No part of the body grows after death. The appearance of continued growth in hair and fingernails is an illusion. This is because the rest of the body dehydrates after death, causing the skin to retract, making the hair and nails seem longer.
The Misconception of Post-Mortem Growth
For centuries, people believed that hair and fingernails continued to grow after death. This is due to a visual illusion resulting from dehydration of the body. As the body loses water after death, the skin shrinks, creating the illusion of growth in hair and nails. This is explicitly stated in one of the provided references.
Organ Regeneration vs. Post-Mortem Growth
It's important to distinguish between organ regeneration during life and any growth after death. The liver, for example, possesses a remarkable ability to regenerate itself after damage, even recovering from the loss of up to 90% of its tissue. This is supported by research from the National Institutes of Health. However, this regenerative capacity ceases upon death.
Other tissues, like cartilage in the ears and nose, continue to grow slowly throughout a person's life. This is mentioned in one of the provided Quora responses. But again, this growth stops after death.
Cancer: A Special Case
While not growth in the traditional sense, cancer cells can continue to divide and proliferate even after the death of the host, though this is not the growth of an organ. This is why cancer can sometimes recur after treatment, even if seemingly eradicated. This point is made in several references discussing cancer recurrence, (https://www.cancerresearchuk.org/about-cancer/what-is-cancer/why-some-cancers-come-back).
