A Pain in the Neck: Vertebral steoarthritis and Related Activity Patterns in Early Bronze Age Jordan

1
A Pain in the Neck Vertebral steoarthritis
and Related Activity Patterns in Early Bronze
Age Jordan
L.A. Gregoricka and J.M. Ullinger Department of
Anthropology, The Ohio State University
Results and Discussion
Introduction
This study hypothesized that an increase in
sedentism at the Early Bronze Age site of Bab
edh-Dhra led to decreased mobility and changing
workload demands. This was tested by evaluating
changes in spinal degenerative joint disease
frequencies over time. Specifically, cervical
vertebrae were examined for changes such as
vertebral body osteophytic growth, Schmorl's
nodes, and eburnation and lipping on the
apophyseal joint surfaces.
Osteophyte frequency increased significantly from
EB IA to EB II-III in all cervical vertebrae
except C7, which had an inadequate sample size
(Table 1). Schmorls node frequencies were low,
with no differences between time periods (Table
2). The incidence of eburnation did not change
significantly and was also rare in both EB IA and
II-III (Table 3). No significant differences
were found in regards to lipping on the
apophyseal joints (Table 4).
TABLE 1 Occurrence of osteophytes in cervical
vertebrae.
Background
Located on the Dead Sea Plain in modern-day
Jordan, the Early Bronze Age (EBA - 3150-2150
BCE) site of Bab edh-Dhra provides evidence of a
turning point in the southern Levant in which
agricultural intensification and urbanization
were taking place (Esse 1989 Mazar 1990). The
continuous occupation of Bab edh-Dhra throughout
the EBA as represented by skeletons from EB I-III
allows for a more comprehensive reconstruction of
changing subsistence strategies and the resultant
modifications in activity patterns.
Significant differences (plt0.05) are indicated
with bold text.
TABLE 2 Occurrence of Schmorls nodes in
cervical vertebrae.
Clinical studies of carrying loads on the head
illustrate pathological modifications on the
cervical spine associated with heavy loading
(e.g., Joosab et al. 1994). Two identified
techniques of load-carrying on the head include
(a) carrying lighter loads over longer distances
or (b) carrying heavier loads over shorter
distances (Echarri and Forriol 2005).
Individuals traveling shorter distances while
supporting heavier loads display a higher
incidence of cervical degeneration and injured
intervertebral disks as compared to those
transporting lighter burdens across a longer
distance. This fits with what is known regarding
mechanical loading in vertebrae, namely that
apophyseal joints are largely responsible for
movement while intervertebral joints limit
mobility but provide much-needed support (Weber
et al. 2003).
Periods of occupation at Bab edh-Dhra.
None of the results are significant (plt0.05).
TABLE 3 Occurrence of eburnation in cervical
vertebrae.
Degenerative joint disease (DJD) is an
age-progressive articular disorder characterized
by osteophytic growth on amphiarthrodial joint
margins and porosity and/or erosion on apophyseal
joint surfaces due to the deterioration of
articular cartilage and the resultant reaction of
subchondral bone (Lovell 1994). The study of DJD
allows for an evaluation of a populations
mechanical loading history as well as a
reconstruction of activity patterns in the past.
For example, cervical vertebral degeneration may
be attributable to the practice of consistently
carrying loads on the head, an activity that
generates substantial axial strain. Moreover,
DJD provides an important glimpse into past
societal organization, enabling bioarchaeologists
to differentiate between changing activity
patterns with the intensification of agricultural
practices (e.g., Bridges 1989 Larsen 1995 Cohen
and Crane-Kramer 2007). A similar pattern shift
has been noted between rural and urban groups
(e.g., Danforth 1999 Slaus 2008). The
continuous occupation of Bab edh-Dhra throughout
the EBA thus presented a unique opportunity to
examine the complex relationship among
subsistence strategies, settlement organization,
and pathological bony responses.
None of the results are significant (plt0.05).
The transition to a more sedentary way of life at
Bab edh-Dhra was accompanied by an increased
frequency of osteophytes but no change in the
incidence of osteoarthritic lipping. More mobile
populations may have carried lighter loads on the
head in order to more efficiently cope with these
burdens over greater distances. The transition
to a more sedentary way of life at Bab edh-Dhra
was accompanied by an increased frequency of
Extensive research into the transition from
pre-agricultural to agricultural lifestyles has
illustrated changes in health and daily
activities in response to shifting subsistence
patterns (e.g., Angel 1984 Bridges 1989 Larsen
1995 Eshed et al. 2004). A similar pattern
shift has been noted between rural and urban
groups (e.g., Danforth 1999 Slaus 2008).
Particularly with regards to degenerative joint
disease, changes in physical activity can result
in both an increase and a decrease in the
frequency of location-specific lesions. For
example, joint deterioration as a result of
modifications in body movement involving the
thoracic region, shoulders, and elbows increased
after the adoption of agriculture, while lower
arm and upper leg degeneration decreased (Larsen
1995). Cervical vertebral degenerative joint
disease may be attributable to the practice of
consistently carrying loads on the head, an
activity that generates substantial axial strain.
As the most mobile region of the spine, cervical
vertebrae are particularly vulnerable to
mechanical stress on the head (Mahbub et al.
2006).
osteophytes but no change in the incidence of
osteoarthritic lipping. More mobile populations
may have carried lighter loads on the head in
order to more efficiently cope with these burdens
over greater distances. Alternatively,
year-round sedentism may have entailed less
overall movement across the landscape, resulting
in shorter distances required to reach the
settlement in conjunction with higher yields
generated by intensified food production, a heavy
load/short distance pattern may have emerged.
Subsequently, increasingly severe cervical
osteophytosis without apophyseal joint change
from the EB IA to II-III may have signaled a
shift in transportation techniques from the more
mobile individuals of the EB IA carrying lighter
loads over longer distances to the more sedentary
agriculturalists of the EB II-III carrying
heavier loads on the head over shorter distances.
This corresponded to increasing stress on
intervertebral joints and hence elevated rates of
osteophytosis while accounting for a lack of
change in apophyseal lipping, as significant
changes in neck movement did not occur.
TABLE 5 Comparative data of degenerative changes
in cervical vertebrae.
BD 1488.82
BD 1275.1089
BD 1448.1001
BD 1134.3004
FIGURE 1 Degree of vertebral body osteophytosis
0-3
Conclusion
Materials and Methods
This study concluded that an increasingly
sedentary lifestyle at Bab edh-Dhra led to a
more strenuous workload characterized by
increased axial loading due to heavier burdens
carried over shorter distances, but a lack of
change in facet joint degeneration suggests that
no changes in neck mobility took place.
Adult cervical vertebrae were examined from EB IA
(n139) and EB II-III (n555). The commingled
nature of these remains precluded the
identification of individual vertebral sequences.
Vertebrae were scored for presence and severity
of osteoarthritic lipping, porosity, eburnation,
and osteophytosis based on standards outlined by
Buikstra and Ubelaker (1994). The rank of
present includes moderate to severe scores,
while absent refers to no or barely discernable
pathological activity. Schmorls nodes were
scored based only on presence or absence.
Acknowledgements
This research was supported by the NSF-REU (SES
0649088) Summer Research in Biocultural
Anthropology at the University of Notre Dame,
Notre Dames Institute for Scholarship in the
Liberal Arts, a Smithsonian Institution
Pre-doctoral Fellowship, and a Sigma Xi
Grant-in-Aid of Research. Thanks to Dr. Susan
Guise Sheridan for use of the collection and
laboratory as well as for her support and
encouragement.