thyroid gland

Question 1

what forms the thyroid gland?

Answer 1

it is formed by 2 lobes

right and left lobes

Question 2

what connects the lobes of the thyroid gland?

Answer 2

they are connective via isthmus

Question 3

when is thyroid visible?

Answer 3

it is not visible under normal conditions

but visible during swallowing

Question 4

what is the extension of thyroid gland in respective of the vertebrae?

Answer 4

C5-T1

HYOID BONE - C3

THYROID CARTILAGE - C4/C5

Cricoid cartilage C6

Question 5

what does the isthmus overlie ?

Answer 5

the connection between the right and left lobe

Question 6

what the extension of the isthmus in respective to cartilage rings?

Answer 6

2nd 3rd and 4th

Question 7

what forms the lateral side that extend from the thyroid cartilage to the 6th tracheal cartilage?

Answer 7

lateral lobes of the thyroid gland

so at the 6th tracheal cartilage it is T1

Question 8

where does the thyroid gland develop from ?

Answer 8

it is from the oral pharynx as well js like the rathke pouche

from the nasopharyngeal tonsils

Question 9

since both rathke pouch and thyroid gland come from the oropharynx what is the difference?

Answer 9

the rathke pouch ascends upwards to the brain area

the thyroid gland descends down to the neck area

Question 10

what is the thyroglossal duct?

Answer 10

short time connection that still connects to the thyroid from the neck to the pharynx

epithelial tube /fibrous cord

Question 11

what happens to the thyroglossal duct in adults?

Answer 11

it disintegrates and disappear

Question 12

when does the gland starts functioning ?

Answer 12

4 months of intra uterine life

Question 13

what is thyroglossal duct cyst?

Answer 13

a condition where part of the thyroglossal duct has not disappeared and its remnants will form cyst

Question 14

where is the cyst usually seen ?

Answer 14

near or within the body of hyoid bone

they form swellings in the anterior part of the neck

Question 15

where the possible locations where the thyroid gland/cyst might form along its way going down?

Answer 15

if it is in the tongue –lingual thyroid

if it is below the tongue –> sublingual thyroid

in front of the trachea/larynx —> prelaryngeal / pretracheal thyroid

Question 16

what is it called when the thyroid gland gets stuck in the trachea before the rings are even formed?

Answer 16

it will get stuck inside the trachea itself —> Intrathoracic thyroid
Retrosternal thyroid

Question 17

is the thyroid gland same in everyone?

Answer 17

no it has variations

Sometimes Isthmus is absent and sometimes there are projections

Question 18

what is pyramidal lobe?

Answer 18

inconstant upward projection from the isthmus or the lateral lobe and it attaches to the hyoid bone

represent embryological descent of the thyroid

Question 19

from which side does the pyramidal lobe usually project from?

Answer 19

the left side

Question 20

how does the pyramidal lobe connect to the hyoid bone?

Answer 20

Levator glandulae thyrideae

fibromuscular extension from hyoid bone to the isthmus / pyramidal lobe

Question 21

what is a true capsule?

Answer 21

fibrous capsule

it is peripheral condensation of connective tissue of the GLAND ITSELF

so its a capsule surrounding the gland itself

Question 22

what is false capsule ?

Answer 22

fascial capsule that surrounds the true fibrous capsule

Question 23

describe the thickness of the false fascial capsule?

Answer 23

it is thick anteriorly

but posteriorly it is weak and thin

Question 24

what happens when a tumor starts to grow inside the capsule ?

Answer 24

it will stop pushing forward because it is hard and thick anteriorly and it will push posteriorly since it is weaker

Question 25

what are the structures found posteriorly to the thyroid lobe?

Answer 25

Trachea treacheoesophageal groove esophagus if tumor grows it will cause dysphagia and difficulty breathing

Question 26

what runs in the tracheoesophageal groove?

Answer 26

recurrent laryngeal nerve if it is stretched it will cause hoarseness of the voice

Question 27

what does the false fascial capsule thickens to form?

