Ball Socket Joint

Define Ball and Socket Joint

A joint is a connection between two bones that links the skeleton and maintains the body as a functional unit. There are various types of joints that are present in the human body. They are classified clinically and numerically, structurally, functionally, biochemically and anatomically. Ball socket joint is one of the different types of joints. It is grouped based upon the functional classification of a synovial joint along with other different types of joints such as plane joint, hinge joint, pivot joint, condyloid joint, and saddle joint.


What is Ball and Socket Joint?

From the introduction, one can have a brief idea of what is ball and socket joint. For answering what is ball and socket joint, it can be said that a ball socket joint (spheroid joint) is a synovial joint, which is freely movable. The ball socket joint is the ball-shaped surface of one bone that goes and fits into a cup-like depression of another bone. The free movement of the ball socket joint is because of its possible movement around indefinite numbers of different axis sharing the same centre of motion.


It is classified as a synovial joint because of the functional characteristic of movement providing flexibility in indefinite directions and because of the structural characteristic of the dense irregular connective tissue that binds the two bones together in a synovial joint. Thus, the ball and socket movement is because of its peculiar function of the cup-like depression and lock and key fit of the ball-shaped surface of one bone into the socket surface of the other bone. This ball and socket joint function are visible in the following ball and socket joint diagram:


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The ball and socket joint location are in the shoulder and the hip joint. The ball socket joint is highly developed in these joint regions. For the hip bone, the ball-shaped surface of the femur bone or the round head of the femur fits into the cup-like surface or the cup-like acetabulum of the pelvis bone. This kind of ball and socket joint function allows the hip movement in different directions for functions like sitting, standing, running, etc. The explanation of what is ball and socket joint in the case of hip structural integrity is given in the following diagram:


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Another example of a ball socket joint is the example of the shoulder joint. In the shoulder joint the upper rounded ball-like extremity of the humerus goes and sits into the cup-like glenoid fossa of the shoulder blade. The major activities such as the swinging of the arms, throwing, etc are possible because of the ball and socket movement in the shoulder joint. The ball and socket joint description in the case of the shoulder region is shown in the diagram given below:


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From the given examples, the functioning and movement of the ball socket joint are pretty clear. Also, structurally classified as a type of synovial joint because of the dense irregular connective tissue, the ball socket joint is the most flexible joint as compared to all other joints in terms of movement. The ball fitting in the socket provides the best combination for the movement of the bones as the ball-like surface can move to a number of free movements in the cup-like depression of the other bone. This type of joint is special because, on one hand, it is essential to provide movement to the two bones taking part in the formation of the joint while on the other hand they also aid in holding the structural integrity of the body without destabilising anything due to the freedom of movement.


Conclusion

There are many kinds of joints classified based on their structural, functional, clinical and biomechanical characteristics. Based on the structural and functional classification, a synovial joint is a type of joint which is known for freedom of movement and no direct joining of the two bones involved in the joint. Out of the six types of synovial joints, the ball-socket joint is one of the most flexible joints. They are also the most flexible joints as compared to any other joints in the human body. The importance of the ball and socket joint function is clear through the above article which also explains what is ball and socket joint and where are such joints found in the human body.

FAQs (Frequently Asked Questions)

1. Which Joint has a Ball and Socket?

Ans: The most prominent join in the human body showing the peculiar combination of ball and socket is the hip joint. The ball-shaped surface of the femur bone fits into the cup-like depression of the pelvis bone. This characteristic allows the free movement of the bones involved in the formation of the joint which in turn allows the functions of sitting, standing, walking and running. Another example of the ball and socket joint is the shoulder joint where the ball-like surface of the humerus bone fits into the corresponding cup-like depression in the shoulder blade thus allowing flexibility for the actions of throwing, swinging of arms, etc.

2. What are the Types of Synovial Joints?

Ans: Based on the structural, functional, clinical, and biomechanical properties the joints in the human body are classified into many different types. Out of all these classifications, depending on the structural and functional characteristics a type of joint known for free movement and no direct joining of the bones is the synovial joint. The synovial joint is further classified into many different joints which are: ball and socket joint, plane joint, hinge joint, pivot joint, condyloid joint, and saddle joint.