SURGICAL ANATOMY of the EAR Fatthi Abdel Baki

SURGICAL ANATOMY of the EAR Fatthi Abdel Baki MD 2019 - 2020

Inner Ear External Ear Middle Ear Cleft

External Ear Auricle (Pinna) External auditory canal

External Ear Auricle • Cartilage • Concha • Tragus • Helix • Absent in 2 areas: • Lobule • Trago-helix Incisura

External Ear APPLIED ANATOMY Auricle Trago-helix Incisura End-aural incision

External Ear APPLIED ANATOMY Auricle Ear Lobule Fat

External Ear APPLIED ANATOMY Auricle Cartilage

External Ear External Auditory Canal 24 mm Outer 1/3: Cartilage Fissures of Santorini: Ant EAC - Parotid Inner 2/3: Bone

External Ear APPLIED ANATOMY External Auditory Canal S- Shaped Up; out and back

External Ear APPLIED ANATOMY External Auditory Canal Outer 1/3: Hair follicles Inner 2/3: No hair follicles

External Ear External Auditory Canal • • End by • Tympanic Membrane Lined by • Stratified squamous epithelium

Inner Ear External Ear Middle Ear Cleft

Middle Ear Cleft

Middle Ear Cleft Middle Ear Cavity Parts Epitympanum (Attic): Above TM Mesotympanum: Opposite TM Hypotympanum: Below TM

Middle Ear Cleft Middle Ear Cavity Contents Ossicles: 3 Muscles: 2 Nerve : 1&1

Middle Ear Cleft Middle Ear Cavity Contents: Ossicles Head in attic Handle in TM Body in attic Short process Long process From lateral to medial Head 2 crurae Foot plate Smallest bone

Middle Ear Cleft Middle Ear Cavity Contents: Ossicles From lateral to medial

Middle Ear Cleft Middle Ear Cavity Contents: Muscles Stapedius muscle: • Attached to stapes • Supplied by 7 th nerve Tensor tympani tendon: • Attached to malleus • Supplied by 5 th nerve Protects cochlea against high sounds

Middle Ear Cleft Middle Ear Cavity Contents: Nerve Chorda Tympani nerve Injury: Taste problem

Middle Ear Cleft Middle Ear Cavity Contents: Nerve Facial Nerve: Runs in the walls of ME Injury: Facial Paralysis

Middle Ear Cleft Middle Ear Cavity Walls (6)

Middle Ear Cleft Middle Ear Cavity Lateral Wall

Middle Ear Cleft Middle Ear Cavity Lateral Wall Scutum • Upper small bony area • Lateral to the attic

Middle Ear Cleft Middle Ear Cavity Lateral Wall Tympanic Membrane Stretched across medial end of EAC

Middle Ear Cleft Middle Ear Cavity Lateral Wall Outer stratified squamous epithelium continuous with skin of EAC Middle Fibrous layer Incomplete Inner Mucosal Layer continuous with mucosa of ME

Middle Ear Cleft Middle Ear Cavity Lateral Wall Pars Flaccida • Skin • MM Pars Tensa • Skin • Fibrous • MM

Middle Ear Cleft APPLIED ANATOMY Middle Ear Cavity Lateral Wall Cone of light

Middle Ear Cleft APPLIED ANATOMY Tympanic Membrane Myringo

Middle Ear Cleft APPLIED ANATOMY Tympanic Membrane Myringo Tympanic Membrane Perforation

Middle Ear Cleft Middle Ear Cavity Medial Wall

Middle Ear Cleft Middle Ear Cavity Medial Wall Inner ear Middle ear (P)

Middle Ear Cleft Middle Ear Cavity Medial Wall Promontory Bulge of cochlea Basal turn of cochlea (P)

Middle Ear Cleft Middle Ear Cavity Medial Wall

Middle Ear Cleft Middle Ear Cavity Medial Wall Above Promontory Horizontal part of Facial nerve: • Tympanic part or second part • In bony canal Oval window: • Fenestrum vestibuli • Closed by foot plate of stapes

Middle Ear Cleft Middle Ear Cavity Medial Wall Below Promontory Round window: • Fenestrum rotundum • Closed by RW membrane (2 ry TM)

Middle Ear Cleft Middle Ear Cavity Superior Wall MCF (Temporal lobe) Tegmen Tympani Middle Ear

Middle Ear Cleft APPLIED ANATOMY Middle Ear Cavity Superior Wall Temporal Lobe Abscess

Middle Ear Cleft Middle Ear Cavity Inferior Wall Bony plate (thin) separating ME from IJV

Middle Ear Cleft Middle Ear Cavity Inferior Wall Dehiscent Bony plate separating ME from IJV

