Head & Neck I Flashcards
When do pharyngeal pouches form? How many?
4th-5th weeks of dev
5 pouches
What structure gives off an arterial branch to each pharyngeal pouch as it forms? What are these branches called? Which branch never completely forms?
Aortic sac
Branches are called aortic arches
V never forms
Name adult structure of the following:
1st aortic arch
2nd aortic arch
3rd aortic arch
1st - maxillary artery
2nd - hyoid and stapedial arteries
3rd - common and proximal internal carotid arteries
What 4 embryological structures form the mesenchyme for formation of the head & neck?
- Paraxial mesoderm
- Lateral plate mesoderm
- Neural crest
- Ectodermal placodes
Otic placodes
Otic vesicles, origin of ear and vestibular structures
Lens placodes
Lens of the eye
Paraxial mesoderm
- Floor of brain case
- Small portion of occipital region
- Voluntary muscles of craniofacial region
- Dermis and connective tissue of dorsal head
- Meninges caudal to prosencephalon
Lateral plate mesoderm
Laryngeal cartilages, connective tissue in region of laryngeal cartilages
1st pharyngeal arch: bones
dorsal portion, ventral portion
Dorsal = maxillary: maxilla, zygomatic bones, part of temporal bone
Ventral = mandibular: mandible and bones of middle ear (malleus and incus)
1st pharyngeal arch: muscles
Muscles - mastication (temporalis, masseter, pterygoids), ant belly of digastric, mylohyoid, tensor tympani and tensor palatini
1st pharyngeal arch: nerve
Trigeminal (CN V)
2nd pharyngeal arch: bones
stapes, styloid process of temporal bone, lesser horn and upper part of body of hyoid
2nd pharyngeal arch: muscles
stapedius, stylohyoid, post. belly of digastric, auricular, muscles of facial expression
2nd pharyngeal arch: nerve
Facial (CN VII)
3rd pharyngeal arch: bones
lower part of hyoid
3rd pharyngeal arch: muscles
stylopharyngeus
3rd pharyngeal arch: nerve
Glossopharyngeal (IX)
4th pharyngeal arch: muscles
Cricothyroid, levator palatini, constrictors of pharynx
4th pharyngeal arch: nerve
superior laryngeal branch of vagus
6th pharyngeal arch: nerve
recurrent laryngeal branch of vagus
Origin of thyroid, cricoid, cartilages of larynx
4th and 6th pharyngeal arches
1st pharyngeal pouch
middle ear cavity, eustachian tube
2nd pharyngeal pouch
Tonsillar fossa, NOT lymphatic tissue
3rd pharyngeal pouch: dorsal wing, ventral wing
Dorsal: inferior parathyroid
Ventral: thymus
4th pharyngeal pouch: dorsal wing, ventral wing
Dorsal: superior parathyroid
Ventral: ultimobranchial body (infiltrates thyroid as parafollicular or āCā cells to secrete calcitonin)
1st pharyngeal cleft
Ext. auditory canal
2nd-4th pharyngeal clefts
NOTHING
Which branchial cleft sinus is the most common? Where is the orifice?
2nd - orifice on ant. border of SCM, travels through carotid bifurcation to tonsillar fossa
