Radiological Interpretation in Neuro-Ophthalmology
Vivek Lal in A Clinical Approach to Neuro-Ophthalmic Disorders, 2023
The ocular movements are determined by CNs III (oculomotor), IV (trochlear) and VI (abducens) through supply of the extraocular muscles, iris muscles and the adjoining region. The nuclei of the oculomotor nerve are located in the mesencephalic periaqueductal region at the level of superior quadrigeminal tubercles. The trochlear nerve nucleus also lies in the mesencephalon, inferior to CN III, behind the medial longitudinal fasciculus (MLF). It innervates the contralateral superior oblique muscles (4–7). The nucleus of the abducens nerve is located in the dorsal pons adjacent to the MLF and in front of the fourth ventricular floor (4–7). The MLF is placed along the anterior side of the mesencephalic aqueduct extending caudally up to the spinal cord. It contains association fibers, which connect the motor nuclei of ipsilateral CN III, IV, CI and XI and each CN VI with the contralateral CN III. It is essential for the o-ordination of horizontal eye and vertical gaze.
Developmental Anatomy of the Pituitary Fossa
John C Watkinson, Raymond W Clarke, Louise Jayne Clark, Adam J Donne, R James A England, Hisham M Mehanna, Gerald William McGarry, Sean Carrie in Basic Sciences Endocrine Surgery Rhinology, 2018
If the bone of the posterior sphenoid sinus is taken down laterally to the anterior sella wall, the anterior aspect of the cavernous sinus is exposed. The prominent anatomical feature is the bulge of the C-shaped curve of the intra-cavernous portion of the internal carotid artery (Figure 54.8a). The nerves in the cavernous sinus are all placed laterally to the carotid artery and the carotid artery needs to be displaced medially in order to identify these (Figure 54.8b). Along the lateral wall of the cavernous sinus the oculomotor, trochlear and abducens nerves may be seen. In addition, the ophthalmic and occasionally the maxillary divisions of the trigeminal nerves may be visible. The oculomotor nerve is large and easily recognizable. It is located superiorly closest to the optic nerve, the trochlear nerve is smaller and is found just below the oculomotor nerve, and the abducens nerve is located more medially and inferior to the carotid artery.19
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
Of course, there are also many similarities between the veins and arteries: There is an inferior thyroid artery branching from the subclavian artery and an inferior thyroid vein usually branching from the brachiocephalic vein; the occipital artery is a posterior branch of the external carotid artery and the occipital vein is a posterior branch of the internal jugular vein; the facial vein gives rise to the inferior labial vein, superior labial vein, and angular vein, and the two major superior branches of the superficial venous system of the head are the maxillary veins and the superficial temporal vein, in a configuration very similar to that seen in the arterial system. Note however that the superior ophthalmic vein and the inferior ophthalmic vein run respectively superior and inferior to the eye, the superior ophthalmic vein anastomosing with the angular vein, which is a branch of the facial vein (Plate 3.22). This anastomosis is clinically important because infections of the nasal cavity, cheeks, forehead, and upper lip can be spread via the facial vein through the angular and superior ophthalmic veins to the cavernous sinus, a dural venous sinus in the base of the cranium, and result in thrombosis of this sinus. This condition affects the abducens nerve and, subsequently, the lateral rectus muscle and the movements of the eye.
