The Skeletal System and Its Movements 27In the upper extremity, two specialized move-
ment pairs are used to describe movements in the
horizontal plane about a vertical axis: pronation-
supination and horizontal abduction-adduction (see
figure 1.16). Pronation refers to internal rotation of
the forearm so that the palm faces backward while
supination refers to external rotation of the forearm
so that the palm faces forward. Anatomical position
utilizes a position of forearm supination. Horizontal
abduction-adduction is terminology that has been
developed because of the common use of the arms
at shoulder height during functional movement. If
the arm is flexed to a 90° position at the shoulder
joint, movement of the arm laterally in the horizontal
plane is termed horizontal abduction or horizontal
extension. Movement in the opposite direction from
a lateral position anteriorly (toward the midline of
the body) is termed horizontal adduction or hori-
zontal flexion.
In the lower extremity, this same terminology
of horizontal abduction-adduction can be used for
movements of the thigh in the horizontal plane
from a position of 90° of hip flexion. With the foot,
terminology of plantar flexion and dorsiflexion is
used in place of flexion-extension due to the con-
troversy regarding which side of the foot should be
considered “anterior.” Plantar flexion of the foot at
the ankle joint corresponds to what dancers term
“pointing” the foot, while dorsiflexion corresponds
to what dancers term “flexing” the foot. So, rememberFundamental Joint Movements
While standing in anatomical position, perform the following movements.- Movements in the sagittal plane. Perform flexion of the fingers, wrist, elbow, shoulder, and hip
joints in which the distal segment is the moving segment. Note that this involves forward movement of
the distal segment of the joint from anatomical position in a sagittal plane such that anterior surfaces
of the joint segments are approximating. Then, extend these joints, returning to anatomical position.
Note that this occurs in a backward direction in a sagittal plane. Can these joints be extended from
anatomical position? Now flex the knee joint. Note that although movement occurs in a sagittal plane,
flexion of the knee involves a backward movement of the distal segment with posterior surfaces of the
segments approximating, while extension involves a forward motion. In some cases, such as when the
hand or foot is weight bearing and fixed, the proximal segment moves alone or simultaneously with
the distal segment. Perform flexion of the hip in which the proximal segment moves and the distal
segment remains stationary. - Movements in the frontal plane. Perform abduction of the shoulder and hip joints in which the
distal segment of the limb (hand and foot) is allowed to move. Note that these movements involve
movement from anatomical position away from the midline of the body in a frontal plane. Then,
adduct these joints, returning to anatomical position. Note that adduction of these joints involves
a movement toward the midline of the body in the frontal plane. Can these joints be adducted from
anatomical position? Now perform abduction and adduction of the hip joint in which the foot is fixed
and the pelvis is the moving segment. How do these movements relate to the dance terminology
“sitting in your hip”? - Movements in the horizontal plane. Perform internal rotation of the shoulder and hip joint in
which the distal segment (hand and foot) is free to move. Note that this involves movement of the
anterior surface of the limb toward the midline in a horizontal plane. Then, perform external rotation
of the shoulder and hip, returning back to anatomical position. Can external rotation be performed
from anatomical position? Note how similar amounts of internal and external rotation can occur from
anatomical position, in contrast to the other movement pairs. How do these movements relate to the
dance terminology “turnout”? Now perform rotation at the hip joint in which the pelvis moves while
the foot remains fixed.