Cleft lip is due to the nonfusion of
Human embryology Tenth edition Inderbier Singh Page no:160 Harelip: when one or both maxillary process do not fuse with the medial nasal process, this gives rise to defect in the upper lip. These may vary in degree and unilateral or bilateral
Maxillary process with lateral nasal process
Maxillary process with medial nasal process
Maxillary process with mandibular process
All of the above
General anatomy