Evaluation of clinical, diagnostic features and therapeutic outcome of neurobrucellosis: a case series and review of literature
Published in International Journal of Neuroscience, 2022
Sudipta Patra, Vandana Kalwaje Eshwara, Aparna Ramakrishna Pai, Muralidhar Varma, Chiranjay Mukhopadhyay
The rate of neurobrucellosis was 2.8% (7/244) in our setting. It is commonly observed that there are three major categories of neurological presentation in patients with neurobrucellosis: meningoencephalitis, polyradiculoneuropathy and diffuse involvement [45,69,70]. From the literature review, we found meningitis (32.2%) with or without encephalitis was the most common physical finding. The peripheral form, polyradiculoneuropathy, was found in around 7% of cases. The central form is diffuse CNS involvement, predominantly observed as myelitis (2%), central nerves (6.5%) or cerebellar involvement (1%). The involvement of various parts of the CNS has been reported in the literature [1,5,6]. Cranial nerve palsies in neurobrucellosis usually resolve completely with the proper administration of antibiotics, whereas those with chronic CNS infections often have permanent neurological deficits [2,12,18]. Partial or permanent hearing loss after Brucella infection was previously reported and cochlear implantation was found to be the best intervention in these patients [10,14]. It was also advised to start the treatment as soon as possible to prevent irreversible ear damage [2,5,10]. Besides the loss of hearing, ophthalmic complications in neurobrucellosis are not as rare as expected. Impaired vision due to optic nerve atrophy and abducens nerve palsy was also observed among 8% cases of neurobrucellosis [12,17,52].
Cranial nerve palsies due to incidental durotomy in lumbar Spine surgery: a case report
Published in British Journal of Neurosurgery, 2020
Thea Overgaard Wichmann, Sanja Karabegovic, Mikkel Mylius Rasmussen
On the 8th postoperative day he presented as an emergency with diplopia, reduced hearing on the left ear and reduced sensitivity on the left cheek corresponding to the mandibular and maxillary branch of the trigeminal nerve. The headache, nausea and tinnitus had disappeared. Ophthalmological examination found bilateral abducens nerve palsies. The diplopia was treated conservatively with an eye patch on the left eye. A MRI of the brain and laboratory test showed no abnormalities. A third MRI of the lumbar spine showed a small progression of the pseudomeningocele at L4/L5 (Figure 1(b)). Since the most likely cause for the patients’ symptoms was the ID, the patient was scheduled for revision surgery 11 days postoperatively with the aim to close the suspected dural fistula. The procedure was successful with drainage of the pseudomeningocele and closure of the fistula. Postoperatively the patient was treated conservatively with bed rest for 72 h. Four weeks after the revision surgery the patient underwent ophthalmological examination. The diplopia had spontaneous resolved during the latest weeks and clinical examination revealed a minor right-sided subfunction of the abducens nerve. At 3 months follow-up there was complete resolution of the diplopia and a fourth MRI of the lumbar spine showed regression of the pseudomeningocele (Figure 1(c)). A follow-up detailed MRI of the brain failed to reveal any anatomical abnormalities (Figure 2).
Trigeminal schwannoma: a single-center experience with 43 cases and review of literature
Published in British Journal of Neurosurgery, 2021
Mingchu Li, Xu Wang, Ge Chen, Jiantao Liang, Hongchuan Guo, Gang Song, Yuhai Bao
Among the 43 patients, the tumor was totally removed in 39 patients (90.7%) and near-totally removed in three patients (7.0%). In one patient (2.3%), the tumor was only partially removed, because the ICA was injured, and the patient died after the operation. The abducens nerve was damaged in two patients (4.7%), and the nerve function achieved a significant improvement during the follow up. One patient developed mild facial paralysis and two patients developed intracranial infection after the operation. However, all of them achieved complete recovery before discharge. All four patients with trigeminal neuralgia achieved total recovery. However, the facial numbness got relief in only four patients, and this still continued in 24 patients (85.7%). In two patients, facial numbness even aggravated after the operation. For the nine patients with preoperative trigeminal motor impairment, the symptom did not achieve relief in any patient. Patients with oculomotor nerve paralysis, abducent paralysis and hearing decrease also achieved significant improvement during the follow-up. At a median of 45.3 ± 25.5 months (6–84 months) of follow up, the tumor recurred in only one patient, and this patient received a second operation via FTSA. The surgical results and follow-up results are shown in Table 4.
Related Knowledge Centers
- Abducens Nucleus
- Fourth Ventricle
- Lateral Rectus Muscle
- Oculomotor Nucleus
- Cranial Nerves
- Extraocular Muscles
- Gaze
- Somatic
- Efferent Nerve Fiber
- Facial Colliculus