Healthcare and Medicine Reference
Fig. 3.5 In development, the SBL shortens to move us from a fetal curve of primary flexion toward the counterbalancing curves of
upright posture. Further shortening of the muscles of the SBL produces hyperextension.
deep lateral rotators), anterior pelvic shift, sacral nuta-
tion, extensor widening in thoracic flexion, suboccipital
limitation leading to upper cervical hyperextension,
anterior shift or rotation of the occiput on the atlas, and
eye-spine movement disconnection.
From toes to heel
Our originating 'station' on this long line of myofascia
is the underside of the distal phalanges of the toes. The
first 'track' runs along the under surface of the foot. It
includes the plantar fascia and the tendons and muscles
of the short toe flexors originating in the foot.
These five bands blend into one aponeurosis that runs
into the front of the heel bone (the antero-inferior aspect
of the calcaneus). The plantar fascia picks up an addi-
tional and important 6th strand from the 5th metatarsal
base, the lateral band, which blends into the SBL on the
outside edge of the heel bone (Figs 3.6 and 3.7).
These fasciae, and their associated muscles that pull
across the bottom of the foot, form an adjustable 'bow-
string' to the longitudinal foot arches; this bowstring
helps to approximate the two ends, thus maintaining the
heel and the 1st and 5th metatarsal heads in a proper
relationship (Fig. 3.8). The plantar aponeurosis consti-
tutes only one of these bowstrings - the long plantar
ligament and spring ligament also provide shorter and
stronger bowstrings deeper (more cephalad) into the
tarsum of the foot (visible below the subtalar joint in Fig.
The SBL is a cardinal line that primarily mediates
posture and movement in the sagittal plane, either limit-
ing forward movement (flexion) or, when it malfunc-
tions, exaggerating or maintaining excessive backward
Although we speak of the SBL in the singular, there
are, of course, two SBLs, one on the right and one on the
left, and imbalances between the two SBLs should be
observed and corrected along with addressing bilateral
patterns of restriction in this line.
Common postural compensation patterns associated
with the SBL include: ankle dorsiflexion limitation, knee
hyperextension, hamstring shortness (substitution for
The plantar fascia
The plantar surface of the foot is often a source of trouble
that communicates up through the rest of the line. Limi-
tation here often correlates with tight hamstrings,