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1. Posterior muscles of Lower Thoracic/
Lumbopelvic Regions

2. ● Muscles of Lower spine regions produce and
control movement of trunk and stabilize the
trunk for motion of lower extremities.
● They assist in reducing the extensive forces
affecting this area and are involved control of
motion of extremities to stabilize the spine.

3. THORACOLUMBAR FASCIA
● Most superficial structure on the posterior aspect
● Also called lumbodorsal fascia
● Blends with the
○ Latissimus Dorsi
○ Gluteus maximus
○ Internal and external abdominal oblique
○ Transverse abdominis
● Fascia surrounds erector spinae and multifidus muscle of
lumbar region.

5. ERECTOR SPINAE
○ Extensor of the trunk
○ Anatomically and functionally there are superficial
and deep layers
○ Consists of longissimus and iliocostalis muscle
groups.
○ Each group has a thoracic portion ( pars thoracis) and
lumbar portion ( pars lumborum)

6. LONGISSIMUS THORACIS PARS THORACIS
LOCATION
Runs from thoracic
transverse process via
erector spinae
aponeurosis to L3 - S3
posterior superior iliac
spine
FUNCTION
● Extension of thoracic spine
● Extension of lumbar spine
via increasing lordosis
● Assist with ipsilateral
lateral flexion

7. ILIOCOSTALIS LUMBORUM PARS THORACIS
LOCATION
Each of the lower 7-8 ribs to
posterior superior sacroiliac spine and
sacrum with contribution to erector
spinae aponeurosis
FUNCTION
● Extension of lumbar spine via
increasing lordosis
● Assist with ipsilateral lateral
flexion

9. ● They have long tendon that joins together to form
ERECTOR SPINAE APONEUROSIS that insert into
spinous process of lower lumbar spine, sacrum, and
iliac crest.
● It acts until approximately two third of maximal
flexion has been attained , at which point this muscle
become electrically silent. - FLEXION - RELAXATION
PHENOMENON

10. DEEP LAYER OF ERECTOR
SPINAE

11. LONGISSIMUS THORACIS PARS LUMBORUM
LOCATION
Arise from posterior superior iliac
spine and insert to the lumbar
transverse processes
FUNCTION
● Ipsilateral lateral flexion
● Posterior shear
● Assist with extension but
close to axis of rotation

12. ILIOCOSTALIS LUMBORUM PARS
LUMBORUM
LOCATION
From each tip of the lumbar
transverse process to the iliac crest
FUNCTION
● Ipsilateral lateral flexion
● Better rotators
● Assist extension

14. MULTIFIDUS
● A part of transversospinales group That also includes
○ Semispinalis
○ Rotatores
■ These both attach to the transverse process below and spinous process
above
● Lumbar multifidi run from dorsal sacrum an posterior superior iliac spine to
spinous process of lumbar vertebrae.
○ They are easily palpable.