Ans. is 'd' i.e. Pupillary asymmetryRef. William Wilkins Neurosurgery page 2732, 2735Craniovertebral anomalies include congenital & developmental anomalies at the base of the skull and atlantooccipital region. It includes the occipito atlanto axial complexFor the classification of craniovertebral junction anomalies, see at the end of this answer. Symptoms and signs of craniovertebral junction anomalies * Signs and symptoms of craniovertebral junction anomalies reflect the abnormalities and compromise of the following structuresPonsMedullaCervicomedullary junction and upper cervical spinal cordLower cranial nervesCervical nerve rootsVascular supply to the neural structures Pupillary asymmetry usually results due to abnormality of 2nd or 3rd nerve. The 2nd nerve is cortical and 3rd nerve is related to the mid brain so quiet obviously they will not get involved in craniovertebral junctional anomaly.In craniovertebral anomalies there is involvement of so many neurological structures that it presents with confusing neurological picture.A patient with congenital anomaly of craniovertebral junction usually presents with an abnormal physical appearance. Congenital anomalies included in craniovertebral anomalies also include Klippel-Feil syndrome and Down's syndrome.* Findings in Klippel - Feil syndrome isHead cocked to one sideShort neckAbnormally low hairline posteriorlyLimitation of neck movement Some more important facts about craniovertebral junction anomalyMost common neurological symptom is posterior occipital headache that worsens with neck flexion and extension.Myelopathy with involvement of pyramidal tract is also very common symptom associated with craniovertebral anomalyMost common cranial nerve dysfunction is hearing loss Classification of Craniovertebral Junction AbnormalitiesCongenital MalformationMalformations of the occipital sclerotomiesRemnants around foramen magnumClivus segmentationsDens segmentation anomaliesCondylar Hypoplasia and basilar invaginationAssimilation of the atlasOccipital vertebraeMalformations of the atlasAssimilation of the atlasAtlanto axial fusionAplasia or Hypoplasia of the atlasMalformations of the AxisAtlanto axial segmentation failuresDysplasias of the DensDevelopmental and acquired abnormalitiesForamen magnum abnormalitiesForamen stenosis (e.g. achondroplasia, spondylo epiphysial dysplasias).Secondary basilar invagination (e.g. Paget's disease, hyperparathyroidism, osteogenesis imperfecta, osteomalacia, acroosteolysis, rheumatoid cranial settlings).Atlanto axial instabilityErrors of metabolism (e.g. Morquio's syndrome)Infections (e.g. Grisel's syndrome)Inflammatory (e.g. rheumatoid arthritis, regional ilitis, psoriasis, ankylosing spondylitis)Traumatic atlanto axial dislocation atlantal dislocationDown syndromeMalignancy (e.g., chordoma, plasma cytoma, osteoblastoma, neurofibromatosis)Degenerative (e.g. ligamentous disruption at the Cranio vertebral junction.Miscellaneous (e.g. fetal warfarin syndrome, Conradi's syndrome, Goldenhar syndrome, Weaver syndrome)