Download Lateral plantar nerve - Yeditepe University Faculty of Medicine 1st

EXAM OF THE LOWER
EXTREMITIES
From A Practical Guide to
Clinical Medicine
University of California, San Diego
1
Region of the lower limb
distal to ankle joint
Subdivided into
Ankle
Metatarsus
Digits
Superior surface (dorsum of foot)
Inferior surface (sole)
 Body's point of contact with the ground
 Provides a stable platform for upright stance.
 Supports the body weight and provides leverage for walking and
running.
 Unique -constructed in the form of arches, adapt its shape to
uneven surfaces.
 Serves as a resilient spring to absorb shocks, such as in jumping.
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1…skin of the foot
Skin of the dorsum of the foot thinner
and less sensitive than that of the sole
The subcutaneous tissue is loose deep
to the dorsal skin
Edema most marked on the dorsal skin
especially anterior to and around the
medial malleolus
Entire sole is sensitive (“ticklish”),
especially the thinner-skinned area
underlying the arch of the foot.
Ticklish?
gargalesis
Neurosci Res. 2010 Dec;68(4):285-9.
Neurogenesis in the dentate gyrus of the rat
hippocampus enhanced by tickling stimulation
with positive emotion.
2. Deep fascia of the foot & Plantar fascia
Thin where it is continuous
proximally with the inferior extensor
retinaculum.
Over the lateral and posterior
aspects of the foot continuous with
the plantar fascia, the deep fascia of
the sole.
Plantar fascia holds the parts of the
foot together, helps protect the sole
from injury, and helps support the
longitudinal arches of the foot.
3. Compartments by the deep fascia
Midfoot and forefoot
Medial compartment of the sole
Central compartment of the sole
Lateral compartment of the sole
Forefoot
4th compartment
interosseous compartment of the foot
Dorsal compartment of the foot
5th compartment
between dorsal fascia
of the foot & tarsal bones & compartment;
Transverse section of the foot: 1, lateralhttp://home.comcast.net/~wn
dorsal interosseous
fascia compartment;
of the midfoot3,and
or/soleoffoot.htm
2, central
medial compartment;
forefoot
4, interosseous compartment. Arrows indicate the highpressure areas that often lead to foot ulceration.
4. Tarsal tunnel
Formed on the posteromedial side of the ankle by:
A depression formed by
Medial malleolus of tibia
Medial &posterior surfaces of talus
Inferior surface of sustentaculum tali
Medial surface of calcaneus
Overlying flexor retinaculum
Contents from ant. to post.
(Tom Dick ANd Harry)
•Tibialis posterior tendon
•Flexor digitorum longus
tendon
•Posterior tibial artery
•Tibial nerve
•Flexor hallucis longus
tendon
5. Flexor retinaculum
Attaches above to medial malleolus below to calcaneus
2 compartments on the posterior surface of medial malleolus for tibialis
posterior & flexor digitorum longus tendons
Laterally
posterior tibial artery ,veins & tibial nerve through tarsal tunnel into
sole of foot
Lateral to tibial nerve
tendon of flexor hallucis longus
Pulse of posterior tibial artery
through flexor retinaculum
midway between medial
malleolus and calcaneus
6. Extensor retinacula
Prevent tendon bowing during
extension of the foot and toes
Superior extensor retinaculum
Superior to the ankle
Attached to anterior borders of the
fibula & tibia
Inferior retinaculum
Y-shaped
Attached to lateral side of calcaneus
Extensor digitorum longus &
fibularis tertius tendons
Medially
Dorsalis pedis artery
Extensor hallucis longus tendon
tibialis anterior tendon
pass under extensor retinacula
7. Fibular (Peroneal) retinacula
Bind the tendons of
fibularis longus & fibularis brevis
to lateral side of the foot
Superior fibular retinaculum
Between lateral malleolus & calcaneus
Inferior fibular retinaculum
Attaches to lateral surface of calcaneus
around fibular trochlea
8. Plantar aponeurosis
A thickening of deep fascia in the
sole of the foot
A thick central part
Weaker medial and lateral parts
Tougher, denser, and elongated than
palmar aponeurosis
Anchored to the medial process of
calcaneal tuberosity
Supports the longitudinal arch of the
foot & protects deeper structures in
the sole
9. Fibrous sheaths of toes
Flexor digitorum longus, flexor digitorum brevis, & flexor hallucis
longus tendons enter fibrous digital sheaths on plantar aspect of
digits.
