Pharyngeal Apparatusr
Pharyngeal Apparatusr
Pharyngeal Apparatusr
Malformations
1
Objectives
⚫ At the end of this lesson student will be able to:
⚫ The part of cartilage between the mesenchymal tissue surrounding the first arch
styloid process and hyoid bone cartilage. This cartilage acts as a template for
regresses; its perichondrium forms development of the mandible, but does not
the stylohyoid ligament. contribute directly to the formation of it.
⚫ The ventral end ossifies to form the Occasionally ossification of the second arch
lesser cornu and the superior part of cartilage may extend from the styloid process
the body of the hyoid bone along the stylohyoid ligament.
3. The third pharyngeal arch cartilage
Location
⚫ in the ventral part of the arch
Fate
⚫ ossifies to form the greater cornu and the inferior part of the
body of the hyoid bone.
4. The 4th and 6th
pharyngeal arch
cartilages
⚫ fuse to form the laryngeal
a capillary network.
Sadler TW, ed. Head and neck. In: Langman’s medical embryology. 10th ed
DEVELOPMENT OF THE TONGUE
⚫ at the end of the 4th week, a median triangular elevation
appears in the floor of the primordial pharynx, just rostral to
the foramen cecum
⚫ this swelling-the median lingual swelling (tongue bud)
(Latin, tuberculum impar)-is the first indication of tongue
development.
⚫ Soon, two oval lateral lingual swellings (distal tongue buds)
develop on each side of the median tongue bud.
⚫ The three lingual swellings result from the proliferation of
mesenchyme in ventromedial parts of the first pair of
pharyngeal arches.
⚫ The lateral lingual swellings rapidly increase in size, merge with
each other, and overgrow the median lingual swelling.
⚫ The merged lateral lingual swellings form the anterior two
thirds (oral part) of the tongue
⚫ The fusion site of the lateral lingual swellings is indicated by the
midline groove of the tongue and internally by the fibrous
lingual septum.
⚫ The median lingual swellings do not form a recognizable part of
the adult tongue.
⚫ Formation of the posterior third (pharyngeal part) of the
tongue is indicated in the fetus by two elevations that develop
caudal to the foramen cecum
⚫ The copula (Latin, bond, tie)
⚫ The hypopharyngeal