nerve injuries of lower limbshomeostasis test
TRANSCRIPT
TESTKhaleel Alyahya, PhD, MEdwww.khaleelalyahya.net
HOMEOSTASIS Khaleel Alyahya, PhD, MEdwww.khaleelalyahya.net
NERVE INJURIES OF LOWER LIMBSKhaleel Alyahya, PhD, MEdwww.khaleelalyahya.net
RESOURCES
Clinical Anatomy Gray’s Anatomy Clinical Neuroanatomy
Overview
▪ The lumbar plexus is a network of nerve fibres that supplies the skin
and musculature of the lower limb.
▪ It is located in the lumbar region, and it is formed by the anterior
rami (divisions) of the lumbar spinal nerves L1, L2, L3 and L4.
▪ The sacral plexus is a network of nerve fibres that supplies the skin and
muscles of the pelvis and lower limb.
▪ It is located on the surface of the posterior pelvic wall, anterior to the
piriformis muscle, and it is formed by the anterior rami (divisions) of the
sacral spinal nerves S1, S2, S3 and S4.
Khaleel Alyahya, PhD, MEd 3
Femoral Nerve
▪ The femoral nerve is one of the major peripheral nerves of the lower
limb.
▪ It originates from roots (L2-L4).
▪ Motor functions:
• Innervates the anterior thigh muscles that flex the hip joint and extend the
knee.
▪ Sensory functions:
• Supplies cutaneous branches to the anteromedial thigh (anterior cutaneous
branches of the femoral nerve) and the medial side of the leg and
foot (saphenous nerve).
Khaleel Alyahya, PhD, MEd 4
Branches of Femoral Nerve
▪ Anterior division:
• Anterior cutaneous branches
• Branch to sartorius
• Branch to pectineus
▪ Posterior division:
• Saphenous nerve
• Branches to quadriceps femoris
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Motor Functions
▪ Hip flexors:
• Pectineus adducts and flexes the thigh, assists with medial rotation of the
thigh.
• Iliacus acts with psoas major and psoas minor (forming iliopsoas) to flex the
thigh at the hip joint and stabilise the hip joint.
• Sartorius flexes, abducts and laterally rotates the thigh at the hip joint. Flexes
the leg at the knee joint.
▪ Knee extensors:
• Quadriceps femoris extends the leg at the knee joint.
• Rectus femoris also steadies the hip joint and assists iliopsoas in flexing the
thigh.
Khaleel Alyahya, PhD, MEd 6
Sensory Functions
▪ Anterior cutaneous branches
• Derived from the anterior division of the femoral nerve.
• They supply the skin of the anteromedial thigh.
▪ Saphenous nerve
• Continuation of the posterior division of the femoral nerve.
• It supplies the skin of the medial leg and foot.
Khaleel Alyahya, PhD, MEd 7
Femoral Nerve Block
▪ Femoral nerve block (in combination with a sciatic nerve block) may
be indicated in patients requiring lower limb surgery who cannot
tolerate a general anaesthetic.
▪ A femoral nerve block can also be used as perioperative and
postoperative analgesia for patients with a fractured neck of femur
who cannot tolerate particular analgesics.
Khaleel Alyahya, PhD, MEd 8
Stripping of Saphenous Vein
▪ The saphenous vein is often stripped in individuals with problematic
varicose veins.
▪ The long saphenous vein is accompanied in its course by the
saphenous nerve.
▪ Damage to the saphenous nerve during this procedure can lead to
pain, paraesthesia or complete loss of sensation the medial side of the
lower leg.
Khaleel Alyahya, PhD, MEd 9
Obturator Nerve
▪ The obturator nerve is also one of the major peripheral nerves of the
lower limb.
▪ It originates from roots (L2-L4).
▪ Motor functions:
• Innervates the muscles of the medial compartment of the thigh.
▪ Sensory functions:
• Cutaneous branches of the obturator nerve innervate the skin of the medial
thigh.
