







































Abstract: The current estimation of postmortem interval (PMI) relies on insect succession, state of 
decomposition, and the external microbiome. Therefore, PMI is influenced by external environmental 
conditions, such as climate and scavenger activity. However, the marrow cavity of skeletal elements is 
protected from the external environment and may be used to determine a more accurate estimate of PMI. 
As no published methodology exists for the extraction of marrow from human cadavers over extended 
periods, this study aimed to develop effective and consistent practices for marrow extraction. Three human 
cadavers were placed at the Southeast Texas Applied Forensic Science facility (STAFS) at Sam Houston 
State University. Prior to sampling, experimental protocol was established. However, changes were made to 
accommodate accessibility of the marrow cavity, weather conditions, insect activity, state of decomposition, 
and marrow content of the left and right femur, humerus, and pelvis. The resulting extraction procedure 
involved the use of medical-grade bone marrow biopsy tools and culture swabs in combination with a 
power drill to collect samples from each cadaver. Each sampling location was cleansed with alcohol wipes 
prior to extraction and sealed with glue after sample collection. Samples were collected over a six-month 
period, starting May of 2016. Bone marrow was present in the femur, pelvis, and humerus of each cadaver 
throughout and upon completion of the project.  

Aisthesis      Volume 8,  201742

A Methodology for Extracting Bone Marrow from Cadavers
by Christiana Fakhri, Lauren Rudie, Stephanie Baker, Meredith 
Mann, Sarah Bivens, Laura Spoonire, Nichole M. Ruble

Introduction
 Estimation of postmortem interval, or time since 
death, is a valuable and practical tool used in field of 
forensic sciences. However, an accurate estimation 
of postmortem interval (PMI) is difficult to obtain, 
as the understanding of human decomposition is 
limited. In the past, researchers focused on insect 
succession, gross external changes, and the external 
microbiome to estimate PMI (Hyde, Haarmann, 
Lynne, Bucheli, & Petrosino, 2013).  However, these 
methods are susceptible to external factors, such as 
temperature, scavenger activity, and moisture level 
(Megyesi, Nawrocki, & Haskell, 2005). Recently, 
use of the microbiome associated with human 
decomposition has shown to be a promising 
component of PMI estimation, as bacteria are 
present throughout all stages of decomposition and 
play a catalytic role in the process (Metcalf et al, 
2013). Cataloging the succession of external bacteria 
is promising but complicated by the diversity of 
bacterial strains, number of species present, and the 
influence of environmental conditions (Vass, 2001). 

 Marrow cavities, however, are protected from 
the external environment. While soft tissues have 
variable decay rates and are only present for a few 
weeks or days, skeletal elements persist for weeks 
to months (Megyesi et al., 2005). The longevity of 
skeletal elements, coupled with the protective nature 
of the bone, should allow the bacterial succession 
of marrow to provide a more accurate estimation of 
PMI over longer periods (Schwarcz, Agur, & Jantz, 
2010). 
 While various studies have been conducted 
to catalog external bacterial succession in animal 
carcasses, no known studies have examined human 
marrow containing bones for extended periods 
(Howard, Duos, & Watson-Horzelski, 2010). As 
such, a method for extracting bone marrow is 
needed to undertake a study of bacterial succession 
inside marrow cavities. Therefore, this study seeks to 
establish a protocol for the effective and continued 
extraction of marrow from the humerus, femur, and 
pelvis of human cadavers.  



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Aisthesis      Volume 8,  201743

 In a clinical setting, bone marrow biopsy 
samples are extracted from patients manually via 
biopsy needles (Voigt & Mosier, 2013).  The sample 
is obtained from the patient’s iliac crest of the pelvis, 
usually near the posterior superior iliac spine (Bain, 
2001).  The pelvis is preferred, as it is a relatively safe 
access site, and the area is easily penetrated using 
the biopsy needle (Bain, 2001). Once an incision has 
been made to expose the superficial surface of the 
ilium, the biopsy needle is inserted slowly towards 
the anterior superior iliac spine (Bain, 2001). The 
needle is turned clockwise and counterclockwise 
in order to dislodge the sample from the marrow 
matrix. Once an adequate sample has been obtained, 
roughly a 20 mm specimen, the needle is carefully 
removed from the patient and the insertion site is 
closed (Voigt & Mosier, 2013).  
 Accordingly, the clinical methodology for 
marrow extraction was adapted for experimental 
use on human cadavers. In this study, sampling 
locations include the humerus, femur, and pelvis as 
these bones not only contain marrow but also persist 
on crime scenes longer than most other elements 
(Galloway, 1996). The humerus is the forearm bone 
located in the upper limb, the femur is the thigh 
bone located in the lower limb skeleton, and the iliac 
crest is the most superficial portion of the ilium. The 
humerus and femur are classified as long bones and 
have high marrow concentrations in the metaphysis 
and epiphysis, or the ends of the bone (Clarke, 2008). 
The ilium is an irregular bone, with relatively high 
marrow concentrations throughout the bone. The 
dense, compact nature of bone stems from cortical 
bone, its outermost layer (U.S. National Library of 
Medicine, n.d.). Cortical bone is composed of many 
small sub-units called osteons, which give bone its 
tensile strength. Deep to cortical bone is trabecular 
bone, which has a spongy appearance and houses 
bone marrow (U.S. National Library of Medicine, 
n.d.).  

