S10 - Cervical Plexus & Thyroid Gland

Question 1

What nerve roots contribute to the cervical plexus?

Answer 1

C1- C4 (their anterior primary rami)

Question 2

Which dermatome covers most of the back of the head and the neck?

Answer 2

C2 dermatome

Question 3

What is the significance of the ansa cervicalis?

Answer 3

A loop of motor branches off the cervical plexus

• mainly supplies the infrahyoid muscles
• located behind the internal jugular vein (IJV)

Question 4

What is the Erb’s point?

Answer 4

A point behind the SCM where 4 superficial branches of the cervical plexus emerge from
- used by anaesthetists to do a cervical plexus block (could be done in thyroidectomy)

Question 5

Which fascia encircles the thyroid gland?

Answer 5

Pre tracheal fascia (in the anterior triangle of the neck)

Question 6

State the anatomical relationship of the parathyroid glands to the thyroid gland

Answer 6

4 parathyroid glands behind the thyroid gland

• secretes PTH
• -> increase Ca2+ absorption in the gut
• -> increase Ca2+ released from bones
• -> increased Ca2+ reabsorption from kidneys

Question 7

Which arteries supply the thyroid gland?

Answer 7

Superior thyroid a. = from ECA

Inferior thyroid a. = from thyrocervical trunk

Question 8

Which nerve could be damaged if superior thyroid artery is damaged?

Answer 8

Superior laryngeal nerve

Question 9

What is thyroid ima?

Answer 9

Artery off the brachiocephalic trunk - very small and could easily be damaged

• a supplies the thyroid gland