Khaleel Alyahya, PhD, MEd 10
Motor Functions
▪ The obturator nerve innervates all the muscles in the medial
compartment of the thigh (except the hamstring part of the adductor
magnus which is innervated by the tibial nerve).
▪ They are collectively known as the hip adductors:
• Adductor longus that adducts thigh
• Adductor brevis that adducts thigh
• Adductor magnus that adducts, flexes and extends thigh
• Gracilis that adducts thigh
• Obturator externus that laterally rotates thigh
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Sensory Functions
▪ The cutaneous branch of the obturator nerve supplies the skin of the
middle part of the medial thigh.
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Obturator Nerve Block
▪ Obturator nerve block is used in the management of pain after lower
limb surgery or for chronic hip pain.
▪ The anaesthetic is injected inferior to the pubic tubercle and lateral to
the tendon of the adductor longus muscle.
▪ This procedure can also be carried out under ultrasound guidance.
Khaleel Alyahya, PhD, MEd 13
Obturator Nerve Damage
▪ The obturator nerve can be damaged during surgery involving the
pelvis or abdomen.
▪ Symptoms include numbness and paraesthesia on the medial aspect
of the thigh and weakness in adduction of the thigh.
▪ Alternatively, the patient could present with posture and gait problems
due to the loss of adduction.
Khaleel Alyahya, PhD, MEd 14
Sciatic Nerve
▪ The sciatic nerve is also one of the major peripheral nerves of the
lower limb.
▪ It originates from roots (L4-S3).
▪ Motor functions:
• Innervates the muscles of the posterior thigh and the hamstring portion of the
adductor magnus (remaining portion of which is supplied by the obturator
nerve).
• Indirectly innervates all the muscles of the leg and foot.
▪ Sensory functions:
• No direct sensory functions.
• Indirectly innervates the skin of the lateral leg, heel, and both the dorsal and
plantar surfaces of the foot.
Khaleel Alyahya, PhD, MEd 15
Motor Functions
▪ The sciatic nerve indirectly innervates several other muscles, via its
two terminal branches:
• Tibial nerve: the muscles of the posterior leg (calf muscles), and some of the
intrinsic muscles of the foot.
• Common fibular nerve: the muscles of the anterior leg, lateral leg, and the
remaining intrinsic foot muscles.
▪ In total, the sciatic nerve innervates the muscles of the posterior thigh,
entire leg and entire foot.
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Sensory Functions
▪ The sciatic nerve does not have any direct cutaneous functions.
▪ It provide indirect sensory innervation via its terminal branches:
• Tibial nerve: supplies the skin of the posterolateral leg, lateral foot and the
sole of the foot.
• Common fibular nerve: supplies the skin of the lateral leg and the dorsum
of the foot.
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Piriformis Syndrome
▪ It refers to compression of the sciatic nerve by the piriformis muscle.
▪ It is also known as deep gluteal syndrome.
▪ Clinical features include radicular pain, numbness, muscle weakness
and buttock tenderness.
▪ The pain can occasionally be exacerbated by internal rotation of the
lower limb at the hip.
▪ X-ray and MRI imaging is usually unremarkable but can exclude other
pathology such as spinal compression of the sciatic nerve.
▪ The treatment of piriformis syndrome can be divided into non-
operative and operative:
• Non-operative – analgesia, physiotherapy and corticosteroid injections
• Operative – piriformis muscle release.
Khaleel Alyahya, PhD, MEd 18
Intramuscular Injections
▪ The anatomical course of the sciatic nerve must be considered
when administering intramuscular injections into the gluteal
region.
▪ The sciatic nerve passes through the lower medial quadrant.
▪ To avoid damaging the sciatic nerve therefore, intramuscular
injections are given only in the upper lateral quadrant of the
gluteal region.
Khaleel Alyahya, PhD, MEd 19
Tibial Nerve
▪ It originates from roots (L4-S3).
▪ Motor functions:
• Innervates the posterior compartment of the leg and the majority of the
intrinsic foot muscles.
