The evolution of the spinal cord in primates: evidence from the foramen magnum and the vertebral canal

It is important to have a picture of the relationship of the brain and spinal cord to the bones of the skull and vertebral column that house and protect them and the protective layers of connective tissues known as the meninges that cover the CNS; these lie between the bones and brain and spinal cord. The brain is housed within the skull which will be described in much more detail in Section 4 . As you can appreciate by feeling your own skull, the top, front, sides, and back are smoothly curved. The surface of the brain is similarly curved and conforms to the shape of the bones. Note that, in reality, it is really the other way round—brain shape determines the shape of the bones of the skull vault forming the braincase. If the top of the braincase and the brain are removed to reveal the floor of the cranial cavity formed by the bones of the cranial base, it is anything but smooth. Viewed from the lateral aspect and going from anterior to posterior, it is like three descending steps. This structure is shown diagrammatically in Figure 15.1 and shows how different parts of the brain conform to these steps. The first step lies above the nasal and orbital cavities and is known as the anterior cranial fossa ; it houses the frontal lobes of the cerebral hemispheres. The second step is the middle cranial fossa and contains the temporal lobes of each cerebral hemisphere laterally and the midbrain and pons medially. The final step is the posterior cranial fossa where the rest of the brainstem and cerebellum lie. The floor of the posterior fossa is pierced by the foramen magnum through which the medulla oblongata and spinal cord become continuous. The spinal cord occupies the vertebral canal running in the vertebral column. As you can see in Figure 3.5 , in adults, the cord occupies the vertebral canal from the upper border of the first cervical vertebra, the atlas, down to the level of the disc between the first and second lumbar vertebrae.

Download Full-text

Fully automatic 3D segmentation of the thoracolumbar spinal cord and the vertebral canal from T2-weighted MRI using K-means clustering algorithm

Spinal Cord ◽

10.1038/s41393-020-0429-3 ◽

2020 ◽

Vol 58 (7) ◽

pp. 811-820 ◽

Cited By ~ 1

Author(s):

Sahar Sabaghian ◽

Hamed Dehghani ◽

Seyed Amir Hossein Batouli ◽

Ali Khatibi ◽

Mohammad Ali Oghabian

Keyword(s):

Spinal Cord ◽

Clustering Algorithm ◽

3D Segmentation ◽

Vertebral Canal ◽

Fully Automatic

Download Full-text

The structure and development of avian lumbosacral specializations of the vertebral canal and the spinal cord with special reference to a possible function as a sense organ of equilibrium

Anatomy and Embryology ◽

10.1007/s00429-005-0016-6 ◽

2005 ◽

Vol 210 (1) ◽

pp. 59-74 ◽

Cited By ~ 17

Author(s):

R. Necker

Keyword(s):

Spinal Cord ◽

Special Reference ◽

Sense Organ ◽

Vertebral Canal

Download Full-text

Combined partial lateral corpectomy and pediculectomy in a Dachshund

Veterinary Record Case Reports ◽

10.1136/vetreccr-2019-001042 ◽

2020 ◽

Vol 8 (1) ◽

pp. e001042

Author(s):

Koen Maurits Santifort

Keyword(s):

Spinal Cord ◽

Intervertebral Disc ◽

Intraoperative Complications ◽

Intervertebral Disc Herniation ◽

Type I ◽

Analgesic Treatment ◽

Vertebral Canal ◽

Compressive Myelopathy ◽

Progressive Paraparesis ◽

Disc Extrusion

A 5-year-old 8. 2-kg Dachshund was presented with progressive paraparesis and ataxia of several weeks’ duration and signs of pain persisting despite conservative treatment consisting of (cage) rest and analgesic treatment with gabapentin (12.2-mg/kg three times a day) and meloxicam (0.1-mg/kg once a day). Neurological examination was consistent with a T3–L3 myelopathy. CT images showed a mineralised mass in the ventrolateral (right) vertebral canal with severe compression of the spinal cord, taking up >50% of the vertebral canal. An intervertebral disc extrusion (Hansen type I intervertebral disc herniation) with compressive myelopathy was (presumptively) diagnosed. A combination of a partial lateral corpectomy and pediculectomy ('mini-hemilaminectomy') was performed. This surgical approach was deemed best suited to provide adequate access and to remove as much material as possible without compromising the spinal cord. There were no intraoperative complications. Signs did not recur postsurgically, and 2 weeks postsurgery, neurological signs were resolved.

Download Full-text

Achondroplasia Foramen Magnum Score: screening infants for stenosis

Archives of Disease in Childhood ◽

10.1136/archdischild-2020-319625 ◽

2020 ◽

pp. archdischild-2020-319625

Author(s):

Moira S Cheung ◽

Melita Irving ◽

Alessandra Cocca ◽

Rui Santos ◽

Meera Shaunak ◽

...

