Ossicle/Pediatric

Pediatric and Developmental ARCHES Pinna forms from 6 hillocks: 1-tragus, 2-helical root, 3=helix, 4=antihelix, 5=antitragus, 6=lobule Middle Ear & External Auditory Canal <li>1st branchial groove migrates inward forming EAC <li>1st and 2nd pouch migrate to form ME (where they meet is TM) <li>Tympanic Membrane: squamous TM=ectoderm, fibrous=mesoderm, mucosal=endoderm ARCHCN AssocARTERIESMUSCLESCARTILAGE/BONE FIRSTCN V-none-Masticators & TensorsMeckel's Cartilage, mandible, head of maleus, body of incus SECONDCN VIIStapedialFacial, Stylohyoid, posterior belly DigastricReichart's cartilage, manubrium of malleus, long process incus, stapes, lesser cornu hyoid, Part of hyoid body THIRDCN IXICAStylopharyngeusGreater cornu of hyoid, rest of hyoid body FOURTHCN X (Sup Laryngeal)L=AortaR=SubclavCricothyroidThyroid Cartilage FIFTHCN X (Recur Laryngeal)PA's, DuctusIntrinsic mm of larynxcricoid, arytenoid, corniculate cartilages SECOND BRANCHIAL CLEFT CYST and sinus tract: <li>Lateral to IX and XII <li>Passes between ICA and ECA <li>Ends at medial constrictor or tonsillar fossa<li>MOST COMMON THIRD BRANCHIAL CLEFT CYST and sinus tract: <li>Ascends Lateral to CCA<li>Passes posterior to ICA<li>Superior to XII and Inferior to IX<li>Courses medially to peirce lateral thyrohyoid membrane to open into pyriform sinus Dysphagia Lusoria - Dysphagia from retroesophageal subclavian artery<li>Assoc with non-recurrent laryngeal 100%<li>From degeneration of Right 4th Arch Parathyroid Development<li> Superior Parathyroid - 4th Arch development; Posterior to RLN & posterior in mediastinum <li>Inferior Parathyroid - 3rd Arch development; Anterior to RLN & Anterior in mediastinum