Nerve injuries in the lower limb can result from various causes, including trauma, compression, inflammation, or certain medical conditions. Nerves play a crucial role in transmitting signals between the brain and different parts of the lower limb, controlling movements, sensations, and functions. Nerve injuries may range from mild to severe, and the symptoms can vary. Early diagnosis and appropriate medical intervention, which may include physical therapy or, in some cases, surgical repair, are crucial for optimal recovery. Rehabilitation and nerve regeneration can take time, and the outcome depends on the nature and extent of the injury.

1. Dr / Ahmed Salah Ashour(Ph.D.)
Associate professor of human anatomy
Dr.Ahmedashour@gmu.ac.ae
USMLE Clinical Anatomy

2. NERVES

3. • Describe the anatomy of lower limb vasculature.
ILOs

4. Nerve injuries in the lower limb can result from various causes,
including trauma, compression, inflammation, or certain medical
conditions.
Nerves play a crucial role in transmitting signals between the
brain and different parts of the lower limb, controlling
movements, sensations, and functions.
Nerve injuries may range from mild to severe, and the symptoms
can vary. Early diagnosis and appropriate medical intervention,
which may include physical therapy or, in some cases, surgical
repair, are crucial for optimal recovery.
Rehabilitation and nerve regeneration can take time, and the
outcome depends on the nature and extent of the injury.

6. Thigh
Front
Femoral
Medial
Obturator
Back
Sciatic

7. • Origin:
Dorsal division of L 2, 3, 4.
• Course :
Enter the psoas major comes out
at its lateral border between it and
iliacus and divides into two
divisions.
FEMORAL NERVE
Femoral n.
iliacus
psoas major

8. • Branches.
Ø Anterior division
gives the following :
ü Medial cutaneous n. of thigh
ü Inter mediate cutaneous n. of thigh
ü Nerve to sartorius.
Ø Posterior division
gives the following :
ü Saphenous
ü Branches to quadriceps
ü Articular to hip
•
Nerve to sartorius
•
Medial cutaneous n. of thigh
•
Inter mediate cutaneous n. of thigh
•
Branches to quadriceps
•
Saphenous

9. Meralgia paresthetica
The lateral cutaneous nerve of thigh is not a
branch of femoral nerve, and it is
susceptible to compression under the
inguinal ligament.
This entrapment, called meralgia
paresthetica, causes burning along the
lateral thigh.
It is also known as gunslinger neuralgia
because it is commonly caused by a low
riding belt.
lateral cutaneous nerve of thigh
inguinal ligament
Clinical Insight

10. Femoral nerve block
is an anesthetic procedure that uses local anesthetic to numb the leg for surgical
procedures on the lower extremity. It leads to anesthesia of the skin and muscles of
the anterior thigh, as well as the femur and knee joint.
Clinical Insight

11. Largest and longest branch of posterior
division of femoral nerve.
It enter the adductor canal crossing femoral
artery from lateral to medial side.
It pierces the deep fascia and becomes
cutaneous passes in front of medial
malleolus to supply the medial side of foot.
It gives an infra patellar branch to the
patellar plexus.
SAPHENOUS NERVE
Saphenous n.
infra patellar branch

12. Saphenous n.
infra patellar branch
femoral artery
adductor canal
Saphenous n. pierces the deep fascia

13. • Origin:
Ventral division of anterior primary rami of
L2,3,4 .
• Course and relations:
it is partly in pelvis and partly in L.L.
ü In the pelvis : It passes on medial side of
psoas major. In the obturator canal : It
divides into anterior and posterior
division.
ü In the thigh: anterior and posterior
divisions access the ant. Compt. Of
thigh.
OBTURATOR NERVE
Obturator n.
psoas major.

