Download cutaneous nerves

Nerves of Lower Limb
Dr. Fadel Naim
Orthopedic Surgeon
Faculty of Medicine
IUG
Nerves Of The Lower Limb


The nerves entering the lower limb provide the following
important functions:
– Sensory innervation to the skin and deep structures
such as the joints
– Motor innervation to the muscles
– Sympathetic vasomotor nerves that influence the
diameters of the blood vessels
– Sympathetic secretomotor supply to the sweat glands.
Originate from:
– The lumbar plexus, situated in the abdomen
– The sacral plexus, situated in the pelvis
 The
lumbar plexus is formed by the
anterior rami of spinal nerves L1 to L3
and part of L4 .
 The rest of the anterior ramus of L4 and
the anterior ramus of L5 combine to
form the lumbosacral trunk,
 The lumbosacral trunk joins with the
anterior rami of S1 to S3 and part of S4
to form the sacral plexus.
Lumbosacral Plexus
(Lumbar and Sacral Plexuses)
 The
major branches:
Femoral (Lumbar)
– Obturator (Lumbar)
– Sciatic (Sacral)
–
 Tibial
 Common
–
peroneal
The posterior cutaneous nerve of the
thigh (Sacral)
Lumbar Plexus
 Formed
in psoas
major:
From ventral rami of
L1- L4.
– Branches emerge
from both lateral
and medial sides of
psoas major
–
Lumbar Plexus
Lumbar Plexus
 L1
variably connected to T12
(subcostal) and L2.
– Two
branches emerge from
lateral side of psoas major:
 Iliohypogastric:
to side of buttock and pubis.
 Ilioinguinal:
to anterior thigh, scrotum labia majora.
Lumbar Plexus
 Genitofemoral
nerve:
Emerges on anterior surface of
psoas major.
– Genital branch: Sensory motor
–



–
Enters inguinal canal.
Supplies scrotum and labia majora
Supplies cremaster muscle
Femoral branch: purely sensory


Enters femoral sheath.
Supplies skin over femoral triangle.
Femoral Nerve
The largest branch of the
lumbar plexus (L2, 3, and 4).
 Emerges from lateral side of
psoas major.
 Supplies all the muscles of the
anterior compartment of the
thigh

–
iliopsoas, pectineus, sartorius, and
quadriceps femoris
Branches of Femoral Nerve

Anterior division
–
Two cutaneous


–
Two muscular branches.


Medial cutaneous nerve of the thigh
Intermediate cutaneous nerves of the thigh
To the sartorius and the pectineus.
Posterior division
–
–
–
The saphenous nerve to medial leg and
foot.
The muscular branch Quadriceps
muscle DR FADEL NAIM
IUG
supplies the
hip joint
DR FADEL NAIM
IUG
Obturator Nerve

The obturator nerve arises
from the lumbar plexus
(L2, 3, and 4)

Emerges on the medial
border of the psoas
muscle within the abdomen

It divides into anterior and
posterior divisions
Branches of
Obturator Nerve

The anterior division:
–
It gives muscular branches to:
 The
gracilis
 Adductor brevis
 Adductor longus
 Occasionally to the pectineus.
–
–
–
It gives articular branches to the hip joint
Terminates as a small nerve that supplies the
femoral artery.
Supplies the skin on the medial side of the
thigh
Branches of Obturator Nerve
 The
posterior division
– Supply
the knee joint
– It gives muscular branches to:
The
obturator externus
The adductor part of the adductor
magnus
Occasionally to the adductor brevis.
Obturator Nerve
The anterior
division passes
downward in
front of the
obturator
externus.
The posterior division
pierces the obturator
externus and passes
downward behind the
adductor brevis and in
front of the adductor
magnus
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Sacral Plexus
•The sacral plexus is formed by:
•the lumbosacral trunk
•the anterior devision of the 1st
sacral nerve
•portions of the anterior divisions
of the 2nd and 3rd sacral nerves
Sacral Plexus
•provides motor and sensory nerves for
•the posterior thigh
•most of the lower leg
•the entire foot
•part of the pelvis
Sacral plexus
Branches of the Sacral Plexus
1. Nerve to quadratus femoris and gemellus
inferior: L4-S1
2. Nerve to obturator internus and gemellus
superior: L5-S2
3. Nerve to piriformis: S1, S2
4. Superior gluteal nerve: L4-S1
5. Inferior gluteal nerve: L5-S2
6. Posterior femoral cutaneous nerve: S1-S3
7. Tibial nerve: L4-S3
8. Common fibular (peroneal): L4-S2
Posterior Cutaneous Nerve of the Thigh



A branch of the sacral plexus,
enters the gluteal region through
the lower part of the greater
sciatic foramen below the
piriformis muscle
It passes downward on the
posterior surface of the sciatic
nerve and runs down the back of
the thigh beneath the deep fascia.
In the popliteal fossa it supplies the
skin.
Posterior Cutaneous Nerve of the Thigh
Branches

