Guidelines to minimize risk when dry needling the rectus capitus posterior major muscle.

BACKGROUND

Headache disorders are prevalent often leading to disability. The rectus capitus posterior major muscle (RCPMaj) may contribute to headache symptoms via nociceptive convergence and myodural bridging.

OBJECTIVES

To establish guidelines for needle length and needle angle to mitigate risks during dry needling RCPMaj.

DESIGN

Cadaveric investigation.

METHODS

Twenty-five cadavers (mean age: 80.1 ± 13.2 years) were placed in prone. Depth measurements from the skin to the C2 spinous process were taken following midline incision. Dissection continued exposing the RCPMaj for three measures including: 1) posterior angle from the frontal plane, 2) lateral angle from midline, and 3) distance from the external occipital protuberance to the lateral most RCPMaj.

RESULTS

Mean values for tissue thickness overlying C2 spinous process (37 ± 7.3 mm), RCPMaj posterior angle from the frontal plane (65.2° ±10°), RCPMaj lateral angle from midline (34.7° ±12.9°), and distance from the external occipital protuberance to the lateral most RCPMaj (30.6 mm ± 9.3 mm) were used to calculate a needle inclination of ≤45° and a needle length <40 mm to reach the occipital portion of RCPMaj with an a priori insertion point of midway between the C2 spinous process and the C1 transverse process.

CONCLUSION

Inserting a dry needle <40 mm in length midway between the C2 spinous process and the C1 transverse process with a cranial angle of ≤45° relative to the frontal plane would increase the likelihood of reaching the RCPMaj and mitigate penetrating deeper structures.