Fascia is very dense and resembles a spiders wed and it is so special because it penetrates and surrounds all of our muscles, bones, nervous system, blood vessels and internal organs. The thing I find so amazing is that it covers all these structures in a endless web from head to toe.
Even though in anatomy book it appears all our muscles are separate entities, fascia is quite sticky and some of the smaller muscles are quite difficult to differentiate from each other. Fascia also divides compartments of muscles such as the quadriceps from the adductors and hamstrings in the upper leg.
When fascia become damaged, such as in a surgery, trauma or by habitual poor posture, it loses its pliability and can lead to pain in the body that can be difficult to diagnose. These fascial restrictions can lead to restrictions in flexibility and can lead to local pain or even achillies tendonitis or cerviogenic headaches. These ailments can be due to fascial pull at the base of the head and at the heel. It is literally the fascia pulling from the dysfunctional area.
Some fascial dysfunctions are more obvious such as Dupuytren's contracture where the fascia in the palm of the hand is noticeably thickened or plantar fasciitis where the fascia on the sole of the foot is thickened.
Obviously not every case of achillies tendonitis is due to this and nor is every cerviogenic headache, but it is something your Osteopath will explore as Osteopathy is about finding the reason why you have your symptoms and trying to correct any problems so that we are addressing the cause and not just the symptoms!