The Leg and Dorsum of the Foot

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The Leg and Dorsum of the Foot
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Objectives

• Differentiate the anterior, lateral, and
  posterior osteofascial compartments of the leg.
• Define the actions of the muscles in the leg.
• Identify the nerve and blood supply to the
  structures in the leg.
• Describe the structures on the dorsal surface of
  the foot.

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Cutaneous Structures

• dorsal venous arch of the foot
• collects most of the cutaneous venous blood from
  the foot
• medially it becomes the greater saphenous vein
• laterally it becomes the lesser saphenous vein
• greater saphenous vein
• passes anterior to the medial malleolus, up the
  medial side of the leg
• ascends the thigh to the saphenous opening in the
  fascia lata to empty into the femoral vein
• receives many tributaries along its course
• accompanied in the leg by the saphenous branch of
  the femoral nerve
• lesser saphenous vein
• passes posterior to the lateral malleolus
• ascends close to the midline of the leg
  posteriorly with the sural and medial sural
  nerves
• pierces the deep fascia near the lower point of
  the popliteal fossa
• usually ends in the popliteal vein

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Cutaneous Innervation

• dermatome charts differ and spinal cord segments
  overlap in theirdistribution
• L4 for patella
• L4 for the great toe
• S1 for the little toe
• S1, S2 for the posterior surface of the leg
• saphenous nerve
• branch of the femoral nerve which travels through
  the subsartorial canal
• pierces the deep fascia on the medial side of the
  knee
• gives off the infrapatellar branch
• supplies the medial side of the leg to the medial
  side of the foot
• medial and lateral sural nerves
• supply the upper calf before uniting to form the
  sural nerve which descends with the lesser
  saphenous vein
• supplies posterior and lateral leg and lateral
  foot
• tibial and common peroneal nerves give rise to
  these nerves
• superficial peroneal nerve
• pierces deep fascia in lower half of leg from the
  anterior intermuscular septum
• supplies dorsum of foot except area between first
  two toes
• deep peroneal nerve
• cutaneous only to area between first two toes

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Lymph Drainage of the Lower Limb

• tends to follow venous drainage
• lymph from lateral side of the foot tends to
  follow the lesser saphenous vein
• enters the popliteal fossa where a few lymph
  nodes are usually found
• lymph from medial side of the foot tends to
  follow the greater saphenous vein
• it is not filtered by lymph nodes until it
  reaches the superficial inguinal lymph nodes over
  the femoral triangle

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Muscles

• The anterior compartment contains muscles that
  are basically extensors of the ankle and toes.
  They include
• tibialis anterior
• extensor digitorum longus
• extensor hallucis longus
• peroneus tertius

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Peroneus Tertius

• appears to be a part of the extensor digitorum
  longus except that its tendon goes to the base of
  the fifth metatarsal rather than to a digit

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Extensor RetinaculaThere are two

• superior extensor retinaculum is a thickening of
  the deep fascia between the tibia and fibula
  above the malleoli
• inferior retinaculum is Y-shaped
• stem of the Y is attached to the upper surface of
  the calcaneus
• as it passes medially over the tendons, it
  divides
• one limb above the medial malleolus
• other limb to the deep fascia on the medial side
  of the foot to the plantar surface
• three short synovial sheaths protect the tendons
  as they pass under the inferior retinaculum

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Nerves

• The nerve of the anterior compartment of the leg
  is the deep peroneal nerve. This nerve terminates
  between the big toe and second toe and can be
  tested at this point.

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Arteries

• The artery of the anterior compartment of the leg
  is the anterior tibial artery which is a branch
  of the popliteal artery. Its terminal branch, the
  dorsalis pedis, can be palpated on the dorsum of
  the foot between the 1st and 2nd metatarsal
  bones.

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Dorsum of the Foot

• when the anterior tibial artery crosses the ankle
  joint, it changes its name to dorsalis pedis
  artery
• supplies the dorsum of the foot and toes
• passes between the first and second metatarsal
  bones to join the lateral plantar artery in
  forming the deep plantar arch
• after supplying the extensor digitorum brevis,
  the deep peroneal nerve supplies the adjacent
  sides of the first two toes with cutaneous
  innervation

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Table of Muscles
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Cross Section Through the Leg

• This is a section through the left leg. You are
  looking up into the leg so medial will be to your
  left.

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Lateral Compartment of the Leg

• The lateral crural compartment, also called the
  peroneal compartment, is made up of two muscles
  whose tendons cross the ankle joint posterior to
  and under the lateral malleolus. This makes them
  flexors of the foot. These muscles are the
• peroneus longus
• peroneus brevis

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Nerves of Lateral Leg Compartment

• The superficial peroneal nerve branches from the
  common peroneal nerve near the neck of the fibula
  and passes between the peroneus longus and brevis
  muscles, at which point they supply the muscles.
  The superficial branch then continues onto the
  dorsum of the foot to supply the skin there.

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Arteries of the Lateral Leg

• The arteries to the tissues in this region are
  from both the anterior and posterior tibial
  branches of the popliteal artery.

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Table of Muscles
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Posterior Compartment of the Leg

• The posterior compartment of the leg is usually
  subdivided into superficial and deep parts. In
  each region that you study, you should first
  identify the major superficial items in that
  region. The fascial septum divides the
  superficial muscles from the deep muscles.

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small saphenous vein

• The superficial structures to identify are
  the
• small saphenous vein
• peroneal communicating branch of the common
  peroneal nerve
• medial cutaneous nerve of the calf
• sural nerve

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• The superficial part of the posterior
  compartment of the leg is made up of three
  muscles
• gastrocnemius
• plantaris
• Soleus
• These muscles are referred to as the triceps
  surae.
• These muscles are strong plantar flexors of
  the foot at the ankle.

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• The deepest layer of muscles includes the
• tibialis posterior
• flexor digitorum longus
• flexor hallucis longus
• popliteus

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Nerve of Posterior Compartment of Leg

• The muscles of the posterior compartment of the
  leg are all supplied by the tibial nerve.

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Artery of the Posterior Compartment of the Leg

• The posterior tibial artery supplies the tissues
  of the posterior compartment of the leg. It is
  one of the terminal branches of the popliteal
  artery.

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Table of Muscles
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