Trevaskis (Holiness, Ethics, and Ritual in Leviticus) proposes a chiastic outline of Leviticus 21-22:

Priestly defects (Lev. 21.16-24) 

A. [4 defects] blind, lame, disfigured, an ‘overgrown limb’ (????) (v. 18) 

B. [2 defects] impaired leg, impaired hand (v. 19) 

C. [6 defects] hunchback, withered member, a discolouration of the eye, a ‘scab,’ ‘scurf,’damaged testicles (v. 20) 

Animal defects (Lev. 22.17-25) 

C.’ [6 defects] blind, broken limb, mutilated, seeping sores, a ‘scab,’ a ‘scurf’ (v. 22) 

B.’ [2 defects] an ‘overgrown limb,’ a stunted appendage (v. 23) 

A.’ [4 defects] bruised, crushed, torn, cut-off testicles (v. 24) 

Among other things, the numerology is worth noting: Not only are there twelve defects listed for both groups (twelve - get it??), but they are listed in symmetrically - 4/2/6//6/2/4.