Pharyngeal Arches Flashcards
The pharyngeal apparatus consists of:
Pharyngeal arches
Pharyngeal pouches
Pharyngeal grooves
Pharyngeal membranes
Most congenital anomalies in head and neck originate during:
Transformation of the pharyngeal apparatus into its adult derivatives
The pharyngeal arches begin to develop early in the ____th week as ___ ___ ___ migrate into the future head and neck regions
4th
Neural crest cells
How are the pharyngeal arches numbered?
In craniocaudal sequence
What are the first pair of pharyngeal arches?
The primordial of the jaws
The first pair of pharyngeal arches appears as what?
Surface elevations lateral to the developing pharynx
When are the well-defined pairs of pharyngeal arches visible externally?
Which pairs are these?
By the end of the fourth week
The first 4 arches
Which arches are rudimentary? What does this mean?
5th and 6th
They are not visible on the surface of the embryo
What separates the arches?
Pharyngeal grooves (clefts)
First pharyngeal arch develops what?
What does this give rise to?
Maxillary prominence - gives rise to maxilla, zygomatic bone and squamous part of the temporal bone
Mandibular prominence- forms the mandible
The 2nd arch, aka the _____ arch makes:
Hyoid arch
Major contribution to the formation of the hyoid bone
The pharyngeal arches cause to the 2nd arch are referred to by:
Number only
Stomodeum (____ ___), appears as a:
It is separated from the:
Primordial mouth
Slight depression of the surface ectoderm
Cavity of the primordial pharynx by a bilaminar membrane (oropharyngeal membrane) (Ectoderm externally and endoderm internally)
The oropharyngeal membrane ruptures at about _____ days. This causes:
26
Brings the primordial pharynx and foregut into communication with the external environment
Initially, each arch consists of a ____ of ____
It is covered externally by ____ and internally by _____.
Core of mesenchyme (embryonic connective tissue)
Ectoderm
Endoderm
The original mesenchyme is derived from ____ in the ____ week
Mesoderm
Third
During the 4th week, most of the mesenchyme is derived from ___ ___ ____ that migrate into the ___ ____
Neural crest cells
Pharyngeal arches
A typical arch contains:
An aortic arch (artery rising from the truncus arteriosus of the primordial heart)
A cartilaginous rod (forms the skeleton of the arch)
Muscular component (forms muscles in head and neck)
Nerve (supples the mucosa and muscles derived from the arch)
First arch, AKA:
Nerve:
Muscles:
Skeletal structure:
Ligaments:
Mandibular
Mandibular nerve
Muscles of mastication, mylohyoid and anterior belly of digastric, tensor tympani and tense yell palatini
Malleus and incus
Anterior ligament of malleus and spent mandibular ligament
2nd arch, AKA:
Nerve:
Muscles:
Skeletal structures:
Ligaments
Hyoid
Facial nerve (CN VII)
Muscles of facial expressions, stapedius m., stylohyoid m., posterior belly of digastric
Stapes, styloid process, Lesser horn and upper part of body of hyoid bone
Stylohyoid ligament
Third arch
Nerve:
Muscles:
Skeletal structures:
Glossopharyngeal (CN IX)
Stylopharyngeus
Greater horn and lower part of body of hyoid bone
4th arch
Nerve:
Muscles:
Skeletal structures:
Superior laryngeal branch of vagus (CN X)
Cricothyroid and levator veli palatini
Thyroid cartilage and cricoid cartilage
6th arch
Nerve:
Muscles:
Skeletal structures:
Recurrent laryngeal branch of vagus (CN X)
Constrictors of pharynx, intrinsic muscles of larynx, striated muscles of esophagus
Arytenoid cartilage, corniculate cartilage and cuneiform cartilage
