In complete dominance, only one allele in the genotype is seen in the phenotype. In codominance, both alleles in the genotype are seen in the phenotype. In incomplete dominance, a mixture of the alleles in the genotype is seen in the phenotype.
When there is either a partial or complete tearing on ligaments that are responsible for supporting the joint of the ankle then it causes an ankle sprain.
Based on the exam findings as well as the loss in functionality of the ankle, an ankle sprain can be categorized as grade I, II or III.
In the given situation the 14-year-old girl has a grade II ankle sprain which is characterized by an incomplete tear of the ligaments along with moderate pain (as she rates it 5/10), moderate tenderness, loss of range of some functions, and swelling.
All of the characteristics of the sprain resemble those of the grade II ankle sprain tear and hence, it is characterized as a grade II ankle sprain.