Tissue Size: Larger tissues require more fixative to ensure complete penetration. Fixative Type: Different fixatives have varying penetration rates. Formalin, for example, penetrates tissues at approximately 1 mm per hour. Tissue Density: Denser tissues like muscle and cartilage need more fixative than less dense tissues. Temperature: Higher temperatures can enhance fixative penetration but may also accelerate tissue degradation if not carefully controlled.
