OBJECTIVE: To evaluate the safety of the circular round window and discus anatomic landmarks of posterior wall of internal auditory canal by investigating the microscopic anatomy of internal auditory canal area of the retrosigmold approach, which can provide the anatomical basis for acoustic neutrinomas surgery. METHOD: Fifteen adult cadaver heads (30 sides) fixed with formalin were used in the study. The retrosigmold approach operations were imitated to dissect the blood vessels and nerves in internal auditory canal area by opening round bony window and removing posterior wall of internal auditory canal. RESULT: Fifteen specimens of 30 sides circular bone window were opened without injury with transverse sinus and sigmoid sinus. The vertical distance between the highest point of bone window margo superior and the lowest point of transverse sinus margo inferior was (4.02 ± 0.32) mm. The vertical distance from the most anterior point of bone window leading edge to the most posterior point of sigmoid sinus trailing edge was (6.31 ± 0.43) mm. The internal auditory canal tubercle located in the anterior superior position of internal auditory canal. The vertical distance from the highest point of internal auditory canal tubercle to the upper margin of internal auditory canal was (2.31 ± 0.32) mm. To expose the whole internal auditory canal, the length and width of the internal auditory canal posterior wall removal was (7.29 ± 0.32) mm, (4.12 ± 0.29) mm. Within this removal range, no case of cochlea, semicircular canal or venous was injured in 30 specimens. CONCLUSION The method of opening round window through retrosigmold approach is simple, practial and convenient. With little variation and easiness of location, the sinternal auditory canal tubercle can be used in the identification of the internal auditory canal. When exposing the whole internal auditory canal, the removal scope of the posterior wall should be paid more attention to, in order to avoid the damage of cochlea, semicircular canal and jugular bulb.
Adult ; Cranial Sinuses ; Ear Canal ; Ear, Inner ; Humans ; Round Window, Ear ; anatomy & histology ; Semicircular Canals ; anatomy & histology ; Temporal Bone

OBJECTIVE: To observe anatomic structure of jugular foramen region by endoscope, to provide anatomic data for avoiding damnification in the surgery. METHOD: We performed the retrolabyrinthine and retrosigmoid endoscopic surgery on 8 fomalin-fixed adult cadaver specimens and observed the structures of jugular foramen by endoscope and compared the different surgeries at the same time. We excised the calvarium and cereburm and exposured and observed the nerves and vessels. Moreover we measured the the distance from internal accoustic pore to glossopharyngeal and analyse the data by SPSS. RESULT: All retrolabyrinthine endoscopic surgeries were performed successfully. Only 4 postsigmoid endoscopic surgeries were performed without damage of cerebellum which is the major obstacles. The distance from internal accoustic pore to glossopharyngeal was(8.26 ± 1.05) mm. About half of posterior inferior cerebellar arteries located to inboard of nerves. CONCLUSION The jugular foramen region endoscopic surgery can be performed successfully by retrolabyrinthine. The "lockhole" technology by retrosigmoid is more difficult for blocking of cerebella. The internal acoustic porus is a fixed structure of the cerebellopontine angleand a perfect landmark to the surgery.
Adult ; Cadaver ; Endoscopy ; Foramen Magnum ; anatomy & histology ; Humans ; Jugular Veins ; anatomy & histology ; Temporal Bone ; anatomy & histology

