1. Dr. Fadel Naim Orthopedic Surgeon Faculty of Medicine IUG
Nerves of Lower Limb
Dr. Fadel Naim
Orthopedic Surgeon
Faculty of Medicine
IUG

2. 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

3. 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.

5. 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)

6. Lumbar Plexus Formed in psoas major: From ventral rami of L1- L4.
Branches emerge from both lateral and medial sides of psoas major

8. Lumbar Plexus

10. L1 variably connected to T12 (subcostal) and L2.
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.

11. 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.

12. 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

14. Branches of Femoral Nerve
Anterior division
Two cutaneous
Medial cutaneous nerve of the thigh
Intermediate cutaneous nerves of the thigh
Two muscular branches.
To the sartorius and the pectineus.
Posterior division
The saphenous nerve to medial leg and foot.
The muscular branch Quadriceps muscle
supplies the hip joint
DR FADEL NAIM
IUG

15. DR FADEL NAIM
IUG

16. 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

17. 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

18. 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.

19. Obturator Nerve
The posterior division pierces the obturator externus and passes downward behind the adductor brevis and in front of the adductor magnus
The anterior division passes downward in front of the obturator externus.

23. 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

24. Sacral Plexus
provides motor and sensory nerves for
the posterior thigh
most of the lower leg
the entire foot
part of the pelvis

25. Sacral plexus

26. Branches of the Sacral Plexus
Nerve to quadratus femoris and gemellus inferior: L4-S1
Nerve to obturator internus and gemellus superior: L5-S2
Nerve to piriformis: S1, S2
Superior gluteal nerve: L4-S1
Inferior gluteal nerve: L5-S2
Posterior femoral cutaneous nerve: S1-S3
Tibial nerve: L4-S3
Common fibular (peroneal): L4-S2

27. 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.

28. Posterior Cutaneous Nerve of the Thigh
Branches
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

29. 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.

30. 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.

31. 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.

32. 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

33. 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.

34. Intramuscular Injection

35. Sciatic Nerve
The sciatic nerve usually consists of the tibial and common peroneal nerves bound together with fascia .

37. 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.

38. 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

39. COMMON PERONEAL NERVE Divides into two terminal branches:
the superficial peroneal nerve
the deep peroneal nerve

40. 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.

41. 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

42. 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

44. 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.

45. Branches Tibial Nerve Cutaneous. Muscular branches supply
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.

47. The Skin Of The Buttock
The cutaneous nerves are derived from posterior and anterior rami of spinal nerves
The upper medial quadrant
The posterior rami of the upper 3 lumbar nerves and the upper three sacral nerves.
The upper lateral quadrant
The lateral branches of the iliohypogastric and 12th thoracic nerves (anterior rami)
The lower lateral quadrant
Branches from the lateral cutaneous nerve of the thigh (L2 and 3, anterior rami)
The lower medial quadrant
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

49. 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

50. 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

51. 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

52. 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

53. 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

54. 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
Divides into two branches that supply the anterior aspect of the thigh

55. Branches from the anterior division of the obturator nerve
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

56. The patellar plexus SKIN OF THE THIGH Cutaneous Nerves
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

58. 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

59. 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

61. 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,
Supplies the skin of the lower part of the antero- lateral surface of the leg

62. 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

63. The sensory nerve supply of the foot
The superficial peroneal nerve
The deep peroneal nerve
The saphenous nerve
The sural nerve

64. The sensory nerve supply to the skin of the sole
medial side of the heel
The medial calcaneal branch of the tibial nerve
medial two thirds of the sole
Branches from the medial plantar nerve
lateral third of the sole
Branches from the lateral plantar nerve

65. The sensory nerve supply of the foot

66. The sensory nerve supply of the foot

67. 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

68. Applied aspects: AFFECTED NERVE SENSORY LOSS FEMORAL NERVE
SCIATIC NERVE
COMMON PERONEAL
TIBIAL
OBTURATOR
SUPERIOR GLUTEAL
INFERIOR GLUTEAL
PUDENDAL
DEEP PERONEAL
SUPERFICIAL PERONEAL
Anterior side of thigh and medial side of leg upto big toe.
Back and lateral side of leg, most of dorsum of foot, sole of foot.
Lateral & anterior side of leg, most of dorsum of foot, most of digits.
Skin of sole. Trophic ulcers can develop.
Small area on the medial side of thigh. -
Skin of perineum
1st inter digital cleft
Lateral side of leg, most of dorsum of foot.

69. INJURED NERVE SENSORY LOSS MEDIAL PLANTAR LATERAL PLANTAR
Medial 2/3 rd of sole and digital nerves to medial 3 ½ toes, including nail beds.
Lateral 1/3 rd of sole and digital nerves to lateral 1 ½ toes, including nail beds.