Lumbar Fascia

• Three layers
  • Anterior
    • Attachement: Anterior transverse process
  • Middle
    • Attachement: Tip of transverse process
  • Posterior
    • Attachement: Tip of spinous process
  • Fuse laterally to form dense aponeurotic sheath
    • This is the attachment for
      • Internal oblique
      • Transversus abdominus
• Muscles attachments
  • Trapezius
  • Gluteus maximus
  • Latissimus Dorsi
• Muscles inbetween
  • Quadratus Lumborum
    • Between anterior and middle
  • Erector spinae and transverse spinous muscles
    • Between middle and posterior

Lumbar portion of the Thoraco-Lumbar Fascia

• 3 layers of fascia enclose 2 muscular compartments
  • Anterior and middle layers occupy only lumbar region
  • Posterior layer extends above to the lower part of the neck and below to the dorsal surface of the sacrum
  • Anterior layer:
    • Extends from front of Iliolumbar Ligament and adjoining Iliac Crest to lower border of 12th Rib
    • Medially: attached to front of each lumbar transverse process adjoining the attachment of the Psoas Fascia
    • Laterally: blends with middle layer along the lateral border of Quadratus Lumborum
      • Transverse abdominis and Internal Oblique take origin
  • Middle layer:
    • Extends from back of Iliolumbar Ligament and adjoining iliac crest up to 12th Rib
    • Medially: attached to tips of lumbar transverse processes
    • Laterally: blends with both anterior and posterior layers
      • Line of fusion with posterior layer is along lateral border of Erector Spinae
  • Posterior layer:
    • Lies over whole Erector Spinae muscle mass
    • Medially: attached to spinous processes and supraspinous ligaments of all sacral, lumbar and thoracic vertebrae
    • Laterally: extends along transverse tubercles of Sacrum to posterior part of Iliac Crest
    • Attaches to 12th Rib
    • Above 12th Rib, attached to angles of all ribs
    • In thorax, single posterior layer constitutes the thoracic part of the Thoracolumbar Fascia
    • Reinforced by fusion of the aponeurotic origin of Latissimus Dorsi
    • Fades out above 1st Rib over the extensor muscles of Neck
    • Replaced by Splenius Muscle
  • Anterior compartment:
    • Occupied by Quadratus Lumborum
  • Posterior compartment:
    • Occupied by Erector Spinae