xnervous injury lower limbt

8/3/2019 Xnervous Injury Lower Limbt

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Neurological lesion

of lower limb



Tendon Reflexes of Lower Limb

•Skeletal muscles receive a segmentalinnervation.

•Most muscles are innervated by two, three, orfour spinal nerves.

•test them by eliciting simple musclereflexes.

•Patellar tendon reflex (knee jerk) L2, 3, & 4(extension of knee j. on tapping patellar tendon)

•Achilles tendon reflex (ankle jerk) S1 and S2:

plantar flexion of ankle j on tapping Achilles



Femoral Nerve Injury (L2, 3, and 4)

can be injured in stab or gunshot wounds,

following clinical features are present when nerve iscompletely divided:

Motor:

The quadriceps femoris muscle is paralyzed, and theknee cannot be extended. In walking, this is compensatedfor to some extent by use of the adductor muscles.

Sensory:

Skin sensation is lost over the anterior and medial sides of the thigh,over the medial side of the lower part of the leg,along the medial border of the foot as far as the ball of thebig toe; this area is normally supplied by saphenous

nerve.



Sciatic Nerve Injury (L4 and 5 and S1, 2, &3)

curves laterally & downward through gluteal region,

situated at first midway between posterosuperior iliacspine & ischial tuberosity,

lower down, midway between tip of greater trochanter

and ischial tuberosity.

passes downward in midline on posterior aspect of thighand divides into :

1. common peroneal and2. tibial nerves, at a variable site above the popliteal fossa.



sciatic nerveTrauma

•is injured by penetrating wounds, fractures of pelvis, ordislocations of hip joint.

•It is most frequently injured by badly placed intramuscularinjections in the gluteal region.

• To avoid this injury, injections into the gluteus maximus

or the gluteus medius should be made well forward on theupper outer quadrant of the buttock .

•Most nerve lesions are incomplete, and in 90% of injuries,

the common peroneal part of the nerve is the mostaffected.

• This can probably be explained by the fact that thecommon peroneal nerve fibers lie most superficial in thesciatic nerve.



clinical features are present:Motor:hamstring muscles are paralyzed, but weak flexion of knee ispossible because of action of sartorius (femoral nerve) and gracilis(obturator nerve).

All the muscles below the knee are paralyzed, and the weight of thefoot causes it to assume the plantar-flexed position, or footdrop.

Sensory:Sensation is lost below knee, except for a narrow area down themedial side of the lower part of the leg and along the medial borderof the foot as far as the ball of the big toe, which is supplied by thesaphenous nerve (femoral nerve).

The result of operative repair of a sciatic nerve injury is poor. It is rarefor active movement to return to the small muscles of the foot, andsensory recovery is rarely complete. Loss of sensation in the sole of the foot makes the development of trophic ulcers inevitable.



Sciatica

pain along sensory distribution of sciatic nerve.

pain is experienced in :1. posterior aspect of thigh,

2. posterior and lateral sides of the leg

3. lateral part of the foot.

caused by :A. prolapse of an intervertebral disc ,with pressure on one or

more roots of the lower lumbar and sacral spinal nerves,

B. pressure on sacral plexus or sciatic nerve by an intrapelvic

tumor,

C. inflammation of sciatic nerve or its terminal branches.

is confined to area of the foot and toes.

C P l N I j



Common Peroneal Nerve Injury

is in an exposed position as it leaves the popliteal fossa

winds around neck of fibula

enter peroneus longus muscle.

Nerve Injury due to:

1. fractures of neck of fibula

2. by pressure from casts or splints.

clinical features :Motor:muscles of anterior and lateral compartments of leg are paralyzed,

the opposing muscles, (plantar flexors of ankle joint &invertors of subtalar andtransverse tarsal joints), cause foot to be plantar flexed (foot drop) andinverted, referred to as equinovarus.

Sensory:Loss of sensation occurs down anterior and lateral sides of leg and dorsumof foot and toes, including the medial side of the big toe.

• lateral border of foot and lateral side of little toe are virtually unaffected (sural nerve).

• medial border of foot as far as ball of big toe is completely unaffected (saphenous

ibi l j



Tibial Nerve Injury

•leaves popliteal fossa by passing deep to gastrocnemius &soleus muscles.

•Because of its deep and protected position, it is rarelyinjured.

clinical features of Complete division :

Motor:opposing muscles dorsiflex foot at ankle joint

evert foot at subtalar and transverse tarsal joints,

referred to as calcaneovalgus.

Sensory:

Sensation is lost on sole of foot;later, trophic ulcers develop.



Obturator Nerve Injury

enters thigh as anterior and posteriordivisions through upper part of obturator

foramen.

anterior division descends in front of obturator externus &adductor brevis, deep

to floor of femoral triangle.

posterior division descends behind

adductor brevis and in front of adductor.



It is injured in :

1. penetrating wounds

2. anterior dislocations of hip joint

3. abdominal herniae through obturator foramen.4. be pressed on by fetal head during parturition.

clinical features :Motor: All adductor muscles are paralyzedexcept hamstring part of adductor magnus, whichis supplied by sciatic nerve.

Sensory: The cutaneous sensory loss is minimalon the medial aspect of the thigh.

Cli i l P bl A i t d With A h f F t



Clinical Problems Associated With Arches of Foot Pes planus (flat foot)

medial longitudinal arch is depressed or collapsed.

forefoot is displaced laterally and everted.

body weight forces head of talus downward and medially between calcaneumand navicular bone.

plantar, calcaneonavicular, become permanently stretched, and boneschange shape.

muscles and tendons are also permanently stretched.

causes of flat foot are both congenital and acquired.

Pes cavus (clawfoot)medial longitudinal arch is unduly high.are caused by muscle imbalance, resulting from poliomyelitis.

xnervous injury lower limbt

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