The Lower Extremity

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The Lower Extremity

• BIOL 1010

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FEMUR
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TIBIA
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FIBULA
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ERROR 7 is CUBOID 4 is LATERAL CUNEIFORM
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• Very similar to the upper extremity
• Some definitions
• a. Thigh part from the hips to knees
• b. Leg part from the knee to the ankle
• Note that the hip joint is a ball and socket
  joint. It allows movement in all direction. The
  knee only allows flexion and extension not
  circumduction. It is never normal for
  hyperextension of knee (genu recurvatum)

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CAT
In humans, the abdominal aorta terminates into
the common iliac arteries. The common iliacs
divide into the external and internal iliacs. In
humans, the aorta terminates as the middle sacral
artery.
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• The nerves of the lower extremity are simpler
  than the upper limb. There are three nerves
  entering the thigh. Their lateral branches serve
  the gluteal muscles.
• femoral nerve L2,3,4
  anterior compartment
• obturator nerve L2,3,4
  medial compartment
• sciatic nerve L4,5,S1,2,3 (sacral
  plexus) posterior compartment

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• The only one of the three that travel below the
  knee is the sciatic nerve.
• The sciatic nerve branches into two nerve
• 1. tibial nerve
• 2. common peroneal nerve
• a. Superficial peroneal nerve
• b. Deep peroneal nerve

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Anterior compartment- Extensors of the
knee Femoral Nerve
lateral
femur
medial
Medial compartment- Adductors of the
knee Obturator Nerve
Posterior compartment- Flexors of the
knee Sciatic Nerve
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• The anterior compartment of the thigh is
  homologous to the posterior compartment of the
  arm.
• The posterior compartment of the thigh is
  homologous to the anterior compartment of the arm.

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• The leg has three compartments
• Anterior compartment
• - dorsiflexors (flexors) of the foot
• - deep peroneal nerve
• Posterior compartment
• - plantarflexors (extensors) of the foot
• - tibial nerve
• Lateral compartment
• - extensors of the foot
• - superficial peroneal nerve

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• The FASCIA LATA (not to be confused with the
  muscle of similar name) is connective tissue on
  the lateral side of the femur. This forms the
  ILIOTIBIAL BAND. This band connects the ilium
  and tibia and is the site of inflammation in
  runners iliotibial band syndrome.

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Muscles of the Medial Compartment of the
ThighObturator Nerve
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Muscles of the Posterior Compartment of the
ThighTibial portion of Sciatic Nerve
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Muscles of Anterior ThighFemoral Nerve
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• The rectus femoris cross two joints, therefore it
  has actions on the two joints involved.
• The patella is articulates with the FEMUR, not
  the tibia.
• The patella is attached to the femur and tibia
  by the PATELLAR LIGAMENT. When this ligament is
  pulled, the patella is lifted superiorly and
  brings the leg into an extended position.
• In the posterior leg, the GASTROCNEMIUS muscle is
  responsible for plantarflexion. It originates at
  the femur and inserts on the posterior surface of
  the calcaneus. It crosses two joints so it can
  flex the knee and plantarflex (extend) the foot.
  It is innervated by the tibial nerve.

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Motor Branches of the Femoral Nerve
L2 L3 L4
Rectus femoris
iliopsoas
pectineus
sartorius
Vastus lateralis
Vastus medialis
Vastus intermedius
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Motor Branches of the Obturator Nerve
Adductor brevis
Adductor longus
gracilis
Adductus magnus
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Motor Branches of the Sciatic Nerve
L4 L5 S1 S2 S3
Semitendinosis Biceps femoris semimembranosus
Hamstrings
Common peroneal nerve
Tibial nerve
Deep peroneal nerve
Anterior compartment of leg
Superficial peroneal nerve
Gastrocnemius and posterior compartment of the
leg and foot
Lateral compartment of leg
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The Foot
Medial, intermediate, and lateral cuneiforms
navicular
talus
calcaneus
phalanges
metatarsals
cuboid
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Anterior Leg Structures - Superficial
Identify the Following Tibialis
Anterior Peroneus Longs Peroneus Brevis Extensor
Digitorum Longus Patellar Tendon Patella Tibia Per
oneus Tertius Extensor Hallucis Longus Popliteus
Tendon Sartorius Tendon
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Posterior Leg Structures - Superficial
Identify the Following Femur Tibia Fibula Soleus
Achilles Tendon Plantaris Popliteus Calcaneus
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Posterior Leg Structures - Deep
Identify the Following Achilles Tendon Flexor
Hallucis Longus Flexor Digitorum
Longus Calcaneus Talus Tibia Fibula Femur
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Intrinsic Muscles of the Foot

• These muscles all originate and insert on foot
  bones.
• They help to flex, extend, abduct, or adduct the
  toes.
• All the intrinsic muscles of the foot are found
  on the plantar surface (except the one on the
  dorsal aspect).
• The plantar muscles are arranged in 4 layers,
  from superficial to deep.

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Intrinsic Muscles of the Foot
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