Too much extensor tone: The banana toe.

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Too much extensor tone.
We are often talking about the subtle balanced relationship of the long and short toe flexors and extensors. We often discuss that hammer toes are too much long flexor and short extensor tone (with too little in the short flexor and long extensor).
Here we see the opposite. We see too much long extensor tone (note the upward banana-shaped orientation of the big toe). When this foot is on the ground, the pad and distal 1/2 of the big toe does not even touch the ground, standing or in gait. IF you look closely at the blown up pic, you can sort of see (sorry, should have taken more pics) the increased callus development in the contact area of the short flexor attachment (FHB, flexor hallucis brevis).

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This relationship is the opposite of the above with hammer toes. Too much long extensor, too much short flexor, and not enough long flexor and short extensor. These clients need more homework for long flexor and short extensor. This is one of the reasons why we developed the exercise below in the youtube link.

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The Banana Toe: The Force has to go somewhere. It’s a Jedi Gait Rule.

* note: there are 4 photos to today’s blog post. Be sure you click through all 4.

When you toe off, you have to toe off from somewhere in the foot unless you like an apropulsive hip flexion gait, where  you just lift you foot off the ground from foot flat, kind of like a true neurologic “foot drop” gait client would.  But, if you are lucky enough not to have a true foot drop, you are going to push off somewhere in the foot.  You can do it off the lateral foot (low gear toe off) and lesser toes, or you can do it off the big toe (high gear) the way we were built to do it. 

The above pictures show a nasty dorsal crown of osteophytes that is limiting hallux (big toe) extension/dorsiflexion. This is true hallus rigidus and hallux limitus. When this client attempts to toe off, the joint cannot normally partake in the activity, there is no Windlass effect, no posturing up over the sesamoids for mechanical advantage etc.   

In this scenario, there are two places you can put it, up into the next proximal joint(s) meaning the met-cuneiform joint or further down into the interphalangeal joint. In other words. the loads go proximal or distal to the limited joint, and they eventually play out there, over and over and over gain. The former option would basically mean you are pronating/dorsiflexing through the midfoot which is never good (can you say Saddle exostosis ! ouch !) or the latter option is to dorsiflex through the interphalangeal joint  and over time that toe begins to attenuate plantar ligamentous structures and extend beyond its normal limits resulting in the “Chiquita” toe (a upward bent toe resembling a banana shape). This will disable the long flexor of the great toe (FHL: flexor hallucis longus).and inhibit mechanical advantage of the extensor digitorum brevis.  If you struggle with the “how and why” behind this sentence in terms of restoration attempts, you need to watch my video here. It will offer you deeper insights.

Will this toe become painful ? yes, in time it is quite possible.  Is there much you can do? Sure, a rocker bottomed shoe will help take the load at toe off instead of forcing it into this toe or the midfoot.  Will an orthotic  help ? Well, this is a loaded question. If you are putting the forces into the midfoot choice as described above, the orthotic will block that motion and you will likely default option into the toe presentation above. So you are merely just moving loading forces around. It can be helpful, but you are quite possibly “robbing Peter to pay Paul” as they say.  The video I asked you to watch can be helpful but it will force that metatarsophalangeal joint into extension, a range it does not have, so it is not a remedy and not recommended.  Perhaps some awareness and slight increase in FHL(long toe flexor) use can be attained however.  These are tricky cases, simple in theory, but execution can be fussy and requires patient awareness and education. We like the rocker bottomed shoe as a nice easy solution and some increased FHL use awareness.  Help them find a little more FHL use by putting a pencil under the crease of the toe and help them to drive the tip of the toe down just a little out of that banana extension posture. It can help them control the overloading of the dorsal aspect of the interphalangeal joint.

