NERVES OF LOWER LIMB AND THEIR INJURIES
LEARNING OBJECTIVES
At the end of lecture students should be able to
•Know the names of nerves and their main branches innervating lower limb
•Know the nerves closely related to a bone or other structure of lower limb
•Know the main nerves commonly vulnerable to injury
•Know the main area and loss of function if particular nerve is injured
•Define and under stand terms neuritis, anesthesia, par aesthesia, paralysis, neuralgia, sciatica
LECTURE OUTLINE
NERVES OF LOWER LIMB
•Arise from lumbar and sacral plexus
•Main nerves of lumbar plexus are
1. Femoral nerve
2. Obturator nerve
3. Lateral cutaneous nerve of thigh
•Main nerves of sacral plexus are
1. Superior gluteal nerve
2. Inferior gluteal nerve
3. Pudendal nerve
4. Sciatic nerve which terminates in popliteal fossa into
a. Tibial nerve
b. Common peroneal nerve
FEMORAL NERVE L2,3,4
•Branch of lumbar plexus
•Nerve of anterior compartment of thigh
•Arise in abdomen, Enters thigh behind inguinal ligament lateral to femoral artery, 2 inch below
inguinal ligament divides into anterior and posterior divisions
Anterior division
•Muscular branches sartorius, Pectineus
•Cutaneous
–Medial cutaneous nerve of thigh
–Intermediate cutaneous nerve of thigh
Posterior division
•Cutaneous --Saphenous nerve---skin of Anteromedial surface of leg, medial border of foot upto
ball of great toe
•Muscular – quadriceps femoris
•Articular to hip and knee joint
FEMORAL NERVE INJURY
•Complete division is rare
•Injured by stab or gunshot wound
•Muscles paralyzed
–
Quadriceps femoris
•Motor loss
–Loss of knee extension
•Sensory loss
–On anterior and medial aspect of thigh
–Medial side of lower leg
–Medial border of foot upto ball of great toe
OBTURATOR NERVE
OBTURATOR NERVE INJURY
Causes
•Penetrating wounds
•Anterior dislocation of hip joint
•Obturator hernia
Muscles paralyzed
•All the adductor muscles except for hamstring part of adductor magnus
Motor loss
•adduction of thigh
Sensory loss
•Medial side of thigh
LATERAL CUTANEOUS NERVE OF THIGH L2,3
•Branch of lumbar plexus
•Enter thigh behind lateral end of inguinal ligament
•Divides into anterior and posterior branches
Distribution
•Lateral aspect of thigh and knee
•Lower lateral quadrant of gluteal region
INJURY OF LATERAL CUTANEOUS NERVE OF THIGH L2,3
Causes
•Compression or inflammation
Presentation
•Sharp pain in the course of distribution
SUPERIOR GLUTEAL NERVE
•Branch of sacral plexus
•Enters gluteal region from pelvis through greater sciatic foramen above piriformis
•Runs between gluteus medius and minimus
Muscles innervated
•Gluteus medius
•Gluteus minimus
•Tensor fascia lata
INJURY TO SUPERIOR GLUTEAL NERVE
Muscles paralyzed
•Gluteus medius
•Gluteus minimus
Motor loss
•Loss of abduction of hip
•Unilateral injury shows lipping gait and positive trendelenberg,s sign i.e. Drooping of pelvis
on one side when ipsilateral foot is lifted off the ground
•Bilateral injury shows waddling gait
INFERIOR GLUTEAL NERVE
Inferior gluteal nerve
•Branch of sacral plexus
•Enter gluteal region from pelvis through greater sciatic foramen below piriformis
•Runs between gluteus maximus and medius
Muscle innervated
•Gluteus maximus
INJURY TO INFERIOR GLUTEAL NERVE
Muscle paralyzed
•Gluteus maximus muscle
Motor loss
•Impairment of hip extension and lateral rotation
•Difficulty in raising the body from sitting or stooping position
SCIATIC NERVE INJURY
Commonly injured in following conditions
•I.V.Disc Prolapse
•Dislocation of hip joint
•Piriformis syndrome
•Intramuscular injection
•Penetrating wound and fracture of pelvis
Most lesions are incomplete
90% cases involve common peroneal due to superficial position
SCIATIC NERVE INJURY IN INTERVERTEBRAL DISC PROLAPSE
SCIATIC NERVE INJURY IN MISPLACED INTRA GLUTEAL INJECTION
•Intramuscular injections are usually given in gluteus maximus
•Sciatic nerve passes midway between greater trochanter and ischial tuberosity
•To avoid injury to sciatic nerve, injection should be given in upper outer quadrant
SCIATIC NERVE AND PIRIFORMIS SYNDROME
Certain leg positions pull the piriformis up against the sciatic nerve causing buttock pain &
radiating leg pain
SCIATIC NERVE INJURY IN DISLOCATION OF HIP JOINT
•Sciatic nerve travels in gluteal region on the posterior surface of hip joint
•Prone to injury in posterior dislocation of hip joint
SCIATIC NERVE INJURY
Muscles
• hamstring muscles and all the muscles below knee;
Motor loss
•Severe impairment in knee flexion
•Loss of all movements at foot
Deformity
• foot drop due to weight of foot.
SCIATIC NERVE INJURY
Sensory loss
•All sensation below knee below the knee except the medial aspect of leg and foot upto ball of
big toe.
•Loss of sensation of sole makes the patient vulnerable to trophic ulcers
SCIATICA
•Pain along the sensory distribution of sciatic nerve
•Posterior aspect of thigh
•Posterior and lateral sides of leg
•Lateral part of foot
Causes
•Prolapse of intervertebral disc
•Intrapelvic tumor
•Inflammation of sciatic nerve
INJURY TO COMMON PERONEAL NERVE
Cause
•Fracture of fibular neck, entrapment by leg casts or splints
Muscles paralyzed
•Anterior and lateral muscles of leg
Deformity
•Equinovarus-- foot is plantar flexed and inverted due to actions of unopposed plantar flexors and
invertors.
INJURY TO COMMON PERONEAL NERVE
Sensory loss
•Anterior and lateral side of leg
•Dorsum of foot and digits
•Medial side of big toe
•Lateral border of foot and lateral side of little toe along with medial border upto the ball of great
toe is unaffected
INJURY TO TIBIAL NERVE
Cause
•Rarely injured in fractures of upper end of tibia or penetrating wound
Muscle paralyzed
•All muscles of back of leg and sole
Deformity
•Calcaneovulgus Dorsiflexion and Eversion of foot
INJURY TO TIBIAL NERVE
Sensory loss
•Whole of the sole of foot
•May result into trophic ulcers