Keyword(s):

Spinal Cord ◽

Clinical Examination ◽

Reliable Method ◽

Significant Risk ◽

Foramen Magnum ◽

Cervical Cord ◽

Signal Change ◽

Infant Morbidity ◽

Low Sensitivity ◽

Mri Score

BackgroundAchondroplasia is associated with foramen magnum stenosis (FMS) and significant risk of morbidity and sudden death in infants. A sensitive and reliable method of detecting infants who require decompressive surgery is required. This study aims to describe the incidence and severity of FMS in an unselected, sequential series of infants using a novel MRI score and retrospectively correlate severity with clinical examination and cardiorespiratory sleep (CRS) studies.MethodsThe Achondroplasia Foramen Magnum Score (AFMS) was developed and scores were retrospectively correlated with clinical and CRS data over a 3-year period.ResultsOf 36 infants (M:F, 18:18), 2 (5.6%) did not have FMS (AFMS0); 13 (36.1%) had FMS with preservation of the cerebrospinal fluid (CSF) spaces (AFMS1); 3 (8.3%) had FMS with loss of the CSF space but no spinal cord distortion (AFMS2); 13 (36.1%) had FMS with flattening of the cervical cord without signal change (AFMS3); and 5 (13.9%) had FMS resulting in cervical cord signal change (AFMS4). Mean Total Apnea and Hypopnea Index (TAHI) for AFMS0–4 was 3.4, 6.41, 2.97, 10.5 and 25.8, respectively. Severe TAHI had a specificity of 89% but only a 59% sensitivity for AFMS3–4. Neurological examination was normal in 34/36 (94%) patients. Overall, 9/36 (25%) infants required neurosurgery with minimal surgical complications.ConclusionsClinical examination and CRS have a low sensitivity for predicting the effects of foramen stenosis on the spinal cord. Routine screening with MRI using AFMS can aid in detecting early spinal cord changes and has the potential to reduce infant morbidity and mortality.

Download Full-text

Dynamic cervicomedullary cord compression and alterations in cerebrospinal fluid dynamics in children with achondroplasia: review of an 11-year surgical case series

Journal of Neurosurgery Pediatrics ◽

10.3171/2014.5.peds12614 ◽

2014 ◽

Vol 14 (3) ◽

pp. 238-244 ◽

Cited By ~ 19

Author(s):

Debraj Mukherjee ◽

Barry D. Pressman ◽

Deborah Krakow ◽

David L. Rimoin ◽

Moise Danielpour

Keyword(s):

Spinal Cord ◽

Head Circumference ◽

Dynamic Mri ◽

Foramen Magnum ◽

Cine Mri ◽

Csf Flow ◽

Cervicomedullary Junction ◽

Increased Risk ◽

Evans Ratio ◽

Cervicomedullary Compression

Object Achondroplasia may be associated with compression at the cervicomedullary junction. Determining which patients are at greatest risk for neurological complications of cervicomedullary compression can be difficult. In the current study the authors reviewed their records to determine the incidence and clinical significance of dynamic cervicomedullary stenosis and obstruction of CSF flow along with surgical outcomes following posterior fossa decompression. Methods The authors reviewed 34 consecutive cases involving symptomatic children with achondroplasia undergoing cervicomedullary decompression performed by a single surgeon over 11 years. Of these patients, 29 had undergone preoperative dynamic MRI of the cervicomedullary junction with cine (cinema) CSF flow studies; 13 of these patients underwent postoperative dynamic MRI studies. Clinical outcomes included changes in polysomnography, head circumference percentile, and fontanel characteristics. Radiographic outcomes included changes in dynamic spinal cord diameter, improvement in CSF flow at the foramen magnum, and change in the Evans ratio. Results Patients were predominantly female, with a mean age at presentation of 6.6 years and mean follow-up of 3.7 years (range 1–10 years). All patients had moderate to excellent improvement in postoperative polysomnography, slight decrease in average head circumference percentile (from 46.9th percentile to 45.7th percentile), and no subjective worsening of fontanel characteristics. The Evans ratio decreased by 2%, spinal cord diameter increased an average of 3.1 mm, 5.2 mm, and 0.2 mm in the neutral, flexed, and extended positions, respectively, and CSF flow improved qualitatively in all 3 positions. There were no postoperative infections, CSF leaks, or other major complications. None of the patients undergoing initial foramen magnum decompression performed at our medical center required reoperation. Conclusions Patients with achondroplasia and symptomatic cervicomedullary compression have increased risk of dynamic stenosis at the foramen magnum evident upon dynamic cine MRI. Operative decompression may be offered with low risk of complications or need for reoperation.

