Which two of the following are examples of ball and socket joints?

Joints are the areas where two or more bones meet. Most joints are mobile, allowing the bones to move. Joints consist of the following:

• Cartilage. A type of tissue that covers the surface of a bone at a joint. Cartilage helps reduce the friction of movement within a joint.

• Synovial membrane. A tissue called the synovial membrane lines the joint and seals it into a joint capsule. The synovial membrane secretes a clear, sticky fluid (synovial fluid) around the joint to lubricate it.

• Ligaments. Strong ligaments (tough, elastic bands of connective tissue) surround the joint to give support and limit the joint's movement. Ligaments connect bones together.

• Tendons. Tendons (another type of tough connective tissue) on each side of a joint attach to muscles that control movement of the joint. Tendons connect muscles to bones.

• Bursas. Fluid-filled sacs, called bursas, between bones, ligaments, or other nearby structures. They help cushion the friction in a joint.

• Synovial fluid. A clear, sticky fluid secreted by the synovial membrane.

• Femur. This is the thighbone.

• Tibia. This is the shin bone.

• Patella. This is the kneecap.

• Meniscus. This is a curved part of cartilage in the knees and other joints.

What are the different types of joints?

There are many types of joints, including joints that don’t move in adults, such as the suture joints in the skull. Joints that don’t move are called fixed. Other joints may move a little, such as the vertebrae. Examples of mobile joints include the following:

• Ball-and-socket joints. Ball-and-socket joints, such as the shoulder and hip joints, allow backward, forward, sideways, and rotating movements.

• Hinge joints. Hinge joints, such as in the fingers, knees, elbows, and toes, allow only bending and straightening movements.

• Pivot joints. Pivot joints, such as the neck joints, allow limited rotating movements.

• Ellipsoidal joints. Ellipsoidal joints, such as the wrist joint, allow all types of movement except pivotal movements.

  Best Answer

  Explanation:

  • The ball and socket joint (also known as the spheroid joint) is a type of synovial joint in which one rounded bone's ball-shaped surface fits into the cup-like depression of another. 
  • The distal bone can move about an infinite number of axes, all of which have the same common centre. The joint can now move in a variety of directions. 
  • The hip joint, where the round head of the femur (ball) rests in the cup-like acetabulum (socket) of the pelvis, and the shoulder joint, where the rounded upper extremity of the humerus (ball) rests in the cup-like glenoid fossa (socket) of the shoulder blade, are both examples of this type of articulation.

  Final Answer:

  • The following are some examples of ball and socket joints:
  • Hip joint, where the femur's rounded head (ball) lies in the pelvis' cup-like acetabulum (socket).
  • Shoulder joint, where the rounded head of the humerus (ball) lies in the shoulder blade's cup-like glenoid fossa (socket).

  
  
  
  
  
  

  (a) Ball and socket joint is a movable joint. In this, a bone with a round head fits into the hollow space of another bone. This makes the bone to rotate freely. For example, bones of the hip and shoulder can move in all directions due to ball and socket joints.

  (b) Lower jaw bone (Mandible bone) is the only skull bone that is movable.

  (c) Our elbow cannot move back because it has a hinge joint which allows the movement in one plane only.

  Synovial joints are further classified into six different categories on the basis of the shape and structure of the joint. The shape of the joint affects the type of movement permitted by the joint (Figure 1). These joints can be described as planar, hinge, pivot, condyloid, saddle, or ball-and-socket joints.

  

  Figure 1. Different types of joints allow different types of movement. Planar, hinge, pivot, condyloid, saddle, and ball-and-socket are all types of synovial joints.

  Planar Joints

  Planar joints have bones with articulating surfaces that are flat or slightly curved faces. These joints allow for gliding movements, and so the joints are sometimes referred to as gliding joints. The range of motion is limited in these joints and does not involve rotation. Planar joints are found in the carpal bones in the hand and the tarsal bones of the foot, as well as between vertebrae (Figure 2).

  

  Figure 2. The joints of the carpal bones in the wrist are examples of planar joints. (credit: modification of work by Brian C. Goss)

  Hinge Joints

  In hinge joints, the slightly rounded end of one bone fits into the slightly hollow end of the other bone. In this way, one bone moves while the other remains stationary, like the hinge of a door. The elbow is an example of a hinge joint. The knee is sometimes classified as a modified hinge joint (Figure 3).

  

  Figure 3. The elbow joint, where the radius articulates with the humerus, is an example of a hinge joint. (credit: modification of work by Brian C. Goss)

  Pivot Joints

  Pivot joints consist of the rounded end of one bone fitting into a ring formed by the other bone. This structure allows rotational movement, as the rounded bone moves around its own axis. An example of a pivot joint is the joint of the first and second vertebrae of the neck that allows the head to move back and forth (Figure 4). The joint of the wrist that allows the palm of the hand to be turned up and down is also a pivot joint.

  

  Figure 4. The joint in the neck that allows the head to move back and forth is an example of a pivot joint.

  Condyloid Joints

  Condyloid joints consist of an oval-shaped end of one bone fitting into a similarly oval-shaped hollow of another bone (Figure 5). This is also sometimes called an ellipsoidal joint. This type of joint allows angular movement along two axes, as seen in the joints of the wrist and fingers, which can move both side to side and up and down.

  

  Figure 5. The metacarpophalangeal joints in the finger are examples of condyloid joints. (credit: modification of work by Gray’s Anatomy)

  Saddle Joints

  Saddle joints are so named because the ends of each bone resemble a saddle, with concave and convex portions that fit together. Saddle joints allow angular movements similar to condyloid joints but with a greater range of motion. An example of a saddle joint is the thumb joint, which can move back and forth and up and down, but more freely than the wrist or fingers (Figure 6).

  

  Figure 6. The carpometacarpal joints in the thumb are examples of saddle joints. (credit: modification of work by Brian C. Goss)

  Ball-and-Socket Joints

  Ball-and-socket joints possess a rounded, ball-like end of one bone fitting into a cuplike socket of another bone. This organization allows the greatest range of motion, as all movement types are possible in all directions. Examples of ball-and-socket joints are the shoulder and hip joints (Figure 7).

  Which of the following is an example of a ball and socket?

  Hip is an example of a ball and socket joint. This is an articulation that resembles a round feature like a ball (in this case the head of the femur) and an indentation like a socket (acetabulum).

  What are some ball and socket joints?

  The only two ball and socket joints of the body are the hips and the shoulder (glenohumeral). The shallow socket of the glenoid cavity permits a more extensive range of motion in the shoulder; the deeper socket of the acetabulum and the supporting ligaments of the hip constrain the movement of the femur.