Things I've Always Wondered But Been too Embarrassed to Ask

Robert, here is the actual text of Root's criteria for normalcy taken from Biomechanical Examinaion of the Foot (Root, Orien, Weed, and Hughes: Clinical Biomechanics Corporation 1971):

BIOPHYSICAL CRITERIA FOR NORMALCY

The following criteria represent the ideal physical relationship of osseous segments of the foot and leg for the production of maximum efficiency during static stance or locomotion. Such ideal relationships are seldom seen clinically, and merely represent the basis for evaluation of the degree of deformity present. Minor variations from these established criteria may be observed without associated symptomatology. Only the clinician can determine when the variance is sufficiently great to produce pathology.


A. The distal one-third (1/3) of the leg is vertical. (Fig. 31)

B. The knee, ankle and subtalar joints lie in transverse planes parallel to the supporting surface. (Fig. 31)

C. The subtalar joint rests at its neutral position. (Fig. 31)

D. The bisection of the posterior surface of the calcaneus is vertical. (Fig. 31)

E. The midtarsal joint is locked in its maximum position of pronation. (Therefore, the forefoot is locked against the rearfoot during stance). (Fig. 31)

F. The plantar forefoot plane parallels the plantar rearfoot plane, and both parallel the supporting surface. In this position, the sagittal bisection of the posterior surface of the calcaneus is perpendicular to the plantar plane of the foot.
(Fig. 31)

G. Metatarsals 2, 3 and 4 are in a totally dorsiflexed position, and the plantar surface of the metatarsal heads describe a common plane parallel to the supporting surface. (Fig. 32)

H. Metatarsals 1 and 5 are maintained in such a position that the plantar surface of these heads lie in the same transverse plane as the metatarsal heads of 2, 3 and 4. (Fig. 32)

In regards to question number 4 (Do other peoples wives shout at them to "Get off that ****ing forum"?) my guess that some of their wives prefer it!

Respectfully
Jeff
www.root-lab.com

 

Thanks Jeff! :drinksConsidering how quick people are to poo poo them its interesting how poorly known they are!

No! Say it ain't so! One of, if not the most well know and most used biomechanical methods of modern times is based on A MISREADING OF THE TEXTBOOK?!?!?!!?

You could never make it up!

Regards
Robert

 

Robert,

I think the technique of palpating the TNJ for congruency as an indicator of STJ position evolved from a section of Biomechanical Examination of the Foot in which the authors described a technique for determining the neutral calcaneal stance position. They described three criteria, used in combination with one another, to determine the neutral calcaneal stance position. Talonavicular congruence was one of the three criteria. I scanned the portion of the text that describes it and posted it below. I hope my scanner didn’t both up the wording somewhere.

I never saw Dr. Root palpate the TNJ in order to find the neutral position of the STJ during an open chain examination of the foot and I know he didn't recommend it. He advocated using the appearance of the curves above and below the lateral mallelous and feeling for the low point in the arc of motion of the forefoot in space as the primary criteria for positioning the STJ in the neutral during open chain examination and casting of the foot.

Respectfully,
Jeff
www.root-lab.com

NEUTRAL CALCANEAL STANCE POSITION


The patient is standing erect on a level hard surface. The feet are placed in their angle and base of gait. The examiner is medial to the foot being examined, to bring his eyes parallel to the posterior surface of the calcaneus.

The subtalar joint is placed in the neutral position (Fig. 127). Three (3) criteria are used to establish this position:

1. The congruity of the medial and lateral edges of the talus to the calcaneus at the subtalar joint.

This can be palpated below or in front of the medial and lateral malleolus. The congruity only occurs, when the subtalar joint is in the neutral position. When the subtalar joint is not in the neutral position, the edges of either the talus or the calcaneus will be prominent.

2. The concavity on the lateral surface of the foot is parallel to the concavity on the lateral surface of the leg.

This is a visual observation made immediately below the lateral malleolus (on the foot), and immediately above the lateral malleolus (on the leg), when the subtalar joint is in the neutral position.

When the subtalar joint is supinated, a convexity appears on the lateral surface of the foot, while the concavity on the leg increases. The convexity is angulated
to the concavity. (Fig. 128)

When the subtalar joint is pronated, the concavity on the foot becomes deeper, and the concavity above the lateral malleolus becomes more shallow. The two (2)
concavities are no longer parallel. (Fig. 129)


3. The lateral surface of the foot describes a straight line in the area of the calcaneal cuboid joint.

This is a visual observation, when the subtalar joint is in the neutral position in stance. (Fig. 127)

When the subtalar joint is supinated, a convexity appears on the lateral surface of the foot. (Fig. 128)

When the subtalar joint is pronated, a concavity appears on the lateral surface of the foot in the area of the calcaneal cuboid articulation. (Fig. 129)


The posterior surface of the calcaneus is bisected, while the subtalar joint is maintained in the neutral position. The neutral calcaneal stance position is measured, using the same technique as measuring the relaxed calcaneal stance position (Figs. 125 & 126). Care must be taken to avoid subtalar joint motion from the neutral position, while the measurement is being made.