Thyroid gland Session 6

Question 1

where is the anterior triangle anatomically located

Answer 1

region located at the front of the neck

Question 2

what r the borders of the anterior triangle

Answer 2

superior: inferior border of mandible
lateral: anterior border of sternocleidomastoid
medial: sagittal line down midline of neck

Question 3

investing fascia vs visceral fasica

Answer 3

investing- covers roof of anterior triangle

visceral- covers floor of anterior triangle

Question 4

Name the suprahyoid muscles

Answer 4

stylohyoid
digastric
mylohyoid
geniohyoid

Question 5

name the infrahyoid muscles

Answer 5

omohyoid
sternohyoid
thyrohyoid
sternothyroid

Question 6

where r the suprahyoid muscles located

Answer 6

superior to hyoid bone

Question 7

where r the infrahyoid muscles located

Answer 7

inferior to the hyoid bone

Question 8

what structures r found in the anterior triangle

Answer 8

common carotid bifurcation (internal and external)
internal jugular vein
CN 7, 9, 10, 11, 12

Question 9

what is platsyma and its innervation

Answer 9

large flat superficial muscle muscle that lies anterior in the neck
CN 7

Question 10

attachments of platysma

Answer 10

superior insertion onto inferior border of mandible

2 heads of origin from fascia of pectoralis major and deltoid

Question 11

what r the attachments of sternocleidomastoid

Answer 11

attachment to sternum, clavicle and mastoid process of temporal bone

Question 12

what innervates sternocleidomastoid

Answer 12

CN 11

Question 13

what is the function of the infrahyoid muscles and what is the exception and why

Answer 13

depress hyoid

except sternothyroid- does not directly attach to hyoid bone unlike the other infrahyoid muscles

Question 14

what r the attachments of sternohyoid

Answer 14

origin: manubrium of sternum, medial end of clavicle
insertion: inferior border ofhyoid bone

Question 15

what are the attachments of omohyoid

Answer 15

origin: inferior belly from superior border of scapula near the suprascapular notch, superior belly from intermediate tendon
insertion: inferior belly intermediate tendon and superior body is body of hyoid bone

Question 16

attachments of sternothyroid

Answer 16

origin: manubrium of sternum and costal cartilage of rib 1
insertion: thyroid cartilage

Question 17

attachments of thryrohyoid

Answer 17

origin: thyroid cartilage
insertion: body of hyoid bone

Question 18

what is the manubrium of sternum

Answer 18

superior part of sternum T3-4

Question 19

what is ansa cervicalis

Answer 19

nerve loop from the cervical plexus

C1-C3

Question 20

what innervates the infrahyoid muscles

Answer 20

omohyoid, sternohyoid and sternothyroid supplied by ansacervicalis
thyrohyoid innervated by CN 10

Question 21

What is the carotid sheath

Answer 21

located posteriorly to sternocleidomastoid
part of deep cervical fascia of the neck
surrounds vital veins, arteies and nerves

Question 22

what r the structures in the carotid sheath

Answer 22

carotid artery
internal jugular vein
common carotid (bifurcates into external/ internal)
vagus nerve
sympathetic plexus
part of recurrently laryngeal neve
on the surface: nerves of ansa cervicalis that supply the infra-hyoids

Question 23

where is the thyroid gland located

Answer 23

in midline of anterior neck

in front of the trachea

Question 24

describe the structure of the thyroid gland

Answer 24

left and right lobes on either side of the trachea

narrow isthmus attaches these lobes together which lies above the 2/3rd tracheal cartilages

Question 25

what is the pyramidal lobe

Answer 25

small third lobe of thyroid found in some individuals
extends from isthmus to hyoid bone
more commonly comes out of left lobe

Question 26

name the two poles of the thyroid gland and what lobes r they located on

Answer 26

upper pole and lower pole

on lateral lobes of thyroid gland

Question 27

what is the relationship of the upper lobe with the oblique line of the thyroid cartilage and the attachment of the sternothyroid and thyrohyoid muscles

Question 28

drainage of the venous drainage

Answer 28

superior, middle and inferior thyroid veins

superior: exits from upper pole and drains into internal jugular vein in carotid sheath
middle: exits from lateral side of gland and drains into internal jugular vein
inferior: drain into brachiocephalic vein

Question 29

where r the parathyroid glands located

Answer 29

two small oval shaped glands on posterior of thyroid gland

Question 30

where is the recurrent laryngeal nerve located and its path

Answer 30

in groove between trachea and oesophagus

travels upwards to the point it enters the larynx

Question 31

what is the thoracic duct and its extent

Answer 31

main lymphatic vessel to systemic venous system

extends from T12 to root of neck

Question 32

where can the vagus nerve be found in the anterior neck and its route

Answer 32

posterior to the carotid artery and internal jugular vein
vagus nerve travels up towards the chest anterior to the subclavian artery
at inferior border of artery, it branches to give the recurrent laryngeal branch

Question 33

route of recurrent laryngeal nerve from its origin

Answer 33

branch of vagus= recurrent laryngeal
recurrent laryngeal passes under and behind subclavian artery
then ascends to the larynx in the groove between the oesophagus and the trachea

Question 34

what does the thyroid gland produce

Answer 34

thyroxine

Question 35

explain feedback of TRH and TSH

Answer 35

high blood thyroxine levels, inhibition of thyrotropin-releasing hormone and thyroid-stimulating hormone= thyroid epithelial cells decrease thyroxine production and vice versa

Question 36

clinical relevance of location of thyroid

Answer 36

thyroid enlargement can suppress trachea (as it surrounds it on three sides) and compress the recurrent laryngeal nerve