Endoscopic Anatomy of the Middle Ear

3.6 Stapes seen from below (60° scope).- B 3.7 Roof and medial wall of protympanum (60° scope).- B 3.8 Floor of protympanum and hypotympanum (60° scope).- C Transmastoid approach.- C 1 Through antrum.- C 1.1 Site of approach.- C 1.2 Antrum mastoideum (rigid scope, 4 mm, 0°).- C 1.3 View into mesotympanum from the top down (rigid scope, 2.7 mm, 30°).- C 1.4.1 Incudostapedial joint and anterior tympanic isthmus (rigid scope, 1.9 mm, 30°).- C 1.4.2 Cochleariform process and anterior epitympanic recess (rigid scope, 1.9 mm, 30°).- C 1.5.1 Incudomallear joint and chorda tympani (rigid scope, 1.9 mm, 60°).- C 1.5.2 Stapes and posterior tympanic isthmus (rigid scope, 1.9 mm, 60°).- C 2 Through facial recess (1.9 mm rigid scope).- C 2.1 Site of approach.- C 2.2.1 Tympanic membrane (30° scope).- C 2.2.2 Pyramidal eminence (30° scope).- C 2.2.3 Facial canal (30° scope).- C 2.2.4 Promontory and round window niche (30° scope).- C 2.2.5 Hypotympanum.- C 2.3.1 Round window niche (60° scope).- C 2.3.2 Tympanic ring and tympanic membrane (60° scope).- C 2.3.3 PRUSSAK's space (60° scope).- D Transtubal approach (0.8 mm flexible steerable scope).- D 1.1 Site of approach.- D 1.2.1 View from tympanic opening of EUSTACHIAN tube into mesotympanum.- D 1.2.2 Scope kept straight to approach mesotympanic structures.- D 1.2.3 Scope advanced into central mesotympanum.- D 1.2.4 Scope crosses over stapes (medially to incus) and looks into mesotympanum.- D 1.2.5 Scope between long limb of incus and facial canal: Aditus ad antrum.- D 1.3.1 Scope in mesotympanum bent laterally: Lateral wall of tympanic cavity.- D 1.3.2 Scope in mesotympanum bent laterally and upward: PRUSSAK's space.- D 1.3.3 Scope in mesotympanum bent laterally and downward: Hypotympanum.- D 1.4.1 Scope in protympanum bent upward: Mucosal fold of tensor tympani.- D 1.4.2 Scope advanced: Perforation of mucosal fold of tensor tympani.- D 1.4.3 Scope above tendon of tensor tympani: Incudomallear joint.- D 1.4.4 Scope medial to incudomallear joint: Posterior epitympanic recess.- D 1.5.1 Scope below tendon of tensor tympani: Incudostapedial joint.- D 1.5.2 Scope medial to long limb of incus: Facial canal and lateral semicircular canal.- D 1.5.3 Scope crosses over stapes: Aditus ad antrum.- D 1.6.1 Scope bent laterally and upward behind handle of malleus: Chorda tympani.- D 1.6.2 Scope lateral to long limb of incus: Course of chorda tympani.- D 1.7.1 Scope in the plane of the handle of malleus: Stapes.- D 1.7.2 Scope below incudostapedial joint: Posterior wall.- E Two-port approach (1.9 mm rigid scope, 30° ' 0.8 mm flexible steerable scope).- E 1.1 Transtubal scope crosses above the tendon of the tensor tympani.- E 1.2 Transtubal scope crosses below the tendon of the tensor tympani.- E 1.3 Transtubal scope looks at the ossicular chain.- E 1.4 Transtubal scope looks at the posterior wall.