Primary and Secondary Cartilaginous Joints

Introduction

A point of connection between two or more bones can be referred to as a joint. The joint helps in movement and provides firmness to the pelvis and skull structures. These joints can show no movement, slight movement, or full movement. Joints can be categorized into synovial joints, fibrous joints, and cartilaginous joints. Cartilaginous joints are the ones that join two or more joints together. Two types of cartilaginous joints exist - primary cartilaginous joints and secondary cartilaginous joints.

What are Cartilaginous Joints?

Cartilaginous joints are the special type of joints in which two bones are connected by fibrocartilage or hyaline. These joints help in bone movement faster than fibrous joints and slower than synovial joints. These are formed by the connective tissue called cartilage.

Cartilaginous joints which are connected by hyaline cartilage cannot show movement and cartilaginous joints which are connected by fibrocartilage show slight movement. Cartilage is a connective tissue that is flexible and strong.

Features of Cartilaginous Joints

• Cartilaginous joints are connected by either hyaline cartilage or fibrocartilage.

• Cartilaginous joints show slight movement or no movement.

• The joint cavity is absent in cartilaginous joints.

• The cartilaginous joint connects two or more bones.

• These joints connect two hip bones.

• They can connect the sternum and ribs.

• These joints can be seen in those areas where no movement or less movement is required.

Types of Cartilaginous joints

Depending on the type, cartilaginous joints can be divided into two types:

• The primary cartilaginous joint is where two bones are joined by hyaline cartilage and

• The secondary cartilaginous joint is where two bones are joined by fibrocartilage.

Primary Cartilaginous Joints

Hyaline cartilage connects two or more bones to form these joints. They can be termed synchondrosis. They can be either short-term or long-lasting. Growth plates are replaced by bones after a certain age. When a child is growing, the bone and cartilage growth are the same so that the size of the growth plate remains the same even after bone growth. After the end of the teenage years, cartilage growth terminates. As a result of this bone formation takes place in the place of cartilage.

Different parts of the hip bone are joined together by cartilaginous joints which are replaced by the hip bone when a child grows old. Examples include joints of Luschka, the cartilaginous joint between sphenoid and occipital bones, and the cartilaginous joint formation between petrous and occipital bones.

Permanent joints are not replaced with bones. They contain hyaline cartilage for lifelong use. For example: rib cage.

Secondary Cartilaginous Joints

These cartilaginous joints connect two or more bones by fibrocartilage. This can be termed symphysis. Many collagen fibers together make the fibrocartilage because of which it can withstand the forces of bending and pulling. This nature allows the secondary cartilaginous joints to hold two or more bones together stronger than hyaline cartilage.

The cartilaginous joints are permanent and movement is low in symphysis. Two sides of the pubic hip bones are connected by a fibrocartilage pad. Relaxing level increases at the time of pregnancy which increases the movement of pubic joints which in turn results in pelvic cavity expansion at the time of labor.

Examples of secondary cartilaginous joints are as follows, intervertebral fibrocartilage, the cartilaginous joint that connects the coccyx and sacrum, joint that connects the manubrium and sternal body.

Disorders

• Costochondritis: Costochondritis refers to a condition in which chest pain occurs due to the swelling of the rib cartilage.

• Osteoarthritis: Osteoarthritis refers to a disease in which the cartilaginous layer becomes decreased or broken down. As a result, bone gets exposed to abrasion and damage.

• Articular Cartilage Damage: Because of less supply of blood, repairing articular damage is much more time-consuming. This cartilage may be ruptured at the time of knee injuries.

• Polychondritis: This condition results in the inflammation of the cartilages of the nose, ears, and respiratory airways.

• Hernia: Occurrence of a prolapsed disc can be due to the rupturing of the cartilaginous disc which can cause pain.

• Cancer: Chondrosarcoma is a malignant tumor and chondroma is a benign tumor that is caused due to the uncontrolled cell division in these cartilaginous joint cells.

Conclusion

A point of connection between two or more bones can be referred to as a joint. Cartilaginous joints are the special type of joints in which two bones are connected by hyaline cartilage or fibrocartilage. The cartilaginous joints are permanent and movement is low in symphysis. Two sides of the pubic hip bones are connected by a fibrocartilage pad. Cartilaginous joints can be categorized into two types based on the cartilage they are made up of. This tutorial helps to understand the features of cartilaginous joints, types of cartilaginous joints, and disorders associated with them.

FAQs

Q1. What are hyaline cartilage and fibrocartilage?

Ans: Hyaline cartilage is the cartilage rich in collagen which can be present in the joints of the trachea, ribs, and nose. Fibrocartilage is the cartilage that has both cartilaginous and fibrous tissues.

Q2. How to treat osteoarthritis?

Ans: In order to treat osteoarthritis, nonsteroidal anti-inflammatory drugs are usually administered, physical therapy is provided, transcutaneous electrical nerve stimulation is applied, joint replacement surgery is performed, and the bones are realigned.

Q3. What is a synovial joint? Write down its functions.

Ans: A synovial joint is a point that connects the fibrous joint capsules and bones and forms the external layer of the synovial cavity. The synovial joint helps in the movement by connecting long bones. This joint can safeguard the connective tissues, muscles, and cartilage.

Q4. Mention the locations of cartilaginous joints.

Ans: Cartilaginous joints are located in the rib cage, pubic symphysis, intervertebral fibrocartilage, and the cartilaginous joint that connects the coccyx and sacrum, a joint that connects the manubrium and sternal body.

Q5. What is the cause of the cartilage tumor?

Ans: Cartilage tumors may occur due to genetic or chromosomal mutations. It can occur as a result of side effects of radiotherapy conducted for other cancers. Enchondroma from different other bone diseases may cause malignant tumors for a longer duration.

Q6. What is the difference between tendon and ligament?

Ans: Tendons are structures that give muscular force to the bone. Ligaments are the structures that connect bone to bone. Tendons are tough and elastic while ligaments are string and elastic. Tendons are composed of white fibrous tissue while the ligament is made of yellow elastic tissue.