Splay

Watch this video a few times through. Did you catch the subtle abduction moment of the Hallux (big toe) on impact? Did you see the collapse of the transverse metatarsal arch? No?  Watch it until you do.

What gives? We thought toes were supposed to be stable when they hit the ground (and in fact they are).  Read on…

Think of the adductor hallucis. It has 2 heads. The oblique head arises from the proximal shafts of metatarsals 2-4 and inserts on the MEDIAL aspect of the proximal phalynx of the hallux (along with medial fibers of the flexor hallucis brevis); the transverse head arises from the metatarsophalangeal ligaments of  digits 3-5, and the transverse metatarsal ligament and inserts blending with the oblique head on the proximal phalynx of the hallux.

The action of the adductor hallucis mirrors that of the abductor hallucis (which inserts on the LATERAL side of the proximal phalynx. Together, they act to keep the hallux straight and provide a compressive force which stabilizes the big toe WHEN IT IS ON THE GROUND.

The problem here, is that the base of the Hallux is NOT anchored to the ground. This person has a faulty tripod (most likely an uncompensated forefoot varus) and cannot anchor the big toe, there fore the adductor cannot do it’s job. Is is weak (from lack of use) and we see the result: an abducting big toe AND collapse of the transverse metatarsal arch (which the transverse head of the adductor, under normal conditions maintains).

Looks like this guy needs some exercises to descend the head of the 1st metatarsal and make an adequate tripod. Flexing the distal phalynx of the hallux while extending the metatarsophalangeal joint would be a good start. (see Dr Allen demonstrate this here: http://www.youtube.com/user/TheGaitGuys?feature=grec_index#p/u/11/TyRE9dReVTE )

The Gait Guys…promoting foot literacy here and everywhere.

Time for a quick pedograph case:

This person presented with arch pain and occasional forefoot pain.

Note the increased size (length) of the heel print with blunting at the anterior most aspect. The midfoot impression is  increased, revealing collapsing medial longitudinal arches. The forefoot print has increased pressures over the 2nd metatarsal heads bilaterally, and the 1st on the left. She claws with toes 2-4 bilaterally.

This demonstrates poor intrinsic stability of the foot (as evidenced by the increased heel impression and midfoot collapse) and well as decreased ankle rocker (as evidenced by the increased forefoot pressures).

We also see increased ink under the distal second digit (esp on the right). This suggests some possible incompetence of the first ray complex and big toe, which is represented by the medial ink presentation under the great toe (suggesting a pinch callus, which is seen when there is spin of the foot and insufficient great toe anchoring and push off).  When the great toe function is compromised, we tend to see increased activity of the 2nd digit long flexors, represented well here by increased ink under the 2nd toe.

The pedograph truly does provide a window to the gait cycle!

We remain: Gait Geeks