As always, lets carry this forward into gait thoughts.  How is  hip extension going to be in this client ? How is glute strength ? Hip joint range ? Hip extension motor patterning ? Will the client go into anterior pelvic tilt to borrow the last range of hip extension ? Will the hamstrings have to accommodate ? Lots of yummy biomechanical and neurological mental gymnastics here. Bottom line answer to all the above ?  “ it depends, they will have to accommodate and compensate”.  And as the Jedi Gait Rule goes, “the Force as to go somewhere”.

Shawn Allen, one of the gait guys

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Ahh yes, the lumbricals. 

One of our favorite muscles. And here it is in a recent paper! This one is for all you fellow foot geeks : )

Perhaps the FDL (which fires slightly earlier than the FHL) and FHL (which fires slightly later and longer) at loading response, slowing pronation and setting the stage for lumbrical function from midstance to terminal stance/preswing (flexion at the metatarsal phalangeal joint (it would have to be eccentric, if you think about this from a closed chain perspective) and extension (actually compression) of the proximal interphalangeal joints.

“The first lumbrical arose as two muscle bellies from both the tendon of the FDL and the tendinous slip of the FHL in 83.3 %, and as one muscle belly from the tendon of the FDL or the tendinous slip of the FHL in 16.7 %. These two muscle bellies subsequently merged to form the muscle belly of the first lumbrical. The second lumbrical arose from the tendinous slips of the FHL for the second and third toes as well as the tendon of the FDL in all specimens. The third lumbrical arose from the tendinous slips of the FHL for the third and fourth toes in 69.7 %, and the fourth lumbrical arose from the tendinous slip of the FHL for the fourth toe in 18.2 %. Some deep muscle fibers of the fourth lumbrical arose from the tendinous slip of the FHL for the second toe in 4.5 %, for the third toe in 28.8 %, and for the fourth toe in 15.2 %.”

Hur MS1, Kim JH, Gil YC, Kim HJ, Lee KS. New insights into the origin of the lumbrical muscles of the foot: tendinous slip of the flexor hallucis longus muscle. Surg Radiol Anat. 2015 May 12. [Epub ahead of print]

Does this foot look like your foot ?  
 There are a few subtle issues here. At first glance this foot looks half-way decent but upon further observation you should note the subtle drift of all of the toes.  In the foot, the toe that delineates abduction and adduction of the toes is the 2nd toe. The 2nd toe is considered the anatomic middle of the digits and forefoot. Any toe or movement that moves away from the 2nd toe is abduction and any movement towards the 2nd toe is adduction. This is obviously different than in the hand where the 3rd digit is the reference digit.   
 In this foot, look at the shape of the 2nd and even the 3rd digit, they have a curve to them. Remember, form follows function and the dead give away here is that the hallux (the big toe) is drifting into adduction towards the 2nd digit. This is referred to as early hallux valgus and it is accompanied by early evidence of a bunion at the medial foot at the metatarsophalangeal joint.  When the shaft of the hallux is not in line with the shaft of the metatarsal long bone we get the angulation between the two causing the hallux valgus.  This is often from excessive pronation (either rearfoot, midfoot and/or forefoot) that collapses the tripod, splays the distal MET head via its dorsiflexion, and the development of complicated long and short hallux flexor muscle dysfunction as well as abductor hallucis (transverse and oblique head) disfunction further driving the hallux pull medially.  When the distal toes are engaged on the ground and there is still forefoot pronation occurring through the medial tripod support, the toes will be forced into a twist or spin, and in time you will get toes that appear drifted or windswept like these toes appear.  A similar phenomenon occurs at the lateral foot and a Tailor’s bunion begins to occur there as the forefoot begins to widen as the MET heads separate and the toes funnel medially (often provoked to do so by pointed footwear).   
 We can also see the 4th and 5th toes curl under from the probably weak lateral head of the quadratus plantae thus encouraging unopposed oblique pull of the long flexors of the digits (FDL).  See this post here  for an explanation of this phenomenon.   
 This is a fairly typical foot that we see in our practices.  This is not a far-gone foot but one has to catch this foot at this stage or it is rather difficult to resuscitate back to a healthy foot. Like a spinal scoliosis, once a bunion and  hallux valgus gets too far, it becomes an issue of symptom management rather than repair.  Hallux abduction must be retaught, tripod skills must be retaught, intrinsic foot muscle strength must be regained as well as strength and endurance of the tibialis anterior and toe extensors to help raise the arch again and control pronation. Sometimes a temporary orthotic can help the person to passively regain some degree of competent tripod while homework earns the changes. In some cases, an orthotic needs to be a permanent intervention if tripod stability cannot be adequately achieved.  But, we never give up and neither should you or your client, amazing things can happen over long periods of time when correction is forced. 
 There is plenty of life left in this foot, but you have to get to it quickly and get them in lower heeled shoes if tolerable and ones with a wider toe box.  Support the midfoot with an orthotic or built up foot bed, if necessary, but don’t leave it there. It is a crutch, and even crutches are intended to be put aside at some point.  
 Shawn and Ivo, The gait guys

