Anatomy of the thyroid and parathyroid Flashcards
Where does the thyroid sit in relation to the spine?
Anteriorly to C7
What is the name of the narrow band that connects between the two lobes of the thyroid?
Isthmus
Where do the two lobes of the thyroid attach to?
Lateral aspects of the thyroid and cricoid cartilages as well as to the trachea
Where does the isthmus lie?
Between anterior 2nd and 3rd cartilages of the trachea
How will a lump in the thyroid gland or an enlarged gland move when a patient swallows?
Superiorly then inferiorly with the larynx This is due to the relationship between larynx, trachea and thyroid
How many parathyroid glands are there?
4
Where are the parathyroid glands situated?
On the posterior surfaces of the thyroid gland’s LATERAL lobes, external to fibrous capsule
What is the thyroid covered by?
Thin fibrous capsule which sends septa deeply into the gland
What do septa contain?
Larger blood vessels, lymphatics and nerves that enter the thyroid gland
What attaches the fibrous capsule to the cricoid cartilage and superior tracheal rings?
Dense connective tissue
What does dense connective tissue attach the fibrous capsule surrounding the thyroid to?
Cricoid cartilage and superior tracheal rings
What is external to the fibrous capsule?
Loose fascial sheath
How is the loose fascial sheath formed?
By the visceral portion of the pretracheal layer of deep cervical fascia
Where does the thyroid gland begin its development?
At the junction between the anterior 2/3rd and posterior 1/3 of the tongue, as a midline epithelial proliferation
What is the junction between the anterior 2/3 and posterior 1/3 of the tongue called in adults?
Foramen caecum
Where does the thyroid gland migrate to during developement?
It migrates inferiorly, whilst remaining attached to tongue via the thyroglossal duct
In its development, how does the tongue remain attached to the tongue as it migrates inferiorly?
Via the thyroglossal duct
When does the thyroid gland reach its final position?
7 weeks of development
Where can thyroid duct cysts or ectopic thyroid tissue be located?
At any point in the migratory path
Where does a pyramidal lobe most commonly originate from?
Left lateral lobe
What is the prevalence of pyramidal lobe?
About 45%
9% of pyramidal lobes arent connected with main thyroid gland. True or false?
True
- Where do most pyramidal lobes attach superiorly? 2. Where may the pyramidal lobe extend as far superiorly as?
- Thyroid cartilage 2. Hyoid bone
Define platysma
Skeletal muscle in the superficial fascia, runs near thyroid gland laterally
Where are the platysma muscles located?
Located immediately deep to the skin, within the superfiscial fascia of the neck, from lower border of mandible down the neck
What group of muscles do the platysma muscles belong to?
Fascial expression
What nerve supplies the platysma muscles?
Facial nerve
What is the name of the fascial compartment shown in green?

Investing (deep) fascia
What is the name of the fascial compartment shown in orange?
Prevertebral (deep) fascia
What is shown in red?

Carotid sheath
What fascial compartment of neck is shown in purple?

Pretrachial (deep) fascia
What muscle sits posterior to the neck?
trapezius
What are the muscles seen at the anterior edge of the neck?
Sternocleidomastoid
Where does the retropharyngeal space run from and to?
Base of skull to superior mediastinum
How fast will infection spread in the retropharyngeal space?
Extremely quickly
Where is the prevertebral (deep) fascia located?
Deep to investing fascia
Located posteriorly
What does the prevertebral fascia enclose?
The cervical vertibrae and postural neck muscles
What does the investing (deep) fascial compartment enclose?
All neck fascial compartments
2 pairs of muscles - R and L trapezius and anteriorly sternocleidomastoid
Where is the investing fascia located?
Deep to superficial fascia
How many carotid sheaths are there?
2