Thyroid And A Parathyroid Gland

Question 1

Describe the thyroid gland ?

Answer 1

1- butterfly shaped gland
2- composes of two lobes attached together by isthmus
3- each lobe is pear shaped has an apex and base

Question 2

Site of thyroid gland

Answer 2

1- apex is at the level of oblique line of thyroid cartilage
2- base is at the level of fourth or fifth tracheal ring
3- isthmus is infront of 2-3-4 tracheal ring

Question 3

Size of thyroid gland

Answer 3

It weighs 25 gm in adults

Question 4

What is pyramidal lobe

Answer 4

It projects upward from the isthmus , to the left of the midline

There is fibrous or muscular band connects pyramidal lobe with hyoid bone called levator glandulae thyroideae

Question 5

Anatomical relations of thyroid gland

Answer 5

• surfaces

1- anterolateral surface (7 layers) + 3
* skin
* superficial fascia that contains muscle called platysma

• deep fascia : envisting fascia

*anterior border of sternomastoid

*superior belly of omohyoid and sternohyoid in one layer
*sternothyroid

*pretracheal fascia that forms a false capsule around the thyroid gland

*anastomosis of sensory fibrous
* anastomoses of veins “ venous plexus and anastomoses of arteries
* the true capsule

2- posterolateral
Carotid sheath
That contains
* common carotid artery
* internal carotid artery
* internal jugular vein
* vagus nerve

3- medial
* larynx
* trachea
* pharynx
* oesophages
* recurrent laryngeal nerve : that is between trachea and oseophages
* external laryngeal nerve ; that is between larynx and pharynx

• borders
1- anterior border : related to superior thyroid A
2- posterior border : related to anastomoses of inferior and superior thyroid and parathyroid glands

3- upper border : related to the anastomoses of right , left and pyramidal lobe

4- lower border : related to inferior thyroid veins

• relations of isthmus
Anteriorly : sternohyoids , sternothyroids and anterior jugular vein
Posteriorly : 2-3-4 tracheal rings

Question 6

Does the thyroid gland move

Answer 6

1- yes, as the false capsule is attached to the hyoid bone so while swallowing, it moves

Question 7

حدوتة ال blood 🩸 supply

Question 8

Blood supply of thyroid gland

Answer 8

• arterial blood supply by
* thyroid ima artery : small branches from bracheocephalic trunk that supplies the anterior surface and isthmus

• superior thyroid artery: comes from external carotid artery and then it < descends> within external laryngeal nerve then separate at the apex where it gives ant. and post.
  the right anterior anastomoses with the left anterior
  The posterior anastomoses with the inferior thyroid artery
• it supplies the upper border and anterior surface
• inferior thyroid artery: comes from thyrocervical trunk from the first part of subclavian artery and it < ascends> meeting the recurrent laryngeal nerve near the base
• it supplies the lower border and posterior surface

• venous by
* superior , middle , inferior thyroid v
Superior and middle drain to internal jugular vein while left and right inferior thyroid veins drain to left bracheocephalic vein

Question 9

Lymphatic drainage of thyroid gland

Answer 9

• pre laryngeal nodes
• pretracheal nodes
• paratracheal nodes
• bracheocephalic nodes
  And they all drain to ~> deep cervical nodes

Question 10

Mention all deep fascia related to thyroid gland

Answer 10

1- envisting fascia
2- pre tracheal fascia : false capsule
3- carotid sheath : posteriorly

Question 11

Location of parathyroid glands

Answer 11

There are
Superior glands that are located 1 cm approximately supperior to entry of inferior thyroid artery

Inferior glands that are located near the inferior poles of thyroid gland

Question 12

Blood supply of parathyroid glands

Answer 12

1- inferior thyroid artery
2- venous supply is the same as thyroid gland

Question 13

Lymphatic drainage of parathyroid glands

Answer 13

The same

Question 14

Hyoid bone is attached to what ?

Answer 14

1- flase capsule
2- pyramidal lobe within the levator glandulae thyroidae

Question 15

Pretracheal attachment ?

Answer 15

Superiorly to the oblique line and hyoid bone
Laterally within carotid sheath
Inferiorly to the adventitia of arch of aorta and fibrous pericardiam

Question 16

During thyroidectomy operation, superior and inferior thyroid artery should be ligated

Answer 16

The superior: Near the gland where it separates from the external laryngeal n

The inferior : far from gland where it is not yet appproching the recurrent laryngeal n

Question 17

Nerve supply of thyroid gland

Answer 17

Mainly sympathetic by sympathetic fibrous that is vasomotor ( causing vc)
And vagus nerve gives also some sensory nerves to it

Question 18

Recurrent injury

Answer 18

•Right is more common to be injured than left as it more approached to inferior thyroid

According to phonation
Unilateral injury ~> hoarseness of voice
Bilateral injury ~> aphonation

According to respiration
Dyspnea but is worst in bilateral with partial injury

Question 19

Bilateral injury of external laryngeal nerve causes

Answer 19

Paralysis of crico thyroid muscles with Loss of high pitch voice and changing of voice

Question 20

Thyroid gland tumour effect on cca

Answer 20

If it is benign, cca is shifted backward but the pulse power is normal
If it is malignant, cca is in normal location but malignant tumour surronds it decreasing power of pulse