Unit 8: Assignment A
Joints
Neck
The neck is a pivot joint. Pivot joints are rounded, pointed or conical surface of one bone is
inserted into a ring made partly of another bone and partly of a ligament. The only
movement allowed is one bone around its axis (rotation). The neck allows the head to turn
so that we can see things to our sides. The neck attaches to the spine and skull,
sternomastoid (a muscle which allows the head to move up and down- flexion) and
trapezius (a muscle involved in the tilting or turning of the neck- rotation and flexion). An
example of what a pivot joint typically looks like is:
Elbow
The elbow is an example of a hinge joint. A hinge joint is where the convex surface of one
bone fits into a concave surface of a second bone. The movement allowed are flexion
(bending) and extension (straightening). These are all in one place around a single axis. The
elbow is the joint which allows the arms to bend. Associated ligaments, tendons and
muscles of the elbow are: Extenders of the wrist and fingers, triceps and biceps. A typical
example of how a hinge joint looks is:
Hip
, The hip joint is a Ball and socket joint. In this type of joint a ball shaped head fits into a cup
shaped depression. These joints are the most freely moving of the kinds of synovial joints
and are able to move in all directions. The hips attach to the femur and allow the leg to
move. The motion allowed in the hips are: abduction (moving away from the midline) and
adduction (moving towards the midline). An example of what a ball and socket joint looks
like is:
Shoulder
The shoulder is a second example of a Ball and socket Joint. As mentioned above ball and
socket joints are comprised of a ball shaped head fits into a cup shaped depression and are
the most free moving of all the synovial joints. The movements of the shoulder are rotation
(rotating on an axis), abduction (moving away from the midline), adduction (moving towards
the midline) and circumduction (complete circular motion). The role of the shoulder is to
allow the upper arm to move. The related ligaments of the shoulder are: Trapezius and
deltoid, biceps and triceps. An example of what a typical ball and socket joint looks like is:
Knee
Joints
Neck
The neck is a pivot joint. Pivot joints are rounded, pointed or conical surface of one bone is
inserted into a ring made partly of another bone and partly of a ligament. The only
movement allowed is one bone around its axis (rotation). The neck allows the head to turn
so that we can see things to our sides. The neck attaches to the spine and skull,
sternomastoid (a muscle which allows the head to move up and down- flexion) and
trapezius (a muscle involved in the tilting or turning of the neck- rotation and flexion). An
example of what a pivot joint typically looks like is:
Elbow
The elbow is an example of a hinge joint. A hinge joint is where the convex surface of one
bone fits into a concave surface of a second bone. The movement allowed are flexion
(bending) and extension (straightening). These are all in one place around a single axis. The
elbow is the joint which allows the arms to bend. Associated ligaments, tendons and
muscles of the elbow are: Extenders of the wrist and fingers, triceps and biceps. A typical
example of how a hinge joint looks is:
Hip
, The hip joint is a Ball and socket joint. In this type of joint a ball shaped head fits into a cup
shaped depression. These joints are the most freely moving of the kinds of synovial joints
and are able to move in all directions. The hips attach to the femur and allow the leg to
move. The motion allowed in the hips are: abduction (moving away from the midline) and
adduction (moving towards the midline). An example of what a ball and socket joint looks
like is:
Shoulder
The shoulder is a second example of a Ball and socket Joint. As mentioned above ball and
socket joints are comprised of a ball shaped head fits into a cup shaped depression and are
the most free moving of all the synovial joints. The movements of the shoulder are rotation
(rotating on an axis), abduction (moving away from the midline), adduction (moving towards
the midline) and circumduction (complete circular motion). The role of the shoulder is to
allow the upper arm to move. The related ligaments of the shoulder are: Trapezius and
deltoid, biceps and triceps. An example of what a typical ball and socket joint looks like is:
Knee
