aortic arch/branchial arch/pouch party Flashcards
CAP covers outside to inside
Clefts = ectoderm (also called branchial grooves) Arches = mesoderm (muscles and arteries) and neural crest (bones of skull, cartilage) Pouches = endoderm
2nd-4th cleft form the TEMPORARY cervical sinuses
which are obliterated by proliferation of 2nd arch mesenchyme
persistant cervical sinus –> branchial cleft cyst within lateral neck
Branchial cleft cyst within the lateral neck
- persistant cervical sinus
- should of been obliterated by proliferation of 2nd arch mesenchyme
1st cleft develops into?
external auditory meatus
6th aortic arch derivatives
-proximal part of pulmonary arteries and (on left only) the ductus arteriosus
side note) the ductus arteriousus turns into the ligamentum arteriosum shortly after birth
2nd aortic arch derivative?
Stapedial artery and hyoid artery
Second = Stapedial SSSSSS
4th aortic arch derivative?
on left, aortic arch, on the right the proximal part of the right subclavian artery
4th arch (4 limbs) = systemic circulation
1st aortic arch derivitive?
part of the maxillary artery (branch of external carotid)
1st arch is maximal
side node the middle menegeal artery is a branch of the maxillary artery
3rd aortic arch derivative?
Common carotid
proximal part of the internal Carotid artery
C is the third letter in the alphabet
Congenital pharyngeal cutaneous fistula
-persistance of the celft and pouch of the 2nd branchial arch derivatives
leads to fistula between tonsillar area and lateral neck
-found along anterior border of sternocleidomastoid muscle
Treacher collins syndrome
1st branchial arch derivative neural crest (facial bones, facial cartilage) fails to migrate
- mandibular hypoplasia
- facial abnormalities
5th Branchial arch
makes nothing!
4th-6th branchial arch
Cartilage:
thyroid, cricoid, arytenoids, corniculate, cuneiform
Muscles:
4th arch: most pharyngeal constrictors, cricothyroid, levator veli palatini
6th arch: all intrinsic muscles of the larynx except cricothyroid
nerves:
4th arch: CN X (superior laryngeal branch) - simply swallow
6h arch: CN X (recurrent laryngeal branch) speak
arches 3 and 4 of the branchial arch form
posterior 1/3 of the tongue
1st and 2nd branchial arches form
anterior 2/3 of the tongue
1st branchial arch
MMMMMMMM
cartilage:
meckel, mandible, malleus, incus, sphenomandibular ligament
muscles of mastication:
temporalis, Masseter, laterial and Medial pterygoids
-mylohyoid, anterior belly of digastric, tensor tympani, tensor veli palatini
nerves:
V2 and V3 maxillary and submandibular branches chew
2nd branchial arch derivative
SSSSSSSSSS
Reichert cartilage:
stapes, styloid process, lessor horn of hyoid, stylohyoid ligament
muslces of facial expression:
stapedius, stylohyoid, platySma, belly of digastric
nerves:
VII smilleee
Branchial arch derivative mnemonic
When at a restaurant of golden ARCHES, children tend to CHEW (1) then SMILE (2) then SWALLOW STYlishly (3) or SIMPLY SWALLOW (4) then SPEAK (6)
Branchial 3rd arch
cartilage:
greater horn of hyoid
muscles:
stylopharyngeous
nerve: CN IX swallooowww stylisshhly
pouch mnemonic
ear, tonsils, bottom to top
remember pouches are derived from endoderm
1 ear 2 tonsils 3 dorsal ( bottom for inferior parathyroids) 3 ventral to thymus 4 top = superior parathyroids
4th pouch
dorsal wings-develops into superior parathyroids
missing in digeorge
3rd pouch
dorsal wings develop into inferior parathyroids
ventral wings develop into thymus
note the 3rd pouch structures end up below the 4th pouch structures
missing 3rd pouch in digeorge
1st pouch
develops into middle ear, cavity, eustachian tube, mastoid air cells
-contributes to endoderm line structures of ear
2nd pouch
-develops into epithelial lining of the palatine tonsil
MEN 2A
Square
germline RET mutation (neural crest cells) ras
-adrenal medulla pheochromocytoma
-parathyroid tumor (3/4th pharyngeal pouch)
-parafollicular cells medullary thyroid cancer: derived from neural crest cells, assoc with 4th and 5th pharyngeal pouches
Digeorge syndrom
- bye bye 3rd and 4th pouch
- results in T-cell def due to no thymus
- hypocalcemia due to no parathyroids
- assoc with cardiac defects like conotruncal anomalies
cleft lip
failure of fusion of the maxillary and medial nasal processes (formation of the primary palate)
cleft palate
failure of fusion of the two lateral palatine processes or failure of fusion of lateral palatine processes with the nasal septum and/or median palatine process (formation of secondary palate)
