Lumbar Plexus

Authors
Affiliations

Nate Yomogida, B.S., SPT

Doctor of Physical Therapy

B.S. in Kinesiology

Chloë Kerstein, B.S., SPT

Doctor of Physical Therapy

B.A. in Neuroscience

Nerve Roots Motor Innervation Cutaneous Innervation
Iliohypogastric N.

L1

Ilioinguinal N.

L1

Genitofemoral N.

L1, L2

Lateral Cutaneous Nerve of the Thigh

L2, L3

Obturator N.

L2, L3, L4

Femoral N.

L2, L3, L4

Direct Branches

Direct Lumbar Plexus Muscle Innervations
Muscle Origin Insertion Innervation Action
Psoas Major

  • [T12-L4 and associated IV discs](/The Archive/Anatomy/Skeletal Muscles/Lower limb muscles/Iliopsoas muscles/psoas_major_muscle.qmd#origin) [@gilroyAtlasAnatomy2020]

  • [L1-L5 TP](/The Archive/Anatomy/Skeletal Muscles/Lower limb muscles/Iliopsoas muscles/psoas_major_muscle.qmd#origin) [@bogdukAnatomyBiomechanicsPsoas1992]
  • [Lesser Trochanter](/The Archive/Anatomy/Skeletal Muscles/Lower limb muscles/Iliopsoas muscles/psoas_major_muscle.qmd#insertion) [@gilroyAtlasAnatomy2020]


L1 - L31

  • [Lumbar Plexus Direct Br.](/The Archive/Anatomy/Skeletal Muscles/Lower limb muscles/Iliopsoas muscles/psoas_major_muscle.qmd#nerve) [@gilroyAtlasAnatomy2020]

[L1](/The Archive/Anatomy/Skeletal Muscles/Lower limb muscles/Iliopsoas muscles/psoas_major_muscle.qmd#nerve) - [L3](/The Archive/Anatomy/Skeletal Muscles/Lower limb muscles/Iliopsoas muscles/psoas_major_muscle.qmd#nerve) [@gilroyAtlasAnatomy2020]

 Hip

  • [Flexion](/The Archive/Anatomy/Skeletal Muscles/Lower limb muscles/Iliopsoas muscles/psoas_major_muscle.qmd#action) [@gilroyAtlasAnatomy2020]
  • [ER](/The Archive/Anatomy/Skeletal Muscles/Lower limb muscles/Iliopsoas muscles/psoas_major_muscle.qmd#action) [@gilroyAtlasAnatomy2020]

L/S (bilateral contraction)

  • [Raises trunk from supine position](/The Archive/Anatomy/Skeletal Muscles/Lower limb muscles/Iliopsoas muscles/psoas_major_muscle.qmd#action) [@gilroyAtlasAnatomy2020]

L/S (unilateral contraction with femur fixed)

  • [I/L spine sidebend](/The Archive/Anatomy/Skeletal Muscles/Lower limb muscles/Iliopsoas muscles/psoas_major_muscle.qmd#action) [@gilroyAtlasAnatomy2020]

Dysfunction

“The lumbar plexus arises from higher levels (L1–L4) of the spinal cord and supplies muscles of the abdominal wall and anterior and medial thigh.”1

References

1.
Gilroy AM, MacPherson BR, Wikenheiser JC, Voll MM, Wesker K, Schünke M, eds. Atlas of Anatomy. 4th ed. Thieme; 2020.
2.
Bogduk N, Pearcy M, Hadfield G. Anatomy and biomechanics of psoas major. Clinical Biomechanics. 1992;7(2):109-119. doi:10.1016/0268-0033(92)90024-X

Citation

For attribution, please cite this work as: