In humans and other primates, the knee joins the thigh with the leg and consists of two joints: one between the femur and tibia, and one between the femur and patella. It is the largest joint in the human body. The knee is a modified hinge joint, which permits flexion and extension as well as slight internal and external rotation. The knee is vulnerable to injury and to the development of osteoarthritis.
In human anatomy, a hamstring is any one of the three posterior thigh muscles in between the hip and the knee. The hamstrings are susceptible to injury. In quadrupeds, the hamstring is the single large tendon found behind the knee or comparable area.
The sacroiliac joint or SI joint (SIJ) is the joint between the sacrum and the ilium bones of the pelvis, which are connected by strong ligaments. In humans, the sacrum supports the spine and is supported in turn by an ilium on each side. The joint is strong, supporting the entire weight of the upper body. It is a synovial plane joint with irregular elevations and depressions that produce interlocking of the two bones. The human body has two sacroiliac joints, one on the left and one on the right, that often match each other but are highly variable from person to person.
The piriformis muscle is a flat, pyramidally-shaped muscle in the gluteal region of the lower limbs. It is one of the six muscles in the lateral rotator group.
In vertebrate anatomy, hip refers to either an anatomical region or a joint.
The biceps femoris is a muscle of the thigh located to the posterior, or back. As its name implies, it consists of two heads; the long head is considered part of the hamstring muscle group, while the short head is sometimes excluded from this characterization, as it only causes knee flexion and is activated by a separate nerve.
The gracilis muscle is the most superficial muscle on the medial side of the thigh. It is thin and flattened, broad above, narrow and tapering below.
The semimembranosus muscle is the most medial of the three hamstring muscles in the thigh. It is so named because it has a flat tendon of origin. It lies posteromedially in the thigh, deep to the semitendinosus muscle. It extends the hip joint and flexes the knee joint.
The sacrotuberous ligament is situated at the lower and back part of the pelvis. It is flat, and triangular in form; narrower in the middle than at the ends.
The acetabular notch is a deep notch in the acetabulum of the hip bone. The acetabular notch is continuous with a circular non-articular depression, the acetabular fossa, at the bottom of the cavity: this depression is perforated by numerous apertures, and lodges a mass of fat.
The iliofemoral ligament is a ligament of the hip joint which extends from the ilium to the femur in front of the joint. It is also referred to as the Y-ligament. the ligament of Bigelow, the ligament of Bertin and any combinations of these names.
The ischiofemoral ligament consists of a triangular band of strong fibers on the posterior side of the hip joint. Its fibers span from the ischium at a point below and behind the acetabulum to blend with the circular fibers at the posterior end of the joint capsule and attach at the intertrochanteric line of the femur.
In human anatomy, the ligament of the head of the femur is a ligament located in the hip. It is triangular in shape and somewhat flattened. The ligament is implanted by its apex into the antero-superior part of the fovea capitis femoris and its base is attached by two bands, one into either side of the acetabular notch, and between these bony attachments it blends with the transverse ligament.
The zona orbicularis or annular ligament is a ligament on the neck of the femur formed by the circular fibers of the articular capsule of the hip joint. It is also known as the orbicular zone, ring ligament, and zonular band.
The intertrochanteric line is a line located on the anterior side of the proximal end of the femur.
The transverse acetabular ligament is a portion of the acetabular labrum, though differing from it in having no cartilage cells among its fibers.
The femoral head is the highest part of the thigh bone (femur). It is supported by the femoral neck.
The articular capsule is strong and dense.
The acetabular branch is an artery in the hip that arises from the medial circumflex femoral artery opposite the acetabular notch and enters the hip-joint beneath the transverse ligament in company with an articular branch from the obturator artery. It supplies the fat in the bottom of the acetabulum, and is continued along the ligament to the head of the femur.
The pelvis is the lower part of the trunk, between the abdomen and the thighs, together with its embedded skeleton.