Methods
 On May 11, 2016, three specimens, one female 
and two males, were placed at the STAFS facility 
(Figure 1). Each specimen was placed in the supine 
position for continued access to the pelvis, humeri, 
and femora with minimal disturbance during early 
decomposition. Each specimen was protected by a 
caged enclosure to prevent scavenging. 

Each sampling day, enclosures were removed so
that the specimens could be accessed. Ideally, three 
to four personnel were available for sampling to 
keep two sets of clean hands (driller, record keeper/
documenter, tool handoff) and two sets of dirty 
hands (samplers). Clean hands were used to drill, 
document, hand off sampling materials, and seal 
extraction sites. Dirty hands were used to collect 
bone marrow.
 Before entering the enclosure and coming 
into physical contact with the cadavers, proper 
protective measures were taken to prevent exposure 
to biohazards. Personal protective equipment (PPE) 
such as non-porous PVC suits, long-cuffed gloves, 
face shields, surgical masks, face shields, and rubber 
boots were donned prior to entering the enclosures. 
The PPE was disposed of as biohazardous waste, 
and boots were cleaned and stored in a designated 
location at the facility for continued use.
 On the day of placement, an I-shaped incision 
was first made on each specimen at the most proximal 
point of the humerus, pelvis, and femur in order to 
retract the soft tissues and provide controlled access 
to skeletal elements. Starting from the most proximal 
point of each bone and moving distally, a 3 to 4-inch 
incision was made using a scalpel. The incision was 
extended distally to provide additional sampling 
sites, thereby minimizing the amount of exposed 
bone at a given time. 
 Prior to extracting marrow, each sampling 
location on the bone was cleansed with an alcohol 
wipe, starting centrally at the point of entry and 
moving radially away from the extraction site. 
Medical grade T-Lok bone marrow biopsy needles 

Figure 1. (From left) Specimens 027 and 033; (In front) 
Specimen 109 during late decomposition.



A Methodology for Extracting Bone Marrow from Cadavers

Aisthesis      Volume 8,  201744

(Figure 2) were used to pierce the cortical bone of 
the pelvis, femur, and humerus on each specimen 
(Argon Medical Devices, n.d.). However, the biopsy 
needle was unable to pierce the long bones due to 
thickness of the cortical bone. Therefore, we used a 
power drill and carbide bit to drill a hole into the 
humeral and femoral marrow cavities. The T-Lok 
biopsy needle, alone, was still used to access the 
pelvis.

 After each use, the carbide bit was cleansed with 
70% alcohol spray and an alcohol wipe. To access the 
pelvis, the T-Lok biopsy stylet and needle cannula, as 
a unit, were inserted into the pelvic crest. Sampling 
moved from the pelvic crest toward the medial 
border of the ilium to allow continued access to new 
extraction points throughout the duration of the 
study . Once inside the pelvis, the T-Lok unit was 
rotated counterclockwise and clockwise to separate 
the sample from the marrow matrix, allowing for 
sample isolation and extraction. The stylet was then 
removed by rotating the needle section 90° and 
pulling it straight up, leaving the needle cannula 
in the bone for access to the marrow cavity. At this 
point, the extraction cannula could then be used to 
extract bone marrow from each sampling location by 
inserting the extraction cannula into the bone cavity 
through the needle cannula and into pelvis (Figure 
3a), or directly into the bone (Figure 3b) through the 
drilled hole for the long bones.
 As decomposition progressed, collection of 
marrow with the extraction cannula became more 
difficult, particularly in the humerus and femur. To 
combat this, a sterile cotton swab (BBL CultureSwaEZ) 

was used to obtain a marrow sample if the extraction 
cannula could not collect any material. If the sample 
was collected with the T-Lok rather than the swab, 
material was transferred into a labeled cryotube by 
inserting the probe into the extraction cannula to 

Figure 2. Medical grade T-Lok bone marrow biopsy kit.

