Healthcare and Medicine Reference
The DFL begins deep in the sole of the foot with the
distal attachments of the three muscles of the deep pos-
terior compartment of the leg: the tibialis posterior and
the two long flexors of the toes, the flexor hallucis and
digitorum longus (Fig. 9.4).
The tissue between the metatarsals can also be
included in this line - the dorsal interossei and accom-
panying fascia. This connection is a little hard to justify
on a fascial level except via the link between the tibialis
posterior tendon and the ligamentous bed of the foot.
The lumbricals clearly link fascially and functionally
with the SFL, but the interossei and the space between
the metatarsals both feel and react therapeutically as
part of the deep structure of the foot.
Depending on how you wield the scalpel, the
tibialis posterior has multiple and variable tendinous
attachments to nearly every bone in the tarsum of
the foot except the talus, and to the middle three
metatarsal bases besides (Fig. 9.5). This tendon resem-
bles a hand with many fingers, reaching under the foot
to support the arches and hold the tarsum of the foot
These three tendons pass up inside the ankle behind
the medial malleolus (see Fig. 3.13). The tendon of the
flexor hallucis (the tendon from the big toe) passes more
posteriorly than the other two, beneath the sustentacu-
lum tali of the calcaneus and behind the talus as well.
This muscle-tendon complex thus provides additional
support to the medial arch during the push-off phase of
walking (Fig. 9.6). The tendons of the two toe flexors
cross in the foot, helping to ensure that toe flexion is
accompanied by prehensile adduction.
The three join in the deep posterior compartment of
the lower leg, filling in the area between the fibula and
tibia behind the interosseous membrane (Fig. 9.7).
Fig. 9.3 An early attempt to dissect out the Deep Front Line
shows a continual tissue connection from the toes via the psoas
to the tongue.
She is as in a field a silken tent
At midday when a sunny summer breeze
Has dried the dew and all its ropes relent,
So that in guys it gently sways at ease,
And its supporting central cedar pole,
That is its pinnacle to heavenward
And signifies the sureness of the soul,
Seems to owe naught to any single cord,
But strictly held by none, is loosely bound
By countless silken ties of love and thought
To everything on earth the compass round,
And only by one's going slightly taut
In the capriciousness of summer air
Is of the slightest bondage made aware.
(Reprinted from the Poetry of Robert Frost, Edward
Connery Lathem, ed. Copyright 1942 by Robert Frost,
Copyright 1970 by Lesley Frost Ballantine, by permis-
sion of Henry Holt & Co, LLC.)
The Deep Front Line in detail
The foot and leg
With a reminder that both function and dysfunction in
any of these lines, but this one especially, can travel
either up or down the tracks or out from the middle, we
will begin once again at the bottom and work our way
Fig. 9.4 The lower end of the
DFL begins with the tendons of
the flexor hallucis longus and
flexor digitorum longus.