▪ Sensory functions:
• Innervates the skin of the posterolateral leg, lateral foot and the sole of the
foot.
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Motor Functions
• The tibial nerve innervates the muscles of the posterior leg and the
majority of the intrinsic foot muscles.
• The muscles of the posterior compartment of the leg are organised
into a superficial and deep compartment, and they are all innervated
by the tibial nerve.
• The medial and lateral plantar branches of the tibial nerve provide
innervation to all the intrinsic muscles of the foot (exept the extensor
digitorum brevis, which is innervated by the deep fibular nerve).
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Sensory Functions
▪ In the popliteal fossa, the tibial nerve gives off cutaneous branches.
▪ These combine with branches from the common fibular nerve to form
the sural nerve.
▪ This sensory nerve innervates the skin of the posterolateral side of the
leg and the lateral side of the foot.
▪ The tibial nerve also supplies all the sole of the foot via three
branches:
• Medial calcaneal branches
• Medial plantar nerve
• Lateral plantar nerve:
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Tibial Nerve Damage
▪ Damage to the tibial nerve is rare, and is often a result of direct
trauma, entrapment through narrow space or compression for long
period of time.
▪ Damage results in loss of plantar flexion, loss of flexion of toes and
weakened inversion (The tibialis anterior can still invert the foot).
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Tarsal Tunnel Syndrome
▪ Tarsal tunnel syndrome refers to the compression of the tibial nerve as
it passes through the tarsal tunnel.
▪ Patients may experience altered sensation in the sensory distribution
of the tibial nerve – the sole of the foot.
▪ The motor function of the nerve can also be affected in severe
disease, causing weakness and wasting of the intrinsic foot muscles.
Khaleel Alyahya, PhD, MEd 24
Common Fibular Nerve
▪ It also known as common peroneal nerve.
▪ It originates from roots (L4-S2).
▪ Motor functions:
• Innervates the short head of the biceps femoris directly.
• Also supplies (via branches) the muscles in the lateral and anterior
compartments of the leg.
▪ Sensory functions:
• Innervates the skin of the lateral leg and the dorsum of the foot.
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Motor Functions
▪ The common fibular nerve innervates the short head of the biceps
femoris muscle (part of the hamstring muscles, which flex at the
knee)
▪ The terminal branches also provide innervation to muscles:
▪ Superficial fibular nerve:
• Innervates the muscles of the lateral compartment of the leg; fibularis
longus and brevis. These muscles act to evert the foot.
• Deep fibular nerve:
• Innervates the muscles of the anterior compartment of the leg.
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Sensory Functions
▪ There are two cutaneous branches that arise directly from the common fibular
nerve as it moves over the lateral head of the gastrocnemius:
▪ Sural communicating nerve:
• Combines with a branch of the tibial nerve to form the sural nerve, which innervates the
skin over the lower posterolateral leg.
▪ Lateral sural cutaneous nerve:
• Innervates the skin over the upper lateral leg.
▪ The terminal branches of the common fibular nerve also have a cutaneous
function:
▪ Superficial fibular nerve:
• Innervates the skin of the anterolateral leg, and dorsum of the foot (except the skin
between the first and second toes).
▪ Deep fibular nerve:
• Innervates the skin between the first and second toes.
Khaleel Alyahya, PhD, MEd 27
Common Fibular Nerve Damage
▪ The common fibular nerve is most commonly damaged by a fracture of
the fibula, or the use of a tight plaster cast.
▪ The anatomical course of the common fibular nerve causes it to wrap
round the neck of the fibular, and so any fractures of the fibular neck
can cause nerve palsy.
▪ Patients with common fibular nerve damage will lose the ability
to dorsiflex the foot at the ankle joint.
▪ Hence the foot will appear permanently plantarflexed (known
as footdrop).
▪ They may also present with a characteristic gait, as a result of the
footdrop.
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Tests & Procedures
Check page 158 from the book Mastering MedicalTerminology for the complete list of tests & procedures.