Figure 3a. Sampling on long bone with T-Lok.

Figure 3b. Sampling on long bone with EB Swab.



A Methodology for Extracting Bone Marrow from Cadavers

Aisthesis      Volume 8,  201745

expel the marrow (Figure 4). If the swab was used 
to collect marrow, then it was placed back into its 
plastic transport container, labeled according to 
specimen identification number, sampling date, and 
sampling location.

 After extracting the sample, the hole of entry 
was sealed before moving to the next bone (Figure 
5a, Figure 5b). Initially, sampling locations were 
sealed with a combination of putty and Elmer’s pro-
bond glue. Putty was used to fill any opening to the 
marrow cavity left by the extraction process, and 
glue was used to seal the putty and adhere it to the 
bone. Once sealed, a sampling location was not used 
again. However, insect activity and rain/moisture 
levels rendered the putty ineffective in sealing 
the extraction site. Therefore, the use of putty was 
discontinued, and glue alone was used throughout 
the remainder of the experiment. Complications 
only arose when the glue was applied during 
heavy and continuous rainfall, as it was unable to 
properly dry and set before being washed away. 
After sampling was completed, each specimen was 
checked to ensure that the extraction site was sealed. 
Any trash or biohazardous waste from the sampling 
process was cleaned, and the cages were placed back 
over each body.
 Extraction tools were reused. Therefore, dirty 
tools (T-Lok kits, scalpels, and drill bits) were 
placed in a sealed container for transport back to the 
microbiology lab at Sam Houston State University 
(SHSU) for cleaning and autoclaving. The power 
drill was sprayed with ethanol and wiped down after 
use. Samples were placed in a separate container for 

transport. At SHSU, the samples were placed and 
stored in a -20°C freezer. The process for cleaning 
dirty tools was performed in four steps: manual 
washing, soaking in ethanol, repackaging, and 

Figure 4. Transfer of marrow sample into labeled cryo-
tube. 

Figure 5a. Sealing of long bone.

Figure 5b. Sealing of pelvis.



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Aisthesis      Volume 8,  201746

autoclaving. First, the tools were washed with water 
and soap. Care was taken during this step to remove 
dirt and tissue. A pipe cleaner was used to clean 
the cannulas. Next, the cleaned tools were placed 
in a tub of 70% ethanol. This tub was placed on a 
shaker set to 2-3 x 1000 rpm for at least 24 hours. 
Then, the tools were rinsed with Millipore water. The 
rinsed tools were packaged in biopsy kits using foil 
sheets, then labeled, dated, sealed, and initialed. A 
strip of autoclave tape was also used on each kit to 
ensure that the appropriate pressure and heat level 
was obtained during the autoclave process. Finally, 
the prepared kits were placed in a large metal tray 
and placed in the autoclave. The autoclave was set 
to Gravity 2 and allowed to cycle. Dirty transport 
containers were washed, sprayed with ethanol, and 
left to dry.

Discussion
 Over a period of six months, the left and right 
femur, pelvis, and humerus of each cadaver was 
sampled per the described protocol. To varying 
degrees of success, different methods and procedures 
were utilized to obtain bone marrow and keep 
the marrow cavity protected. Initially, extraction 
protocol called for the use of medical grade biopsy 
needles to obtain marrow samples from the femur, 
pelvis, and humerus. However, the needles were 
unable to pierce through the cortical diaphysis, or 
shaft, of the long bones. To address this problem, a 
cordless drill was used to create the hole in the long 
bones. The drill was disinfected between each use. 
The integration of a power drill was an effective and 
easy amendment to the sampling protocol, ensuring 
access into the marrow cavity of long bones without 
complicating extraction procedure. 
 However, the most problematic issue was 
keeping the cavity protected after sampling. At first, 
putty and glue were used, in combination, to seal 
the extraction site. The putty was intended to act as 
a plug while the glue acted as a seal. However, the 
putty-glue combination proved ineffective under 
the stress of rainfall and insect activity. The material 
would either wash away or be chewed through by flies 
(maggots) and beetles, leaving the cavity exposed to 
the external environment. We suspect that the putty 
did not form a strong enough bond with the bone 
and that the surface of the bone was too soft for the 

