2 Pharyngeal Arches Flashcards
Pharyngeal arches appear as pairs of bulges overlying the head and neck regions due to migration of ______.
Neural crest cells
Each arch is lined externally by _____, internally by _____, and has a core of _____.
Ectoderm
Endoderm
Mesenchyme
Each pharyngeal arch contains these 4 things:
- Artery
- Cranial n.
- Muscle
- Cartilage
Cartilage from the 1st arch forms the ______ and ______.
Maxillary process
Mandibular process
The maxillary process gives rise to:
- Maxillary bones (including inferior nasal conchae)
- Zygomatic bones
- Vomer
The mandibular process gives rise to:
- Mandible
2. Squamous portion of temporal bone
The ______ is the former site of 1st arch (meckel) cartilage
Mandibular canal
The second arch cartilage gives rise to:
- Lesser Cornu of hyoid bone
- Stapes
- Styloid process
- Stylohyoid ligament
3rd arch cartilage gives rise to the:
- Body of hyoid
2. Greater cornu (horn) of hyoid
4th and 6th arch cartilage give rise to:
- Thyroid cartilage
2. Cricoid cartilage
1st arch muscles give rise to:
Innervated by CN ___
- MOM
- Mylohyoid m
- Anterior belly of digastric m.
- “Two tiny tensors” (tensor tympani and tensor veil palatini mm.)
CN V (Trigeminal)
2nd arch muscles give rise to:
Innervated by CN ___
- Muscles of facial expression
- Stapedius m.
- Posterior belly of digastric m.
- Stylohyoid m.
CN VII (Facial)
3rd arch muscle gives rise to:
Innervated by CN ___
Stylopharyngeus m.
CN IX (Glossopharyngeal)
4th arch muscles give rise to:
Innervated by CN ___
- Pharyngeal constrictor mm.
- Levator veli palatini m.
- Cricothyroid m.
CN X (Vagus)
6th arch muscle gives rise to:
Innervated by CN ___
Intrinsic mm of the larynx
CN X
Pouch 1 Derivatives:
- Middle ear (Middle portion of tympanic cavity and mastoid antrum)
- Pharyngotympanic tube (Eustachian tube)
- Endoderm of tympanic membrane (eardrum)
Pouch 2 derivatives:
Palatine tonsils
Pouch 3 derivatives:
Dorsal buds -> inferior parathyroid glands
Ventral buds -> thymus (fuse at midline)
(These derivatives Migrate caudally -> common ectopic tissue)
Pouch 4 derivatives:
Dorsal buds -> superior parathyroid glands
Ventral buds -> Ultimopharyngeal body -> parafollicular cells (C cells) -> calcitonin
The 1st pharyngeal groove/cleft forms the:
- External acoustic meatus
2. External surface of tympanic membrane
2nd-4th pharyngeal grooves/clefts merge and form the _____
Cervical Sinus -> Cervical vesicle (eventually disappears)
Remnants of a cervical sinus/vesicle or 2nd groove can form a _____ that often develops just below the _____.
Cervical (Branchial) Cyst (fluid filled)
(Cyst that leads to opening -> fistula)
Angle of the mandible
The _____ develops between what will be the anterior 2/3 and posterior 1/3 of tongue
Foramen Cecum
The median lingual swelling and 2 lateral lingual swellings develop at the level of the ____ arch to form the ______ of the tongue
1st
Anterior 2/3
