Would fibrous and cartilaginous joints be able to perform their functions if the
ID: 91736 • Letter: W
Question
Would fibrous and cartilaginous joints be able to perform their functions if they had joint cavities? Explain. Your father plans to visit an alternative medicine practitioner for "cranial therapy." You read the brochure for this proposed treatment and more that it involves the movement and manipulation of the cranial sutures, which the practitioner claims will cure nearly all diseases. What kine of joint is a cranial suture, both structurally and functionally? Given these facts, what do you think of the claims made about "cranial therapy"? The term double-jointed describes individuals who have an abnormally large range of motion in a given joint. This excess range of motion is not because of the presence of a second joint but, instead, weakness of the ligaments surrounding the joint. Why would weakness of ligaments lead to a greater range of motion at a joint? Compare the structure of the hip joint and the shoulder joint. Which joint do you think would be more likely to dislocate? Why?Explanation / Answer
1. Fibrous and cartilaginous joints are either immobile or nearly immobile joints. The immobile nature of these joints provides a strong union between the articulating bones. This is important at locations where the bones provide protection for internal organs.
But if they posses joint cavities they will never perform their work properly because joint cavity provides the majority of body movements. As a result if they possess joint cavities they will never provide strong union and protection for internal organs.
Examples include sutures, the fibrous joints between the bones of the skull that surround and protect the brain. If joint cavities present outer rigid cranium will never form which protects our brain.
The manubriosternal joint, the cartilaginous joint that unites the manubrium and body of the sternum for protection of the heart. The same type of result will also see in this case if manubriosternal joint possess joint cavities.
2. Structurally cranial suture is fibrous joint and functionally it is synarthrosis or immobile joint .
Claims about Cranial Therapy :
Cranial therapy is a light-touch hands-on therapy in which therapist uses gentle touch to manipulate the synarthrodial joints of the cranium. It enhances the body's natural capacity for healing. Besides this it has also been shown to be effective in treating a wide range of physiological issues associated with pain and loss of biomechanical, systemic and emotional function/wellbeing.
3. The term double jointed is also known as hypermobility joint or having joint laxity. This occurs due to presence of loose ligaments in a variety of ways.
Normally ligaments are naturally tight in such a way that the joints are restricted to normal ranges of motion which creates normal joint stability. But in this case muscles are very weak so muscular control does not compensate for hypermobility, as a result joint instability occurs. That’s why muscle weakness leads to hypermobility.
4. (a) Difference between hip and shoulder joint –
Hip Joint
Shoulder Joint
1. In this case ball and socket joint is deep.
1. In this case ball and socket joint is shallow.
2. Here articular capsule encloses large head and neck of femur.
2. Here loose articular capsule encloses anatomical neck.
3. Pelvic girdle is complete.
3. Pelvic girdle is incomplete.
4. In this case mobility sacrificed for stability.
4. In this case stability sacrificed for mobility.
5. In the hip, the labrum acts as a gasket seal that helps to contain joint fluid but also helps in stability.
5. The labrum in the shoulder is responsible for acting as a bumper that the ligaments connect to and aid in stability of the shoulder.
6. The socketof the hip is referred to as the acetabulum.
6. The socket of the shoulder is called the glenoid
(b) Shoulder joint is more likely to dislocate because the glrnoid fossa into which the humeral head inserts is very shallow and the humeral head is held in place by the muscles and tendons of the rotator cuff.
But in case of hip joint, the acetabulum is deep normally and covers the majority of the femoral head (think ball and socket joint). Dislocations of the hip will occur with acetabular fractures and also when the acetabulum is abnormally shallow as in congenital hip dysplasia.
So, shoulder joint is more likely to dislocate.
Hip Joint
Shoulder Joint
1. In this case ball and socket joint is deep.
1. In this case ball and socket joint is shallow.
2. Here articular capsule encloses large head and neck of femur.
2. Here loose articular capsule encloses anatomical neck.
3. Pelvic girdle is complete.
3. Pelvic girdle is incomplete.
4. In this case mobility sacrificed for stability.
4. In this case stability sacrificed for mobility.
5. In the hip, the labrum acts as a gasket seal that helps to contain joint fluid but also helps in stability.
5. The labrum in the shoulder is responsible for acting as a bumper that the ligaments connect to and aid in stability of the shoulder.
6. The socketof the hip is referred to as the acetabulum.
6. The socket of the shoulder is called the glenoid
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