Last modified on 11 June 2009, at 20:26

Ossicle/Pediatric

Pediatric and DevelopmentalEdit

ARCHESEdit

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 sublclavian 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