An individual with normal male habitus, body proportions, and secondary sexual 
characteristics was admitted to the hospital with head trauma. A routine blood 
smear demonstrated that 36% of the granulocytes had "drumsticks". Chromosomal 
analysis revealed a 46,XYqh+ karyotype. the extremely large Y chromosome was 
located by quinacrine fluorescence in the "drumstick" of the polymorphonuclear 
granulocytes. The presence of a large Y chromosome may thus produce 
pseudo-drumsticks. Fluorescent staining can distinguish between true drumsticks 
bearing the inactive X of normal females and the pseudo-drumsticks in a normal 
male produced by a large Y chromosome.