Glossary

Posterior Atlanto-Dental Interval.  This is the horizontal distance from the posterior (dorsal) odontoid surface to the anterior (ventral) surface of the posterior arch of the atlas. This measures the  space available for the spinal cord (so-called SAC).  A value of less than 13 mm suggests cord compression.

– aka dorsal midbrain syndrome: Abnormalities in eye movement and pupillary function die to a lesion in the midbrain. The abnormal eye movements associated with this syndrome are paralysis in upgaze, paresis in accommodation with convergence-retraction nystagmus and sunsetting due to retraction of the upper eyelids (sun setting).

pB-C2 line – Also referred to as the Grabb-Oakes line. A line drawn through the odontoid that is perpendicular to a line extending from the posterior basion to posterior-inferior body of C2. The distance of the segment of this line from the anterior edge of the odontoid to the ventral dura represents the degree of encroachment of the odontoid into the upper spinal canal and potential ventral brainstem compression.

Patient controlled analgesia – refers to any method that allows a patient to control their administration of pain medication. Typically the delivery mechanism is set up so that an over-dosage of medication cannot be delivered.

Polymerase chain reaction, a technique that uses a small sample of DNA and quickly makes millions to billions of copies thereby amplifying the initial sample to one large enough to study and identify.

Platelet derived growth factor – A potent mitogen for cells of mesenchymal origin, including smooth muscle cells and glial cells. it plays a significant role in blood vessel formation (angiogenesis) and the growth of blood vessels. This is a prominent feature in the growth of cancerous tumors.

Peabody Developmental Motor Scale.  An assessment tool used on neonates and young children (through 5 years of age) that measures a child’s gross and fine motor skills.  The child’s scores for fine, gross and overall motor development can then be compared to normative data.

Peabody Developmental Measure Scales Edition 2.  An assessment tool used on neonates and young children (through 5 years of age) that measures a child’s gross and fine motor skills.  The child’s scores for fine, gross and overall motor development can then be compared to normative data.

Pediatric Evaluation of Disability Inventory.  A validated testing tool used to evaluate functional abilities and performance in children ages 6 months to 7 years.  It has also been used in children older than seven years of age whose disabilities cause them to function below that expected for a normal seven-year-old child.