Answer 27

it thickens to form the suspensory ligament of berry

Question 28

what is the function of suspensory ligament of berry ?

Answer 28

it attaches the thyroid lobe to the cricoid cartilage then it will make it so that the thyroid moves with the cricoid cartilage

Question 29

what is present in the space between true fibrous capsule and false fascial capsule?

Answer 29

parathyroid gland

Question 30

what is the difference between the thyroid gland and prostate in respective of venus plexus ?

Answer 30

Thyroid gland has the venus plexus deep to the true capsule --> it is within the true capsule, SO during surgery we have to remove the gland itself with the true fibrous capsule to avoid bleeding Prostate --> venous plexus it is between the true fibrous and false fascial capsule --> in surgery we can take the prostate alone and leave the capsule behind

Question 31

what is the shape of the lobes of thyroid gland?

Answer 31

cone shaped

Question 32

where is the apex located?

Answer 32

apex extends to oblique line of thyroid cartilage sandwiched between inferior constrictor and sternothyroid

Question 33

which muscles lies medially to the apex of thyroid lobe?

Answer 33

inferior constrictor

Question 34

which muscles lies LATERALLY to the apex of thyroid lobe?

Answer 34

sternothyroid

Question 35

where is the base of the thyroid lobe located?

Answer 35

located between 5-6 tracheal cartilage

Question 36

what are the 3 surfaces of thyroid lobe?

Answer 36

anterolateral posterolateral medial

Question 37

what are the borders of thyroid lobe?

Answer 37

anterior border posterior border

Question 38

what are the branches of vagus nerve?

Answer 38

superior laryngeal nerve Recurrent laryngeal nerve

Question 39

what are the divisions of the superior laryngeal nerve?

Answer 39

external laryngeal nerve internal laryngeal nerve

Question 40

what does the internal laryngeal nerve supply?

Answer 40

mucosa of larynx ABOVE the level of the vocal fold

Question 41

what is cricothyroid muscle?

Answer 41

muscle extending from cricoid to thyroid

Question 42

what is the function of cricothyroid muscle?

Answer 42

stretch the vocal cords to make the voice higher in pitch

Question 43

what is the nerve supplying the cricothyroid muscle?

Answer 43

external laryngeal nerve

Question 44

what is the muscle posterior/deep to the thyroid gland?

Answer 44

inferior constrictor

Question 45

what is the muscles anterior/superficial to the thyroid gland ?

Answer 45

sternothyroid

Question 46

what are the structures related to the medial surface of the thyroid gland ?

Answer 46

2 tubes 2 muscles 2 nerves

Question 47

what are the 2 tubes related to the thyroid gland ?

Answer 47

larynx / trachea Pharynx / esophagus

Question 48

what are the 2 nerves related to the medial surface of the thyroid gland ?

Answer 48

external laryngeal nerve --> supply cricothyroid recurrent laryngeal nerve

Question 49

what are the 2 muscles related to the medial surface?

Answer 49

inferior constrictor cricothyroid

Question 50

what lies on the posterolateral surface ?

Answer 50

carotid sheath and its contents

Question 51

what lies in the anterolateral surface?

Answer 51

all the muscles Strap muscles

Question 52

where is the location of the recurrent laryngeal nerve?

Answer 52

it is not specific and very variable

Question 53

what is the artery running in the anterior border?

Answer 53

anterior descending branch of superior thyroid artery

Question 54

what is found in the posterior border of the thyroid gland?

Answer 54

anastomosis of the superior and inferior thyroid artery parathyroid gland lower part of thoracic duct

Question 55

what is anterior to the isthmus?

Answer 55

sternothyroid and sternohyoid muscle

Question 56

what is posterior to the isthmus?

Answer 56

2nd 3rd 4th tracheal rings

Question 57

what is superior to the ishmus?

Answer 57

pyramidal lobe levator glanduli thyroidae

Question 58

what is inferior to the isthmus ?

