Embryo of Head and Neck

Question 1

Branchial Arch 1: Cartilage

Answer 1

Meckel’s Cartilage:

• Mandible
• Malleus
• Incus
• Spenomadibular ligament

Maxillary prominences
Zygoma

Question 2

Branchial Arch 2: Cartilage

Answer 2

Reichart’s cartilage:

• Stapes
• Styloid process
• Lesser horn of hyoid
• Stylohyoid ligament

Question 3

Branchial arch 3: cartilage

Answer 3

Greater horn of the hyoid

Question 4

Branchial arch 4-6: cartilage

Answer 4

Thyroid
Cricoid
Arytenoids
Conriculate
Cuneiform

Question 5

Branchial arch 1: muscles

Answer 5

Muscles of mastication - Massester, Temporalis, Medial and lateral pterygoid

• Mylohyoid
• Anterior belly of digastricus
• Tensor Tympani
• Tensor Veli palatini
• Anterior 2/3 of tongue

Question 6

Branchial arch 2: muscles

Answer 6

• Muscles of Facial Expression
• Stapedius
• Arytenoids
• Posterior belly of the digastricus

Question 7

Branchial arch 3: muscles

Answer 7

-Stylopharyngeus

Question 8

Branchial arch 4: muscles

Answer 8

• Most pharyngeal constrictors
• cricothyroid
• Levator veli palatini

Question 9

Branchial arch 6: muscles

Answer 9

-All intrinsic muscles of the larynx (except cricothyroid)

Question 10

Branchial arch 1: Nerve

Answer 10

Trigeminal CN V2 and V3 (chewing)

Question 11

Branchial arch 2: Nerve

Answer 11

Facial CN VII (facial expression)

Question 12

Branchial arch 3: Nerve

Answer 12

Glossopharyngeal CN IX

Question 13

Branchial arch 4: Nerve

Answer 13

Vagus CN X (Superior Laryngeal branch - Swallowing)

Question 14

Branchial arch 6: Nerve

Answer 14

Vagus CN X (recurrent laryngeal - speaking)

Question 15

Barnchial arch artery derivatives

Answer 15

3rd Arch - Internal carotid artery
4th Arch - Aortric arch, right subclavian
6th Arch - Pulmonary artery, Ductus arteriosus

Question 16

Pharyngeal Pouch derivatives

Answer 16

Pouch 1- Middle Ear
Pouch 2 -Palatine Tonsil
Pouch 3 - Inferior parathyroid, Thymus
Pouch 4 - Superior Parathyroid

Question 17

Circle of willis, cranial nerve correlations

Answer 17

Anterior cerebral and anterior communicating = Optic Chiasm with internal carotid runninng infralateral.

Posterior Cerebral and Superior Cerebellar sandwich CN 3

CN VI between Anterior inferior cerebellar artery (inferior) and branch off basilar superior.

Anterior inferior cerebellar artery runs between VII and IX

Question 18

Opening of the larynx

Answer 18

Posterior Crico-arytenoid

All other intrinsic muscles close the larynx

Question 19

Tightening of the vocal chords

Answer 19

Cricothyroid (innervated by superior laryngeal)

All intrinsic muscles of the larynx loosens the chords. (innervated by recurrent laryngeal

Question 20

All muscles of the palate are supplied by pharyngeal plexus (IX, X, sympathetics) except:

Answer 20

Tensor Palatini - mandibular nerve (V3)

Question 21

All cell bodies for taste lie in geniculate ganglion except

Answer 21

IX and X - sensory just below jugular foramen

Question 22

All muscles of the tongue are supplied by hypoglossal nerve (XII) except

Answer 22

Palatoglossus which is supplied by X.

Question 23

All strap muscles are supplied by ansa cervicalis except:

Answer 23

Thyrohyoid - C1 on hypoglossal

Question 24

Parasympathetics in the head supply salivary or mucus glands, except:

Answer 24

Ciliary ganglion - supplies eye with accomodation and pupillary constriction

Question 25

Greater petrosal nerve

Answer 25

Parasympathetic innervation to the lacrimal gland, mucosal glands of the nose, palate and pharynx

Question 26

Innervation of the Tympanic membrane

Answer 26

Inner surface - glossopharyngeal | Outer surface - VII, X, V (auriculotemporal)

Question 27

Telencephalon Derivations

Answer 27

Cerebral hemispheres, lateral ventricles

Question 28

Diencephalon Derivations

Answer 28

Thalami, Third ventricle

Question 29

Mesencephalon Derivations

Answer 29

Midbrain, cerebral aqueduct

Question 30

Metencephalon Derivations

Answer 30

Pons, Cerebellum, Upper part of 4th Ventricle

Question 31

Myelencephalon Derivations

Answer 31

Medulla, Lower part of 4th Ventricle.

Question 32

Microphthalmia

Answer 32

Arrested development of the eye due to maternal Toxoplasmosis

Question 33

Congenital cataracts

Answer 33

Caused by maternal rubella infection

Question 34

Coloboma of Iris

Answer 34

Keyhole pupil due to failure of closure of the retinal fisure

Question 35

Congenital Aniridia

Answer 35

Absence of the Iris due to arrested development at the rim of the optic cup

Question 36

Congenital Aphakia

Answer 36

Absence of the lens due to failure of lens placode to form

Question 37

Cryptopthalmos

Answer 37

Failure of the development of palpebral fissures resulting in a hidden eye.

Question 38

Chalazion

Answer 38

obstructed tarsal gland of the eyelid

Question 39

Branchial Cyst vs. Fistula

Answer 39

Cyst - failure of obliteration of cervical sinus and 2nd paryngeal groove Fistula - Persistence of proximal part of 2nd pharyngeal groove