14. Anterior division
Runs between adductor longus and
brevis.
Supplies:
• Adductor longus
• Adductor brevis
• Gracilis
• Pectineus
• Articular to hip joint
• Cutaneous branch [join saphenous
nerve to form subsartorial plexus
and skin of medial side of thigh].
Obturator n.
Anterior division
•
Articular to hip joint
•
Adductor brevis
•
Adductor longus
•
Gracilis
•
Cutaneous branch

15. Posterior division:
Runs between adductor brevis and
magnus.
It supplies
• adductor magnus
• obturator externus
• articular to knee joint.
•
adductor magnus
•
articular to knee joint.
Obturator n.
Posterior division
Adductor magnus.
adductor brevis

16. SCIATIC NERVE
Sciatic n.
•
Medial popliteal
•
Lateral popliteal
• Origin:
Anterior primary rami of
L.4,5 S1,2,3
• End:
At the middle and lower 1 /3 of
back of thigh by dividing into
• Medial popliteal (Tibial)
• Lateral popliteal (Common –
fibular -- peroneal)

17. • Branches:
Articular to hip joint.
Hamstring muscles.
NOT cutaneous to back of thigh
Terminal branches.
Sciatic n.
Hamstring muscles
Medial popliteal
Lateral popliteal

18. Sciatica
Sciatica is pain shooting down
from the low back into the posterior
thigh, along the distribution of the
sciatic nerve.
Most cases are due to disease of the
L4-L5 or L5-S1 discs causing
impingement of L5 or S1 spinal
nerves.
Clinical Insight

19. Popliteal fossa
Medial
Med. popliteal
Lateral
Lat. Popliteal

20. Med. Popliteal
Tibial
Lat. Popliteal
Common fibular
Common peroneal
Post. Tibial

21. • Origin:
L 4,5 S1,2,3
Begins at the junction of middle and lower 1/3
of thigh.
• End :
At lower border of popliteus by becoming
posterior tibial nerve.
MEDIAL POPLITEAL [TIBIAL] NERVE
Sciatic n.
Tibial n.
popliteus
posterior tibial n.

22. • Branches:
Ø Genicular: Superior and inferior medial
genicular and middle genicular (knee)
Ø Muscular:
ü To superficial group of the leg post. Compt.
1. Two heads of gastrocnemius.
2. Plantaris.
3. Soleus.
ü Popliteus and its nerve curves along its
lower border.
Ø Cutaneous: Sural nerve which runs behind
lateral malleolus to supply lateral side of
foot.
Sciatic n.
Tibial n.
Superior medial genicular
n. To Plantaris
n. To gastrocnemius
n. To Popliteus
n. To Soleus
posterior tibial n.

23. Sciatic n.
Tibial n.
Sural nerve

24. • Origin:
One of the two main divisions of the sciatic
nerve. It arises from the sciatic nerve in the
popliteal fossa.
• End :
divides into two main branches:
ü Superficial Fibular (Peroneal) Nerve
ü Deep Fibular (Peroneal) Nerve
LATERAL POPLITEAL NERVE [COMMON FIBULAR (PERONEAL)
NERVE
Tibial n.
common fibular

25. lateral popliteal nerve [common fibular
(peroneal) nerve
Superficial Fibular (Peroneal) Nerve
Deep Fibular (Peroneal) Nerve

26. • Branches:
Ø Genicular: Superior and inferior
lateral genicular (knee)
Ø Cutaneous: Lateral sural cutaneous
nerve, provides sensory innervation to
the skin on the lateral aspect of the leg
Tibial n.
common fibular n.
Superior lateral genicular
Lateral sural cutaneous nerve

27. Common fibular n.
A
Tibial n.
B
Lateral sural cutaneous nerve
C
Sural nerve
D
A
B
C
D

28. Leg
Front
Deep peroneal
Lateral
Superficial peroneal
Back
Post. Tibial

29. Med. Popliteal
Tibial
Lat. Popliteal
Common fibular
Common peroneal
Post. Tibial superficial peroneal
Superficial fibular
Deep peroneal
Deep fibular
Anterior tibial

30. • Origin :
Continuation of medial popliteal nerve at lower
border of popliteus.
• End:
Under flexor retinaculum by dividing into
ü lateral plantar.
ü medial plantar.
POSTERIOR TIBIAL NERVE
medial popliteal nerve
Posterior tibial n.
flexor retinaculum
popliteus

31. • Branches:
Ø Muscular
to deep group of posterior compt. of leg
ü Flexor digitorum longus
ü Flexor hallucis longus
ü Tibialis posterior
Ø Cutaneous
ü Medial calcaneal nerve.
Ø Articular
ü Ankle joint.
Ø Terminal
ü Lateral plantar
ü Medial plantar
medial popliteal nerve
Posterior tibial n.
flexor retinaculum