Middle Ear Cleft Middle Ear Cavity Anterior Wall

Middle Ear Cleft M Middle Ear Cavity Anterior Wall Canal of tensor tympani

Middle Ear Cleft Middle Ear Cavity Anterior Wall Bony plate separating ME from ICA

Middle Ear Cleft Middle Ear Cavity Anterior Wall Bony opening of ET

Middle Ear Cleft

Middle Ear Cleft Eustachian Tube Upper 1/3: • Near ME • Bony m m 36 Lower 2/3: • Near NP • Cartilaginous From Middle ear To Nasopharynx

Middle Ear Cleft Eustachian Tube Bony opening: • Patent Cartilaginous opening: • Potentially closed • Opens on • Yawning • Swallowing

Middle Ear Cleft APPLIED ANATOMY Eustachian Tube Children ET: • Shorter • Wider • More horizontal Infection of Middle Ear is commoner in infants

Middle Ear Cleft Middle Ear Cavity Posterior Wall • Vertical part of facial nerve • Mastoid

Middle Ear Cleft Middle Ear Cavity Posterior Wall Vertical part of facial nerve: • Third part or mastoid part • Bony canal • Exit from stylomastoid foramen

Middle Ear Cleft Middle Ear Cavity Posterior Wall Mastoid

Middle Ear Cleft

Middle Ear Cleft Mastoid Superificial part

Middle Ear Cleft Mastoid Deep part

Middle Ear Cleft Mastoid Antrum: • Largest Mastoid air cell • Deep in mastoid process • Communicates anteriorly with attic (uppermost part of ME) through aditus ad antrum

Middle Ear Cleft Mastoid Aditus ad antrum: • Superiorly • Narrow passage between: • Mastoid antrum & • Attic

Middle Ear Cleft APPLIED ANATOMY Mastoid Canal UP Mastoidectomy

Middle Ear Cleft APPLIED ANATOMY Mastoid Canal Down Mastoidectomy

Middle Ear Cleft APPLIED ANATOMY Mastoid Majority • Air cells Minority : • Diploic (bone marrow) • Sclerotic

Middle Ear Cleft APPLIED ANATOMY Mastoid

Middle Ear Cleft Middle Ear Cavity Function Magnification of sounds Protection of inner ear from high sounds

Middle Ear Cleft Eustachian Tube Function Equalize Pressure Middle & External Ear

Inner Ear External Ear Middle Ear Cleft

Inner Ear Labyrinth Hearing Cochlea Equilibrium Vestibular apparatus

Inner Ear Labyrinth Inner Membranous Outer Bony

Inner Ear Fluid Inner Membranous: Endolymph Outer Bony: Perilymph

Inner Ear Cochlea (P) Two & Half Turns

Inner Ear Cochlea

Inner Ear Stria vascula ris Cochlea Organ of Corti

Inner Ear Stria vascul aris Cochlea Basilar Membrane

Inner Ear Stria vascularis Cochlea Stria Vascularis

Inner Ear Stria vascularis Cochlea Reissner’s Membrane

Inner Ear Vestibular System Semi. Circular Canal (SCC) Vestibule (utricle & saccule)

Inner Ear Vestibular System SCC (3) Angular acceleration

Inner Ear Vestibular System Ampulla Cupula Cristae Ampulla of SCC Cristae ampullaris

Inner Ear Vestibular System Cupula: gelatinous material covering cristae Ampulla Cupula Cristae Ampulla of SCC Cristae hair cells

Inner Ear Vestibular System Vestibule Linear acceleration

Inner Ear Vestibular System Utricle & Saccule Maculae

Inner Ear Vestibular System Maculae of utricle & saccule

Inner Ear Fluid Inner Membranous: Endolymph Outer Bony: Perilymph

Inner Ear Fluid Stria vasc ulari s Endolymph (K+) Formation Cochlea: Stria vascularis Absorption Endolymphatic sac

Inner Ear Fluid Perilymph (Poor K+) Absorption venules Formation CSF

Internal Auditory Canal

Internal Auditory Canal Facial Nerve Vestibulocochlear Nerve

Facial Nerve

Nerve Supply of Ear Auricle (Medial Surface) C 2 & C 3

Nerve Supply of Ear Auricle (Lateral Surface) V X C 2 & C 3

Nerve Supply of Ear External Auditory Canal X V

Nerve Supply of Ear Mucosa of Middle Ear IX

Nerve Supply of Ear Tympanic Membrane V&X IX

Nerve Supply of Ear APPLIED ANATOMY • V: Trigeminal • IX: Glossopharyngeal • X: Vagus • C 2 & C 3 Referred Otalgia

Vasculature