Session 1 - organisation of the neck Flashcards
What is the action and innervation of the Platysma muscle
Action- depresses the corners of the mouth and assists in depression of the jaw and draws down the lower lip
Innervation- cervical branch of facial nerve
What is the action and innervation of the Sternocleidomastoid muscle
Action- lateral flexion of the neck, tilting chin up on controlateral side
I- Accessory nerve
What is Torticollis
Involuntary contraction of the Sternocleidomastoid
What is the action and innervation of the Trapezius muscle
A-Superior fibers contract to elevate the shoulders (shrug) and rotate the scapula on the back
i-Accessory nerve
What are the borders of the anterior triangle of the neck
Imaginary mid-line of neck, inferior margin of mandible, anterior margin of sternocleidomastoid
What are the borders of the posterior triangle of the neck
Posterior margin of sternocleidomastoid, anterior margin of trapezius, clavicle
What are the borders of the carotid triangle
Sup: Posterior belly of the digastric muscle
Lat: Medial border of the sternocleidomastoid muscle
Inf: Superior belly of the omohyoid muscle
What are the main contents of the carotid triangle
Common carotid artery, internal jugular vein hypoglossal nerve and vagus nerve, carotid sinus (baroreceptors)
What are the five fascial planes of the neck
Superficial cervical fascia Investing layer Carotid Sheath Pre tracheal Pre vertebral
What space in the fascia when infected is at risk of allowing further spread of infection inferiorly to involve the mediastinal structures
The retropharyngeal space
What is a complication of infection of the medastinal structures
mediastinitus
What nerve innervates the muscles of facial expression
Facial nerve
What nerve innervates the muscles of mastication
Trigeminal nerve
What are the three key branches of the trigeminal nerve
Va- opthalmic division
Vb-maxillary division
Vc-mandibular division
What nerve provides the main sensory innervation for the face and scalp
Trigeminal nerve
Name the five key extra-cranial branches
Temporal Zygomatic Buccal Mandibular Cervical
What structures does the Internal jugular vein drain
Head and neck
also receives venous drainage from the face (facial nerve)
What the external jugular vein drain
Scalp and face
What area is defined as the neck
from the lower margin of the mandible to the suprasternal notch of the manubrium and the upper body of the clavicle
what is found in the superficial cervcial layer
loose connective tissue largely containing adipose
superficial blood vessels e.g. external jugular vein
cutaneous nerves
superficial lymph nodes
Platsyma muscle
what does the investing layer enclose
sternocleidomastoid and trapezius muscles and the subamndibular and parotid salivary glands
what does the pretracheal layer enclose
muscular layer- infrahyoid muscles
visceral layer- thyroid gland, trachea and oesophagus
what is enclosed in the carotid sheath
common carotid artery
internal jugular vein
vagus nerve
what is the action and innervation of the orbicularis oculi muscle
A: it closes the eye
I: temporal and zygomatic branches of the facial nerve
how do you examine orbucularis oculi
close eyes and resist opening
What are the three parts of orbucularis oculi and what are there functions
- orbital- surrounds orbital margin - thick muscle used to consciously close the eye- used for forceful closure
- palpebral- found in the eyelid- used for unconscious light closure of the eye in blinking/sleep
- lacrimal- from lacrimal bone to lacrimal sac - acts as tear pump
What is the action and innervation of levator palpebrae superioris
A: elevates upper eyelid
I: oculomotor nerve
examination of oculomotor nerve
inspection of eye for ptosis
what is the the action and innervation of occipitofrontalis
A:elevates eyebrows
I: frontal belly - temporal branch of the facial nerve
occipital belly- posterior auricular branch of facial nerve
how do you examine occipitofrontalis
elevate eyebrows against resistance
what is the action and innervation of orbicularis oris
A: closes mouth
I: buccal branch of facial nerve
how do you examine orbicularis oris
inspection of the face - drooping angle of the mouth in CNVII palsy
what is the action and innervation of buccinator
A: flattens cheek - holds cheek close to teeth when chewing - prevents food pooling between cheek and gums
how do you examine the action of buccinator
blow out cheeks and resist expulsion of air
what is the action of the lateral and medial pterygoid
and innervation
lateral- protrude mandible, opens jaw, contralateral excursion
medial- elevation and contralateral excursion
I- mandibular branch of the trigeminal nerve
how do you examine the medial and lateral pterygoids
open mouth against resistance and move jaw side the to side
what is the action ad innervation of masseter
action: elevates mandible (closes jaw), stronger then medial pterygoid
innervation: mandibular branch of trigeminal nerve
