Part 2 of the EHB: Bringing the Extensor Hallucis Brevis of the Foot Back to Life.

Today we show you a proprietary exercise we developed here at The Gait Guys. It was developed out of necessity for those clients who are too EHL dominant (long big toe extensor muscle) and big toe short flexor dominant (FHB). These two muscles are what we call a foot functional pair.  Big toes like these will be dysfunctional and will not be able to gain sufficient purchase on the ground to produce stability and power without impacting the joint (1st metatarsophalangeal joint).  Imbalances like these lead to altered joint loading responses and can be a possible predictor for premature damage to the joint over time. These imbalances are also what lead to injuries to the big toe, the arch and other areas of the foot. After all, when the big is weak or dysfunctional gait will be compensated.  When imbalance at this joint occurs because of EHB weakness the medial tripod anchor (the head of the 1st metatarsal) is compromised possibly transmitting stress into the foot, arch and medial stabilizers such as the tibialis posterior for example.

This exercise is to be weaned back to less and less yellow band resistance until the EHB can be engaged on its own. Then the gait retraining must begin. Simply reactivating and strengthening the skill and muscle is not enough. The pattern must be then taken to the floor and learned how to be used in the gait cycle.

Do we need to mention the critical function this muscle plays in extension of the 1st MPJ, of its importance in hallux rigidus/limitus, in bunions, hallux valgus, toe off function, arch height and function ? We hope not.

It is a process restoring gait. All too often the “Devil is in the Details”.
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Shawn and Ivo
The Gait Guys

all material copyright 2012 The Gait Guys/ The Homunculus Group: all rights reserved.

Gait Topic: The Mighty EHB (The Short extensor of the big toe, do not dismiss it !)

Look at this beautiful muscle in a foot that has not yet been exposed to hard planar surfaces and shoes that limit or alter motion! (2 pics above, toggle back and forth)

The Extensor Hallicus Brevis, or EHB as we fondly call it (beautifully pictured above causing the  extension (dorsiflexion) of the child’s proximal big toe) is an important muscle for descending the distal aspect of the 1st ray complex (1st metatarsal and medial cunieform) as well as extending the 1st metatarsophalangeal joint. It is in part responsible for affixing the medial tripod of the foot to the ground.  Its motion is generally triplanar, with the position being 45 degrees from the saggital (midline) plane and 45 degrees from the frontal (coronal) plane, angled medially, which places it almost parallel with the transverse plane. With pronation, it is believed to favor adduction (reference). Did you ever watch our video from 2 years ago ? If not, here it is, you will see good EHB demo and function in this video. click here

It arises from the anterior calcaneus and inserts on the dorsal aspect of the proximal phalynx. It is that quarter dollar sized fleshy protruding, mass on the lateral aspect of the dorsal foot.  The EHB is the upper part of that mass. It is innervated by the lateral portion of one of the terminal branches of the deep peronel nerve (S1, S2), which happens to be the same as the extensor digitorum brevis (EDB), which is why some sources believe it is actually the medial part of that muscle. It appears to fire from loading response to nearly toe off, just like the EDB; another reason it may phylogenetically represent an extension of the same muscle.

*The EDB and EHB are quite frequently damaged during inversion sprains but few seem to ever look to assess it, largely out of ignorance. We had a young runner this past year who had clearly torn just the EHB and could not engage it at all. He was being treated for lateral ankle ligament injury when clearly the problem was the EHB, the lateral ligamentous system had healed fine and this residual was his chief problem.  Thankfully we got the case on film so we will present this one soon for you !  In chronic cases we have been known to take xrays on a non-standard tangential view (local radiographic clinics hate us, but learn alot from our creativity) to demonstrate small bony avulsion fragments proving its damage in unresolving chronic ankle sprains not to mention small myositis ossificans deposits within the muscle mass proper.

Because the tendon travels behind the axis of rotation of the 1st metatarsal phalangeal joint, in addition to providing extension of the proximal phalynx of the hallux (as seen in the child above), it can also provide a downward moment on the distal 1st metatarsal (when properly coupled to and temporally sequenced with the flexor hallicus brevis and longus), assisting in formation of the foot tripod we have all come to love (the head of the 1st met, the head of the 5th met and the calcaneus).

Wow, all that from a little muscle on the dorsum of the foot.

The Gait Guys. Definitive Foot Geeks. We are the kind of people your podiatrist warned you about…