Thyroid Gland

Question 1

What are the components of the thyroid gland?

Answer 1

Two lateral lobes

Connecting isthmus

Question 2

Where do the lobes of the thyroid attach?

Answer 2

Lateral aspects of the thyroid and cricoid cartilages and trachea

Question 3

Where does the isthmus lie?

Answer 3

Anterior to the 2nd and 3rd cartilages of the trachea

Question 4

In what direction would a lump on the thyroid move when swallowing?

Answer 4

Superiorly then inferiorly

Question 5

Where are the parathyroid glands located?

Answer 5

Posterior surface of the thyroid’s lateral lobes

Question 6

What is a pyramidal lobe of the thyroid gland?

Answer 6

Extra thyroid tissue (due to embryological migration)
Most commonly originates from left lateral lobe
Most attach superiorly to thyroid cartilage but ca extend to the hyoid bone

Question 7

What is the developmental path of the thyroid gland?

Answer 7

Foramen caecum
Migrates inferiorly via thyroglossal duct
Final position by week 7

Question 8

What are the platysma muscles?

Answer 8

Muscles of facial expression
located immediately deep to the skin within superficial fascia of the neck
Supplied by CN VII

Question 9

What are the fascial compartments of the neck?

Answer 9

Prevertebral fascia
Investing fascia
Carotid sheaths
Pretracheal fascia

Question 10

Where is the prevertebral fascia and what is contained within it?

Answer 10

Deep to investing fascia
Posteriorly
Cervical vertebrae and postural neck muscles

Question 11

Where is the investing fascia and what is contained within it?

Answer 11

Deep to supeficial fascia
Encloses all other neck fascial compartments
Trapezius and sternocleidomastoid

Question 12

Where are the carotid sheaths and what is contained within them?

Answer 12

Deep to investing fascia
Anetrolaterally
IJVs, carotid arteries, vagus nerves, deep cervical lymph nodes

Question 13

Where is the pretracheal fascia and what is contained within it?

Answer 13

Deep to investing fascia
Anteriorly
Strap muscles, thyroid gland trachea, oesophagus, recurrent laryngeal nerves

Question 14

Where does the retropharyngeal space lie and why is it clinically significant?

Answer 14

Between pre tracheal and prevertebral fascia

Site for infection spread

Question 15

What are the attachments of the sternocleidomastoid?

Answer 15

Sternal head = manubrium of sternum
Clavicular head = medial end of the clavicle
Both heads = Mastoid process of temporal bone

Question 16

What is the innervation of trapezius and sternocleidomastoid?

Answer 16

CN XI (Spinal Accessory)

Question 17

What are the inferior attachments of trapezius?

Answer 17

Spine of the scapula and lateral end of clavicle

Question 18

Where does the anterior jugular vein drain to?

Answer 18

External jugular vein

Question 19

Where does the external jugular vein drain to?

Answer 19

Subclavian vein

Question 20

What are the attachments of the carotid sheaths?

Answer 20

Superiorly = base of the skull (around jugular foramen and entrance to carotid canal) 
Inferiorly = blend with mediastinal fascia

Question 21

What is the arterial supply to the thyroid gland?

Answer 21

Inferior and superior thyroid arteries

Question 22

Where does the inferior thyroid artery branch from?

Answer 22

Subclavian artery

Question 23

Where does the superior thyroid artery branch from?

Answer 23

External carotid artery

Question 24

What is the venous drainage of the thyroid gland?

Answer 24

Superior, middle and inferior thyroid veins

Question 25

Where do the superior and middle thyroid veins drain to?

Answer 25

Internal jugular vein on right and left sides

Question 26

Where does the inferior thyroid vein drain to?

Answer 26

Brachiocephalic vein, usually on left side

Question 27

Where does the right lymphatic duct drain to?

Answer 27

Right venous angle

Question 28

Where does the thoracic duct drain to?

Answer 28

Left venous angle

Question 29

What is the course of CN X within the cranial cavity?

Answer 29

Connects with medulla oblongata | Passes through jugular foramen

Question 30

What is the course of CN X in the neck?

Answer 30

Descends in carotid sheath | Gives somatic branches to the larynx - superior laryngeal nerve and right recurrent laryngeal nerve

Question 31

What is the course of CN X in the chest?

Answer 31

Right vagus Right lateral aspect of trachea Posterior to right lung root Onto oesophagus ``` Left vagus Left side of arch of aorta Gives left recurrent laryngeal nerve Posterior to left lung root Onto oesophagus ```

Question 32

What is the course of CN X in the abdomen?

Answer 32

L and R pass through diaphragm with oesophagus Divide into terminal branches on stomach surface Supply abdominal organs with parasympathetic axons to distal midgut

Question 33

Where does the left recurrent laryngeal nerve recur?

Answer 33

Under arch of aorta

Question 34

Where does the right recurrent laryngeal nerve recur?

Answer 34

Under the subclavian artery

Question 35

What are the strap muscles?

Answer 35

Sternohyoid Omohyoid Thyrohyoid Sternothyroid

Question 36

What is the function of the strap muscles?

Answer 36

Movement of larynx during speech and swallowing

Question 37

What is the purpose of the fascial sling?

Answer 37

Attaches intermediate tendon of omohyoid to the clavicle

Question 38

What are the surgical approaches to the thyroid gland?

Answer 38

Classical thyroidectomy Endoscopically assisted thyroidectomy Endoscopic trans-axillary approach Endoscopic trans-breast approach

Question 39

What are the surface markers for the anterior triangle of the neck?

Answer 39

Inferior border of mandible/angle of mandible Sternal head of sternocleidomastoid Midline

Question 40

What are the surface markers of the posterior triangle of the neck?

Answer 40

Clavicular head of sternocleidomastoid Trapezius Clavicle

Question 41

Where should the classical thyroidectomy incision be made?

Answer 41

Within a natural skin crease or in the direction of Langer's lines Just superior to the clavicles and jugular notch Through skin and platysma

Question 42

What is the function of the right recurrent laryngeal nerve?

Answer 42

Somatic motor supply to most of the skeletal muscles that move the right vocal cord

Question 43

What is the result of unilateral recurrent nerve injury?

Answer 43

Hoarseness or weakness of the voice and cough

Question 44

What is the result of bilateral recurrent nerve injury?

Answer 44

Aphonia | Inability to close the rima glottidis to prevent aspiration or to produce a good cough