Head and Neck, Session 1 Flashcards
What is a suture?
type of fibrous joint in terms of its structure, and synarthrosis in terms of function
virtually no movement
attaches bones of skull together, apart from mandible which forms the lower jaw
why is the mandible moveable?
articulates with the cranial base at the temporomandibular joint
How may cervical pain be caused?
inflamed LNs
muscle strain
displacement/protrusion of inter-vertebral discs
what do the buccinators do?
these are the muscles of the cheek, keep cheek taut and aid in chewing
nerve supply to muscles of mastication?
mandibular division of trigeminal nerve (branch of 5th cranial nerve)
what does the facial nerve (7th cranial) supply?
derivatives of 2nd pharyngeal arch: muscles of facial expression muscles of ear e.g. stapedius stylohyoid P belly of digastric
where does the facial nerve divide into extracranial branches?
parotid gland
what is the facial artery a branch of?
the external carotid
which artery provides main arterial supply to face?
facial artery
what does the external carotid artery terminate as?
the superficial temporal and maxillary arteries
drainage of blood from face?
facial vein into internal jugular vein=MAIN
superficial temporal vein, maxillary and others form external jugular vein
both internal and external jugular drain into subclavian
*L subclavian vein receives drainage from thoracic duct in superior mediastinum
what is bell’s palsy?
paralysis of facial muscles due to dysfunction of facial nerve- can be compressed in the intracranial facial canal by inflammation near its exit from cranium at stylomastoid foramen as oedema
why might surgery on parotid gland cause facial paralysis?
may damage facial nerve innervating muscles of facial expression as nerve and its branches pass through gland
what is enclosed by the investing layer of deep cervical fascia which surrounds entire neck, deep to skin?
sternocleidomastoid, trapezius, parotid and submandibular salivary glands
what is the 2nd layer of deep cervical fascia?
pretracheal layer
this forms a muscular layer enclosing infrahyoid muscles (strap)- thyrohyoid, sternothyroid, sternohyoid, omohyoid , and visceral enclosing thyroid gland, trachea and oesophagus
laterally blends with carotid sheath
what do the carotid sheaths enclose?
common carotid artery
internal jugular vein
vagus nerve
deep cervical LNs
what is the innermost layer of deep cervical fascia?
prevertebral layer
forms a sheath for VC and assoc muscles
extends from base of cranium of 3rd T vertebra, and extends laterally as axillary sheath
where might an infection occur that can spread into thoracic cavity anterior to pericardium?
between investing layer of deep cervical fascia and visceral layer of the pretracheal layer of deep cervical fascia
symptoms of patient with a retropharyngeal abscess?
dysphagia
dysphonia
what is the retropharyngeal space?
potential space between prevertebral layer of fascia and fascia surrounding pharynx superficially (buccopharyngeal fascia)
what is the pterion?
the junction where the frontal, parietal, sphenoid and temporal bones are in close proximity
clinical relevance of pterion?
fractures of skull in this region very serious
bone part. thin and lateral fracture may lacerate middle meningeal artery (anterior divison of)- from the maxillary from ECA, casing an epidural arterial haematoma between skull and periosteal layer of dura mater, haematoma exerts pressure on underlying cerebral cortex
what is a countercoup fracture?
fracture occurs on opp side of cranium rather than at site of impact
how may an infection of the scalp cause osteomyelitis- an infection of bone?
infection can spread to skull bones via emissary veins which connect superficial veins of scalp with diploic veins of skull bones and with intracranial venous sinuses
which bone forms the upper jaw?
maxillae, fixed to cranial base
how is the odontoid (dens) process of C2 held in place?
transverse ligament of atlas
how can bleeding from common carotid arteries be controlled?
by compression against anterior tubercles of C6, found at ending of transverse processes (carotid tubercles)
what is a simple skull fracture?
break in bone without damage to skin
what is a linear skull fracture?
thin line, without splintering, depression or distortion of bone
what is a depressed skull fracture?
bone pushed towards brain
what is a compound skull fracture?
break in or loss of skin, and splintering of bone accompanied by brain injury and bleeding
what is the calvaria?
vault of the skull formed by cranial bones, forms roof of cranial cavity, protecting superior aspect of brain.
comprises frontal bone anteriorly, paired parietal bone in middle and occipital bone post.
what sutures are visible internally in calvaria?
coronal suture: between frontal and parietal bones
sagittal: between paired parietal bones
lambdoid: between parietal and occipital bones
visible junctions of these sutures are the bregma- where coronal and sagittal meet, and lambda, where lambdoid and sagittal meet
which are the main bones contributing to the cranial base (floor of cranial cavity)?
sphenoid, temporal and occipital bones
at which joint do the muscles of mastication act?
temporomandibular joint