Techniques of Maceration
The interest in maceration, in the anthropological perspective, began in the 19th century. Over the following century the largest ambitious endeavor was the maceration of thousands of individuals, this collection is known as the Hamann-Todd Collection (Dawnie 11). Maceration according to the Merriam-Webster Dictionary is, “to cause to become soft or separated into constituent elements by or as if by steeping in fluid”. Maceration is a form of controlled putrefaction done by forensic anthropologist and, occasionally, some medical examiners. Forensic investigators often recover a body too badly decomposed for any use in of an autopsy. Often there is still enough flesh remaining to obscure macroscopically visible evidence, such as cut-marks, making maceration needed. Medical examiners and forensic anthropologist are often faced with the difficulty of removing soft tissue from the human skeleton without damaging the bones, teeth, and sometimes cartilage. Methods that use chemicals are fast yet destructive to bone. Safer methods can require more time and labor. Cost, also plays a factor in the available resources used in different maceration techniques. Finding a method that is both cost-effective while not being harmful to the bones, or too time-consuming is a challenge. While there is a struggle to find the standard maceration method, many various methods today are being used in hopes of finding the best technique.
The University of Arizona created a three-step procedure when the Human Identification Laboratory still existed. This safe and inexpensive non-bleaching three stage cooking method for removing tissue to recover bone was developed over 30 years (Todd 1). Many argue that with regard to the overall time it takes this method to work, including degreasing the specimen, that it might be the most efficient method in skeletal preparation. One main interest is in learning the effects different chemicals have on the human skeleton. In the article, The Effects of Household Corrosive Chemicals on Human Dentition, this paper discusses the effects eight different household chemicals have on human teeth. One of the most common methods to identify human skeletal remains is through antemortem and postmortem dental records. A murders goal when destroying evidence is to destroy all of the important parts that can be identified. So the goal of this article is to help start research in this area of identifying which chemicals cause which kind of damage. Some chemicals can start to destroy bone in as little as one hour. Corrosive chemicals such as hydrochloric acid, sulfuric acid, phosphoric acid, and sodium hydroxide, not only macerate but also destroy the bone at a very fast rate. This type of maceration and destruction can leave anthropologist and medical examiners with little or nothing at all, when trying to identify human remains.
There are a large number of maceration recipes, but can be grouped into six basic categories; cold water bacterial maceration, warm water bacterial maceration, maceration via cooking, chemical maceration, enzymatic maceration and invertebrate maceration (Dawnie 13). If the funding and land is available another option is to allow the remains to decompose/putrefy naturally. Different pH levels in the soil will play a role in how fast a body is decomposed aiding in the maceration time.
Whether to use bleach or not is a controversial topic. Many say that if the remains are carefully monitored then there is no need to dilute the bleach. However many results have shown that bleaching bone can be potentially damaging and inhibit DNA extraction. Bleach, “attacks and oxides the protein bond in bone causing the hard tissue to break apart, particularly effective for removing soft tissue such as muscle, tendons, and ligaments from small sections of bone (Robert 441).” For many medical examiners bleach has, “proven to be a safe quick and effective way to examine cartilage and remove soft tissue from delicate bones such as the hyoid, turbinates, and fractured maxilla without having to use force...the speed associated with bleaching provides a means to examine and document skeletal evidence at autopsy in case where the specimen cannot be retained but must be released with the body (Robert 440).” Many times, time is against science and a fast and safe way of maceration is desperately needed.
The basic triad of flesh removal, drying, and degreasing, is the basic formula of maceration used today. Enzyme macerations are almost odorless and can be useful in an educational institution and small private conservation workshops. When using water soaking to macerate, water from previous macerations can be added to speed up the process. In the article A Fast Preparation of Skeletal Materials Using Enzyme Maceration, Dr. Simonsen found that, “enzyme maceration using a dilute aqueous mixture of protease and lipase can be performed within hours.” Other enzymes can come from various sources such as papain from papaya fruit, and pancreatin (Kim 484). Enzyme maceration can be completed in one to three hours compared to the traditional warm water maceration method, which can take many weeks. Dermestid beetles and other invertebrate species are also useful in macerating skeletal remains. Also these beetles are only interested in dried tissue and can take weeks to completely consume the soft tissue. The downfall to dermestid beetles is that the upkeep can be difficult and expensive. They can also live within the bone for weeks requiring extreme temperature treatment, alcohol baths or several weeks of quarantine to eliminate all the insects from the specimen (Dawnie 15). Tenebrionid beetle larvae or mealworms can also be used. These worms are cheap and much easier to upkeep. There is also no risk with infestation.
