head and neck anatomy Flashcards
what structures are included in the surface anatomy of the neck
- mandible
- hyoid bone
- thyroid cartilage
- cricoid cartilage
- trachea
- trapezius
- sternocleidomastoid
- clavicle
- suprasternal notch
the skeletal component of neck is comprised of what three things
- cervical vertebrae
- hyoid bone
- laryngeal cartilages [thyroid and cricoid]
what is the difference between cricoid cartilage and thyroid cartilage
- cricoid cartilage is a continuous ring of cartilage
- thyroid cartilage - not continuous - U shape
what is a characteristic of hyoid bone
- does not articulate with bones - only attached to muscles and ligaments
3 differences between cervical and thoracic vertebra
cervical has
- smaller body
- bifid spinous process
- transverse foramen [allowing transmission of blood vessels and nerves]
cervical vertebrae 1
- known as atlas
- has no body
- articulates with occipital condyles on base of the skull allowing for nodding movements
cervical vertebrae 2
- known as axis
- has a structure called dens which projects from the body upwards
- the anterior surface of dens articulates with posterior surface of arch of atlas
- allows for shaking movement
what is platysma
- most superficial muscle lying below surface of skin and neck
- forms a flat sheet that attaches to inferior border of mandible and muscles around the mouth
- platysma is innervated by cervical branches of facial nerve
- tightens skins and depresses corners of the mouth
where does sternocleidomastoid originate from
- head is at clavicle and sternum
- the two heads join and attach to the mastoid process
- if one muscle contracts head and neck bend to same side therefore face tilts upwards and opposite side
- if both muscles contract neck is flexed and head is extended
where does the trapezius insert from and what is its function
- inserts from clavicle and parts of scapula
- used to shrug shoulders and raises scapula
what cranial nerve is sternocleidomastoid and trapezius innervated by
- spinal accessory nerve [11]
what structures form the posterior triangle
- sternocleidomastoid
- trapezius
- accessory nerve
- external jugular vein
- levator scapulae [elevates the scapula]
what structures form the anterior triangle
- external jugular vein
- sternocleidomastoid
- trapezius
- hyoid bone
- suprahyoid muscles [superior to hyoid] - opposite to infra hyoid
- infra hyoid muscles [when contracts depresses hyoid bone and larynx]
what is a cricothyrotomy and tracheostomy
- a small incision made through the skin and the cricothyroid membrane is located
- a small midline incision is made in the membrane and the tracheostomy tube is inserted
- a tracheostomy - surgical operation to keep airway open - tube inserted directly into trachea
what is the clinical test, what do they supply [accessory nerves]
- they are motor nerves
- supplying the sternocleidomastoid and trapezius
- clinical test; turn head and shrug shoulders against resistance
where do the accessory nerves enter and exit from
- the spinal part of the nerve originates from the upper 5 cervical segments and enters the cranium through the foramen magnum
- before the nerve leaves the cranium it is joined by fibres from the vagus nerve and leave the cranium through jugular foramen
what is venous drainage and what is it done via
- it is where deoxygenated blood is drained
- drainage of head and neck via internal and external jugular veins
internal jugular vein
- responsible for draining the brain and deeper structures of head and neck
- it leaves via jugular foramen and travels inferiorly within carotid sheath alongside internal carotid artery and vagus nerve
- along its way is receives facial, lingual, pharyngeal veins
external jugular vein
- drains superficial extracranial structures
- travels superficial to sternocleidomastoid before emptying into subclavian vein
what is carotid sheath made from and what does it contain
- connective tissue
- contains vagus nerve, internal jugular vein and common carotid artery
what do the main arteries supplying head and neck branch from
- subclavian and
- common carotid
the common carotid bifurcate in the neck forming what
- internal and external common carotid
internal carotid artery
- has no branches
- travels adjacent to internal jugular vein within the carotid sheath towards cranium to supply head
external carotid artery
- external to carotid sheath
- supplies tissues of head, neck and oral cavity
what is the superior thyroid artery
- it is the first branch from external carotid artery
- supplies structures inc. thyroid gland, infra hyoid muscles, sternocleidomastoid and muscles of larynx
what do the ascending pharyngeal arteries supply
- supplies pharyngeal walls and
- palatine tonsils
what do lingual arteries supply
- supplies tongue, suprahyoid and floor of mouth
what is the route of the facial artery
- arises from superior lingual artery - emerges on the face at inferior border of mandible, anterior to masseter muscle and then travels diagonally across the face to medial corner of the eye
what arteries supply the posterior of the neck, scalp and behind the ears
- occipital
and posterior auricular arteries
what are the two terminal branches of the external carotid arteries
- superficial temporary artery - smaller and branches to supply skin of scalp
- maxillary artery - gives of 2 branches
; middle meningeal artery - supplies dura and skull
; inferior alveolar artery - supplying mandibular detention
where do the inferior thyroid artery branch from and what do they supply
- branches from thyrocervical trunk
- supplies thyroid gland, larynx and trachea
what does the vertebral artery branch from and what does it supply
- branches from subclavian artery
- travels through neck via transverse foramen of cervical vertebrae and enters cranium via foramen magnum to supply brain
