New population-based reference values for spinal mobility measures based on the 2009-2010 National Health and Nutrition Examination Survey.
OBJECTIVE
To report population-based percentile reference values for selected spinal mobility measures in a nationally representative sample of 5,001 US adults ages 20-69 years who were examined in the 2009-2010 US National Health and Nutrition Examination Survey (NHANES).


METHODS
Occiput-to-wall distance (OWD), thoracic expansion (TE), and anterior lumbar flexion (ALF; by modified Schober test) were measured by trained examiners in a standardized manner. TE was measured at the xiphisternal level, while the lower reference point for ALF was a line marked at the level of the superior margin of the lateral iliac crests. We report reference values based on the 95th percentile for the OWD and the 5th percentile for TE and ALF, as well as other summary statistics for these measures, in the study population.


RESULTS
An OWD of >0 was present in 3.8% of the participants, while 8.8% of them had out-of-range values for TE based on the commonly used threshold of 2.5 cm. The 95th percentile of the OWD measurement was 0, while the 5th percentile for TE and ALF were 1.9 cm and 2 cm, respectively. The spinal measures were significantly associated with sex, age, ethnicity, height, and body mass index (BMI). Exclusion of individuals with severe obesity (BMI >35 kg/m(2) ) changed the proposed reference values for TE and ALF to 2.2 cm and 1.9 cm, respectively.


CONCLUSIONS
We verified a reference value of 0 for the OWD in the general population. Using the reported population-based percentile values, new reference values for TE and ALF can be derived.
University of Texas Health Science Center at, Houston.
Shervin
S
Assassi
Michael H
MH
Weisman
MinJae
M
Lee
Laurie
L
Savage
Laura
L
Diekman
Tiffany A
TA
Graham
Mohammad H
MH
Rahbar
Joan I
JI
Schall
Lianne S
LS
Gensler
Atul A
AA
Deodhar
Daniel O
DO
Clegg
Robert A
RA
Colbert
John D
JD
Reveille
D000328:Adult; D000368:Aged; D015992:Body Mass Index; D001835:Body Weight; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys; D016059:Range of Motion, Articular / Q000502:physiology*; D012016:Reference Values; D013131:Spine / Q000502:physiology*; D055815:Young Adult