32. Posterior tibial n.
flexor retinaculum
Medial calcaneal nerve
Medial plantar
Lateral plantar

33. • Origin :
One of two terminal of lateral popliteal under
peroneus longus.
• End :
Terminal branches on dorsum of foot which are
lateral and medial.
• Course and relations:
Passes between peroneus longus and brevis. At
the lower 1 /3 of leg it pierces the deep fascia to
divides into its terminal branches.
SUPERFICIAL PERONEAL - FIBULAR- NERVE
lateral popliteal
superficial peroneal
peroneus longus

35. • Branches:
Ø Muscular:
ü peroneus longus
ü peroneus brevis lateral popliteal
superficial peroneal
peroneus longus

36. Ø Terminal :
ü Medial
divides into two branches
1. First to medial surface of big toe
2. Second to interval between 2nd
and 3rd toe.
ü Lateral
divides into two branches
1. First to interval between 3rd and
4th toes
2. Second to interval between 4th
and 5th toes.
superficial peroneal
Medial branch
Lateral branch
First
Second
First
Second
Sural

37. • Origin :
One of the branches of lateral popliteal at neck of
fibula
• End:
Two terminal branches lateral and medial.
DEEP PERONEAL - FIBULAR- NERVE
ANTERIOR TIBIAL NERVE
lateral popliteal
superficial peroneal
Deep peroneal

38. • Branches
Ø Muscular : to the muscles of anterior
compartment.
Ø Articular : to knee Joint .
lateral popliteal
superficial peroneal
Deep peroneal

39. Ø Terminal branches :
ü Medial : supply the skin of adjacent
sides of 1st and 2nd toes .
ü Lateral supplies the extensor
digitorum brevis.
Deep peroneal
Lateral branch
extensor digitorum brevis
Medial branch

40. Foot
Medial
Med. Planter
Lateral
Lat. Planter

41. Med. Popliteal
Tibial
Lat. Popliteal
Common fibular
Common peroneal
Post. Tibial
Lateral plantar
Medial plantar

42. • Origin:
It is one of terminal branches of the
posterior tibial nerve
• Ends:
Divides into superficial and deep
branches.
• Course:
it passes towards base of 5th metatarsal
bone between the 1st and 2nd layer.
LATERAL PLANTER NERVE
lateral planter nerve
posterior tibial nerve

43. • Branches:
Ø Cutaneous
ü supply the lateral side of sole.
Ø Muscular
ü Flexor digitorum accessorius.
ü Abductor digiti minimi.
lateral planter nerve
posterior tibial nerve

44. Ø Terminal
ü Superficial branch
§ Flexor digiti minimi brevis
§ 3rd plantar and 4th dorsal interossei
§ Two cutaneous digital to lat. 1 ½ toes:
o Adjacent sides of 4th and 5th toes
o Lateral surface of the 5th toe
ü Deep branch
§ Lateral three lumbricals
§ 1st three dorsal interossei
§ 1st two plantar interossei
§ Adductor hallucis.
lateral planter nerve
posterior tibial nerve
Deep branch
Superficial branch
Two cutaneous digital

45. • Origin:
It is one of terminal branches of the
posterior tibial nerve
It is the larger terminal branch of the
posterior tibial nerve. It passes between
the 1st and 2nd layers of sole.
MEDIAL PLANTER NERVE
lateral planter nerve
posterior tibial nerve
Medial planter nerve

46. • Branches:
Ø Muscular :
ü Abductor hallucis
ü Flexor digitorum brevis
ü Flexor hallucis brevis
ü 1st lumbrical
Ø Cutaneous branches :
Four digital nerves: supply skin of
medial 3 ½ toes and larger medial
portion of the sole.
Ø Articular branches : supply Joints of
tarsus and metatarsus
lateral planter nerve
posterior tibial nerve
Medial planter nerve

47. Clinical Insight
Sensory Innervation of the
Lower Leg and Foot
The lateral leg and the dorsum of
the foot are supplied mainly by
the superficial fibular nerve, with
the exception of the first dorsal
web space, which is supplied by
the deep fibular nerve.