Formed by fibrous arches & cruciate (cross-shaped) ligaments
Hold the tendons to the bony plane and prevent tendon bowing
when the toes are flexed.
10. Extensor hoods
Extensor digitorum longus, extensor
digitorum brevis, and extensor hallucis
longus expand over the proximal phalanges
to form complex dorsal digital expansions
("extensor hoods").
Many of the intrinsic muscles of the foot
insert here.
This allows the forces from these muscles to
be distributed over the toes
to cause flexion of the metatarsophalangeal joints while at the same
time extending the interphalangeal joints.
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20 individual muscles of the foot
14 located on the plantar aspect
2 on the dorsal aspect
4 intermediate in position
 Plantar muscles function primarily
as a group during the support
phase of stance, maintaining the
arches of the foot
 Few delicate functions compared
to hand muscles
 Concerned with supporting the
arches of the foot
Muscles in the dorsum
Extensor digitorum brevis
Attached to a roughened area
on the superolateral surface of
the calcaneus lateral to the
tarsal sinus
Extensor hallucis brevis
The part of the muscle
associated with the great toe
Deep fibular nerve
Muscles in the sole
Organized into four layers
From superficial to deep
or plantar to dorsal
First layer
Medial to lateral
Abductor hallucis
Flexor digitorum brevis
Abductor digiti minimi
Second layer
Quadratus plantae
Lumbrical muscles
Third layer
Flexor hallucis brevis
Adductor hallucis
Flexor digiti minimi brevis
Fourth layer
Dorsal & plantar interossei
Functions & innervations of the muscles of the foot
1st layer
Abductor hallucis
Flexor digitorum brevis
Abductor digiti minimi
2nd
Medial plantar nerve (S2, S3)
Lateral plantar nerve (S2, S3)
layer
Quadratus plantae
Lumbricals
3rd layer
Assists flexor digitorum longus in flexing lateral four digits
Flex proximal phalanges, extend middle & distal phalanges
of lateral four digits
4th layer
Flexor hallucis brevis
Adductor hallucis
deep branch
Flexor digit minimi brevis
superficial branch
Plantar interossei (three muscles)
Adduct digits (2-4) and flex
metatarsophalangeal joints
Dorsal interossei (four muscles)
Abduct digits (2-4) and flex
metatarsophalangeal joints
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Supply of the foot
Terminal branches of
anterior tibial artery & posterior tibial artery
dorsalis pedis artery & plantar arteries
Posterior tibial artery
in the sole divides into
lateral & medial plantar arteries
Lateral plantar artery + Dorsalis pedis artery
Deep plantar arch
Major branches of the
deep plantar arch
Digital branch to lateral side of
little toe
4 plantar metatarsal arteries
3 perforating arteries
Passes deep to abductor hallucis
Ends by joining the digital branch of the deep plantar arch
Superficial branch
Dorsalis pedis artery
Major source of blood supply to
forefoot
Continuation of anterior tibial
artery
Begins midway between
malleoli
Runs deep to inferior extensor
retinaculum between extensor
hallucis longus & extensor
digitorum longus tendons on
the dorsum of the foot
Dorsalis pedis artery
 Passes inferiorly as
deep plantar artery
 Joins deep plantar arch in
the sole of the foot.
Branches
lateral & medial tarsal aa.
arcuate artery
first dorsal metatarsal artery
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As in the rest of the lower limb, there are both superficial and deep
veins in the foot.
