Cartilaginous

Overview of Joints

  • Summary of joints, focusing on cartilaginous joints after discussing fibrous joints.

Types of Joints in Cartilaginous Category

General Definition of Cartilaginous Joints

  • Definition: Cartilaginous joints are those where adjacent bones are joined by cartilage.

  • Types of Cartilage: The cartilage may be either hyaline cartilage or fibrocartilage.

  • Characteristic Feature: These joints do not possess a joint cavity.

1. Synchondroses

  • Definition: Synchondroses are joints that are joined by hyaline cartilage.

  • Functional Classification: Classified as synarthrosis, indicating a lack of movement.

    • Examples of Synchondroses:

    • Temporary Synchondrosis:

      • Epiphyseal Plate:

      • Definition: The region of growing bone where the diaphysis and epiphysis meet, made of hyaline cartilage that allows for bone lengthening.

      • Process:

        • During growth, cartilage at the epiphyseal plate is gradually replaced by bone.

        • At puberty, this process slows, and upon complete ossification, forms a synostosis (complete bone fusion).

      • Coxal Bones (Hip Bones):

      • Formation involves separate bones (ileum, ischium, pubis) that fuse together in childhood to form a single coxal bone.

    • Permanent Synchondrosis:

      • The first sternocostal joint between the first rib and the sternum where the rib is anchored to the manubrium by cartilage that does not ossify, remaining as hyaline cartilage throughout life.

2. Symphyses

  • Definition: Symphyses are joints joined by fibrocartilage.

  • Functional Characteristics: They provide a strong attachment between bones due to thick bundles of collagen fibers, which enhances resistance to pulling and resistive forces.

    • Examples of Symphyses:

    • Pubic Symphysis:

      • Located between the two pubic bones, providing strong connection.

    • Manubriosternal Joint:

      • Joint at the sternum, also composed of fibrocartilage.

    • Intervertebral Discs:

      • Filled with fibrocartilage, these discs cushion vertebrae and provide substantial adhesion between them.

Importance of Structural Joints

  • Functionality: Symphyses and synchondroses are crucial in areas requiring greater resistance to mechanical stress and weight-bearing, such as the spine.

  • Mechanical Forces: The strength and resilience provided by fibrocartilage in symphyses are essential for activities that involve load-bearing and mobility.

Conclusion

  • Review of types of structural joints, emphasizing the need for understanding weight distribution, load resistance, and movement functions in the human body.