Non-traumatic subluxation of the atlanto-axial joint following
peripharyngeal inflammation (Grisel's syndrome) has been attributed to
laxity of the transverse ligament caused by hyperemia, but a satisfactory
anatomical rationale for the association of these conditions has been
lacking. Injection of the cervical epidural sinuses of a series of human
perinatal cadavera showed retrograde filling of a previously undescribed
system of veins with frequent lymphovenous anastomoses. This system appears
to drain the posterosuperior pharyngeal region. Clinical Relevance: Because
of their direct connection with the periodontoidal venous plexus and the
suboccipital epidural sinuses, the pharyngovertebral veins may provide a
hematogenous route for the transport of peripharyngeal septic exudates and
neoplastic cells to the upper cervical spinal structures and provide an
anatomical explanation for the atlanto-axial hyperemia of Grisel's
syndrome.