While there are several types of methods used in maceration, there is no silver bullet for all situations. Choosing an appropriate skeletal preparation method depends on the preparator’s goal, and the amount of time available. Each maceration technique has its own strength and weakness. Bleach can clean and whiten bones needing to be used for a museum or other display. However it isn’t practical in the use examination. Forensically bleach will hinder the examination of the bones and cause cortical exfoliation. Cooking bones can cause distortions and warp them, causing permanent damage that can remove or mask evidence or trauma such as cut marks. Boiling can cause teeth and bones to scorch, split, and crack if done to rapidly. Hydrogen peroxide and enzymatic laundry detergent can also alter the cortical surface and leaves the bones chalky (Dawnie 15). Also complete loss of fats would cause bone to become brittle and unstable. Dangers of using sharp instruments can cause pseudo-trauma and may require explanation in a judicial setting. No matter which method is use close attention is needed so no damage is done to the specimen. Constant monitoring is also required with any maceration. Some macerations need to be stirred constantly or new chemicals added every other hour. Finding a fast and safe method produces durable, high quality skeletal specimens for analysis, documentation, and curation (Todd 3).
“Forensic anthropologists and medical examiners routinely macerate human bone for the purpose of identity and trauma analysis, but heat and chemical treatments used can destroy genetic evidence” (Esther 1032). Maceration if done improperly cannot only destroy genetic evidence but also as mentioned above create pseudo-trauma. DNA testing is essential in human identification, particularly from skeletal remains. If DNA is destroyed then the case is hindered severely. Skeletal markers and or identification tools would then be needed if maceration were to destroy all DNA. After maceration takes place forensic anthropologist will then be able to complete a biological profile on the remains. The amount of time maceration can take is unknown. Each and every maceration has different variables, and therefore different techniques needed.
In the labs of Western Carolina University maceration is also completed in several different ways. The amount of tissue that remains on the bone is observed and a plan is made on which techniques will be used. Safety is always a concern when using any technique. Goggles and gloves must be worn at all times. Long hair and clothing must be restrained or pulled back. Heating techniques that are use are, microwaves, incubators, hot plates, and large vats. Large vats are typically used for long bones, skull, thorax, and os coxae. Heating plates are used for little bones of the hands and feet, which can be boiled down much quicker. Dawn, meat tenderizer, borax, and bleach aid in the maceration process. Tools that are used down in the lab are usually simple tools such as bamboo or wood skewers, toothbrush, and occasionally scissors. Metal tools are very rarely used to avoid any pseudo-trauma. Strainers and shifts are used in draining and making sure that no bones are lost. In infants and young animals, knowledge of bone growth and fusion is critical. In infused bones all the epiphyses will need to be recovered. Currently the use of Drano is the new technique being tested down in the lab. Many experiments are tested on pigs and bears to prevent any damage to a human skeleton. Biochemically and size wise pigs are the closest to decomposing like a human. Pigs are also easily accessible. Animals with fur decompose differently then humans. After maceration is complete a full skeletal analysis is completed on the human skeleton.
The methods and techniques of maceration will continue to expand and become greater in perfection over the years. Further research of maceration techniques will be adapted and passes on into the fore. Higher quality maceration techniques will allow for greater understanding of macroscopic evidence and materials.
Maceration is becoming more popular field of work as shown in the amount of research that is being put into this topic. More and more articles and research on maceration, is being accredited and submitted through the American Academy of Forensic Sciences. Maceration is an important tool in forensic cases. Maceration allows medical examiners and forensic anthropologist to work together on particular cases. This union of expertise will continue to increase the knowledge of maceration techniques and procedures
Darcy, C., & Tosha, D. (2009). The effects of household corrosive chemicals on human dentition. (Vol. 54.6, pp. 1238-1246). Journal of Forensic Sciences.
Todd, F., Walter, B., & Jered, C. (2003). A fast and safe non-bleaching method for forensic skeletal preparation. (Vol. 48.1, pp. 1-3). Journal of Forensic Sciences.
Esther, L., Jennifer, L., Jamie, A., Carolyn, A., Andrew, M., & Dawnie, S. (2010). The effects of different maceration techniques on nuclear dna amplification using human bone. (Vol. 55.4, pp. 1032-1038). Journal of Forensic Sciences.
Merriam-Webster. Merriam-Webster, n.d. Web. 28 Oct. 2013. .
Robert, M., & Huge, B. (2012). A method for defleshing human remains using household bleach. (Vol. 57, pp. 440-442). Journal of Forensic Sciences.
Kim, S., Arne, R., Pernille, M., Henriette, P., & Flemming , B. (2011). A fast preparation of skeletal materials using enzyme maveration. (Vol. 56.2, pp. 480-484). Journal of Forensic Sciences.
Dawnie, S., Lisa, D., Jeremy, W., Kevin, S., & Steven, T. (2006). The effects of chemical and heat maceration techniques on the recovery of nuclear and mitochondrial dna from bone. (Vol. 51.1, pp. 11-17). Journal of Forensic Sciences.