Embryology Neck

Question 1

Embryology of thyroglossal duct ?

Answer 1

3rd week, FORAMEN CECUM develops between anterior 2/3 and posterior 1/3 of the tongue. Then develops into Thyroid GLAND. The latter dives into the neck and creates this DUCT. Process ends 7th week

Question 2

TGD in relation with hypoid bone?

Answer 2

Usually in the midline, but infrahyoid the duct can move off midline

Question 3

Types of cells in the TGD?

and

How is TGD cyst formed ?

Answer 3

Walls lymphoid and epithelial cells and stick to each other by third trimester duct gone

It is filled with mucus from epithelial cells.

Question 4

Complications of a congenital cyst?

Answer 4

Infection -> Respiratory tract -> Cyst
Inflammation more mucus
If the cyst bursts -> Discharging sinus (fistula)

Question 5

Where is ectopic thyroid located?

Answer 5

Remains in the residual duct

Question 6

What is the pharyngeal apparatus?

Contents of each arch?

Answer 6

Pairs of branhcia/pharyngeal arches, pouches and clefts

Artery, nerve and cartilage

Question 7

Embryology of the arches, pouches and clefts

Answer 7

Arches: Mesoderm
Pouches: Endoderm
Clefts: Ectoderm

Question 8

How many arches?

Answer 8

1-6 but 5 either doesn’t form or regresses immediately

Question 9

Function of 1st Paryngeal Arch?

Function of 2nd Paryngeal Arch?

Answer 9

Chewing

Facial expressions

Question 10

Nerves of 1st Pharyngeal Arch

Bones 1st Pharyngeal Arch

Answer 10

Nerves:
Trigeminal n. CN5
Mandibular n. V3

Bones: Mandible, Zygomatic bone, Maxilla, Incus, Malleus

Question 11

Muscles 1st Pharyngeal Arch

Answer 11

Chewing muscles: Temporalis, Pterygoid, Masseter

Swallowing : Tensor veli palatini, Mylohyoid muscles and ANTERIOR Belly digastric
+
Tensor tympani

Question 12

Origin of the post belly of digastric mucle?

Answer 12

2nd Pharyngeal Arch

Question 13

Nerves and bone 2nd Pharyngeal Arch?

Answer 13

Facial N.

Hyoid bone, styloid process, stapes

Question 14

Embryology of the ossicles?

Answer 14

Upper part malleus - incus = 1st Arch
Lower part malleus - incus and staple = 2nd Arch
BUT FOOTPLATE of stapes from otic capsule (inner ear)

Question 15

Muscles 2nd Pharyngeal arch?

Answer 15

Sound and swallowing

Post belly digastric and stapedial muscle

Question 16

Origin of tensor tympani muscle?

Origin of stapedius muscle?

Answer 16

1st Arch

2nd Arch

Question 17

Muscles, nerve, bones 3rd Arch?

Answer 17

Stylopharyngeus m.
Glossopharyngeal nerve IX
Hyoid bone

Question 18

Function and derivatives of 4 and 6th Pharyngeal Arches?

Answer 18

Everything we need to speak!

Vagus nerve
Superior Laryngeal n. 4th arch
Recurrent Laryngeal n. 6th arch

Laryngeal Cartilage
Muscles of Larynx, pharynx and mouth

Question 19

Derivatives of 1st Pharyngeal Cleft?

Answer 19

Helps form EAR
EAC
Ear Drums

Question 20

What is the location of a First Branchial Cleft cyst?

Answer 20

From EAC to angle of mandible

Question 21

What is the most common location of a second branchial cleft cyst?

Answer 21

Anteromedially to SCM, laterally to carotid and posteriorly to submandibular . Type II most common

Question 22

What are the derivatives of the 1st Pharyngeal Pouch?

Answer 22

Cavity that forms IAM and Eustachian tube

Question 23

2nd Pharyngeal pouch?

Answer 23

Primitive tonsils

Question 24

Which malformations often come together?

Answer 24

Middle and external ear

Question 25

What is the importance of 3rd and 4th pharyngeal pouches?

Answer 25

Calcium regulation 3rd primitive thymus 4th parafollicular cells of thyroid gland

Question 26

What is the origin of the inferior parathyroid? What is the origin of the superior parathyroid?

Answer 26

3rd pouch 4th pouch

Question 27

What is the superficial cervical fascia?

Answer 27

Thin layer of fat that lies between the dermis of the skin and the SL of the DCF.

Question 28

contents of the superficial cervical fascia?

Answer 28

Platysma, nerves, blood/lymphatics fat (σημαντικά για την παθολογία)

Question 29

Pathology related to the superficial cervical fascia?

Answer 29

``` Teratoma Vasc Malformations (vessels) Tumors/Haemangioma Cellulitis (fat) NF1 (neuromas along nerves) Subcutaneous fat fibrosis (fat) ```

Question 30

3 layers of the Deep Cervical Fascia

Answer 30

Superficial Layer DCF Middle Layer DCF Deep Layer DCF

Question 31

Superficial layer DCF spaces

Answer 31

Suprahyoid: Masticator space Parotid space Part of Carotid space Infrahyoid: Surrounds strap m., SCM, trapezius m

Question 32

Middle layer DCF spaces

Answer 32

SHN: Pharyngeal mucosal space deep margin, contributes to carotid space IHN: Surrounds visceral space. Contributes to carotid space.

Question 33

Deep Layer DCF spaces

Answer 33

SHN & IHN: Surrounds perivertebral space (paraspinal and pre-vertibral). Contributes to carotid

Question 34

What is the Alar Fascia?

Answer 34

Part of the DL-DCF which forms the lateral and posterior walls of the retropharyngeal space and separates from the Danger space

Question 35

What is the Danger Space?

Answer 35

Virtual space between retropharyngeal space and pre-vertebral component of the perivertebral space

Question 36

How many arches, clefts, pouches?

Answer 36

5 Arches (1-6 but 5 doesn't form) 4 clefts 4 pouches

Question 37

Embryology of the footplate of the stapes

Answer 37

Ottic capsule together with inner ear

Question 38

Summary of derivatives of the pharyngeal apparatus

Answer 38

Arches - Mesoderm : Bones, muscles of head and neck Clefts - Ectoderm : Stuctures of ear canal Pouches - Endoderm: Parts of the ears , Tonsils, Parathyroid, Thyroid

Question 39

Where is the posterior cervical space?

Answer 39

Space between the SL-DCF surrounding the SCM and the DL of the DCF surrounding the paraspinal muscles. Contains fat and lymph nodes.

Question 40

Parts of the perivertebral space

Answer 40

Prevertebral space anteriorly | Paraspinal space posteriorly (posterior elements)

Question 41

Lymph node levels, what are the two horizontal planes?

Answer 41

Hyoid bone and cricoid cartilage Level I = below the mandible Behind the mandible/angle = Level II Down to hyhoid Level III and down to cricoid level IV