Thyroid and Parathyroid Gland

Question 1

What are thyroid glands?

Answer 1

An endocrine gland, consisting of right and left lobes connected by a narro isthmus

Question 2

What organ is the Thyroid gland and what surrounds it.

Answer 2

TG= vascular organ surrounded by a sheath derived from pre tracheal layer of deep fascia.

The sheath attaches gland to larynx and trachea

Question 3

Where is the base and the apex of TG?

Answer 3

1. APEX: directed upward as far as oblique line on lamina of thyroid cartilage
2. BASE: at level of 4th or 5th tracheal ring

Question 4

Where does the isthmus extend in the thyroid gland?

Answer 4

across the midline in front of 2nd-4th tracheal rings with sometimes a pyramidal lobe projecting upward.

Question 5

What are the boundaries of the thyroid gland?

Answer 5

1. ANTEROLATERALLY:
   - Sternothyroid
   - Omohyoid (SB)
   - Sternohyoid
   - SCM
2. POSTEROLATERALLY:
   - carotid sheath (common carotid artery)
   - internal jugular vein and vagus
3. MEDIALLY:
   - larynx
   - trachea
   - pharynx
   - Oesophagus
   - trachea is recurrent laryngeal nerve

Question 6

Relations of the isthmus in the TG

Answer 6

1. ANTERIORLY:
   - sterno THYROID
   - sternoHYOID
   - anterior jugular veins
   - fascia and skin
2. POSTERIORLY :2-4th rings of trachea

Question 7

In the TG what is the rounded posterior border of each lobe related posterior to?

Answer 7

rounded posterior border of each lobe related posteriorly to

• SUPERIOR AND INFERIOR PARATHYROID GLANDS &
• anastamosis between superior and inferior thyroid arteries

Question 8

Arterial supply of TG

Answer 8

Superior.Inferior thyroid artery

Sometimes Thyroid Ima

Question 9

Superior thyroid artery in TG:

Answer 9

a branch of external carotid that descends to upper pole of each lobe, accompanied by external laryngeal nerve

Question 10

Inferior thyroid artery:

Answer 10

1. branch of thyrocervical trunk
2. ascends behind gland to level of cricoid cartilage
3. then turn medially and downward to reach posterior border of the gland
4. recurrent laryngeal nerve crosses either in front of or behind the artery or it may pass between its branches

Question 11

Thyroidea ima in TG

Answer 11

sometimes present and arise from brachiocephalic artery or arch of aorta.
Ascends in front of trachea to isthmus

Question 12

What are superior and inferior thyroid arteries branched from?

Answer 12

1. superior is external carotid artery

2. inferior TA= branch of thyrocervical trunk

Question 13

Venous drainage of TG

Answer 13

1. superior and middle thyroid veins: drain into internal jugular vein
2. Inferior thyroid veins: anastomose with one another and drain into left brachiocephalic vein in the thorax

Question 14

Lymph drainage of thyroid gland:

Answer 14

drains mainly laterally into deep cervical nodes,

a few lymph vessels descend to paratracheal nodes

Question 15

Nerve Supply, of TG

Answer 15

Superior middle inferior cervical sympathetic ganglia

Question 16

What are parathyroid glands/

Answer 16

they are 4 endocrine glands with ovoid shape (6mm long max) closely related to posterior border of thyroid gland and lying within its fascial capsule

Question 17

superior and inferior parathyroid glands

Answer 17

1. SUPERIOR PARATG: are more constant in position and lie at level of middle of posterior border of thyroid
2. INFERIOR PARATHG: usually lie close to inf poles of thyroid gland

Question 18

arterial supplya nd venous drainage of parathyroid glands

Answer 18

ARTERIAL SUPPLY: superior and inferior Arteries

VD:: into superior, middle, inferior thyroid veins