MSK Joints - Fibrous Joints

Summary

In this video, Dr. Alsup discusses fibrous joints, a category of joints where bones are connected by dense irregular connective tissue. The video covers the three types of fibrous joints: sutures (found between skull bones with minimal movement), gomphoses (connecting teeth to bone, allowing slight movement), and syndesmoses (with longer sheets of connective tissue between bones like the interosseous membrane in the forearm and leg). The explanation highlights the structural differences and functional implications of each type of joint, with a brief review question to reinforce the material.

Takeaways

• 😀 Fibrous joints are a structural classification of joints where bones are connected by a solid sheet of connective tissue.
• 😀 The connective tissue in fibrous joints is dense irregular connective tissue, and the amount of tissue can vary between joint types.
• 😀 There are three main types of fibrous joints: sutures, gomphoses, and syndesmoses.
• 😀 Sutures are found only between the bones of the skull and involve short connective tissue ligaments called sutural ligaments.
• 😀 Sutures allow very little movement in adults, and they can become immovable with age, sometimes even fusing into bone (synostosis).
• 😀 Gomphoses are unique joints found between a tooth and its socket in the bone, connected by the periodontal ligament (PDL).
• 😀 Gomphoses do not involve bones directly connecting to other bones, unlike other fibrous joints.
• 😀 Syndesmoses involve longer sheets of fibrous connective tissue, which allow slight movement between the connected bones.
• 😀 An example of syndesmosis is the interosseous membrane, which connects the diaphyses of the radius and ulna or tibia and fibula.
• 😀 Syndesmoses, while slightly movable, are classified as amphiarthrotic joints, meaning they allow limited movement compared to synovial joints.
• 😀 The interosseous membrane can sometimes be considered its own category but is typically included within syndesmoses for classification purposes.

Q & A

What are fibrous joints?

Fibrous joints are a type of structural joint where bones are connected by a solid sheet of dense irregular connective tissue, without a space in between, unlike synovial joints.

What type of connective tissue is present in fibrous joints?

Fibrous joints contain dense irregular connective tissue, which can vary in length depending on the specific type of fibrous joint.

What are the three types of fibrous joints discussed in the video?

The three types of fibrous joints discussed are sutures, gomphoses, and syndesmoses.

What is unique about sutures as a type of fibrous joint?

Sutures are unique because they occur only between the bones of the skull. They are connected by a short sheet of fibrous tissue called a sutural ligament, allowing minimal movement, which decreases with age.

What is the term for a suture that has completely ossified with age?

When a suture becomes fully ossified and the fibrous connective tissue is replaced by bone, it is referred to as a bony joint or synostosis.

What is a gomphosis and where is it found?

A gomphosis is a peg-and-socket joint between a tooth and its corresponding bony socket in the jaw. The fibrous tissue connecting the tooth to the bone is the periodontal ligament (PDL).

How does the connective tissue in gomphoses compare to that in sutures?

In gomphoses, the fibrous connective tissue (periodontal ligament) is longer than that in sutures, allowing a slight amount of movement, though still limited.

What is the main characteristic of syndesmoses?

Syndesmoses have longer sheets of fibrous connective tissue between the bones, which allows for a small amount of movement. This type includes structures like the interosseous membranes.

What is an example of a syndesmosis, and where can it be found?

An example of a syndesmosis is the interosseous membrane, which connects the diaphyses of the radius and ulna in the forearm, as well as the tibia and fibula in the lower leg.

What type of fibrous joint is the interosseous membrane between the tibia and fibula?

The interosseous membrane between the tibia and fibula is an example of a syndesmosis. It consists of a longer sheet of fibrous tissue than other fibrous joints, allowing for limited movement.