Paper 2
Amanda Rabone, Benedict Thomson, Nicky Dineen, Vincent Helyar, Aidan Shaw in The Final FRCR, 2020
In terms of clinical relevance, which finding is most important to prioritise in your report?Bilateral regions of parenchymal SWI signal hypointensityCerebellar tonsil positionLeft cerebellopontine angle lesionNew collection adjacent to left frontal lobeRight subdural collection
The management of major injuries
Ashley W. Blom, David Warwick, Michael R. Whitehouse in Apley and Solomon’s System of Orthopaedics and Trauma, 2017
As the pressure rises, the conscious level decreases and the GCS falls. The medial part of the temporal lobe (the uncus) herniates through the tentorial notch, compressing the third cranial nerve and the midbrain pyramidal tracts. This usually results in pupillary dilatation on the side of the injury, and hemiplegia on the opposite side. Pressure changes in the medulla cause a sympathetic discharge, with a rise in blood pressure and reflex bradycardia. With further pressure rise, cerebral blood flow is compromised, and it ceases terminally when the ICP rises above the mean arterial pressure (MAP). Ultimately, the cerebellar tonsil is forced into the foramen magnum, resulting in a loss of vital cardiorespiratory function; this is known as brainstem or brain death, and it is a terminal event.
Balance Disorders 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
Type 1 Chiari malformation is characterized by cerebellar tonsil herniation through the foramen magnum. Children most commonly present with bilateral vocal cord paralysis and associated upper airway obstruction but they can also present with positional vertigo and a central type of nystagmus. The condition can be more severe and associated with syringomyelia, in which case there can be neurological improvement after foramen magnum surgical decompression. Type 1 may present to otolaryngologists.
Craniometrical imaging and clinical findings of adult Chiari malformation type 1 before and after posterior fossa decompression surgery with duraplasty
Published in British Journal of Neurosurgery, 2019
Mehdi Nikoobakht, Hamidreza Shojaei, Peter C. Gerszten, Seyedeh Fahimeh Shojaei, Reza Mollahoseini, Maziar Azar
McRae line length is drawn on a midsagittal MRI from the basion to opisthion. Obex displacement length is measured as the distance from Obex to mid-point of the McRae line. The odontoid height is from odontoid tip to epiphyseal plate of C2. Angle of retroflexion formed between the line drawn from the epiphyseal plate of C2 and its insertion with a line drawn from the odontoid tip. The angle of retroversion is formed between the line drawn from the base of C2 and its insertion with a line drawn from the odontoid tip. The pB-C2 line is drawn perpendicular to the line from the C2 and basion. The length of cerebellar tonsil ectopia is the distance from the caudal extent of the tonsils to the midpoint of the McRae line. The caudal extension of the cerebellar tonsils was determined in relation to the C1 and C2 vertebra. A diagram of these measurements is presented in Figure 1.
Possible predictive clinical and radiological markers in decision making for surgical intervention in patients with Chiari Malformation type 1
Published in Neurological Research, 2022
Ulaş Yuksel, Veysel Burulday, Suleyman Akkaya, Selcuk Baser, Mustafa Ogden, Aslihan Alhan, Bulent Bakar
Linear parameters (Figures 1 and 2) Chamberlain line: the line joining the back of the hard palate with the opisthion.McRae line: the line between the basion and opisthion.Odontoid height: the perpendicular distance between the cephalad and caudal aspect of the odontoid bone.Cerebellum height and length: the perpendicular distance from the most anterior portion of the tentorium to the McRae line; and the perpendicular distance from the posterior portion of the brainstem to the internal protuberance of the occipital bone.Depth of the tonsillar herniation: the perpendicular distance between the tip of the cerebellar tonsil and the McRae line.
The active feedback program: bringing medical students out of the shadows
Published in Medical Education Online, 2021
Matthew A. Edwardson
During my two-week Neurosurgery rotation in medical school I found myself turned into a glorified fly on the wall in a short white coat. I was largely ignored save for fetching compact discs from the Neurosurgeon’s office to play in the operating room. Rarely he asked me anatomy questions like, ‘which part of the cerebellum shares a name with another part of the body?’. I could not answer, ‘the cerebellar tonsil!’, because my mind was clouded by an unhealthy fear of authority figures. During an aneurysm coiling procedure a nurse saw how eager I was to get involved and sent me to draw blood from the IV. In the process my head brushed up against the divider separating the patient’s head from the surgical field. To this day I do not know if I broke the sterile field. My only feedback was a searing glance from the attending Neurosurgeon filled with disgust and contempt. Little did I know that my Neurosurgeon was battling 2 unseen enemies that likely prevented him from providing the mentorship and feedback I desperately needed during the rotation.
Related Knowledge Centers
- Brain Herniation
- Cerebellar Hemisphere
- Cerebellar Vermis
- Cerebrospinal Fluid
- Flocculonodular Lobe
- Foramen Magnum
- Medulla Oblongata
- Uvula of Cerebellum
- Chiari Malformation