FACIAL AND PALATAL ABNORMALITIES (Exam 1) Flashcards
What are the two developmental mechanisms involved in the proper development of the craniofacial area?
- Appropriate amount of tissue proliferation (Cell migration) in the region is required to eliminate the space (Cell proliferation)
- Fusion: Process by which the two regions of tissue that were initially separated grow together
What causes a cleft to be formed?
A failure of tissue to merge or fuse together; which leads to a persisted deficit of tissue
Embryological basis for clefts may include a failure to fuse due to:
- Excesses tissue (i.e. excess proliferation)
- Deficits of tissue (i.e. under proliferation tissue which could be related to cell death
- Alterations in the shape and size of head or jaw leading to misalignment of the regions of tissue
Fusion between maxillary and lateral nasal process forms:
Side of nose
Fusion between with maxillary and medial nasal process (IM) will form:
Upper lip
The primary palate is formed by:
Maxillary and inter maxillary segment
The cheek is formed by:
Maxillary and mandibular process
The secondary palate is formed by:
Lateral palatal shelves of maxilla
Fusion between both medial nasal =
Midline/tip of nose and INtermaxillary segment
IM ->
Primary palate and philtrum of lip
Fusion between with each mandibular process forms the:
Chin
Fusion of right/left lateral palatal shelves with primary palate and nasal septum forms the:
Complete palate
What are the types of facial Anomalies:
- Midline facial defects can be: Hypoplasia (under developed), Hyperplasia (overdeveloped)
- Facial clefts can be : Oblique, Lateral (transverse)
- Palatal clefts and lips
- Mandibular clefts
What is Holoprosencephaly?
Failure of forebrain to divide, which leads to spectrum of cdraniofacial disorders released to a aarrested development of frontonasal tissue to form or proliferate; can be associated with failure of NC migration from forebrain region
Clinical Phenotype: Single to close set eyes (hypotelorism); absent to single nostril; missing premaxilla
Most severe: Single cerebral lobe instead of right and left hemispheres; single nostril (cebocephaly); single eye (cyclopia)
Embryological basis for Holoprosencephaly:
The forebrain directs the development of frontonasal process:
- Developmental defects in the forebrain such as a failure of the forebrain to divide, leads to arrested development of frontonasla process
Outcome: midline facial abnormalities
** DEFICIENT AMOUNT OF TISSUE IN MIDLINE**
What is Frontonasal Dysplaisa?
(Median Facial Cleft): is a spectrum of conditions associated with the failure of tissue to fuse in midline due to an excess of amount of tissue:
Clinical Phenotype: Spectrum of median craniofacial hyperplasia
- Small eyes (Microphthalmia) eyes wide set (hypertelorism
- Bifid nose or a brand nose with cleft/groove-the nasal tip may be absent
- Cleft of primary and or secondly palate
** EXCESS AMOUNT OF TISSUE IN MIDLINE**
Embryological basis for Frontonals displays (Midline Facial Cleft):
Midline defect due to over-proliferation of tissue and or lack of growth inhibition in the frontonasal process following placed formation
What is an oblique facial cleft:
Persisten groove from inner eye to the ala of the nose:
Embryological basis: Failure of maxillary process to mere with lateral nasal process and premaxilla
What is a Lateral facial Cleft?
Associated with Macrostomia (large mouth)
Embryological basis: Incomplete fusion between the soft tissue of the maxillary and mandibular processes leads to distortion of labial commissures
What is congenital Macrostomia?
A rare congenital anomaly seldom occurring alone and is frequently associated with deformities of the structures developing from the first arch. It maybe part of a group of disorders known as Hemifacial microsomes which exhibit defects in first and second arch
What is Hemifacial microsomia?
A birth defect that occurs when a part of the face fails to grow and appears small or underdeveloped. The syndrome varies in severity but always includes the maldevelopment of the ear and the mandible. This is the second most common facial birth defect after clefts
What is a Primary Cleft?
Clefts anterior to incisive foramen are considered primary (anterior) and may be bilateral or unilateral
What is a Secondary Cleft?
Secondary (posterior) Clefts are located posterior to the foramen and may involve the hard and or soft palate
What is a complete cleft?
A complete cleft includes the entire definitive palate and may be bilateral or unilateral
