Lecture Notes: Fibrous Joints

Key Concepts

• Fibrous Joints: Joints that lack a synovial cavity but are held together by fibrous material, usually ligaments or tissues.
• Functional Classifications:
  • Synarthritic: No movement allowed.
  • Amphiarthritic: Allows some movement.

Types of Fibrous Joints

1. Sutures

   • Location: Found between skull bones.
   • Structure: Made of dense irregular connective tissue.
   • Movement: Synarthritic (no movement in adults).
   • Examples: Coronal suture between the frontal and parietal bones.
   • Special Note: In infants, sutures are not fully formed allowing for growth.

2. Syndesmoses

   • Definition: Means ligament or band.
   • Examples & Locations:
     • Distal Tibiofibular Joint: Between tibia and fibula.
     • Gonphosis (Dental Alveolar): Tooth in socket, held by the periodontal ligament.
   • Movement:
     • Tibia and fibula syndesmosis: Amphiarthritic (allows some movement).
     • Gonphosis: Synarthritic (no movement, but orthodontics can manipulate teeth).

3. Interosseous Membranes

   • Definition: Membrane between two bones.
   • Locations:
     • Between the shafts (diaphysis) of the tibia and fibula.
     • Between the shafts (diaphysis) of the radius and ulna.
   • Function: Provides stability with some movement.
   • Movement: Amphiarthritic.

Anatomy Overview

• Fibrous Joints are categorized into three types: Sutures, Syndesmoses, and Interosseous Membranes.
• Sutures are located in the skull and are immovable in adults.
• Syndesmoses include ligaments like the tibia-fibula ligament and gonphosis, which allows for little to no movement.
• Interosseous Membranes found between long bones like radius-ulna and tibia-fibula, allowing slight movement.

Summary

• Fibrous joints are crucial for stability and slightly restricted movement in certain body parts.
• Sutures and gonphosis are synarthritic, while interosseous membranes and certain syndesmoses are amphiarthritic.