LOWER LIMB GROSS FEATURES
GROSS ANATOMY OF LOWER LIMB
In human anatomy, the lower leg is the part of the lower limb that lies between the knee and the ankle. The thigh is between the hip and knee and makes up the rest of the lower limb. The term lower limb or “lower extremity” is commonly used to describe all of the leg.
The lower extremity refers to the part of the body from the hip to the toes. The lower extremity includes the hip, knee, and ankle joints, and the bones of the thigh, leg, and foot. Many people refer to the lower extremity as the leg. In fact, the leg is the part of the body between the knee and ankle joints.
The thigh, leg, and foot constitute the lower limb. The bones of the lower limbs are considerably larger and stronger than comparable bones of the upper limbs because the lower limbs must support the entire weight of the body while walking, running, or jumping.
The lower limbs (extremities) are extensions from the trunk specialized to support body weight, for locomotion (the ability to move from one place to another), and to maintain balance. The lower limbs have six major regions:
1. The gluteal region is the transitional region between the trunk and free lower limbs. It includes two parts of the lower limb: the rounded, prominent posterior region, the buttocks, and the lateral, usually less prominent hip region, which overlies the hip joint and greater trochanter of the femur. The “width of the hips” in common terminology is a reference to one’s transverse dimensions at the level of the greater trochanters. The gluteal region is bounded superiorly by the iliac crest, medially by the intergluteal cleft, and inferiorly by the skin fold (groove) underlying the buttock, the gluteal fold (L. sulcus glutealis). The gluteal muscles, overlying the pelvic girdle, constitute the bulk of this region.
2. The femoral region (thigh) is the region of the free lower limb that lies between the gluteal, abdominal, and perineal regions proximally and the knee region distally. It includes most of the femur (thigh bone). The transition from trunk to free lower limb occurs abruptly in the inguinal region or groin. Here the boundary between the abdominal and perineal regions and the femoral region is demarcated by the inguinal ligament anteriorly and the ischiopubic ramus of the hip bone (part of the pelvic girdle or skeleton of the pelvis) medially. Posteriorly, the gluteal fold separates the gluteal and femoral regions.
3. The knee region includes the prominences (condyles) of the distal femur and proximal tibia, the head of the fibula, and the patella (knee cap, which lies anterior to the distal end of the femur), as well as the joints between these bony structures. The posterior region of the knee (L. poples) includes a well-defined, fat-filled hollow, transmitting neurovascular structures, called the popliteal fossa.
4. The leg region is the part that lies between the knee and the narrow, distal part of the leg. It includes most of the tibia (shin bone) and fibula (calf bone). The leg (L., crus) connects the knee and foot. Often laypersons refer incorrectly to the entire lower limb as “the leg.”
5. The ankle or talocrural region (L. regio talocruralis) includes the medial and lateral prominences (malleoli) that flank the ankle (talocrural) joint.
6. The foot or foot region is the distal part of the lower limb containing the tarsus, metatarsus, and phalanges (toe bones). The toes are the digits of the foot. The great toe (L. hallux), like the thumb, has only two phalanges (digital bones); the other digits have three.
Functions of LOwer Limb:
It functions in supporting the weight of the body and allowing motion of the leg. The femur articulates proximally with the acetabulum of the pelvis forming the hip joint, and distally with the tibia and patella to form the knee joint.
GROSS ANATOMY OF LOWER LIMB