Healthcare and Medicine Reference
Perhaps a better image would be of a strip of wood with a
string stretched on either side (Fig. 4.28A). As the string on
one side was shortened, the wood would bend, stretching,
perforce, the string on the other side (Fig. 4.28B).
A commonly observed pattern shows the hamstrings and
the muscles surrounding the sacrum becoming shortened and
bunched, pushing the pelvis and hip forward. The muscles on
the front of the hip then become tight as they are stretched
and strain to contain the forward push from the back. It is very
important clinically to distinguish between the muscle that is
tense because it is shortened, and the muscle that is tense
because it is strained, as treatment of the two conditions will
differ (Fig. 4.29).
Just as often, however, we see the opposite pattern
between the SFL and the SBL: the front is locked short, round-
ing the thoracic spine or flattening the lumbar curve, creating
Balance between the Superficial Front and the
Superficial Back Lines
The first aspect of the SFL to note is its disjointed, disparate
nature compared to the long conjoined flow of the SBL. In
contrast, the SFL shows more discrete functioning of its con-
stituent parts: the anterior crural compartment, the quadri-
ceps, the rectus abdominis, and the SCM. Though they often
work together to create consistent pulls along the SFL, they
tend to conjoin truly into a single band only in relatively extreme
hyperextended postures such as a backbend (Fig. 4.26 or Fig.
4.7A), or in extreme contraction (Fig. 4.30).
This brings us to the obvious, but complex, relationship
between the SFL and the SBL, the two lines that traverse the
front and back aspects of the body. In the example of the
'military' or 'compensated oral' postural preference, the SBL
(or some portion of it) is 'locked short' like a bowstring (Fig.
4.27). In the same example, the SFL (or some portion of it) will
be 'locked long' - i.e. strained, stretched, or pulled on, with
the visceral contents of the ventral cavity pushed forward
against its restraining tension. If the SBL is acting like a bow-
string, the SFL starts to act like the wood on the front of the
Fig. 4.27 The 'military' style of
posture involves shortening and
tightening the SBL, especially the
middle part, while the SFL must
lengthen in some other part to
Fig. 4.28 (A) Myofascial units
are often arranged in antagonistic
pairs on either side of the
skeletal armature. (B) When one
side is held chronically short,
either muscularly or fascially
('locked short'), the other side is
stretched tight ('locked long').
Fig. 4.26 The four tracks of the SFL are able to work separately in
standing, but will conjoin in trunk hyperextension.