Retraction ball is seen after injury' to:

Ans: C (Brain) "Concussion of Brain: Microscopic examination does not show axonal injuries up to 12 hours after injury. After 12 hours, the axons first appear dilated, then club-shaped and finally appear as round balls known as 41retraction balls", which indicates transected axons. The number of retraction balls begins to decrease 2 to 3weeks after injury, and clusters of microglial cells appear, followed by astrocytosis and demyelinisation"- Reddy 27th/223Periventricular Leucomalacia Manual of Neonatal Care by John P. Cloheny 6th/514# Found predominantly in preterm infant# Characteristic neuropathology: b/E areas of focal necrosis, gliosis & disruption of axons with the so called "retraction clubs & balls