Unlike the leg and thigh, however, the venous drainage of the foot is
primarily to the major superficial veins
Medial side
Great saphenous
vein
Lateral side
Small
saphenous vein
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 Tibial nerve
 Deep fibular nerve
 Superficial fibular nerve
 Sural nerve
 Saphenous nerve
Tibial nerve
All intrinsic muscles of the foot
except for the extensor digitorum
brevis, innervated by the deep
fibular nerve
Deep fibular nerve often also
contributes to innervation of the
first and second dorsal interossei.
Tibial nerve
Enters the foot through
tarsal tunnel
posterior to medial malleolus
Lateral to posterior tibial artery
Medial calcaneal branches heel
Midway between
medial malleolus & heel
large Medial plantar nerve
smaller Lateral plantar nerve
Medial plantar nerves
Larger & more anterior terminal branch
Arises deep to the flexor retinaculum
Major sensory nerve in the sole
Compared to lateral plantar nerve,
supplies more skin area but fewer
muscles.
Its distribution to both skin and muscles
of comparable to that of the median
nerve in the hand.
Skin on most of the anterior two-thirds of the sole and adjacent
surfaces of the medial three and one-half toes, which includes the
great toe.
Four intrinsic muscles- abductor hallucis, flexor digitorum brevis,
flexor hallucis brevis, and the first lumbrical.
Lateral plantar nerve
Smaller & more posterior terminal
branch
Also courses deep to the abductor
hallucis but runs anterolaterally
between the 1st and 2nd layers of
plantar muscles, on the medial side of
the lateral plantar artery.
Ends @ lateral compartment, dividing
into superficial and deep branches.
Lateral plantar nerve
Superficial branch
Two plantar digital nerves
(one common and one proper)
Skin of the plantar aspects of the
lateral one and a half digits, the
dorsal skin and nail beds of their
distal phalanges, and skin of the
sole proximal to them.
Deep fibular nerve
Passes deep to extensor retinaculum
Enters dorsal aspect of the foot on
the lateral side of dorsalis pedis
artery.
Muscles on dorsum of the foot
When finally emerges as a cutaneous
nerve, so far distal in the foot ;
small area of skin remains available for
innervation: web of skin between and
contiguous sides of the 1st and 2nd toes
Divides into two dorsal digital nerves
Superficial fibular nerve
Emerges as a cutaneous nerve about
two thirds of the way down the leg
Skin on the anterolateral aspect of leg
Divides into
Medial and intermediate dorsal
cutaneous nerves
Most of the skin on the dorsum of the
foot
Terminal branches
Dorsal digital nerves
(common & proper)
Skin of the proximal aspect of the
medial half of the great toe & that of
the lateral three and a half digits.
Sural nerve
Cutaneous branch of tibial nerve
Originates high in the leg
Sural nerve formation:
 Medial sural cutaneous nerve (from
the tibial nerve)
 Sural communicating branch of
common fibular nerve
Accompanies small saphenous vein
Enters the foot posterior to the lateral
malleolus
ankle joint & skin on the lateral side of
the foot and dorsolateral surface of
the little toe.
Saphenous nerve
• Longest & most widely distributed
cutaneous branch of the femoral nerve
•Only branch to extend beyond the
knee
•Originates in the thigh
Skin and fascia on the anteromedial
aspect of the leg, ankle joint
Skin along the medial side of the foot
as far anteriorly as the head of the 1st
metatarsal , medial side of the
proximal foot
Cutaneous innervation of the foot
Medially
Saphenous nerve distally to the
head of 1st metatarsal
Superiorly (dorsum of foot)
Superficial (primarily)
Deep fibular nerves
Inferiorly (sole of foot)
Medial & lateral plantar nerves
Laterally
Sural nerve
Posteriorly (heel)
Medial & lateral calcaneal branches of tibial & sural nerves,
respectively