Facial Paralysis in Children
John C Watkinson, Raymond W Clarke, Christopher P Aldren, Doris-Eva Bamiou, Raymond W Clarke, Richard M Irving, Haytham Kubba, Shakeel R Saeed in Paediatrics, The Ear, Skull Base, 2018
The geniculate ganglion has a separate origin from the facial nerve.6 It is well defined by the seventh week and gives rise to the sensory roots that form the nervus intermedius. As the main facial trunk descends down the second branchial arch there is caudal movement of the first arch due to rapid expansion, producing the horizontal segment and the first and second genu of the vertical nerve with the greater superficial petrosal nerve acting as an anchor. Proctor and Nager’s seminal papers7,8 describe the many variations encountered in the vertical segment of the facial nerve including a bipartite nerve, an anteriorly displaced nerve or one with a posterior hump. Failure to appreciate an anomaly of the facial nerve during surgery can have serious consequences.9–12 Conditions related to malformations of the first or second arch such as Treacher Collins and Goldenhar syndromes will usually mean that the facial nerve is abnormal too.
Head and Neck
Rui Diogo, Drew M. Noden, Christopher M. Smith, Julia Molnar, Julia C. Boughner, Claudia Barrocas, Joana Bruno in Understanding Human Anatomy and Pathology, 2018
The facial nerve (CN VII) follows a complicated course through the temporal bone, giving off several branches (Plate 3.16; described in detail in Section 3.3.1.7). It enters the internal auditory meatus and performs a hairpin turn behind the cochlea. At the anterior point of the turn, the geniculate ganglion is found. This is a sensory ganglion, whose axons carry information from the taste receptors of the anterior tongue and from the skin of the external auditory meatus. A branch of the facial nerve projects anteriorly from the geniculate ganglion, forming the greater petrosal branch of the facial nerve. These fibers emerge from the tegmen tympani of the temporal bone into the middle cranial fossa, and join the deep petrosal nerve to form the nerve of the pterygoid canal (Vidian nerve). They are preganglionic fibers running to the pterygopalatine ganglion. The next branch is the chorda tympani, which passes between the incus and malleus near the tympanic membrane and then exits the temporal bone through the petrotympanic fissure, just posterior to the mandibular fossa, to join the lingual nerve. The third branch goes to the stapedius muscle in the middle ear. The rest of the facial nerve is entirely motor and exits the temporal bone through the stylomastoid foramen.
Head, neck and vertebral column
David Heylings, Stephen Carmichael, Samuel Leinster, Janak Saada, Bari M. Logan, Ralph T. Hutchings in McMinn’s Concise Human Anatomy, 2017
The facial nerve leaves the brainstem at the junction of the pons and medulla to enter the internal acoustic meatus and run to the genu (bend), where the geniculate ganglion is located, before passing through the facial canal within the temporal bone, lying medial to and then behind the middle ear. It then emerges through the stylomastoid foramen without its sensory and autonomic fibres, which branch off between the dura and this skull foramen. (The sensory fibres for taste, with cell bodies in the geniculate ganglion, leave just proximal to this foramen, cross the tympanic membrane and leave through the small petrotympanic fissure before the chorda tympani crosses to join the lingual nerve, p. 66).
Minimally invasive endoscopic removal of primary inner ear schwannomas
Published in Acta Oto-Laryngologica Case Reports, 2021
Safeer Mohammed, Seung Hyun Jang, Dong Hee Han, In Seok Moon
Because of intractable vertigo, she strongly wanted surgical removal and a minimally invasive modified Exclusive Endoscopic Transcanal Transpromontorial approach (mEETTA) was done [10]. Surgical procedures: 1) tympanomeatal flap elevation, all ossicles were removed, 2) facial nerve was demarcated from geniculate ganglion to proximal second genu, 3) transcanal endoscopic drilling of the promontory was done exposing basal turn filled with tumor and drilling continued inferiorly to expose the vestibule, 4) tumor was entirely removed, 5) promontory opening was plugged with soft tissue from tragal area, and 6) a tragal cartilage tympanoplasty was done (Supplement 1). The tumor was removed (Figure 1(B)) and histological diagnosis proved to be consistent with Intra labyrinthine schwannoma. The patient improved symptomatically and well-healed tympanic membrane was observed (Figure 1(C)) on regular follow up.
High-resolution computed tomography temporal bone imaging in achondroplasia
Published in Baylor University Medical Center Proceedings, 2021
Puneet S. Kochar, Priti Soin, Ayah Megahed
HRCT demonstrated upward tilted petrous ridges, giving a characteristic appearance of “towering” petrous ridges (Figure 1a). The IACs were also tilted upwards with an IAC-IAC angle of approximately 126° (normal 165°) (Figure 1b). Secondary to rotation, the orientation of the middle ear ossicle changes gave an appearance of a broader ice cream cone on axial images (Figure 1c, 1d). Bilateral geniculate ganglion had a “vertical” orientation due to rotation of the cochlea (Figure 2a, 2b). The oval windows were facing directly downwards (Figure 2c, 2d). Coronal CT at the level of the scutum demonstrated a downward-pointing scutum projecting inferior to the promontory (Figure 3a). The Körner septum was rotated horizontally (Figure 3b). Additionally, because of changes at the skull base, the carotid canals were foreshortened with distal ends approaching the midline (Figure 3c). Instead of being vertical, the proximal ascending portion of the carotid canals were angled medially toward the midline (Figure 3d).
Two pediatric cases of post-traumatic facial paralysis with delayed onset
Published in Acta Oto-Laryngologica Case Reports, 2018
Taku Ito, Hiroki Watanabe, Motomu Honjo, Tomoaki Asamori
Post-traumatic facial paralysis is usually associated with temporal bone fractures, but it can sometimes occur in the absence of radiologically demonstrable bone disruptions [5]. In those cases, microtrauma causing nerve edema can be assumed. Microtrauma would be due to severe traction and stretching of the greater superficial petrosal nerve, potentially leading to the formation of an intraneural hematoma and secondary edema that extends in a retrograde direction along the proximal nerve [6,7]. Neural edema in such a case has the same deleterious effect as that in inflammatory palsy and, therefore, enhanced MRI is sensitive to such nerve edema and can clearly display the nerve itself [8,9]. Moreover, MRI can also show a thickened geniculate ganglion. Even in cases of facial paralysis without any bone fractures seen on CT, MRI can reveal abnormal findings in the geniculate ganglion [9]. Actually, case 2 showed abnormal signal intensity around geniculate ganglion on MRI without apparent bone fractures on CT, which would be helpful in surgical procedure.