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Cervical Conundrum

Diagnostic Tests

MRI

An MRI of the brain was performed.

The MRI shows evidence of cerebellar tonsillar descent below the level of the foramen magnum, along with a large syrinx extending well into the thoracic region.

Anatomy and Physiology of the Cerebellum

Within the posterior fossa lies the brainstem, cerebellum and the fourth ventricle. The midbrain is the most rostral structure, and contains the cerebral peduncles. The cerebral aqueduct traverses the midbrain, connecting the third and fourth ventricles. The cerebellum is a bilaterally symmetrical structure, composed of three major lobes: the flocculonodular lobe, the anterior lobe, and the posterior lobe. The three lobes are composed of afferent and efferent fibers connecting the cerebellum with other parts of the central nervous system.

The function of the cerebellum is believed to be responsible for coordination and fluidity of movement. Gait, balance, posture and the execution of volitional, coordinated movements arise from the cerebellum. Disorders of the cerebellum manifest with clinical signs such as ataxia, dysmetria, and dyssynergia.

Objectives

• What is the significance of tonsillar descent?
• What is a syringomyelia? What is the significance of this finding in this patient?
• What is the diagnosis, and how do the symptoms relate to the diagnosis?

Tonsillar Descent

The cerebellar tonsils are thought to be abnormal if there is evidence of caudal displacement of 5mm or more. This abnormal position of the cerebellar tonsils is called Chiari malformation.