Nerves of Lower Limb and Their Injuries

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 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 L3 L2 abdomen L4

pelvis Anterior division Posterior division

Adductor Hip joint magnus pectineus adductor part Adductor adductor brevis Adductor longus region of Adductor brevis thigh Knee joint gracilis Popliteal Subsartorial plexus artery

Femoral artery

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 AND TIBIAL NERVE L5 S1 L5 S2 S3 PELVIS

TIBIAL NERVE SCIATIC GLUTEAL hip joint NERVE REGION

To all hamstrings muscle BACK OF THIGH

Knee joint LOWER LEG Muscles of back of leg Sural nerve

Lateral plantar nerve Medial plantar nerve All other Abductor hallucis muscles SOLE OF FOOT Flexor hallucis and of sole Skin and digitorum brevis Skin of joints of Ist lumbrical sole sole

SCIATIC AND COMMON PERONEAL NERVE S1 L5 S2 L4 S3 SACRAL PLEXUS

GLUTEAL REGION COMMON PERONEAL NERVE

SCIATIC NERVE

BACK OF THIGH BICEPS FEMORIS SHORT HEAD LATERAL CUTANEOUS OF KNEE JOINT LEG SUPERFICIAL PERONEAL

LOWER DEEP PERONEUS LEG PERONEAL LONGUS AND BREVIS

SKIN OF LATERAL MUSCLES OF FRONT OF LEG SKIN LEG OF ANKLE JOINT LEG

FOOT EXTENSOR SKIN OF LATERAL DIDITORUM SKIN OF CLEFT SIDE OF FOOT BREVIS BETWEEN FIRST 2 SKIN OF DORSUM AND LITTLE TOE TOES

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