Thoracodorsal fascia | Anatomy Tutorial | : Thoraco-lumbar Fascia : 10 min Tutorial

Lumbo-sacral spine plays a central role in sustaining the postural stability of the body, however the lumbar spine alone is not capable of sustaining the normal load that it carries daily. To stabilize the lumbar vertebrae on the sacral base, require the assistance of complex myofascial and aponeurotic girdle surrounding the torso.
On the posterior body wall, the central point of this girdling structure is thoraco lumbar fascia (TLF), a blend of aponeurotic and fascial planethat form the retinaculum around the paraspinal muscles of lower back and sacral region.
muscular forces are transmitted through associated endo and epimysium connective tissue into the surrounding skeletal system via ligaments, tendon and aponeuroses.
TLF is a critical part of myfascial girdles tat surround the lower portion of the torso playing an important role in posture, load transfer and respiration.
TLF is a complex of several layers that separate the paraspinal muscles of the posterior abodminal wall, the quadratus lumborum and psoas major.
The three layered model consists of posterior layer - which consists of superficial and deep lamina.
in between these laminae above the L4 level, aponeurosis of SPI is present.
The Three layered model is the most commonly used model in recent research studies.
Posterior layer has superficial and Deep Lamina.
Superficial layer has composite of superficial fascial continuous extension of thin epimysium layer of latissimus dorsi, however these superficial layer is not continuous with the central component, the central component has deep lamina of PLF forming a fascial sheath coined the paraspinal retinaculum sheath (PRS)anterior wall blended to this retinaculum is MLF. posteriorly, on the midline THE PRS is attached to lumbar spinous process and the associated supraspinal ligament.
This Cylindrical sheath then passes laterally around the border of paraspinal muscls, coursing between these muscles and QL to reach the tip of transverse process of lumbar vertebrae of l2 - l4. As PRS enter the space between the QL and Paraspinal muscles, it is joined by aponeurosis of transverse abdominis. These 2 thickened bands fuses with epimysium of QL this is MLF.
MLF is situated between the QL and Paraspinal Muscles, it is thick strong aponeurotic structure arising from the tip of transverse process.
ALF - around the Quadratus and Psoas Muscles.
in next video - we will discuss, nerve supply, blood supply and function in details .