion of the ethmoid bone that forms the roof of the nasal cavity, it contains cranial nerve number one, olfactory nerve
What blood vessels supply the head and neck
The arch of aorta
Common carotid artery (includes the internal carotid artery and the external carotid artery)
What vein drains the head and neck
The internal jugular vein
This vein collects blood from the brain, superficial regions of the face and neck and delivers it to the right atrium
What does the ascending pharyngeal artery supply
Supplies the pharynx
What does the superior thyroid artery supply
Supplies the thyroid
What does the lingual artery supply
Supplies the blood underneath the tongue
What does the facial artery supply
The face
What does the occipital artery supply
Supplies the back of the head
What does the superior temporal artery supply
The superficial temporal artery (STA) is one of the terminal branches of the external carotid artery (ECA), and it together with other branches of the ECA, supplies the face and scalp
What does the maximally artery supply
The maxillary artery supplies deep structures of the face including the mandible, pterygoid, infratemporal fossa and segments of the pterygopalatine fossa.
What structures are found in the parotid gland
- facial nerve
- retromandibular vein
- maxillary vein
- external carotid artery
Describe the venous drainage of the face
Mirrors the arterial supply
Interjugular vein drains the cerebrum the inside of the skull and most of the external structures on the head and neck
What is the venous sinus in the skull
A blood vessel that contains endothelium and is in the folds of the dura
What does the dura venous sinus drain
The brain
What is the cavernous sinus
The danger triangle in the skull, infection from the nose can potentially pass into the veins and cause thrombosis
What cranial nerves supply the face
Cranial nerves V, VII, IX, XII
What are the three branches of the trigeminal nerve
Ophthalmic, maxillary, Mandibular
What is the ophthalmic branch of the trigeminal nerve
Sensory branch, contains the frontal nerve which contains the supratrochlear nerve and the supra orbital nerve
Also contains the lacrimal and nasociliary nerves
What is the maxillary branch of the trigeminal nerve
Sensory, contains zygomatic nerve/intraorbital nerve/ anterior, middle and superior alveolar nerves
Describe the Mandibular division of the trigeminal nerve
It is a mixed nerve, sensory and motor functions, motor to muscles of mastication and sensory to the auriculotemporal nerve, lingual nerve, buccal nerve inferior alveolar nerve
Why has incidence of temporomandibular joint dysfunction increased
Due to more people clenching there teeth due to an increase in stress
What is the function of the lateral pterygoid muscle
The only muscle that opens the mouth
What is the disc called in the TMJ
Articular disc
What structure prevents dislocation of the temporomandibular joint
Articular eminence
What does the temporomandibular joint consist of
Consists of articulations between 3 surfaces, the mandibular fossa and Articular tubercle (from the squamous part of the temporal bone) and the head of the mandible
What is the unique mechanism of the TMJ
The Articular surfaces of the bones never come into contact with each other, they are separated by an Articular disc
What covers the Articular surface of the bones in the TMJ
Fibrocartilige
What does the presence of the disc split the TMJ into
Two synovial joint cavities each lined with a synovial membrane
What are the 3 extracapsular ligaments that stabilise the TMJ
Lateral ligament, sphenomandibular ligament, stylomandibular ligament
What is the function of the stylomandibular ligament
A thickening of the fascia of the parotid gland, along with the facial muscles it supports the weight of the jaw
What does the upper part of the TMJ allow for
Allows for protrusion and retraction of the mandible, the anterior and posterior movements of the jaw
What is the lower part of the TMJ responsible for
Elevation and depression, the lower part of the joint permits elevation and depression of the mandible
Elevation is a very strong movement caused by the contraction of the facial muscles
Describe the arterial supply of the TMJ
The arterial supply is provided by branches of the external carotid, principally the superficial temporal branch
What nerves innervate the temporal mandibular joint
The auriculotemporal and masseteric branches of the mandibular nerve
What would happen in the case of a TMJ dislocation
The patient would not be able to close their mouth
What is the role of the medial pterygoid muscle
Arises from the medial surface of the lateral pterygoid plate and inserts into the medial surface of the angle of the mandible and ramus, elevates and protrudes the mandible
What is the role of the lateral pterygoid
Depresses and protrudes the mandible
