Sentences with phrase «foramen magnum»

In classical CM, the cerebellum and medulla herniate into or through the foramen magnum.

Cerebellar volume is potentially a key factor in determining the degree of obstruction and interference in normal CSF flow through the foramen magnum, which disposes dogs to the subsequent development of SM.

Dogs with round cerebellum shape and no evidence of narrowing or obstruction of the CSF channels were defined as unaffected, dogs with indentation of the cerebellum by the supraoccipital bone and a narrowed but not obstructed CSF channel (signal consistent with CSF between the caudal vermis and the foramen magnum) were defined as mild CM and dogs where the cerebellar vermis is impacted into or herniated through the foramen magnum were defined as affected.

This has been attributed to high - velocity jets of CSF caused by obstruction of the foramen magnum by the herniated portion of the cerebellum and overcrowded brain parenchyma in the caudal occipital region [5] which is hypothesised to set up a hydrostatic pressure differential between the spinal cord and subarachnoid space and results in the accumulation of perivascular fluid which eventually forms a syrinx [9].

Our results show that in CKCS the Cerebellum is more crowded in the caudal CCF than in small breed dogs and Labradors, supporting the theory that CM is due to descent and herniation of the cerebellum through the foramen magnum.

Occipital dysplasia (i.e. widened foramen magnum) also may be seen [29]; however this is probably an acquired condition due to overcrowding of the caudal cranial fossa, mechanical pressure from the cerebellum and supraoccipital bone resorption [30].

CM is characterised by foramen magnum cerebellar herniation [5], [6] and occurs in approximately 95 % of the CKCS population [7].

The term craniovertebral junction refers to the bony structures surrounding the medulla oblongata, the cervicomedullary junction and the upper cervical spinal cord and is constructed of the occipital bones forming the foramen magnum, the atlas and the axis.

It has also been noted on post-mortem examination of CKCS and other small breed dogs that the supraoccipital bone overlying the cerebellar vermis is remarkably thin and sometimes eroded so that the foramen magnum is enlarged dorsally [23], which could indicate that there has been substantial bone resorbtion.

Both conditions are characterized by increased proximity of the cranial cervical spine to the base of the skull [25]; however a defining characteristic of human basilar invagination is invagination of the odontoid process of the axis through or towards the foramen magnum, often with compression of the neural tissue by the dens [25].

Mechanically the craniocervical junction consists of a central pivot (basioccipital bone, dens and axis) and two rings (foramen magnum and atlas).

Arnold — Chiari malformation is a complex malformation of the caudal brain stem and cerebellum and typically consists of herniation of cerebellar tissue through the foramen magnum into the cervical spinal canal.

The malformation is comparable to the Chiari type I malformation described in people and includes a congenital malformation of the occipital bone, resulting in a crowded caudal fossa and cerebellar herniation at the foramen magnum.

At the bottom of the skull, there is a large hole called the foramen magnum.

When the lower lobe of the brain, the cerebellum, is displaced to the level of the foramen magnum (mild CM) or through the foramen magnum (severe CM) there is overcrowding in the foramen magnum.

The brain may push through the hole at the base of the skull (known as the foramen magnum).

The foramen magnum allows the brainstem to exit the skull and become the spinal cord.

In this procedure, a caudal occipital craniectomy + / - dorsal laminectomy of C1 is performed to decompress the spinal cord and cerebellum at the level of the foramen magnum, aid the flow of cerebrospinal fluid (CSF) and slow the progression of the syrinx.

This is the most common form of obstruction of the foramen magnum, which is the hole in the base of the skull through which the spinal cord passes.

We can describe magnetic resonans imaging findings as a narrow subarachnoid space in cervicomedullar junction, occipital bone compression on caudal cerebellum, rostral movement of caudal cerebellum, syringomyelia, cerebellar herniation from foramen magnum and kinked appearance of caudal medulla.

Durotomy and marsupilization of dura to the muscular structures around the foramen magnum window is the common procedure but cerebrospinal fluid leakage can cause an inflamation and this inflamation can lead severe soft tissue thickening which can cause compression in the area.

T2 and T1 weightened midsagital and transversal images of the foramen magnum, caudal occipital fossa and cervical spinal cord will show syringomyelia.

In normal dogs CSF move from cerebral subarachnoid space to cervical spinal subarachnoid space through foramen magnum in every sistom and diastol in a pulsative manner.

Lateral borders of the window are atlantooccipital joints and lateral vertebral foramens of atlas, rostral borders are midpoint of the distance between protuberentia occipitalis and dorsal border of foramen magnum, caudal border is 3/4 of atlas.

In this MRI image of a Cavalier with Syringomyelia you can see the hindbrain poking down through the foramen magnum, clear overcrowding of the cranial structures, and brainstem «kinking».

SM occurs secondary to obstruction of cerebrospinal fluid (CSF) especially if that obstruction is at the foramen magnum.

When part of the cerebellum is located below the foramen magnum, it is called Chiari malformation.

The clinical improvement is probably attributable to improvement in CSF flow through the foramen magnum.

CMs may develop when the bony space, caudal occipital bone, is smaller than normal, causing the cerebellum and brain stem to be pushed downward into the foramen to the level of the foramen magnum (mild CM) or through the foramen magnum (severe CM) into the upper spinal canal.

In some cases scaring and fibrous tissue adhesions over the foramen magnum seem to result in re-obstruction and 25 % to as many as 50 % of cases can eventually deteriorate.

The foramen magnum is a funnel - like opening to the spinal canal at the bottom of the skull.

In the instance of CM / SM the cerebellum and medulla extend into or through the foramen magnum which is occluded with little or no CSF around the neural structures.

The most common procedure for Chiari like malformation is suboccipital decompression where the hypoplastic occipital bone and sometimes the cranial dorsal laminae of the atlas are removed (with or without a durotomy) to decompress the foramen magnum.