Introduction
Body movement is the main function of the muscular and the skeletal system. This is a system consisting of the skeletal muscles and the bones involved in movement of the body. The two are connected by a connective tissue known as the tendons. In this paper, the relationship between the three will be determined focusing on the ball and socket joint. The components of each system will be analyzed and how they create movement at this joint as well.
The Skeletal System
This is a system that consist of the bones in the body. It serves to protect the body organs as well as allow movement. There are other functions such as production of blood by the bone marrows, storage of minerals which is done when minerals are excess in the blood, and provision of body support. This system has 206 bones that provide a frame work to which body organs and tissues are attached, for example the muscles (Martini and Bartholomew, 2007).
As had been noted, it offers protection to the vital organs like the brain, the heart and the lungs. In its role of allowing body movement, it interacts with the muscular system that has the components to make body movements. These are the skeletal muscles. This relationship is completed by the tendons which connect the bones to the muscles and transmit the muscle action to the bone. The bones of the skeletal system are connected to each other via ligaments. Movements are always made possible by the bone joints and muscle contraction and relaxation (muscle movement) (Martini and Bartholomew, 2007).
The Muscular System
This is a network of body tissues that controls any movements of the body. The body has internal as well as external movements. External movements are such as moving of the hand, walking and many others. Internal movements are such as the pumping of the heart, peristalsis and others. These movements occur due to the contraction and relaxation of specific muscles. The muscular system has muscles of the body divided into two, the skeletal muscles and the smooth muscles (Martini and Bartholomew, 2007).
It is the skeletal muscles that are always attached to the bones and aid in movements associated with the bones, therefore movement of various parts of the body. Skeletal muscles are voluntary muscles since they are controlled by the conscious mind. A person controls how to use them. Smooth muscles are involuntary as a person cannot consciously control them. Smooth muscles are found around the stomach, walls of the intestine and in artery and vein walls. The heart muscles are neither classified as smooth nor skeletal. They have the characteristics of both types, that is, the heart muscles are striated like the skeletal muscles, yet are involuntary like the smooth muscles (Martini and Bartholomew, 2007).
Skeletal Muscles
These are the main concern in this discussion as they are the ones that are attached to the skeleton to result into voluntary body movement. They make stable the joints of the body, give the body the overall shape and maintain posture. They are attached to the bones by the tendons as had been mentioned earlier. The tendons are fibrous connective tissue consisting of protein collagen and having the ability to stretch to allow movement at the muscle-joint junction (Martini and Bartholomew, 2007).
The contraction and relaxation of skeletal muscles is done through acting in pairs. When one muscle relaxes, the other contracts. This means that in their arrangement in the body, they are always paired. The pairing though can be between one muscle (the agonist) verses one other or so many muscles as the antagonists. The action of one pair will always antagonize the action of the other. It is this agonistic and antagonistic action that open and close joints of the bones. Examples are such as in the knee joint and the elbow. Example of such type of muscles are the biceps and the triceps. When the biceps of the arm contract, the triceps relax and the arm bends towards the biceps (Martini and Bartholomew, 2007).
Connective Tissue
These are the tendons that connect the skeleton and the skeletal muscles. The action of the muscle whether relaxation or contraction is passed through to the skeleton via the tendon. The tendons consist of fibrils with protein collagen and show both elasticity and strength (Martini and Bartholomew, 2007).
The Ball and Socket Joint
The skeletal muscles, the bones and the connective tissue are responsible for movement of the joints. This is also the case in the ball and socket joints that have a wide range of movements. Most movements at the joints are extension and flexion alone, but the ball and socket joints have all these movements possible; circumduction, abduction-aduction, flexion-extension and rotation. Apart from the tendons, muscles and the bones, what facilitates movement of the ball and socket joint is the cartilage and the synovial fluid that lubricates the joint. What the ligaments do is to keep the bones in place. Examples of ball and socket joint are the joints at the human shoulder and the joint between the femur and the pelvis (hip joint) (Templin, 1998).
Hip Joint
As this is a ball and socket joint, it will be used to show the skeletal, muscle and connective tissue components and functions. Hip joint is a multiaxial synovial joint. It is formed by the femur, which is the bone with the rounded head and the acetabulum of the pelvis, which is the cup like bone. This joint therefore forms a link between the bones of the lower limb and the axial skeleton bones of the pelvis and trunk. The rounded head of the femur and the cup like structure of the acetabulum are both covered by hyaline cartilage which facilitates movement since it is lubricated (Templin, 1998).
This joint has a fibrocartilaginous rim (labrum) that helps secure the femur head in the joint. As had been noted earlier, the bones are covered by hyaline cartilage, but in the femur head, there is a part that is not covered. This is left for the connection of the bone to bone by the intracapsular ligament. It is the ligament that connects the femur head to the acetabulum (Templin, 1998).
Ligaments in the Ball and Socket Joint of the Hip
This joint has loose but strong fibrous capsule making it to have a wide range of movements. Ball and socket joints are able to extend, to flex, abduct, adduct, rotate and to circumduct. It has the second largest movement after the shoulder joint which is also a ball and socket joint. There are three types of ligament in the hip joint (Templin, 1998).
Iliofemoral ligament (from the pelvis to the femur) which is at the front of the joint and prevents excessive extension of the hip joint. Another ligament is the pubofemoral which attaches across from the pubis bone through the pelvis to the femur. It is meant to reinforce the interior part of the joint. The last is the ischiofemoral ligament which lies on the posterior of the hip joint. It is attached from the acetabulum rim ischial part to the femur (Templin, 1998).
From the skeletal system literature, the skeletal system function to provide support is assisted by the ligaments. These ligaments in the ball and socket joint of the hip provides necessary support for the bones of the joint that in turn provide the support to the body weight, arms and head that the joint is responsible for (Templin, 1998).
Muscles of the Ball and Socket Joint
Movement of the hip joint is caused by four different types of muscles. Movement of the body is always as a result of the contraction and relaxation of the muscles connected to the bones by the connective tissues. In this case, the muscles do not only relax and contract, but rotate, abduct, adduct, and even circumduct. This is made possible by the different types of muscles for the different actions. They are divided according to their orientation around the ball and socket joint. They are; extensor muscles, lateral rotator muscles, adductor group muscles, flexors, abductors and tensor group muscles. The different muscles of a ball and socket joint act on there tendons in different ways to result into the various movements that a ball and socket joint has. The force from the muscle is passed to the skeleton through the connective tissue (Templin, 1998).
Conclusion
Based on the above information about the hip joint, it is clear that there are different types of skeletal muscles responsible for the different types of movement that is always possible in a ball and socket joint. The movements of the skeletal muscles are voluntary and are controlled by the person or the central nervous system of a person. If one wants to dance for example, this will be communicated to the brain which will interpret the message and send the responsible neurotransmitter to initiate the right kind of movement at the right place. Muscle movement is triggered by the neurotransmitters which give messages of whether to rotate, to abduct or to extend depending on the persons control, of his/her movements. The movements are created by the action of the muscles on the bones through the tendons.
References
Martini, F. andBartholomew, E. (2007). Essentials of Anatomy and Physiology, 4th edition,
Pearson/Benjamin Cummings.
Templin, M. J. (1998). The Essentials of Anatomy and Physiology. Research & Education Association, Essentials. Research & Education Assoc.