Palatal Anomalies & Development of the Salivary Glands, Skull & Limbs & Intro to Normal Dentition

Question 1

congenital anomalies

Answer 1

hare lip (cleft lip) and cleft palate
facial cleft
microstomia - small mouth - due to over-fusion of the maxillary and mandibular processes
macrostomia - wide mouth - due to inadequate fusion of the two processes

Question 2

clefting can affect what

Answer 2

feeding, speech, hearing and social integration
often part of multiple congenital anomalies and syndromes

Question 3

cleft lips and palate

Answer 3

two major groups
- cleft involving upper lip and anterior part of palate
-cleft involving posterior part of palate (hard and soft palate)

cleft palate, cleft lip and palate are etiologically distinct anomalies

Question 4

what increases the risk of cleft palate

Answer 4

anticonvulsant drugs, such as Phenobarbital and Phenytoin if taken during pregnancy increases the risk of cleft palate

Question 5

secondary cleft palate due to small lower jaw (micrognathia) and glossoptosis (backward displacement of tongue) is called

Answer 5

Pierre Robin sequence

Question 6

basic cleft classification

Answer 6

A normal
B cleft of lip and alveolus
C cleft of lip and primary palate
D unilateral cleft lip and palate
E bilateral cleft lip and primary palate
F bilateral cleft lip and palate
G cleft palate only

Question 7

types of cleft lips and palate

Answer 7

unilateral cleft lip: due to failure of fusion of the medial nasal process with the maxillary process

unilateral left cleft lip and cleft of anterior palate: due to failure of fusion of the palatine shelves of the maxillary process and primary palate derived from merged medial nasal processes

alveolar cleft: lack of supporting bone for eruption and support of the adjacent dentition

posterior cleft palate and uvula: the palatine shelves fail to fuse with each other

complete cleft lip and palate: unilateral cleft lip with cleft palate

Question 8

craniofacial clefts: tessier clefts

Answer 8

clefts of the cranio-facial region are classified into types 0-14

clefts affecting the orbit, nose and the mouth

Question 9

salivary glands major pairs

Answer 9

parotid gland
submandibular
sublingual

Question 10

saliva

Answer 10

can be serous or mucous
helps in lubrication, digestion and taste
essential for oral health

Question 11

salivary gland defects can lead to

Answer 11

periodontal disease, dental caries, mouth ulcers

Question 12

parotid develops from

Answer 12

an invagination of ectoderm between the maxillary and mandibular processes and grows towards the ear
proximal part forms duct (Stenson’s duct)
distal end proliferates to form the gland

Question 13

lacrimoauriculodentodigital (LADD) syndrome

Answer 13

affects lacrimal & salivary glands, in addition to the ear, teeth and distal limb
development of these tissues depends on interaction between the epithelium and mesenchyme

Question 14

neurocranium

Answer 14

bones surrounding the bran

Question 15

viscerocranium

Answer 15

bones of the face

Question 16

development of the skull

Answer 16

endochondral bones (chondrocranium): formed by ossification of cartilaginous percursor, lies under the brain

membranous bones (dermal bones): formed by ossification of mesenchyme (consists of both neural crest and mesoderm), surrounds the brain (cranial vault) and the facial bones

Question 17

fontanelle

Answer 17

bones of cranial vault not completely ossified during fetal life
at birth there are soft fibrous sutures between them which allow the skull to deform as it passes through the birth canal
6 fontanelles - membranous sutures at birth
anterior and posterior, two (right and left) anterolateral and two posterolateral fontanelles

Question 18

craniosynostosis is caused by

Answer 18

a congenital anomaly due to premature closure of sutures
commonly affects the coronal or sagittal suture
closure of one suture causes increased growth at other sutures and deforms the brain and skull

Question 19

sutures

Answer 19

joints that occur when two membrane bones meet

Question 20

what cranial deformity constitutes about one half the cases of craniosynostosis

Answer 20

if the sagittal suture closes early, the cranium becomes long, narrow and wedge-shaped (scaphocephaly)

Question 21

what is 30% of cases involving closure of sutures

Answer 21

premature closure of the coronal suture, results in a high, tower-like cranium (brachycephaly)

Question 22

development of limbs

Answer 22

limb buds arise form the developing trunk: 2 limb buds for the right and left upper extremities and 2 for the lower extremities
the buds grow and enlarge in size, then the cartilaginous bones form within them to give rise to the different parts of the limb
the distal end of the bud goes on to develop into the hands and feet
the distal end expands to form a palate and then digital rays are formed along which apoptosis is induced to give rise to the 5 fingers and 5 toes

Question 23

polydactly

Answer 23

supernumerary fingers and toes
due to anomalous development of digital rays and apoptosis