48. Clinical Insight
Sensory Innervation of the
Lower Leg and Foot
The sole o f the foot is supplied by
the lateral and medial plantar
branches of the tibial nerve.
The sural nerve supplies the
posterior leg and lateral side of the
foot.
The saphenous nerve supplies the
medial leg and medial foot.

51. Segmental Innervation to Muscles of Lower Limb
• The muscles that cross the anterior side of the hip are innervated by L2 and L3.
• The muscles that cross the anterior side of the knee are innervated by L3 and L4.
• The muscles that cross the anterior side of the ankle are innervated by L4 and LS
(dorsiflexion).
• The muscles that cross the posterior side of the hip are innervated by LS-S2.
• The muscles that cross the posterior side of the knee are innervated by LS and
S2.
• The muscles that cross the posterior side of the ankle are innervated by Sl and S2
(plantar flexion).
Clinical Insight

52. Clinical Insight

53. Common fibular (peroneal)
nerve injuries
can occur with fracture to the
fibular neck.
Patients will present with an
inability to dorsiflex and evert.
Patients often have a steppage
gait as a result of foot drop and
may also present with pain
and paresthesia in the lateral leg
and dorsum of the foot.
Clinical Insight

54. Clinical Insight

55. Sensory changes
Femoral nerve can be detected over the anterior thigh, medial
knee, and medial aspect of the leg.
Obturator sensory changes are detected over the medial thigh
Sciatic nerve over the mid-posterior thigh, knee,
posterolateral leg and entire sole of the foot.
Clinical Insight

56. Sensory area leg + foot
The sensory area of the common fibular
nerve is over the lateral and anterolateral
aspect of the leg and dorsum of the foot.
Deep fibular nerve sensation can be
tested over the skin between the great toe
and second toe dorsally.
Clinical Insight

57. Sciatic nerve lesion
The sciatic nerve is often
damaged following posterior hip
dislocation.
A complete sciatic nerve lesion
results in sensory and motor
deficits in the posterior
compartment of the thigh and all
functions below the knee.
Clinical Insight

58. Intramuscular gluteal injections
are given in the upper outer quadrant of
the buttock to avoid injuring the sciatic
nerve, which passes just inferior to or
through the piriformis muscle in the
middle of the gluteal region.
Clinical Insight

59. Tibial shaft fractures
can cause lacerations of the
anterior or posterior tibial arteries,
producing either anterior or
posterior compartment syndromes.
Clinical Insight

60. Meralgia paresthetica
is a condition that causes a patient to complain of
numbness, tingling, or a burning sensation on the
outer thigh.
It is due to compression of the lateral cutaneous
nerve of the thigh (also called the lateral femoral
cutaneous nerve, or L2-L3), and is often seen
with individuals who wear tight clothing, are
obese, have diabetes, or have experienced injury,
among other causes.
Clinical Insight

61. Formative Quiz

62. Q1. Which nerve is responsible for supplying motor innervation to the muscles of
the anterior compartment of the thigh and is commonly involved in conditions like
meralgia paresthetica?
a) Sciatic nerve
b) Femoral nerve
c) Obturator nerve
d) Tibial nerve

63. Q2. The common peroneal nerve and the tibial nerve are branches of a major nerve
in the lower limb. What is the parent nerve from which they originate?
a) Femoral nerve
b) Sciatic nerve
c) Superior gluteal nerve
d) Saphenous nerve

64. Q3. Damage to the sciatic nerve can result in weakness or paralysis of which muscle
group in the lower limb?
a) Anterior compartment muscles
b) Medial compartment muscles
c) Posterior compartment muscles
d) Lateral compartment muscles

65. Q4. The tibial nerve primarily innervates the muscles of the posterior compartment
of the lower leg. Which muscle is not innervated by the tibial nerve?
a) Gastrocnemius
b) Soleus
c) Popliteus
d) Tibialis anterior

66. Q5. The sciatic nerve is the largest nerve in the body and is formed by two
divisions. What are these two divisions, which often separate in the gluteal region?
a) Common peroneal and tibial nerves
b) Femoral and obturator nerves
c) Superior and inferior gluteal nerves
d) Saphenous and sural nerves

