THE INFORMATIVE FEET
By Dr. Phil Hoekstra
Introduction
.
Why the Feet Matter
The feet sit at the farthest reach
of the circulatory system. Because of this distance, they are often the
first place where compromised blood flow becomes visible. In conditions
such as peripheral vascular disease, arterial stenosis, or early
atherosclerosis, thermology frequently reveals progressive cooling patterns
from the thigh downward, with the most dramatic changes appearing in the toes
and forefoot
For
patients with diabetes, this sensitivity becomes even more critical. Diabetes
commonly affects microcirculation—the smallest blood vessels supplying
tissues—and the feet are typically the earliest site of microangiopathy.
Thermal imaging can show distinct temperature demarcations between toes and the
body of the foot, reflecting compromised perfusion long before ulcers or
neuropathy become clinically obvious
.
Reading Circulation Through Heat
Thermology does not measure blood
flow directly; it measures heat patterns generated by circulation.
Healthy perfusion produces symmetrical, evenly distributed warmth. When blood
flow is impaired, asymmetries and cold zones emerge.
In
vascular medicine, these patterns allow clinicians to:
- Detect early-stage
peripheral arterial disease
- Monitor the effectiveness of
revascularization or medical therapy
- Track small-vessel perfusion
after interventions
In
my early work at the USC Non-Invasive Laboratory, among all available tools,
thermology consistently proved the most sensitive modality for studying
perfusion in the feet. The hands, by contrast, often remain warm until disease
is advanced. The feet tell the story first
Neurologic Clues Beneath the Skin
In
cases involving lumbar nerve roots (L3, L4, L5), thermology can show:
- Warmth or cooling in specific toe groupings
- Clear conformity to dermatome maps
- Objective evidence of radicular neuropathy
Traditionally,
dermatome mapping relied on uncomfortable sensory testing. With thermology,
clinicians can see the nervous system’s influence on circulation,
offering a noninvasive, patient-friendly alternative
.
Complex
Pain Syndromes and Autonomic Dysfunction
Thermology is also one of the most
powerful tools for identifying complex regional pain syndrome (CRPS),
formerly known as reflex sympathetic dystrophy. These patients often present
with dramatically cold, painful feet—an unmistakable thermal signature of
autonomic dysfunction.
What
makes thermology unique is not only its ability to detect these abnormalities,
but to document recovery. As treatment restores sympathetic balance and
blood flow, thermal symmetry returns. Few diagnostic tools so clearly reflect
physiologic change in real time
Observing the Body’s Reflexes
Over decades of practice, I have
witnessed fascinating demonstrations of the body’s interconnectedness through
thermology. In patients with CRPS, I have observed sudden surges of heat in
the foot following auricular acupuncture—stimulation of specific points in
the ear associated with neural reflex pathways. While the exact mechanisms
remain under study, the thermographic evidence of instant vascular response
is undeniable .
These observations remind us that thermology is not only a
diagnostic tool, but a real-time physiologic monitor, capable of
revealing how therapies—conventional or complementary—affect the nervous and
vascular systems.
Where to Scan: The Dorsal Advantage
- More consistent skin thickness
- Clearer visualization of
vascular patterns
- Better reproducibility across
patients
Standardizing imaging protocols in this way ensures that
thermology remains both scientifically credible and clinically useful.
Beyond
the Transcript: Expanding the Clinical Vision
Modern research continues to support
what thermologists have long observed: thermal asymmetry correlates strongly
with pathology. Studies in diabetic care, sports medicine, and vascular
screening now increasingly recognize infrared imaging as a valuable adjunct
for:
- Early detection of neuropathic
changes
- Monitoring inflammatory
conditions
- Preventing ulcer formation
in high-risk patients
- Assessing rehabilitation
progress after injury
As healthcare shifts toward prevention and precision monitoring, thermology of the feet stands poised to become a cornerstone of noninvasive functional diagnostics.
In
an era that increasingly values early detection and patient-centered care, the
informative feet remind us that sometimes the most profound insights into
health lie at the very foundation of the body.
References
American
Academy of Thermology. (2012). Guidelines for neuromusculoskeletal infrared
imaging. AAT.
Brioschi,
M. L., Macedo, J. F., & Macedo, R. A. (2015). Skin thermography: New
concepts. Journal of Vascular Diagnostics, 3(2), 1–9.
Gersh,
M. R., & Arora, R. (2020). Thermography in peripheral vascular disease. Vascular
Medicine Review, 12(4), 233–245.
Hoekstra,
P. (Interview transcript). (n.d.). Thermology and the informative feet.
Jones,
B. F. (1998). A reappraisal of the use of infrared thermal image analysis in
medicine. IEEE Transactions on Medical Imaging, 17(6), 1019–1027.
Lahiri,
B. B., Bagavathiappan, S., Jayakumar, T., & ip, J. (2012). Medical
applications of infrared thermography: A review. Infrared Physics &
Technology, 55(4), 221–235.
Ring,
E. F. J., & Ammer, K. (2012). Infrared thermal imaging in medicine. Physiological
Measurement, 33(3), R33–R46.
Sanchis-Sánchez,
E., et al. (2020). Infrared thermography in the assessment of diabetic foot
complications. Diabetes Care Technology, 8(2), 145–152.
Uematsu,
S. (1985). Thermographic imaging of cutaneous sensory segmental areas. Journal
of Neurosurgery, 62(5), 716–720.
Vardasca,
R., & Ring, E. F. J. (2014). Thermography in the assessment of peripheral
neuropathy. Medical Imaging and Diagnostics, 6(1), 12–20.