OBJECTIVE: To provide the anatomic data for the correlated otologic microsurgery by the microdissection of temporal bone through facial recess approach. METHOD: Sixteen human temporal bones of eight adult cadaveric heads were dissected under surgical microscope through facial recess approach, and the relative anatomic structures were observed and measured, such as the bony entrance of facial recess approach, facial nerve, stapes, round window, round window niche, pyramidal eminence, cochleariform process, etc. The data were analyzed statistically. RESULT: The width of the bony entrance of facial recess approach was (2.94 +/- 0.32) mm, the height was (8.83 +/- 0.84) mm, the depth was (3.51 +/- 0.17) mm. The distances from stapes to tympanic segment of facial nerve, mastoid segment of facial nerve, round window, cochleariform process and anterior ligament of malleus were (1.38 +/- 0.21) mm, (6.94 +/- 0.47) mm, (3.60 +/- 0.55)mm, (2.23 +/- 0.33)mm, (4.93 +/- 0.61) mm, respectively. The distances from pyramidal eminence to tympanic segment of facial nerve, mastoid segment of facial nerve, round window, round window niche and cochleariform process were (1.05 +/- 0.09) mm, (5.63 +/- 0.41) mm, (3.01 +/- 0.34) mm, (3.29 +/- 0.44) mm, (4.13 +/- 0.51) mm, respectively. The distances from round window to cochleariform process and tympanic segment of facial nerve were (5.11 +/- 0.61) mm and (3.97 +/- 0.61) mm. The distances from round window niche to tympanic segment of facial nerve and mastoid segment of facial nerve were (4.13 +/- 0.38) mm and (7.28 +/- 0.29) mm. CONCLUSION The facial recess approach played an important role in modern otologic microsurgery. The position of anatomical structure was constant relatively, including short crus of incus, stapes, pyramidal eminence and cochleariform process, etc. These could be used as reference marks for otologic microsurgery.
Adult ; Ear, Middle ; anatomy & histology ; surgery ; Facial Nerve ; anatomy & histology ; surgery ; Humans ; Microsurgery ; Round Window, Ear ; anatomy & histology ; surgery ; Stapes ; anatomy & histology ; Temporal Bone ; anatomy & histology ; surgery

OBJECTIVE: To investigate the related parameters of temporal bone structure in the surgery of cochlear implantation through facial recess approach so as to offer a theoretical reference for the avoidance of facial nerve injury and the accurate localization. METHOD: In a surgical simulation experiment, twenty human temporal bones were studied. The correlation parameters were measured under surgical microscope. RESULT: Distance between suprameatal spine and short process of incus was (12.44 +/- 0.51) mm. Width from crotch of chorda tympani nerve to stylomastoid foramen was (2.67 +/- 0.51) mm. Distance between short process of incus and crotch of chorda tympani nerve was (15.22 +/- 0.83) mm. The location of maximal width of the facial recess into short process of incus, crotch of chorda tympani nerve were (6.28 +/- 0.41) mm, (9.81 +/- 0.71) mm, respectively. The maximal width of the facial recess was (2.73 +/- 0.20) mm. The value at level of stapes and round window were (2.48 +/- 0.20 mm) and (2.24 +/- 0.18) mm, respectively. Distance between pyramidalis eminence and anterior round window was (2.22 +/- 0.21) mm. Width from stapes to underneath round window was (2.16 +/- 0.14) mm. CONCLUSION These parameters provide a reference value to determine the position of cochlear inserting the electrode array into the scale tympani and opening facial recess firstly to avoid potential damage to facial nerve in surgery.
Anatomic Landmarks ; anatomy & histology ; Chorda Tympani Nerve ; anatomy & histology ; Cochlea ; anatomy & histology ; Cochlear Implantation ; methods ; Ear, Middle ; Facial Nerve Injuries ; prevention & control ; Humans ; Incus ; anatomy & histology ; Organ Sparing Treatments ; methods ; Round Window, Ear ; anatomy & histology ; Stapes ; anatomy & histology ; Temporal Bone ; anatomy & histology ; Tympanic Membrane ; anatomy & histology

There are several studies concerning branches of the facial nerve, but we encountered less information about the trunk of the facial nerve in the literature. During the routine dissection of a 65-yr-old Caucasian male cadaver, double facial nerve trunk emerged from the stylomastoid foramen and petrotympanic fissure were encountered. Because of an extremely rare variation, we presented this case report. In addition this cadaver had two buccal plexuses. These plexuses and other branches were formed to structures like to polygon. These anatomic peculiarities were described, photographed and illustrated. Finally, magnetic resonance imaging was performed by using 1.5T scanner to this cadaver. The facial nerve trunk can be damaged during surgical procedures of the parotid gland tumours and submandibular region. Surgeons who are willing to operate on this area should be aware of the possible anatomical variations of the facial nerve trunk.
Aged ; Cadaver ; Facial Nerve/*anatomy & histology/surgery ; Humans ; Magnetic Resonance Imaging ; Male ; Parotid Gland/innervation ; Temporal Bone/*innervation

OBJECTIVETo study the anatomy of mandibular bone flap pedicled with temporal muscle for midfacial bone defects.

METHODSThe shape and blood supply of the temporal muscle and mandibular ramus, as well as their relationship, were observed and measured in 30 sides of adult head specimens.

