Ossicle/Pediatric
< Ossicle
Pediatric and Developmental
[edit | edit source]ARCHES
[edit | edit source]Pinna forms from 6 hillocks: 1-tragus, 2-helical root, 3=helix, 4=antihelix, 5=antitragus, 6=lobule
Middle Ear & External Auditory Canal
- 1st branchial groove migrates inward forming EAC
- 1st and 2nd pouch migrate to form ME (where they meet is TM)
- Tympanic Membrane: squamous TM=ectoderm, fibrous=mesoderm, mucosal=endoderm
| ARCH | CN Assoc | ARTERIES | MUSCLES | CARTILAGE/BONE |
|---|---|---|---|---|
| FIRST | CN V | -none- | Masticators & Tensors | Meckel's Cartilage, mandible, head of maleus, body of incus |
| SECOND | CN VII | Stapedial | Facial, Stylohyoid, posterior belly Digastric | Reichart's cartilage, manubrium of malleus, long process incus, stapes, lesser cornu hyoid, Part of hyoid body |
| THIRD | CN IX | ICA | Stylopharyngeus | Greater cornu of hyoid, rest of hyoid body |
| FOURTH | CN X (Sup Laryngeal) | L=Aorta R=Subclav | Cricothyroid | Thyroid Cartilage |
| FIFTH | CN X (Recur Laryngeal) | PA's, Ductus | Intrinsic mm of larynx | cricoid, arytenoid, corniculate cartilages |
SECOND BRANCHIAL CLEFT CYST and sinus tract:
- Lateral to IX and XII
- Passes between ICA and ECA
- Ends at medial constrictor or tonsillar fossa
- MOST COMMON
THIRD BRANCHIAL CLEFT CYST and sinus tract:
- Ascends Lateral to CCA
- Passes posterior to ICA
- Superior to XII and Inferior to IX
- Courses medially to peirce lateral thyrohyoid membrane to open into pyriform sinus
Dysphagia Lusoria - Dysphagia from retroesophageal subclavian artery
- Assoc with non-recurrent laryngeal 100%
- From degeneration of Right 4th Arch
Parathyroid Development
- Superior Parathyroid - 4th Arch development; Posterior to RLN & posterior in mediastinum
- Inferior Parathyroid - 3rd Arch development; Anterior to RLN & Anterior in mediastinum