Graphics Reference
In-Depth Information
The position of the pelvis shifts through movement of the spine and the hip
joints. Other than slight movements during childbirth, there is considered
to be little or no movement within the pelvic girdle itself under normal
conditions. The position of the pelvis at these joints allows for a tilt forward,
backward, and sideward. Rotation at the hips is provided through the
movement of the torso via the spine and the legs via the hip joints.
Hip Joints
The hip joints are typical ball-and-socket joints that connect the pelvic girdle
to the femur. The femur terminates in a spherical ball at an angle of around 45
degrees of the upright, the head of which fits into a cup-shaped recess, the
acetabulum, located at the juncture of the ilium, ischium, and the pubis. The
acetabulum is lined with a cartilaginous material that serves as a protection
between the two bony structures and provides a degree cushioning against
impacts or stresses. It also allows for a smooth movement within the joint.
The hip joints provide for a range of movements—forward and backward,
sideways and rotational.
FIG 5.9
Hip joints.
The Legs
The femur is a long weight-bearing bone that is angled inward slightly
from the upper end, where it joins the hips, to its juncture with the tibia.
However, this angle is not really evident by looking at our bodies and is
only evident once the skeleton is revealed. At the upper end of the femur
the bone has a ball that fits into a recess inside the hip. At the lower end the
femur sits on top of the tibia, with two ball-like protuberances called
condyle
that sit side by side. The condyle rest within two depressions on the upper
extremity of the tibia; these depressions are separated by a roughened area
called the
intercondyloid eminence
.
