anatomy of thyroid Flashcards
what is highlighted blue?
external jugular vein
where is external jugular vein found?
within superficial fascia
what does the external jugular vein drain into?
-subclavian vein
what is highlighted blue?
anterior jugular vein
where is the anterior jugular vein found?
within superficial fascia
what does the anterior jugular vein drain in to?
the external jugular vein
what is highlighted blue (and what both the arrows are)?
sternocleidomastoid
top arrow=sternal head
bottom arrow= clavicular head
what does the sternal head of the sternocleidomastoid attach to?
the sternal head attaches to the manubrium of the sternum and passes superiorly to attach to the mastoid process of the temporal bone
what does the clavicular head of the sternocleidomastoid attach to?
it attaches to the medial end of the clavicle and passes superiorly to attach to the mastoid process of temporal bone
what is highlighted blue?
trapezius (superior part)
what is highlighted blue?
CN XI- spinal accessory nerve
what does CN XI (spinal accessory nerve) supply?
-sternocleidomastoid and trapezius
what is highlighted blue?
right platysma (in superficial fascia)
what group of muscles does the platysma belong to?
‘muscles of facial expression’
what is the platysma innervated by?
cranial nerve VII (facial nerve)
what does investing fascia enclose?
encloses all other neck fascial compartments, encloses 2 pairs of muscles:
- trapezius
- sternocleidomastoid
what does the prevertebral (deep fascia) enclose?
- postural neck muscles
- cervical vertebrae
what does the carotid sheath enclose?
- deep cervical lymph nodes
- vagus nerve
- common carotid artery
- internal jugular vein
what does the pretracheal fascia enclose?
- osophagus
- trachea
- thyroid gland
- strap muscles
- recurrent laryngeal nerves
what is the fascial compartment highlighted green?
investing fascia
what is the fascial compartment highlighted orange?
prevertebral (deep) fascia
what is the fascial compartment highlighted red?
carotid sheath
what is the fascial compartment highlighted purple?
pretracheal fascia
where are carotid sheaths located?
deep to investing fascia; located anterolaterally in neck posterolateral to thyroid gland
where do carotid sheaths attach to in the skull?
they attach superiorly to the base of the skull (around jugular foramen and entrance to carotid canal)
what is found within each carotid sheath?
- internal jugular vein
- common, then internal carotid arteries
- vagus nerve
- deep cervical lymph nodes
what is the arrow pointing to?
thyroid gland
what are the group of 4 muscles that cover the anterior part of the neck called?
the strap muscles
what are the 4 strap muscles?
- sternohyoid
- omohyoid
- sternothyroid
- thyroyoid
what is highlighted blue?
hyoid bone
what is highlighted blue?
thyroid cartilage
what is highlighted blue?
thyrohyoid muscle
what is highlighted blue?
sternothyroid muscle
what is highlighted blue?
omohyoid muscle
arrow above=superior belly
arrow below= inferior belly
what is highlighted blue?
sternohyoid muscle
how does the thyroid gland develop in the embry?
- begins development as a midline epithelial proliferation at junction between anterior two thirds (oral/horizontal part) and posterior one third (oropharyngeal/vertical part) of tongue
- it then migrates inferiorly whilst remaining attached to the tongue via the thyroglassal duct
- the gland reaches its final position in relation to larynx/trachea in 7th week of development
what does the thyroid gland consist of?
-two lateral lobes and an isthmus (narrow connecting band)
is it worrying if a patient presents with a pyramidal lobe in their thyroid?
no- it is normal but not everyone has it (prevalence of 28-55%)
where does a pyramidal lobe usually originate from?
left lateral lobe
what are the 4 glands called found on the thyroid?
4 parathyroid glands
where are the 4 parathyroid glands found on the thyroid?
located on posterior surfaces of thyroid gland lateral lobes
what is highlighted blue?
external carotid artery
what is highlighted blue?
left common carotid artery
what is highlighted blue?
arch of the aorta
what is highlighted blue?
subclavian artery
what is highlighted blue?
inferior thyroid artery
what is highlighted blue?
superior thyroid artery
what is highlighted blue?
superior thyroid vein
what is highlighted blue?
middle thyroid vein
what is highlighted blue?
inferior thyroid vein
what is highlighted blue?
brachiocephalic vein
what is highlighted blue?
superior vena cava
what is highlighted blue?
internal jugular vein
what are the lymphnodes highlighted yellow?
superior deep cervical lymph nodes
what are the lymphnodes highlighted purple?
inferior deep cervical lymph nodes
what are the lymphnode highlighted red?
pretracheal node
what are the lymphnodes highlighted green?
paratracheal nodes
how is lymph returned from the lymph nodes in the thyroid gland?
- lymph is returned via right lymphatic duct to right venous angle
- lymph is returned via the thoracic duct to left venous angle
how would a classical thyroidectomy incision be made?
- either a ‘collar incision’ is made within the natural skin crease or in direction of Langer’s lines
- inciscion should be just superior to clavicles and jugular notch
- the inciscion is made through skin and platysma
what would an injury to the recurrent laryngeal nerve cause?
-paralysis of vocal cord
what would a unilateral injury to the recurrent laryngeal nerve cause?
-hoarseness or weakness of voice and weak cough
what would a bilateral injury to the recurrent laryngeal nerve cause?
-aphonia (inability to produce sound) and inability to close rima glottidis (opening between vocal cords), to prevent aspiration, or to produce good cough which requires close of rima glottidis