1.
2.
3.
Gluteal branches to the skin over the
lower medial quadrant of the buttock
Perineal branch to the skin of the back
of the scrotum or labium majus.
Cutaneous branches to the back of the
thigh and the upper part of the leg
Superior Gluteal Nerve

Abranch of the sacral plexus

Leaves the pelvis through the upper part of the
greater sciatic foramen above the piriformis

It runs forward between the gluteus medius and
minimus

Supplies gluteus medius and minimus and ends by
supplying the tensor fasciae latae.
Inferior Gluteal Nerve



A branch of the sacral plexus
Leaves the pelvis through the lower part of the
greater sciatic foramen below the piriformis
It supplies the gluteus maximus muscle.
Nerve to the
Quadratus Femoris



A branch of the sacral plexus
Leaves the pelvis through the lower part of
greater sciatic foramen
It ends by supplying quadratus femoris and
the inferior gemellus.
Pudendal Nerve and the
Nerve to the Obturator
Internus






Branches of the sacral plexus
Leave the pelvis through the lower
part of the greater sciatic foramen,
below the piriformis
They cross the ischial spine with the
internal pudendal artery and
immediately reenter the pelvis
through the lesser sciatic foramen
They then lie in the ischiorectal fossa
The pudendal nerve supplies
structures in the perineum.
The nerve to the obturator internus
supplies the obturator internus
muscle
Sciatic Nerve




A branch of the sacral
plexus (L4 and 5; SI, 2, and
3)
Emerges from the pelvis
through the lower part of
the greater sciatic foramen
It is the largest nerve in the
body .
Gives no branches in the
gluteal region.
Intramuscular Injection
Sciatic Nerve


The sciatic nerve usually consists of the tibial and common
peroneal nerves bound together with fascia
.
Branches of the
sciatic nerve
The tibial nerve
 The common peroneal
nerve
 Muscular branches to:

–
–
–
–
the long head of the
biceps femoris
the semitendinosus
the semimembranosus
the hamstring part of the
adductor magnus.
COMMON PERONEAL NERVE




The smaller terminal branch
of the sciatic nerve
arises in the lower third of
the thigh
It then passes behind the
head of the fibula, winds
laterally around the neck of
the bone
it is subcutaneous and can
easily be rolled against the
bone
COMMON PERONEAL NERVE

Divides into two terminal
branches:
–
–
the superficial peroneal nerve
the deep peroneal nerve
Deep Peroneal Nerve



One of the terminal branches of the
common peroneal nerve
The nerve enters the anterior
compartment of the leg by
piercing the anterior fascial septum.
Branches
–
Muscular branches to:




–
The tibialis anterior
The extensor digitorum longus
The peroneus tertius
The extensor hallucis longus.
Articular branch to the ankle joint.
Superficial Peroneal Nerve





One of the terminal branches of
the common peroneal nerve
It arises on the lateral side of the
neck of the fibula
It descends between the peroneus
longus and brevis muscles
In the lower part of the leg it
becomes cutaneous
Muscular branches to
–
–
The peroneus longus
The peroneus brevis
Superficial
Peroneal Nerve

Cutaneous.
–
–
–
Medial and lateral branches are distributed to the skin on the lower
part of the front of the leg and the dorsum of the foot.
Branches supply the dorsal surfaces of the skin of all the toes
Except


The adjacent sides of the first and second toes
The lateral side of the little toe
TIBIAL NERVE




The larger terminal branch of the sciatic nerve
The tibial nerve arises in the lower third of the
thigh.
It runs downward through the popliteal fossa,
The nerve enters the posterior compartment of
the leg by passing beneath the soleus
muscle.
Branches Tibial
Nerve

Cutaneous.
–

The sural nerve
Muscular branches supply
–
–
–
–
Both heads of the gastrocnemius
The plantaris
Soleus
Popliteus
Lateral and medial plantar nerves
 Articular

–
Branches supply the knee joint.
The Skin Of The Buttock

The cutaneous nerves are derived from posterior and
anterior rami of spinal nerves
–
The upper medial quadrant
–
–
The upper lateral quadrant
–
–
Branches from the lateral cutaneous nerve of the thigh (L2 and 3,
anterior rami)
The lower medial quadrant
–
–
The lateral branches of the iliohypogastric and 12th thoracic
nerves (anterior rami)
The lower lateral quadrant
–
–
The posterior rami of the upper 3 lumbar nerves and the upper
three sacral nerves.
Branches from the posterior cutaneous nerve of the thigh (S1, 2,
and 3, anterior rami).
The skin over the coccyx
–
Small branches of the lower sacral and coccygeal nerves
SKIN OF THE THIGH
Cutaneous Nerves

The femoral branch
of the genitofemoral
nerve
–
–
A branch of the lumbar
plexus (L1 and 2)
Supplies a small area
of skin
SKIN OF THE THIGH
Cutaneous Nerves

