Discussion on Trigger points with Leon Chaitow

There is a long, but good, discussion thread batting ideas around about trigger points over on Leon Chaitow's Facebook page. The thread is getting reasonably long and tricky to find so I thought I'd post a section here relating to muscle spindles and stretch.

LC: but question, when palpating an area housing a trigger point, is 'what is the orientation of spindles, so that they can be stretched longitudinally?' The main origin and insertion attachments would seem to offer that sense of direction....but is it accurate in any given situation?

 

MS: I would suggest there are a number of considerations, as you say in any given situation, whether we are looking at upper limb, lower, trunk or neck.

Spindles lie in parallel with skeletal muscle fibres so we must consider the fascicle orient...ation with any given muscle with a trigger point that we are seeking to address.

Another factor to consider is the variable number of spindles in skeletal muscle tissue. The variation is startling (6 to 1300 per muscle according to Hasan & Stuart (1984)). Is interesting to note that there are almost double the number of spindles in the lower extremities as the upper extremities (Prochazka, 1996). Gregor (cited in Barker, 1974) showed that:

"spindle density is highest in the hand, foot and neck muscles, longest in the shoulder and thigh muscles, and medium in the more distal muscles of the arm and leg, with relatively high values for the rotating muscles such as pronator quadratus and popliteus. Generally speaking, high spindle densities-characterize muscles initiating fine movement (i.e. lumbricals, extraocular muscles and small vertebral muscles) or maintaining posture (i.e. soleus), low densities in those initiating gross movement (i.e. gastrocnemius)."

Finally, the palpation skills required to identify spindles would need to be rather refined as these spindle structures are 2 to 6 mm in length, although I have found another source that reports muscle spindles of 2.4 to 13.7mm of length in cat rectus femoris.