RESULTSThe temporal muscle has a fan-shaped main portion, then is scattered into three bundles as anterolateral, anteromedial, posterior bundles, which end respectively at anterior border of ramus, the temporal ridge and posterior portion of coronoid process. Then the muscle goes downward until it reaches the distal side of the third medial surface molar and attaches the 3/4 of medial surface of anterior portion of ramus. The blood supply of temporal muscle includes the medial temporal artery with external diameter of (0.76 +/- 0.20) mm, the anterior deep temporal arteries with external diameter of (0.79 +/- 0.21) mm, posterior deep temporal arteries with external diameter of (0.98 +/- 0.64) mm, the accessory deep temporal artery formed by many little branches. The anterior part of ramus is supplied by the periosteal arteries and the bony perforator of the deep temporal arteries. Rectangular ramus of mandible was divided into anterior portion and posterior portion by the line linking the lowest point of mandibular notch, mandibular foramen and mandibular canal. Anterior portion can supply a bone flap with a size of (46.67 +/- 6.85) mm x (17.98 +/- 2.64) mm x (11.49 +/- 0.99) mm.

CONCLUSIONSThe mandibular bone flap pedicled with temporal muscle has a reliable blood supply and abundant bone volume. It is feasible to design a mandibular bone flap pedicled with temporal muscle for midfacial bone defect.

Adult ; Bone Transplantation ; Female ; Humans ; Male ; Mandible ; anatomy & histology ; surgery ; Surgical Flaps ; Temporal Muscle ; anatomy & histology ; blood supply ; innervation

OBJECTIVE: To study the management of basic parameters related to individual piston shaping on malleostapedotomy by MDST 3D reconstruction and microanatomy and to assess the accuracy of MDST method. METHOD: Ten Chinese temporal bones without ear diseases were numbered randomly and scanned by GE Light Speed Ultra 64 rows of spiral CT. 3D structure of ossicular chain were reconstructed by MPR and VR methods in AW4. 1 workstation. Then measurements of distances between stapes head to stapes footplate (A line), and manubrium to stapes head (B line), and manubrium to stapes footplate (C line), angle between line A and line B (angle AB) are completed. After that, all samples of temporal bone were undergone canal wall down mastoidectomy under microscope and the relevant measurements were completed. RESULT: The MPR and VR technique of MDCT reconstructed ossicular chain clearly, and revealed the spatial relationship between every structure stereoscopically. Respectively, lengths of A, B, C line by MDST and microanatomy are (3.42 +/- 0.86) mm and (3.60 +/- 0.94) mm, (3.42 +/- 0.80) mm and (2.96 +/- 0.42) mm, (5.86 +/- 0.60) mm and (6.22 +/- 1.10) mm, while angle AB (141.05 +/- 30.07) degrees and (144.57 +/- 41.86) degrees. There are no statistically significant differences between two groups (P>0.05). CONCLUSION The MPR and VR technique of MDCT can clearly reconstructed the 3D shapes of the temporal bone and finish the exactly managements on A, B, C lines and AB angel which is crucial for shaping a individual piston on malleus-to-oval window surgery.
Adult ; Ear, Middle ; anatomy & histology ; Female ; Humans ; Image Processing, Computer-Assisted ; Imaging, Three-Dimensional ; Male ; Malleus ; anatomy & histology ; surgery ; Stapes ; anatomy & histology ; diagnostic imaging ; Temporal Bone ; anatomy & histology ; diagnostic imaging ; Tomography, Spiral Computed