Answer 58

inferior thyroid veins

Question 59

what are the veins of the thyroid gland?

Answer 59

superior middle inferior --> inferior border of the isthmus

Question 60

where do the veins of the thyroid gland empty to?

Answer 60

brachiocephalic vein

Question 61

what is the blood supply of the thyroid gland? ( arteries )

Answer 61

superior thyroid artery inferior thyroid thyroidea ima artery

Question 62

where does the superior thyroid artery come from?

Answer 62

external carotid artery

Question 63

what does the superior thyroid artery divide into to?

Answer 63

anterior and posterior branches

Question 64

what does it supply?

Answer 64

upper 1/3 of the lobes upper half of isthmus

Question 65

where does the inferior thyroid artery come from?

Answer 65

branch of thyrocervical trunk 15% of ppl it is from subclavian

Question 66

what does the inferior thyroid artery supply?

Answer 66

lower 2/3 of lobes lower half of isthmus

Question 67

where does the thyroidea ima artery come from?

Answer 67

in 3% individuals from the brachiocephalic trunk

Question 68

what are the veins of thyroid gland?

Answer 68

superior thyroid middle thyroid inferior thyroid vein 4th thyroid vein of kocher

Question 69

where does the superior thyroid vein drain into?

Answer 69

upper part of thyroid gland ends in internal jugular vein

Question 70

where does the middle thyroid vein drain from?

Answer 70

middle thyroid gland empty in internal jugular vein

Question 71

where does the inferior thyroid vein drain from?

Answer 71

drain inferior part of the gland plexus infront of trachea empty to the left brachiocephalic

Question 72

where does the 4th thyroid vein of kocher empty to?

Answer 72

form betweeen middle and inferior vein drain into Internal jugular vein

Question 73

where is the lymphatic drainage of the upper part of the gland?

Answer 73

upper deep cervical via prelaryngeal , pretracheal , paratracheal nodes

Question 74

where is the lymphatic drainage of the lower part thyroid gland?

Answer 74

lower deep cervical nodes

Question 75

what is the nerve supply of the gland?

Answer 75

superior cervical sympathatic ganglia middle cervical sympathetic ganglia inferior cervical sympathetic ganglia

Question 76

how do the nerves reach the gland?

Answer 76

cardiac , superior and inferior thyroid , peri arteriolar plexuses accompanying the thyroid arteries

Question 77

what type of fibers are the nerves supplying the gland?

Answer 77

vasomotor not secreto motor

Question 78

what is horners syndrome?

Answer 78

when the sympathetic ganglia get removed cuz it appeared like a lymph node

Question 79

what are the complications that could happen due to thyroidectomy?

Answer 79

injury to the external laryngeal nerve --> paralysis of cricothyroid muscle injury of the recurrent laryngeal nerve --> hoarsensess of the voice or stridor injury to the cerivcal sympathetic trunk or sympathetic ganglion---> due to confusion with lymph nodes --> horners syndrome

Question 80

what are the possible variations of the recurrent laryngeal nerve?

Answer 80

4% intrathyroid 42% paratracheal 48% tracheosoph groove 6% parasophageal

Question 81

what happens in cases of atrophy of one lobe due to tumor?

Answer 81

the other lobe will hypertrophy to compensate

Question 82

what are the changes that happens to the colloid in regard to the activity?

Answer 82

inactive gland --> large colloid filled with thyroid and flat cells due to compression moderately active glands ---> cuboid cells and moderate colloid hyperactive gland --> small colloid and COLUMNAR CELLS

Question 83

what is the blood , lymphatic and nerve supply of the parathyroid gland?

Answer 83

same as thyroid

Question 84

what is the embyro origin of the parathyroid gland?

Answer 84

3rd and 4th brachial pouches

Question 85

which pouch give raise to the SUPERIOR GLAND?

Answer 85

4th pouch

Question 86

which pouch give raise to INFERIOR GLAND?

Answer 86

3rd pouch

Question 87

what happens to the inferior gland ?

Answer 87

descend with the thymus