- Fgf8 (growth), BMP7 (apoptosis), Shh (patterning)

Endodermal signals

- primary mesodermal signal

Hox (segmentation)

- signal associated with the formation of the pharyngeal clefts

Bmp7

- can persist posteriorly on the thyroid due to a lack of deterioration following descension

Pyramidal lobe

- endodermal connection with descending thyroid that can persist as the most common cystic midline mass

thyroglossal duct

- begins to function around 3 months of development

- interfaces with ultimobranchial body "c"-cells (calcitonin)

- can persist ectopically as a midline neck mass

Thyroid

- in descending order of likelihood a swollen lymph node, cervical sinus cyst and fistula, thymic remnant, or ectopic parathyroid are ddx for this

Lateral Neck Mass

- a thyroglossal duct remnant (cyst) or ectopic thyroid tissue (pyramidal lobe) can present as this

Midline Neck Mass

- the term used to describe a developmental defect involving the tongue being anchored too tightly to the floor of the mouth

Ankyloglossia (tongue tied)

- congenital absence or partial absence of the lower jaw

agnathia

- cardiac abnormality, abnormal faces, thmyic aplasia, cleft palate, hypocalcemia

DiGeorge syndrome (CATCH-22)

- congenital 1st pharyngeal arch deformity resulting in facial problems (eyes slanting down, micrognathia, hearing loss, and malformed/absent ears)

Treacher-collins syndrome

- anomalous development of the 1st and 2nd branchial arch leading to incomplete development of the ear, nose, soft palate, lip, and mandible

- asymmetrical

Goldenhar syndrome

- the facial placode that does not rupture a cyst to form a cavity

Optic/lens

- when the nasal placode becomes the nasal pit these two process form, and then fuse to form nares

Medial and Lateral Nasal Processes

- forms between the maxillary process and the lateral nasal process following the growth of the maxillary process and fusion of the nasal processes

Nasolacrimal groove (duct)

- forms primitive cloanae following the expansion of the nasal pits into nasal sacs

- eventually partially replaced by the secondary palate

Oronasal membrane

- extends from the wall of the brain into the roof of the nasal cavity during development and remains as epithelium

Olfactory nerve fibers

- formed with the secondary palate and function to filter incoming air through turbulence

- superior, middle, & inferior

Conchae

- these processes fuse to create the nasal septum and eventually fuse to the primary and newly formed secondary palate

Medial nasal processes

- the inferior fusing of the medial nasal processes form a segment joining this bony structure

- forms a superficial skin portion and 2 bony portions as well as the primary palate

Maxilla (intermaxillary segment)

- this structure is formed superficial to the median palatine process and has the nickname "cupids bow"

Philtrum

- lies between the philtrum and the primary palate during development

- is the precursor to the front 4 upper teeth (incisors)

Premaxilla

- remnant channel in the palate that allows for neural and vascular communication from the nasal cavity and the oral cavity

Incisive foramen (canal)

- fuses with its opposite counterpart and the primary palate after migrating superiorly and medially to form the hard and soft secondary palate

- through development, separates the nasal and oral cavities (and w/ nasal septum the bilateral nasal cavities)

Lateral Palatine Processes

- this type of mouth cleft is more common in males than females

- does not usually inhibit speech and/or feeding and the dental arch

Cleft Lip

- the most common side of clefting

Left

- this race is the most susceptible to clefting

Asian

- this type of clefting causes complications with feeding and the dental arch (4 incisors)

Primary Palate

- this type of clefting causes the most problems with speech and making explosive verbal sounds ("p)

Secondary Palate

- an incomplete clept lip does not involve this structure

Primary Palate

- Time period that it takes teeth to progres from development --> Bud --> Cap --> Bell --> Deciduous eruption (baby teeth)

6-24 months