The lumbar plexus is formed from the ventral rami of the L1-L4 spinal nerves and contribution from T12. It provides motor and sensory innervation to the anterior and medial thigh. The branches include the iliohypogastric, ilioinguinal, genitofemoral, femoral, lateral femoral cutaneous, and obturator nerves. The ilioinguinal nerve provides cutaneous sensation to the proximal medial thigh and genitals. The obturator nerve supplies the adductor muscles and medial thigh sensation. The femoral nerve is the largest branch, supplying the anterior thigh and quadriceps muscles.

1. LUMBAR PLEXUS
Aditya johan Romadhon, SST.FT, M.Fis

2. Introduction
Lumbar
plexus is
formed
within the
psoas major
muscle
From the
ventral rami
of the first
four lumbar
nerves (L1-L4)
and a
contribution
of the last
thoracic
nerve (T12)
The fourth
lumbar nerve
(L4) makes a
contribution
to both the
lumbar and
the sacral
plexus
these nerve
roots divide
into the
dorsal rami
and the
ventral rami
as they exit
through the
intervertebral
foramina
The dorsal or
posterior
rami
innervate the
paraspinal
muscles and
supply nearby
cutaneous
sensation
The ventral or
anterior rami
of the lumbar
plexus form
the motor
and sensory
nerves to the
anterior and
medial sides
of the thigh
and the
sensation on
the medial
aspect of the
leg and foot

3. Lumbar plexus
The branches of the lumbar plexus include the iliohypogastric, ilioinguinal,
genitofemoral, femoral, lateral femoral cutaneous, and obturator nerves

5. The main Root of T12
Start from T12, which is the formed the main nerve of subcostal nerve, it
gives motor supply of pyramidalis muscle performs the function of tensing
the linea alba, and gives motor supply to transverse abdominis muscle

6. The main root of L1
• The main root from L1 formed Ilioinguinal nerve, but it also form
iliohypogastric nerve with contributions from the subcostal (T12) nerve
• Illiohypogastric has cutaneous branch supply 2 areas : skin on the pubis and
lateral of buttock, for motor supply it innervate transverse abdominis
(increased intra-abdominal pressure and force diaphargm to force expiratory
procces) and internal oblique muscle which primarily responsible for
vertebrae collumn flexion

8. Illioinguinal nerve the
primary L1 root supply as
cutaneous branch : on the
skin proximal and medial
part of thigh, also upper part
of scrotum, roof of the penis
(male), mons pubis and labia
majora (female) (Primary
Action)
Illioinguinal also give motor
supply to internal oblique
and transverse abdominis
L1 root also form
genitofemoral nerve with
contribution from L2 root,
cutaneous branch supply
scrotum (male) and labia
majora (female) and anterior
thigh superior to medial
inguinal region, while motor
supply to elevate the testis
(cremester muscle)

9. Lateral Femoral Cutaneous (L2-L3)
• L2 and L3 comes together and formed important nerve called lateral
femoral cutaneous to supply sensation for lateral thigh (along iliotibial
tract) and peritoneum

10. Obturator nerve (L2-L3-L4)
• Anterior division (rami) from L2-L3-L4, giving cutaneous supply to medial thigh and
also motor supply to adductor muscle, adductor longus, magnus, brevis, gracilis
(helping hip adduction and flexion), obturator externus (laterally rotates thigh at
the hip)
• The accessory obturator consist of L3-L4, giving cutaneous supply to hip joint and
also motor supply to pectineus (adducts and flexes thigh at hip joint)

11. Femoral nerve (L2-L3-L4)
Posterior division of L2-
L3-L4 form femoral
nerve, which has 2
cutaneous supply
Anterior femoral
cutaneous = supply
anterior and lateral
sensation from thigh
Saphenous branch
supply medial hip joint,
medial thigh, medial
aspect of knee joint,
medial aspect of calf
and heel
Femoral nerve has
motor supply to illiacus
(stabilizer and flexor of
the hip), pectineus,
quadriceps femoris and
sartorius muscle
(flexion of the hip and
knee)

13. THANKS