Page 123 - ASOP Orthopedic Casting Manual

Anatomy Lower Extremity

cont...

Bony Structures

The skeletal framewor k of the lower ex tremit y is divided into the pel vic girdle, thigh, leg, and foot.

• Pelvic Girdle: Compr ised of the ilium, ischium, and pubis, the pelvic girdle provides structural suppor t and
weight distr ibution bet ween the spine and lower limbs.
• Femur: The longest and strongest bone in the body, the femur ar ticulates proximally with the pelvis at the hip
joint and distally with the tibia and p atella at the knee joint.
• Patella: A sesamoid bone within the quadr iceps tendon that enhances the mechanic al advantage of the
quadr iceps muscle group.
• Tibia and Fibula: The tibia, or shinbone, be ars the major it y of weight, while the fibula provides lateral suppor t
and ser ves as an attachment site for muscles and ligaments.
• Foot Bones: The tarsal bones (including the talus and c alc aneus), metatarsals, and phalanges cre ate a r igid
yet adaptable structure for weight distr ibution and movement.

Soft Tissue Structures

The lower ex tremit y consists of essential soft tissues that facilitate movement and stabilit y.

• Muscles: Major muscle groups include the quadr iceps and hamstr ings in the thigh, the gastrocnemius and
soleus in the lower leg, and the intr insic foot muscles that aid in b alance and propulsion.
• Ligaments: These connective tissues stabilize joints, such as the anter ior and poster ior cruciate ligaments
LACL and PCL) in the knee and the del toid ligament in the ankle.
• Tendons: The Achilles tendon, p atellar tendon, and other structures transmit muscular forces to bones,
allowing movement.
• Fascia: The deep fascia of the leg, including the iliotibial b and, plays a crucial role in comp ar tmentalization
and force distr ibution.

Neurovascular Structures

The lower ex tremit y is richl y supplied by blood vessels and ner ves that provide oxygen, nutrients, and
sensor y-motor control.

• Ar ter ies: The femoral ar ter y (a continuation of the ex ter nal iliac ar ter y) provides major circulation to the leg,
branching into the poplite al, anter ior tibial, poster ior tibial, and perone al ar ter ies.
• Veins: The gre at and small saphenous veins aid in venous retur n to the he ar t, alongside deep veins such as
the femoral and poplite al veins.
• Ner ves: Major ner ve structures include the sciatic ner ve (which bifurc ates into the tibial and common
perone al ner ves), femoral ner ve, and obturator ner ve, all of which contr ibute to motor and sensor y
inner vation.