Does this foot look like your foot ? 

There are a few subtle issues here. At first glance this foot looks half-way decent but upon further observation you should note the subtle drift of all of the toes.  In the foot, the toe that delineates abduction and adduction of the toes is the 2nd toe. The 2nd toe is considered the anatomic middle of the digits and forefoot. Any toe or movement that moves away from the 2nd toe is abduction and any movement towards the 2nd toe is adduction. This is obviously different than in the hand where the 3rd digit is the reference digit.  

In this foot, look at the shape of the 2nd and even the 3rd digit, they have a curve to them. Remember, form follows function and the dead give away here is that the hallux (the big toe) is drifting into adduction towards the 2nd digit. This is referred to as early hallux valgus and it is accompanied by early evidence of a bunion at the medial foot at the metatarsophalangeal joint.  When the shaft of the hallux is not in line with the shaft of the metatarsal long bone we get the angulation between the two causing the hallux valgus.  This is often from excessive pronation (either rearfoot, midfoot and/or forefoot) that collapses the tripod, splays the distal MET head via its dorsiflexion, and the development of complicated long and short hallux flexor muscle dysfunction as well as abductor hallucis (transverse and oblique head) disfunction further driving the hallux pull medially.  When the distal toes are engaged on the ground and there is still forefoot pronation occurring through the medial tripod support, the toes will be forced into a twist or spin, and in time you will get toes that appear drifted or windswept like these toes appear.  A similar phenomenon occurs at the lateral foot and a Tailor’s bunion begins to occur there as the forefoot begins to widen as the MET heads separate and the toes funnel medially (often provoked to do so by pointed footwear).  

We can also see the 4th and 5th toes curl under from the probably weak lateral head of the quadratus plantae thus encouraging unopposed oblique pull of the long flexors of the digits (FDL). See this post here for an explanation of this phenomenon.  

This is a fairly typical foot that we see in our practices.  This is not a far-gone foot but one has to catch this foot at this stage or it is rather difficult to resuscitate back to a healthy foot. Like a spinal scoliosis, once a bunion and  hallux valgus gets too far, it becomes an issue of symptom management rather than repair.  Hallux abduction must be retaught, tripod skills must be retaught, intrinsic foot muscle strength must be regained as well as strength and endurance of the tibialis anterior and toe extensors to help raise the arch again and control pronation. Sometimes a temporary orthotic can help the person to passively regain some degree of competent tripod while homework earns the changes. In some cases, an orthotic needs to be a permanent intervention if tripod stability cannot be adequately achieved.  But, we never give up and neither should you or your client, amazing things can happen over long periods of time when correction is forced.

There is plenty of life left in this foot, but you have to get to it quickly and get them in lower heeled shoes if tolerable and ones with a wider toe box.  Support the midfoot with an orthotic or built up foot bed, if necessary, but don’t leave it there. It is a crutch, and even crutches are intended to be put aside at some point. 

Shawn and Ivo, The gait guys