The ilioinguinal nerve
–
–
a branch of the lumbar plexus
(Ll)
It is distributed to the skin of the



root of the penis and adjacent part of
the scrotum
root of the clitoris and adjacent part of
the labium majus in the female
a small skin area below the medial part
of the inguinal ligament
SKIN OF THE THIGH
Cutaneous Nerves
–
The posterior cutaneous
nerve of the thigh
A
branch of the sacral
plexus
 It descends on the back of
the thigh, and in the popliteal
fossa
 It gives off numerous
branches to the skin on the
back of the thigh and the
upper part of the leg
SKIN OF THE THIGH
Cutaneous Nerves

The lateral cutaneous nerve of
the thigh
–
–
–
–
A branch of the lumbar plexus (L2
and 3), enters the thigh behind the
lateral end of the inguinal ligament
Having divided into anterior and
posterior branches
It supplies the skin of the lateral
aspect of the thigh and knee
It also supplies the skin of the lower
lateral quadrant of the buttock
Meralgia paresthetica





Compression on lateral cutaneous nerve of
the thigh
common in men than in women
Paraesthesiae and often burning pain over the
anterolateral aspect of the thigh.
Prolonged standing, or sitting may provoke
symptoms
Whereas flexion of thigh on the pelvis improves
symptoms
SKIN OF THE THIGH
Cutaneous Nerves

The medial cutaneous nerve of
the thigh
–
–
–

A branch of the femoral nerve
Supplies the medial aspect of the
thigh
Joins the patellar plexus
The intermediate cutaneous
nerve of the thigh
–
–
–
A branch of the femoral nerve
Divides into two branches that supply
the anterior aspect of the thigh
Joins the patellar plexus
SKIN OF THE THIGH
Cutaneous Nerves
 Branches
from the anterior
division of the obturator
nerve
–
Supply a variable area of
skin on the medial aspect
of the thigh
SKIN OF THE THIGH
Cutaneous Nerves

The patellar plexus
–
–
Lies in front of the knee
Formed from the terminal branches
of:
 The
lateral cutaneous nerves of the
thigh
 Intermediate cutaneous nerves of the
thigh
 Medial cutaneous nerves of the thigh
 The infrapatellar branch of the
saphenous nerve
The Back of the Leg
Cutaneous Nerves

The posterior cutaneous nerve of the thigh
descends on the back of the thigh
–

In the popliteal fossa, it supplies the skin over the
popliteal fossa and the upper part of the back of the
leg
The lateral cutaneous nerve of the calf,
–
a branch of the common peroneal nerve supplies the
skin on the upper part of the posterolateral surface of
the leg
The Back of the Leg
Cutaneous Nerves
 The sural nerve,
– a branch of the tibial nerve supplies the
skin on the lower part of the posterolateral
surface of the leg
 The saphenous nerve,
– a branch of the femoral nerve gives off
branches that supply the skin on the
posteromedial surface of the leg
The Front of the Leg
Cutaneous Nerves

The lateral cutaneous nerve of
the calf
–
–

A branch of the common peroneal
nerve
Supplies the skin on the upper part
of the lateral surface of the leg
The superficial peroneal nerve,
–
–
A branch of the common peroneal
nerve
Supplies the skin of the lower part
of the antero- lateral surface of
the leg
The Front of the Leg
Cutaneous Nerves

The saphenous nerve,
–
–
A branch of the femoral
nerve
Supplies the skin on the
antero-medial surface of
the leg
The sensory nerve
supply of the foot




The superficial peroneal nerve
The deep peroneal nerve
The saphenous nerve
The sural nerve
The sensory nerve
supply to the skin of
the sole

medial side of the heel
–

medial two thirds of the sole
–

The medial calcaneal branch of the tibial nerve
Branches from the medial plantar nerve
lateral third of the sole
–
Branches from the lateral plantar nerve
The sensory nerve
supply of the foot
The sensory nerve
supply of the foot
The dermatomes of the lower body
L1: the upper, inner thigh
L2: 5cm above the
kneecap
L3: the kneecap
L4: 5cm below the
kneecap
L5: the lateral calf
S1: the little toe
Applied aspects:
AFFECTED NERVE
SENSORY LOSS
FEMORAL NERVE
Anterior side of thigh and medial side of leg upto big toe.
SCIATIC NERVE
Back and lateral side of leg, most of dorsum of foot, sole of foot.
COMMON PERONEAL
Lateral & anterior side of leg, most of dorsum of foot, most of digits.
Skin of sole. Trophic ulcers can develop.
TIBIAL
Small area on the medial side of thigh.
OBTURATOR
SUPERIOR GLUTEAL
INFERIOR GLUTEAL
Skin of perineum
PUDENDAL
1st inter digital cleft
DEEP PERONEAL
Lateral side of leg, most of dorsum of foot.
SUPERFICIAL
PERONEAL
INJURED NERVE
SENSORY LOSS
MEDIAL PLANTAR
Medial 2/3 rd of sole and digital
nerves to medial 3 ½ toes,
including nail beds.
LATERAL PLANTAR
Lateral 1/3 rd of sole and digital
nerves to lateral 1 ½ toes,
including nail beds.