Anatomy C9

Question 1

Where is the thyroid gland located and at what vertebral level

Answer 1

Anterior aspect of the neck C5 - T1

Question 2

What unites the right and left lobes and where?

Answer 2

a thin isthmus over the trachea, anterior to second and third tracheal rings

Question 3

What cervical fascia is the capsule made from?

Answer 3

Pre tracheal

Question 4

Describe the lateral lobe

Answer 4

The apex extends up to the oblique of the thyroid cartilage and the base to the level of 4th/5th ring

Question 5

Describe the Isthmus

Answer 5

Crosses anterior to the 2nd - 4th tracheal ring

Question 6

Describe the pyramidal lobe

Answer 6

Projects upwards from isthmus to left of the midline

Question 7

What are the anterolateral relations of the lobes?

Answer 7

• Sternothyroid
• superior belly of omohyoid
• sternohyoid
• anterior border of the sternocleidomastoid

Question 8

What are the posterolateral relations of the thyroid lobes?

Answer 8

• carotid sheath with common carotid
• internal jugular vein
• vagus nerve

Question 9

What are the medial relations of the thyroid gland?

Answer 9

• Larynx
• trachea
• pharynx
• oesophagus
• cricothyroid muscle and nerve supply
• external laryngeal
• between oesophagus and trachea is a recurrent laryngeal nerve

Question 10

What are the anterior relations of the isthmus?

Answer 10

• sternothyroid
• sternohyoid
• anterior jugular veins
• fascia
• skin

Question 11

What are the posterior relations of the isthmus?

Answer 11

• 2nd - 4th rings of the trachea

Question 12

• What artery supples the upper pole of each lobe?

Answer 12

superior thyroid artery

Question 13

Where does the superior thyroid artery arise from?

Answer 13

External carotid

Question 14

What nerve accoompanies the superior thyroid artery?

Answer 14

External laryngeal

Question 15

What does the inferior thyroid artery supply?

Answer 15

posteroinferior aspect of the thyroid gland

Question 16

Where does the inferior thyroid artery arise from?

Answer 16

Thyrocervical trunk a branch of subclavian, it ascends behind the gland to the level of cricoid cartilage

Question 17

What nerve accompanies the inferior thyroid artery?

Answer 17

Reccurent laryngeal nerve crosses behind/in front/ in between the vessels

Question 18

Where does the thyroid ima arise from?

Answer 18

• brachiocephalic
• arch of aorta
• right common carotid
• subclavian
• internal thoracic arteries

Question 19

What nodes do the lymphatic vessels of thyroid gland drain to?

Answer 19

• Pretracheal
• paratracheal
• efferent vessels from these nodes go to deep cervical nodes

Question 20

Where is the lymphatic network of the thyroid gland located

Answer 20

Connective tissue septa of the thyroid gland

Question 21

Describe the innervation to the thyroid glland

Answer 21

• SNS innervation
• post ganglionic SNS fibres arise in the superior, middle and inferior cervical ganglia and pass through the cardiac, superior and inferior thyroid plexus to reach the gland
• vasomotor information

Question 22

What is a thyroid goitre

Answer 22

An enlargement of the thyroid gland which may occur due to over activity or underactivity of the gland

Question 23

Which direction does a thyroid goitre enlarge in?

Answer 23

• anterior
• infeiror
• lateral
• posterior

Question 24

What structures may be compressed by a thyroid goitre?

Answer 24

• Oesophagus
• Recurrent laryngeal nervers
• Trachea

Question 25

What prevents the thyroid gland from enlarging superiorly

Answer 25

The superior attachments of sternothyroid and sternohyoid muscles

Question 26

Describes the development of the thyroid gland?

Answer 26

• The thyroid gland develops from a thickening on the floor of the embryonic pharynx in the developing tongue
• A diverticulum develops from this thickening forming the thyroglossal duct
• The thyroglossal duct elongates and its distal end becomes bi-lobed and proliferates into the thyroid gland
• The thyroid gland descends through the neck anterior to the hyoid bone.
• At 7 weeks the gland reaches its adult position
• The thyroglossal duct degenerates but a pit remains on the dorsum of the tongue marking its site of origin (foramen caceum)

Question 27

What do the parathyroid glands secrete?

Answer 27

parathyroid hormone

Question 28

Describe the structure of parathyroid glands?

Answer 28

• ovoid bodies
• 6mm long
• posterior border of the thyroid gland lying within its fascial capsule
• there are four glands: x2 superior and x2 inferior

Question 29

Describe the two superior parathyroid glands?

• Where do they lie?

Answer 29

The more constant in position and lie at the level of the middle of the posterior border of the thyroid gland, lie below the point where the superior thyroid vessels enter the thyroid gland

Question 30

Wherer do the inferior parathyroid glands lie?

Answer 30

Close to the inferior poles of the thyroid gland, may be located in the superior mediastinum, they may lie within or outside the facial sheath

Question 31

What is the arterial supply to the parathyroid glands

Answer 31

• Superior thyroid arteries
• inferior thyroid arteries

Question 32

Describe the innervation of the parathyroid glands?

Answer 32

Postganglionic sympathetic fibres from the superior or middle cervical ganglia, SNS provides secretomotor fibres to the parathyroid glands