Head and Neck review Flashcards
(225 cards)
What is a fontanelle?
a large membranous, unossified gap that exists in the neonate and the newborn between the bones of the skull.
Anterior= where coronal and sagittal sutures will meet
Posterior= where sagittal and lambdoid sutures will meet
function of fontanelles?
allow movement of skull bone during birthing process so head can deform as it passes out through the birth canal, so moulding occurs
allow for post-natal growth
how is neonatal skull different from adult?
sutures between adjacent cranial bones open in newborn, closed in adult
2 frontal bones normally fuse, but occasionally persist in the adult (metopic suture)
Bony proportions different – facial skeleton small at birth
Alveolar processes and paranasal sinuses rudimentary at birth
When does the anterior fontanelle and posterior fontanelle close?
anterior- within 2 yrs
posterior- within 6-9mnths
Problem of small foetal mastoid process during childbirth?
forceps may damage facial nerve as will be relatively superficial so close to surface as it emerges from the stylomastoid foramina
what is the antrum in the facial skeleton?
maxillary sinus in body of maxilla
3 major divisions of trigeminal nerve before leaving middle cranial fossa?
opthalmic
maxillary
mandibular
where does the mandibular nerve exit the skull?
foramen ovale
why might a fracture of the mandible cause numbness of the lower lip?
damage to the inferior alveolar nerve, a branch of the mandibular nerve which is a branch of the trigeminal nerve, which hence causes a loss of function of the mental nerve which branches from the inferior alveolar nerve, passes through the mental formaina in the body of the mandible and innervates the oral mucosa of the inferior lip
What is the ligamentum nuchae?
It is a thickened fibroelastic tissue that attaches to the external occipital protuberance and the posterior border of the foramen magnum to the spinous processes of the cervical vertebrae.
What does the ligamentum nuchae help to do?
maintain normal curvature of cervical spine
why are cervical vertebrae prone to dislocation in whiplash injuries?
almost horizontal alignment of the articular facets between adjoining vertebrae.
problem of a posterior prolapse of IV disc between C2 and C3?
The prolapse may cause pressure on the spinal cord above the phrenic nerve outflow of C3, C4 and C5. If this happens suddenly, respiration will cease as phrenic nerve innervates the diaphragm which is necessary for inspiration (respons. for 70% of chest expansion in quiet respiration)
where does the middle meningeal artery enter the cranial cavity?
through foramen spinosum, and then lies just behind pterion
type of cranial fracture causing an epidural haematoma?
depressed fracture
what might a depressed fontanelle mean?
dehydration
what might a bulging fontanelle indicate?
increased intra-cranial pressure
where is the stylomastoid foramen located?
on lower surface of temporal bone, between the styloid and mastoid processes
how are the head and face positioned in congenital torticollis?
head tilts toward, and face turns away from, the affected side
how does the articular capsule of TMJ fit the mandibular fossa and articular tubercle?
upper surface of disc is concavo-convex (A-P)
why is an infection deep in the pterygoid region of danger to the eye?
pterygoid venous plexus located in the infratemporal fossa is connected with both the opthalmic and anterior facial veins, it drains into the cavernous sinus- receives blood from s and i opthalmic veins, so infection may cause a cavernous sinus thrombosis which can cause paralysis of extraocular muscles, or pus from infection may cause direct increased opthalmic venous pressure
what is the parotid duct and how can it be palapated?
route that saliva takes from parotid gland, into the mouth
when jaw clenched tight, it can be felt lying on the contracted masseter muscle
when does the parotid duct enter the mouth?
on piercing the buccinator muscle (CN XII), it opens into the mouth opposite the second upper molar tooth
function of occipitofrontalis
occipital belly: scalp retraction, increasing effectiveness of frontal belly, innervated by post auricular branch
frontal: protracts scalp, elevates eyebrows and wrinkles skin of forehead