Anatomy of the Thyroid Gland

Question 1

Answer 1

Question 2

Answer 2

Question 3

which cartilages of the trachea does the isthmus lie anterior to

Answer 3

2nd and 3rd

Question 4

goitre

Answer 4

enlarged thyroid gland

Question 5

how will a lump in the gland move during swallowing

Answer 5

superiorly then inferiorly

Question 6

Answer 6

Question 7

what is the prevalence of a pyramidal lobe

Answer 7

approx 50% of thyroid glands

Question 8

pyramidal lobe

Answer 8

extends superiorly from isthmus - due to embryological development

most attach superiorly to thyroid cartilage. may extend as far as hyoid bone (superiorly)

isthmus may be complete or absent

most commonly originate from left lateral lobe

Question 9

where are the parathyroid glands located

Answer 9

on the posterior surfaces of the thyroid glands lateral lobes

Question 10

what is the junction between the anterior and posterior parts of the tongue called in adults

Answer 10

foramen caecum

Question 11

describe the development of the thyroid gland

Answer 11

migrates inferiorly from the foramen caecum in the tongue to its final position in relation to the larynx/trachea - whilst still attached to the tongue by the thyroglossal duct

Question 12

when does the gland reach its final position

Answer 12

in the 7th week of development

Question 13

where can thyroglossal duct cysts or ectopic thyroid tissue be located in the migratory path

Answer 13

anywhere

Question 14

platysma

Answer 14

superficial muscle that overlaps the sternocleidomastoid

located immediately deep to the skin within the superfical fascia of the neck

Question 15

where are the platsymas

Answer 15

Question 16

what muscle group does platysma belong to, an so what is its innervation

Answer 16

muscles of facial expression

CNVII (facial nerve)

Question 17

which fascia encloses all other neck fascial compartments

Answer 17

investing (deep) fascia

Question 18

investing (deep) fascia

Answer 18

deep to superficial fasica

encloses trapzius and sternocleidomastoid (CNXI)

Question 19

Answer 19

Question 20

carotid sheath position

Answer 20

deep to investing fascia

anterolaterally

Question 21

what do the carotid sheaths contain

Answer 21

internal jugular veins

common and internal carotid arteries

CNX

deep cervical lymph nodes

Question 22

prevertebral (deep ) fascia location

Answer 22

deep to investing fascia

posteriorly

Question 23

what does the prevertebral fascia contain

Answer 23

cervical vertebrae

postural neck muscles

Question 24

where is the pretracheal (deep) fascia

Answer 24

deep to investing fascia

anteriorly

Question 25

what does the pretracheal fascia enclose

Answer 25

strap muscles thyroid gland trachea oesophagus recurrent laryngeal nerves

Question 26

where is the retropharyngeal space

Answer 26

between the pretracheal and prevertebral fascia

Question 27

how can infection spread in the neck

Answer 27

in the planes between the fasical tubes - the retropharyngeal space

Question 28

what fascia is the sternocleiomastoid enclosed in

Answer 28

investing along with trapezius

Question 29

what are the attachments of the sternocleidomastoid

Answer 29

sternal head - manubrium of sternum clavicular head - medial end of clavicle

Question 30

where do both heads of the sternocleidomastoid attach superiorly

Answer 30

mastoid process of temporal bone

Question 31

what are the attachments of the trapezius

Answer 31

originiates from occipital bone inf: spine of scapula and lateral end of clavicle

Question 32

describe the jugular vein drainage

Answer 32

anterior drains into external jugular vein external drains into subclavian vein

Question 33

what are the carotid sheaths made of

Answer 33

deep fascia

Question 34

where do the carotid sheaths attach superiorly

Answer 34

base of the skull around the jugular foramen and entrance to the carotid canal

Question 35

desribe the venous drainage of the thyroid and parathyroid glands

Answer 35

superior and middle thyroid veins drain into IJV inferior thyroid vein drains into L braciocephalic vein (most of the time)

Question 36

describe the arterial supply of the thyroid and parathyroid glands

Answer 36

Question 37

describe the lypmhatic drainage of the thyroid and parathyroid glands

Answer 37

Question 38

how is lymph returned to the right and left lymphatic ducts

Answer 38

right - via the right lymphatic duct to right venous angle left - via thoracic duct to left venous angle

Question 39

where does CNX orignate in the skull and exit the cranium

Answer 39

originates from medulla of brainstem exits cranium through jugular foramen

Question 40

describe CNX in the neck

Answer 40

descends through the neck in the carotid sheath gives somatic branches to larynx: superior laryngeal nerve and right recurrent laryngeal nerve

Question 41

describe CNX in the thorax

Answer 41

R CNX descends on the right lateral aspect of trachea, posterior to R lung root, and onto the oesophagus L CNX descends on the left side of the arch of aorta, gives off the **left recurrent laryngeal nerve,** posterior to the left lung root and onto the oesophagus

Question 42

describe CNX in the abdomen

Answer 42

both vagus nerves pass through diaphragm with the oesophagus (T10) an ddivide into their terminal branches on the surface of the stomach supply the abdominal organs with parasympathetic axons to the distal midgut

Question 43

describe the course of the recurrent laryngeal nerves

Answer 43

branches of CNX left - recurs under arch of aorta right - recurs under subclavian artery

Question 44

Answer 44

Question 45

what are teh strap muscles enclosed in

Answer 45

pretracheal (deep) fascia along with thyroid gland, trachea and oesophagus

Question 46

strap muscles

Answer 46

Question 47

where are the strap muscles located

Answer 47

infra hyoid muscles - inferior to hyoid bone

Question 48

what is the arterial supply of the strap muscles

Answer 48

sup and inf thyroid arteries

Question 49

describe the attachment and course of omohyoid

Answer 49

inferior belly arises from scapula, runs superomedially under stenocleidomastoid muscle attached to superior belly by an intermediate tendon that is anchored to the clavicle

Question 50

Answer 50

Question 51

describe a classic thyroidectomy incision

Answer 51

collar incision made within a natural skin crease or in the direction of Langer's lines incision just superior to clavicles and jugular notch incision made through skin and platsyma

Question 52

in thyroidectomy why is the incison made just superior to the clavicles and jugular notch

Answer 52

optimal aesthetics - scar hidden by clothing and reduced risk of keloid formation

Question 53

Answer 53

Question 54

Answer 54

Question 55

what is the function of the right recurrent laryngeal nerve

Answer 55

somatic motor supply to most of the skeletal muscles that move the right vocal cord

Question 56

what does recurrent nerve injury result in

Answer 56

paralysis of vocal cord

Question 57

unilateral recurrent nerve injury

Answer 57

hoarseness or weakness of voice and weak cough

Question 58

bilateral recurrent nerve injury

Answer 58

aphonia (inability to produce sound) and inability to close rima glottidis to prevent aspiration or produce a good cough (requries closure of rima glottis)