Page 122 - ASOP Orthopedic Casting Manual

3.1 Anatomical

Considerations of the

Lower Extremity

Overview of Lower Extremity

Anatomy

The lower ex tremit y is a complex region of the human body that plays a fundamental role in mobilit y, b alance,
and weight-be ar ing activities. This anatomic al region consists of mul tiple interconnected structures, including
bones, muscles, ligaments, tendons, and neurovascular components. These elements wor k in synchrony to
facilitate movement, provide structural suppor t, and maintain stabilit y dur ing dynamic and static activities.
The lower ex tremit y is divided into distinct regions: the pelvic girdle, thigh, leg, and foot. The pelvic girdle ser ves
as the foundation, anchor ing the lower limbs to the axial skeleton while also transmitting weight from the trunk to
the legs. The femur, the longest and strongest bone in the human body, for ms the pr imar y framewor k of the
thigh, connecting proximally with the pelvis at the hip joint and distally with the tibia and p atella at the knee joint.
The tibia, or shinbone, is the pr imar y weight-be ar ing bone of the lower leg, while the fibula, though smaller,
ser ves as a stabilizer and attachment site for muscles and ligaments.
The foot is an intr ic ate structure composed of the tarsal, metatarsal, and phalange al bones, for ming a highly
adaptable and suppor tive framewor k. The arches of the foot contr ibute to shock absor ption and energy
conser vation dur ing gait. Soft tissues, including muscles, ligaments, tendons, and fascia, play an essential role in
movement and stabilization. The quadr iceps and hamstr ings in the thigh, gastrocnemius and soleus in the lower
leg, and var ious intr insic muscles of the foot all wor k collectively to enable walking, running, jumping, and other
functional activities. Ligaments, such as the anter ior cruciate ligament LACL) in the knee and the del toid ligament
in the ankle, provide stabilit y and restr ict excessive motion, preventing injur ies.
The neurovascular system of the lower ex tremit y is equally signific ant. The femoral ar ter y, a continuation of the
ex ter nal iliac ar ter y, supplies oxygenated blood to the leg, branching into the poplite al, anter ior tibial, poster ior
tibial, and perone al ar ter ies. The venous system, including the gre at and small saphenous veins, facilitates blood
retur n to the he ar t. Major ner ve structures such as the sciatic ner ve, which bifurc ates into the tibial and common
perone al ner ves, along with the femoral and obturator ner ves, provide motor and sensor y inner vation crucial for
movement and sensation.