67. Q6 A 34-year-old woman gives birth at 40 weeks of gestation by spontaneous
vaginal delivery that is complicated by perineal laceration. Local nerve block with
lidocaine is given before the repair. The needle is introduced transvaginally and
directed inferolaterally, and the local anesthetic is injected in close proximity to the
sacrospinous ligament and ischial spine.
Which of the following is the spinal root composition of the nerve most likely
blocked?
L4-S1
L4-S2
L4-S3
L5-S2
S2-S4

68. Q7 A 15-year-old boy is brought to the emergency department after falling off his
skateboard. He reports numbness on the outside of his right leg. Physical
examination reveals a swollen right knee. He is unable to dorsiflex or evert the right
ankle. In addition, there is decreased sensation to the lateral leg and dorsum of the
right foot. While walking, he raises the right leg high off the ground, and his foot
subsequently slaps the ground. X-ray of the right lower leg shows a fracture.
Which of the following nerves is most likely to be compromised by the fracture?
Common fibular (peroneal) nerve
Deep peroneal nerve
Femoral nerve
Superficial peroneal nerve
Tibial nerve

69. Q8 A 35-year-old sanitation worker comes to the clinic with severe lower back pain
that began suddenly as he was lifting a heavy load. He describes the pain as sharp
and radiating down his left leg and foot. He does not report bowel or urinary
incontinence. The pain is reproduced when the patient’s left leg is lifted at a 30-
degree angle. Ankle jerk reflex testing reveals 1+ on the left side and 2+ on the right
side. Sensation to pinprick is diminished markedly on the lateral portion of his left
foot.
This patient will most likely experience weakness in which of the following
movements?
Dorsiflexion of foot
Hip flexion
Knee extension
Plantarflexion of foot
Toe extension

70. Q9 A 15-year-old boy presents to the emergency department after falling off his
skateboard. On physical examination he is unable to dorsiflex or evert at the ankle.
In addition, the patient reports pain and numbness in the lateral leg and dorsum of
the foot. When asked to walk, he raises his affected leg high off the ground and his
foot slaps the ground when walking. He is diagnosed with a fracture. Which of the
following structures is most likely to be com- promised by this fracture?
(A)Common peroneal nerve
(B) Femoral nerve
(C) L4 nerve root
(D) Obturator nerve
(E) Tibial nerve

71. Q1. b) Femoral nerve
Q2. b) Sciatic nerve
Q3. c) Posterior compartment muscles
Q4. d) Tibialis anterior
Q5. a) Common peroneal and tibial nerves
Q6 S2-S4
Q7 Common fibular (peroneal) nerve
Q8 Plantarflexion of foot
Q9 Common peroneal nerve

72. List of Texts and Recommended Readings
• Last's Anatomy, Regional and Applied. Chummy S. Sinnatamby. 12th edition 2011, ISBN:13 - 978 0 7020 3394 0
(Available in ClinicalKey: https://www.clinicalkey.com/#!/browse/book/3-s2.0- C2009060533X)
• Estomih Mtui, Gregory Gruener and Peter Dockery. Fitzgerald's Clinical Neuroanatomy and Neuroscience. 7th
edition; 2016, ISBN: 13 - 978-0-7020- 6727-3 (Available in ClinicalKey:
https://www.clinicalkey.com/#!/browse/book/3-s2.0- C20130134113
• Drake, Richard L. Gray's Anatomy for Students, Third Edition, Elsevier Saunders 2015. ISBN-13: 978-0702051319
(Available in ClinicalKey: https://www.clinicalkey.com/#!/browse/book/3- s2.0-C20110061707).
• Sobotta Atlas of Human Anatomy. F. Paulsen. Vol.1, 15th Edition; 2013, ISBN: 9780702052514 (Available in
ClinicalKey: https://www.clinicalkey.com/#!/content/book/3- s2.0-B9780702052514500067)
• Sobotta Atlas of Human Anatomy. F. Paulsen. Vol.2, 15th Edition; 2013, ISBN:13 - 978-0-7020-5252-1 (Available in
ClinicalKey: https://www.clinicalkey.com/#!/browse/book/3- s2.0-C20130046919)

73. Recap