glue to adhere to. Therefore, Elmer’s Pro-bond glue 
was used to seal the holes without use of the putty. 
The glue, as the primary means of sealing extraction 
points, proved effective under most conditions. 
Scavengers were unable to eat through or displace it, 
and the glue dried quickly. Problems only occurred 
under extreme conditions of heavy rainfall, as the 
glue was unable to set before being washed away.
 Relative to the methodology described are the 
four stages of decomposition: fresh, early, advanced, 
and skeletonization. Each stage is characterized by 
qualitative observations, such as appearance, and 
general characteristics of the remains. During the 
fresh stage, the body does not have any discoloration 
of the skin. In early decomposition, the skin’s 
appearance becomes discolored, progressing from 
a pink/white appearance to a brown/black leathery 
appearance. The advanced decomposition stage 
is characterized by minimal bone exposure and 
mummification of the skin. The skeletonization stage 
includes extensive bone exposure with minimal 
tissue and body fluids remaining (Megyesi et al., 
2005). Depending on environmental factors and 
bodily conditions upon death, the decomposition 
process can proceed at different rates and spend 
variable amounts of time in each stage. Specific 
to our specimens, boney elements became fragile 
and brittle at the onset of advanced decomposition 
stage, around the third month of sampling. When 
obtaining samples with the biopsy needles and drill, 
bones were prone to breaking. If breaks occurred, 
the pieces were glued back together to prevent any 
further exposure of the bone marrow cavity.
 Despite complications, the established protocol 
for extraction and sampling of bone marrow in 
human cadavers proved effective and practical for 
extended use. 

Acknowledgments
We would like to thank Dr. Joan Bytheway and Kevin 
Derr at Southeast Texas Applied Forensic Science 
Facility.  Our research advisors, Drs. Aaron Lynn and 
Patrick Lewis, assisted us throughout the project. 
We would also like to thank the Texas Academy of 
Science (TAS) and the Federal and State Technology 
(FAST) Partnership Program for funding this study. 
Thanks to Sarai Mesa, Connor Carlton, and Eric 
David for assisting with this project. For all of the 
families and those who have donated their bodies to 
science, we extend our deepest gratitude and respect.



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Aisthesis      Volume 8,  201747

References
Argon Medical Devices. (n.d.). Argon products. 

Retrieved from http://www.argonmedical.
com/argon-products/#bone-marrow-biopsy-
needlesFigures

Bain, B. (2001). Bone marrow aspiration. Journal of 
Clinical Pathology, 54(9), 657–663.

Clarke, B. (2008). Normal bone anatomy and 
physiology. Clinical Journal of the American 
Society of Nephrology: CJASN, 3(Suppl 3), S131–
S139. http://doi.org/10.2215/CJN.04151206

Galloway, A. (1996). The process of decomposition. 
In W. D. Haglund & M. H. Sorg (Eds.), Forensic 
Taphonomy: The Postmortem Fate of Human 
Remains. Boca Raton, FL: CRC Press.

Howard, G. T., Duos, B., & Watson-Horzelski, E. 
J. (2010). Characterization of the soil microbial 
community associated with the decomposition 
of a swine carcass. International Biodeterioration 
& Biodegradation, 64(4), 300-304.

Hyde, E. R., Haarmann, D. P., Lynne, A. M., Bucheli, 
S. R., & Petrosino, J. F. (2013). The living dead: 
Bacterial community structure of a cadaver 
at the onset and end of the bloat stage of 
decomposition. PLoS ONE, 8.

Megyesi, M. S., Nawrocki, S. P., & Haskell, N. H. 
(2005). Using accumulated degree-days 
to estimate the postmortem interval from 
decomposed human remains. Journal of Forensic 
Sciences, 50(3), 1-9.

Metcalf, J. L., Parfrey, L. W., Gonzalez, A., Lauber, 
C. L., Knights, D., Ackerman, G.,…Knight, R. 
(2013). A microbial clock provides an accurate 
estimate of the postmortem interval in a mouse 
model system, eLife, 1-19.

Schwarcz, H. P., Agur, K., & Jantz, L. M. (2010). 
A new method for determination of postmortem 
interval: Citrate content of bone. J Forensic 
Science, 55, 1516-1522.

U.S. National Library of Medicine – PubMed Health. 
(n.d.). Cortical bone. Retrieved from https://
w w w. ncbi . n l m . n i h . gov / pubme d he a l t h /
PMHT0022810/ 

Vass, A. A. (2001). Beyond the grave - Understanding 
human decomposition. Microbiology Today, 28, 
190-192.

Voigt, J., & Mosier, M. (2013). A powered bone 
marrow biopsy system versus manual methods: 
A systematic review and meta-analysis of 
randomised trials. Journal of Clinical Pathology, 
66(9), 792–796. http://doi.org/10.1136/
jclinpath-2013-201605


