In general, muscle spindles are important for the control of movement and posture in mammals as they sense muscle length and changes in muscle length.

In humans, the deep muscles of the neck (rectus capitis posterior major, rectus capitis posterior minor, obliquus capitis inferior and obliquus capitis superior) are located deep in the suboccipital region.

Structure: These muscles are quite small and short. The deep neck muscles have an unusually high muscle spindle density and special features of the muscle spindles.

Function:

• To supply proprioceptive information to CNS needed both for control of head position and movements and for eye/head movement coordination.
• Fine rotatory movements of the head and help maintain the stability of the cervical spine.

Muscle spindles have been proposed to play a major role in increasing muscle tone and in the pathophysiology of muscle pain syndromes and some muscles with a high spindle density are involved in chronic muscle pain syndromes.

When I received my initial training, dry needling of this region was said to be a big ‘no no’, because of safety concerns relating to the vertebral artery and occipital nerve. Is this really and issue though?

Perhaps its time to start paying more attention to dry needling in this region given the importance of these small structures on the input they provide to the central nervous system.

Reference:

Jing-Xia Liu, Lars-Eric Thornell, and Fatima Pedrosa–Domellöf. 2003. Muscle Spindles in the Deep Muscles of the Human Neck: A Morphological and Immunocytochemical Study The Journal of Histochemistry & Cytochemistry. Volume 51(2): 175–186