Pharyngeal Arches

Question 1

1st Pharyngeal Arch, Cleft, Pouch

Answer 1

Mandibular Arch:

• mandibular and maxillary processes
• Meckel’s cartilage = precedes the mandible but doesn’t contribute to it. Primary ossification centre for mandible located between lingual and mental nerve.
• Trigeminal Nerve
• Muscles of mastication: pterygoids, masseter, temporalis, ABD, mylohyoid.
• Maxillary and internal carotid arteries

No 1st cleft

1st Pouch:

• eustacian tube
• tympanic membrane
• middle ear cavity

Question 2

2nd Pharyngeal Arch, Cleft, Pouch

Answer 2

Hyoid Arch
  - Reichart's cartliage 
  - Stapes, lesser wings and superior body of hyoid
  - styloid process and stylohyoid ligament 
  - Muscles of facial expression and PBD
  - Facial Nerve
  - Thyroid gland and tonsils
2nd Cleft - disappears rapidly
2nd Pouch - tonsillar fossa

Question 3

3rd Pharyngeal Arch, Cleft, Pouch

Answer 3

Greater horn and inferior body of hyoid
Glossopharyngeal nerve
Stylopharyngeus muscle

3rd pouch: inferior parathyroid gland and THYMUS

Question 4

4th Arch, Cleft, Pouch

Answer 4

Thyroid cartilage
Pharynx and Epiglottis
Soft Palate and pharyngeal constrictor muscles
Vagus nerve

4th Pouch - superior parathyroid gland

Question 5

6th Arch, Cleft and Pouch

Answer 5

Cricoid and arytenoid cartilages
Larynx
Muscles of larynx
Vagus Nerve

Question 6

What type of germ layer covers pouches and what covers grooves?

Answer 6

ENDOderm = POuches
ECTOderm = GROOves 

*** entire first arch is ectoderm

Question 7

Where does a branchial fistula/cyst appear?

Answer 7

Along the ABD or SCM muscles