OBJECTIVE: To provide the anatomic data for operation on the middle ear through the observation and measurement of related anatomic structure. METHOD: Forty human temporal bones of 20 voluntary bone donors were dissected, relative anatomical data of operation were observed and measured under operating microscope through posterior tympanum approach entering posterior tympanum. RESULT: The average distances from suprameatal spine to short crus of incus, pyramid segment of facial canal were 19.14 mm, 16.30 mm, respectively. The average distances from pyramid segment of facial canal to the surface of mastoid, crotch of chorda tympani nerve, posterior wall of auditory meatus were 20.84 mm, 11.28 mm, 4.40 mm, respectively. The average length of facial nerve in the horizontal segment, the perpendicular paragraph was about 11.60 mm, 15.30 mm, respectively. The average distance from pyramidal eminence to the anterior lip of round window niche, from oval window to round window niche, from incudostapedial joint to round window niche was 4.46 mm, 3.74 mm, 3.80 mm, respectively. The included angle of facial nerve in the horizontal segment and chorda tympani nerve with facial nerve in the perpendicular paragraph was 110.4 degrees, 24.8 degrees, respectively. Horizontal semicircular canal and facial nerve in the level paragraph was 17.5 degrees, long process of incus and incus buttress was 46.0 degrees. CONCLUSION The position of anatomic structure in middle ear was constant and the relationship including distance and angle between anatomic structures changed in limited region. The anatomical parameters provide a reference value for avoiding the injury during the operation.
Adult ; Chorda Tympani Nerve ; anatomy & histology ; Ear, Middle ; anatomy & histology ; surgery ; Facial Nerve ; anatomy & histology ; Female ; Humans ; Male ; Round Window, Ear ; anatomy & histology ; surgery ; Temporal Bone ; anatomy & histology ; innervation

OBJECTIVE: To provide anatomic data for cochlear implantation, and to find the method of locating lamina spiralis (LS) on the surface of promontory. METHOD: Microanatomical study was carried out on 30 sides of human temporal bones by observing and measuring lamina spiralis below promontory, including its location, course and adjacent structures. RESULT: (1) The basal turn of lamina spiralis below promontory can be divided into three segments: the hook segment (1.52 +/- 0.16) mm, the anteroinferior round window segment (3.83 +/- 0.37) mm and the forwarding segment (2.70 +/- 0.36) mm by two hinge points of which one was located at anterior of the junction of superior margin and anterior border of RW, and the other was located at anteroinferior of the round window; (2) The plane of round window anteroinferior segment of LS lay (51.00 +/- 5.97) degrees anteroinferior to horizontal segment of the facial nerve and comparative permanently meet posterior margin of'stapes head. Made posterior margin of stapes head as a fixation point and draw a line on promontory lay (51.00 +/- 45.97) degrees anteroinferior to horizontal segment of the facial nerve. This line can be thought as the projection of anteroinferior round window segment of LS on promontory; (3) The width of scala tympani at cochleostomy site on promontory: width of scala tympani at midpoint of superior margin of round window was (0.36 +/- 0.06) mm; width of scala tympani at midpoint of anterior border of round window was (0.97 +/- 0.14) mm; width of scala tympani at 3 mm point of anteroinferior round window segment was (1.24 +/- 0.21) mm. CONCLUSION (1) The basal turn lamina spiralis below promontory can be divided into three segments (the hook segment, the anteroinferior round window segment and the forwarding segment) by two hinge points; (2) The projection of anteroinferior round window segment of LS and the features exhibited in its course provide reference for locating the basal turn scala tympani and offer reliable anatomical basis for minimal invasive intervention during cochlear implantation.
Adult ; Cochlear Implantation ; methods ; Facial Nerve ; anatomy & histology ; surgery ; Humans ; Round Window, Ear ; anatomy & histology ; surgery ; Scala Tympani ; anatomy & histology ; surgery ; Temporal Bone ; anatomy & histology ; surgery

OBJECTIVE: Through the observation and the measurements of the significant anatomical landmark the lateral skull base, to provide anatomical data of clinical location and navigation for surgery at the lateral skull base. METHOD: Significant anatomical landmarks of twenty adult cadaveric heads (40 sides) fixed in 10% formaldehyde and 20 operation cases (20 sides) had been observed and measured. Lateral skull bases of cadaveric heads were numbered from 1st to 40th, while the operation cases were numbered from 1st to 20th. RESULT: The anatomical data was achieved by measuring related anatomical landmark as follows: the distances between the significant landmark of the lateral skull base and the pars neuraxis, vein of the jugular foramen; the areas of trautmann triangle; post labyrinths triangle and the superficial triangle of processus mastoideus; the maximal distance of initiative displacement of facial nerve in the lateral skull base operations. CONCLUSION The data measured at lateral skull base could effectively help operators not only to enlarge the field of vision in operations with security and to avoid the damagement of the important blood vessel and nerves, but also to retain the function of the facial nerve to the utmost.
Adult ; Female ; Humans ; Male ; Mastoid ; anatomy & histology ; Skull Base ; anatomy & histology ; Temporal Bone ; anatomy & histology