Download Full-text

Foramen Magnum Arachnoid Cyst Induces Compression of the Spinal Cord and Syringomyelia: Case Report and Literature Review

International Journal of Medical Sciences ◽

10.7150/ijms.8.345 ◽

2011 ◽

Vol 8 (4) ◽

pp. 345-350 ◽

Cited By ~ 8

Author(s):

Haiyan Huang ◽

Yuanqian Li ◽

Kan Xu ◽

Ye Li ◽

Limei Qu ◽

...

Keyword(s):

Spinal Cord ◽

Case Report ◽

Literature Review ◽

Arachnoid Cyst ◽

Foramen Magnum

Download Full-text

Evaluation of epiduroscopy for detection of vertebral canal and spinal cord lesions in dogs

American Journal of Veterinary Research ◽

10.2460/ajvr.77.7.766 ◽

2016 ◽

Vol 77 (7) ◽

pp. 766-770

Author(s):

Fernando L. Garcia-Pereira ◽

Timo Prange ◽

Aaron Seller ◽

Victoria Obert

Keyword(s):

Spinal Cord ◽

Spinal Cord Lesions ◽

Vertebral Canal

Download Full-text

Clinical Indications for Computer-assisted Myelography

Neurosurgery ◽

10.1227/00006123-198301000-00009 ◽

1983 ◽

Vol 12 (1) ◽

pp. 47-47 ◽

Cited By ~ 7

Author(s):

Daniel L. Barrow ◽

James H. Wood ◽

James C. Hoffman

Keyword(s):

Spinal Cord ◽

Pathological Condition ◽

Spinal Dysraphism ◽

Intrathecal Administration ◽

Foramen Magnum ◽

Pathological Process ◽

University Hospital ◽

Primary Study ◽

Computer Assisted ◽

Clinical Indications

Abstract Computer-assisted myelography (CAM) is a technique in which computed tomography (CT) is combined with the intrathecal administration of metrizamide to demonstrate the spinal cord and surrounding structures. This retrospective study of 139 CAMs performed at Emory University Hospital included 125 CAMs that were preceded by routine metrizamide myelography (secondary CAM). The remaining 14 CAMs were primary studies without concomitant myelography. These CAMs and conventional myelograms were reviewed to provide indications for the use of CAM as a replacement for other radiodiagnostic studies or as an adjunct to radiological diagnosis. Eighty-one CAMs (58%) were positive for some pathological process. Of the 69 secondary CAMs demonstrating a pathological condition, 46 (67%) revealed some aspect of the lesion not apparent on routine metrizamide myelography. In no case with positive myelography was CAM negative. However, conventional myelography often added valuable diagnostic information. Although high resolution CT has allowed limited visualization of the spinal cord. CAM is often indicated for cases in which diagnosis requires more definition of cervicomedullary, extradural, intradural, extramedullary, and intramedullary lesions. Our clinical review found CAM to be extremely useful in the diagnostic evaluation of pathological conditions involving the spine and spinal cord and suggests clinical indications for the use of CAM based upon selected illustrative cases. Furthermore, CAM seemed to be superior to other radiological procedures in certain instances, such as in cases of spinal dysraphism and in the evaluation of lesions at the foramen magnum. Until more experience is obtained using spinal CT and CAM, CAM should not replace myelography altogether. The present study indicates that, rather than replacing conventional CT and myelography, CAM should be used as a primary study in situations where it has been shown to be superior and as a complementary study when other neurodiagnostic examinations are equivocal or nondiagnostic.

Download Full-text

Syringohydromyelia in Cavalier King Charles spaniels

Journal of the American Animal Hospital Association ◽

10.5326/15473317-36-1-34 ◽

2000 ◽

Vol 36 (1) ◽

pp. 34-41 ◽

Cited By ~ 101

Author(s):

C Rusbridge ◽

JE MacSweeny ◽

JV Davies ◽

K Chandler ◽

SN Fitzmaurice ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

Spinal Cord ◽

Clinical Signs ◽

Foramen Magnum ◽

Spinal Cord Lesion ◽

Resonance Imaging ◽

Thoracic Limb ◽

Shoulder Region ◽

Inflammatory Drugs ◽

Cord Lesion

Syringohydromyelia secondary to foramen magnum overcrowding is described in seven Cavalier King Charles spaniels. Clinical signs were consistent with a central spinal cord lesion. The most common signs were persistent scratching at the shoulder region with apparent neck, thoracic limb, or ear pain and thoracic limb lower motor neuron deficits. The diagnosis was made by magnetic resonance imaging. The syringohydromyelia is postulated to be a consequence of an occipital bone malformation resulting in a small caudal fossa and cerebellar herniation. Clinical signs improved but did not completely resolve when the dogs received treatment with corticosteroids or nonsteroidal anti-inflammatory drugs.

Download Full-text