Question

Identify/List descriptions, characteristics, and examples of the following: fibrous, cartilaginous & synovial joints.

Answer 1

1 -Fibrous Joint -
A fibrous joint is a fixed joint where fibrous tissue comprised primarily of collagen connects bones. Fibrous joints are usually immoveable (synarthroses) and have no joint cavity. They are subdivided in to following types -

Suture
Sutures are immobile joints in the cranium. The plate-like bones of the skull are slightly mobile at birth because of the connective tissue between them, termed fontanelles. This initial flexibility allows the infant’s head to get through the birth canal at delivery and permits the enlargement of the brain after birth. As the skull enlarges, the fontanelles reduce to a narrow layer of fibrous connective tissue, called Sharpey’s fibers, that suture the bony plates together. Eventually, cranial sutures ossify- the two adjacent plates fuse to form one bone; this fusion is termed synostosis.

Gomphoses-
Gomphoses are the immobile joints between the teeth and their sockets in the mandible and maxillae. The periodontal ligament is the fibrous tissue that connects the tooth to the socket.

Syndesmosis -

these are slightly movable joints (amphiarthroses). In syndesmosis joints, the two bones are held together by an interosseous membrane. For example, the tibia connects to the fibula, forming the middle tibiofibular joint, and the ulna attaches to the radius, forming the middle radio-ulnar joint.

Example - joints between teeth , tibiofibular joint

2-Cartilaginous Joint -

In cartilaginous joints, the bones attach by hyaline cartilage or fibrocartilage. Depending on the type of cartilage involved, the joints further classify as primary and secondary cartilaginous joints.

Primary cartilaginous joints, also known as synchondroses, only involve hyaline cartilage. These joints may be slightly mobile or immobile.
The secondary cartilaginous joint, also known as symphysis, may involve either hyaline or fibrocartilage. These joints are slightly mobile .
Example - Pubic Symphysis
Joint between epiphysial and diaphysis of growing bones.

Synovial

Arthritis is inflammation of the synovial joint. There are many types of arthritis, distinguished by different mechanisms of injury. The most common type of arthritis is osteoarthritis, which, by definition, is gradual damage to and subsequent thinning of the articular cartilage. This condition is considered a “wear and tear” injury and presents in older patients; it often correlates with prior injury to the joint and longstanding high-impact stress on the joint (due to sports or excessive body weight). Because the articular cartilage has no innervation, the degradation itself does not cause pain. Instead, as the articular cartilage becomes thinner, more pressure is placed on the bones. The joint responds by overproducing synovial fluid, which leads to swelling and inflammation, that stretches the highly innervated articular capsule to cause pain and stiffness of the joint. The underlying bone also has a rich nerve supply that perceives pain.
Gout is another form of arthritis caused by the deposition of uric acid crystals within a joint. Uric acid causes gout when there is an excessive amount in the body; this is either due to over-production or improper excretion by the kidneys. The most commonly affected joint is the metatarsophalangeal (MTP) joint of the big toe. Patients often present with excruciating pain and swelling.
Synovitis is inflammation of the synovial membrane that lines the articular capsule of synovial joints. The most common cause is the overuse of a synovial joint in an active, healthy person. Persistent synovitis in multiple joints can indicate rheumatoid arthritis, where the synovium is the target of the autoimmune attack. Patients with synovitis often present with pain out of proportion to examination; in fact, sometimes the patient has pain without swelling or tenderness, or arthralgia.
Example - Ball and Shocket Joint.