And what have we here?
The above is a pedograph, a simple, effective pressure map of the foot as someone is walking across an inked grid. For more info on pedographs, click here.
Did you note the increased ink present under the great toe bilaterally? What could be causing this? If you look carefully, you will note that it is at the base of the proximal phalynx of the great toe. This could be none other than the tendon of the flexor hallucis brevis!
This bad boy arises from the medial part of the under surface of the cuoid and the adjacent 3rd cunieform, with a small slip from the tendon of the tibialis posterior. As it travels forward it splits into two parts, which are inserted into the medial and lateral sides of the base of the proximal phalanyx of the great toe. There is a sesamoid bone present in each tendon, which offers the FHB a mechanical advantage when flexing the toe. The medial portion is blends with the abductor hallucis and the lateral portion blends with the adductor hallucis.
Had the increased printing on the pedograph been more distal, it most likely would have been due to increased action of the flexor hallucis longus. Had it been more proximal (under the head of the 1st metatarsal) it would have been due to the peroneus longus.
Reading pedographs and making you a sharper clinician/coach/trainer/sales person is just one of the many skills we try to teach here on the blog. Keep up the great work!
The Gait Guys