Reliability of thickness measurements of the dorsal muscles of the upper cervical spine: an ultrasonographic study.
METHODS
Clinical measurement, reliability.


OBJECTIVE
To examine the intraday intrarater reliability of measuring thickness of the upper dorsal neck muscles at rest, as well as at 50% of maximum voluntary isometric contraction (MVIC), for upper cervical extension.


BACKGROUND
Methodology for measuring the thickness of the lower dorsal neck muscles, including semispinalis capitis and multifidus muscles, during contraction using ultrasonography has been established. Thickness measurements for the upper dorsal neck muscles have not been documented.


METHODS
Ten subjects (21 to 30 years of age) without neck pain and headache were recruited. Their upper dorsal neck muscles were measured both at rest and during 50% MVIC for upper cervical extension in sitting position using rehabilitative ultrasound imaging (RUSI). Muscles measured included the rectus capitis posterior major, oblique capitis superior, semispinalis capitis, and splenius capitis. All measurements were repeated after 10 minutes of rest, on the same day, by the same rater. Descriptive statistics were supplemented by calculations of intraclass correlation coefficient (ICC3,1), standard error of measurement (SEM), within-subject coefficient of variation (CVw), and minimal detectable change (MDC).


RESULTS
ICC3,1 results ranged from 0.87 to 0.99 for thickness measurements made at rest and from 0.90 to 0.98 for thickness measurements made with a 50% MVIC. The SEMs for thickness measurements at rest and at 50% MVIC ranged from 0.11 to 0.46 mm and 0.23 to 0.52 mm, while the CVws ranged from 3.5% to 6.1% and 3.7% to 6.4%, and MDC95 ranged from 0.35 to 1.46 mm and 0.73 to 1.65 mm, respectively. The thickness of all upper dorsal neck muscles measured during a 50% MVIC was greater than when measured at rest (P<.029).


CONCLUSIONS
Thickness measurements of the upper dorsal neck muscles using RUSI were reliable both at rest and during a 50% effort isometric contraction.
Lin
Ya-Jung
YJ
Department of Physical Medicine and Rehabilitation, National Taiwan University Hospital, Taipei, Taiwan.
Chai
Huei-Ming
HM
Wang
Shwu-Fen
SF
D000328:Adult; D004576:Electromyography; D005260:Female; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D008297:Male; D009334:Neck Muscles / Q000033:anatomy & histology* / Q000000981:diagnostic imaging* / Q000502:physiology; D012016:Reference Values; D015203:Reproducibility of Results; D014463:Ultrasonography; D055815:Young Adult