how do you examine the masseter muscle
palpation during jaw clench
what is the action and innervation of temporalis
action- elevates mandible (also retrusion of mandible)
how do you examine the temporalis
palpation during jaw clench
what is the action and innervation of the sternocleidomastoid
action- head rotation to opposite side (one side contracts). lateral neck fexion (one side contracts). neck flexion (both contract)
innervation- accessory nerve
how do you examine SCM
turn head against resistance (remember to right=left SCM)
What is the action and innervation of trapezius
A- upper and lower fibers rotate scapula (acromion and inferior angles move up). middle fibres retract scapula . when scapulae stable, contraction of both sides extends the neck
I- accessory nerve
how do you examine trapezius
get them to elevate shoulder
what are the contents of the skin of the scalp
hair follicles and sebaceous glands
why does profuse bleeding of the scalp occur
the blood vessels are highly adherent to the deep connective tissue and so cannot constrict if fully lacerated
what muscles does the epicranial aponeurosis connect
the occipitalis and frontalis muscles
what is the function of the loose areolar connective tissue and what does it contain
it is a thin connective tissue layer that separates the periosteum of the skull from the epicranial aponeurosis.
It contains numerous blood vessels, including emissary veins. which connect the veins of the scalp to the diploic veins and intracranial venous sinuses.
where does the periosteum become continuous with endosteum
at suture lines
in which layer of the scalp is a scalp infection most likely to occur and why is this dangerous
the area of loose CT
pus and blood spread easily within it and pass into the cranial cavity along emissary veins. so infection can spread from the scalp to the meninges causing meningitis
which two main arteries does the scalp receive its blood supply from?
the external carotid artery and the opthalmic artery (via internal carotid artery)
which three branches of the external carotid artery are involved in supplying the back of the scalp and which region do they supply
superficial temporal- supplies the frontal and temporal regions
posterior auricular- supplies the area superiorly and posteriorly to the auricle
occipital- supplies the back of the scalp
which branches of the opthalmic artery supply the scalp
supra orbital and supratrochlear arteries
which veins drain the superficial scalp
superifical temporal, occipital, posterior auricular, supraorbital and supratrochlear
what drains the deep temopral region of the skull
the pterygoid venous plexus
where is the pterygoid plexus located
between the temporalis and lateral pterygoid
what does the ptergoid plexus drain into
the maxillary vein
which trigeminal nerves innervate the scalp
supratrochlear, supraorbital, zygomaticotemporal, auriculotemporal
which cervical nerves innervate the scalp
lesser occipital nerve
greater occipital nerve
why do deep lacerations of the scalp tend to bleed profusely
- The pull of the occipitofrontalis muscle prevents the closure of the bleeding vessel and surrounding skin.
- The blood vessels to the scalp are adhered to dense connective tissue, preventing the vasoconstriction that normally occurs in response to damage.
- The blood supply to the scalp is made up of many anastomoses, which contribute to profuse bleeding.
why does loss of blood supply to the scalp NOT lead to bone necrosis?
most of the blood supply to the scull is from the middle meningeal artery
what are emissary veins
The emissary veins connect the extracranial venous system with the intracranial venous sinuses. They connect the veins outside the cranium to the venous sinuses inside the cranium. They drain from the scalp, through the skull, into the larger meningeal veins and dural venous sinuses.
what symptoms does a retro-pharyngeal abscess present with?
visible bulge on inspection of the oropharynx, sore throat, difficulty swallowing, stridor, reluctance to move their neck and a high temperature
why does a lump associated with the thyroid gland move up when swallowing
the thyroid gland is enclosed in pre tracheal fascia which is attached to the hyoid bone, the hyoid bone and larynx move up on swallowing.
If a goiter extends retrosternally, what symptoms may be present and why?
breathlessness and stridor due to tracheal compression and facial odema because of compression of the veins draining the head and neck
what is the likely cause of parotid enlargement resulting in ispilateral facial palsy?
parotid cancer
what is the major artery supplying the face
facial artery
what is the major vein draining the face
facial nerve
where can the pulse of the facial artery be palpated
the inferior border of the mandible
why is it necessary to compress both facial arteries if one is bleeding
many anastomoses with other arteries of the face
