Types of joints in the human body - Anatomy & Examples | Kenhub

Summary

This tutorial delves into the anatomy of human joints, distinguishing them by structure, mobility, and range of motion. It covers synovial, fibrous, and cartilaginous joints, highlighting six synovial subtypes like ball-and-socket and hinge joints. The video explains how joint stability is influenced by factors like articular surface contact, ligaments, and muscle tone, emphasizing the trade-off between mobility and stability.

Takeaways

• 🦴 A joint is a connection between two bones in the skeleton and can be classified by structure, mobility, and range of motion.
• 🔍 There are three main types of joints based on structure: synovial, fibrous, and cartilaginous joints.
• 🌀 Synovial joints are the most common and are surrounded by an articular capsule with an outer fibrous layer and an inner synovial layer.
• 🧽 The articular surfaces of synovial joints are covered in hyaline cartilage which reduces friction and assists in shock absorption.
• 🔄 Synovial joints can be further subclassified into six types based on the shape of their articular surfaces and range of motion: ball-and-socket, hinge, pivot, condylar, saddle, and plane joints.
• 💺 Fibrous joints have little to no mobility and include sutures, gomphoses, and syndesmoses.
• 🦷 Gomphoses are a type of fibrous joint found in the mouth where the roots of teeth articulate with the dental alveoli.
• 🔗 Cartilaginous joints are connected by fibrocartilage or hyaline cartilage and include synchondroses and symphyses.
• 🤸‍♂️ Diarthroses are freely mobile joints like the knee joint, while amphiarthroses and synarthroses are less mobile or immobile, respectively.
• 🔄 Joints can be classified by their range of motion into uniaxial (one axis), biaxial (two axes), and polyaxial/multiaxial (three axes).
• 🏋️‍♀️ Factors contributing to joint stability include the degree of contact between articulating surfaces, presence of ligaments, and tone of surrounding muscles.

Q & A

What is the definition of a joint in the human skeleton?

A joint is defined as a connection between two bones in the skeleton.

How can joints be classified according to their structure?

Joints can be classified into synovial joints, fibrous joints, and cartilaginous joints based on their structure.

What are the characteristic features of synovial joints?

Synovial joints are surrounded by an articular capsule with an outer fibrous layer and an inner synovial layer, have articular surfaces covered in hyaline cartilage, and may contain additional structures like articular discs and bursae.

What are the different types of fibrous joints mentioned in the script?

The script mentions sutures, gomphoses, and syndesmoses as the types of fibrous joints.

How are the bones connected in a cartilaginous joint?

In a cartilaginous joint, the bones are connected by either fibrocartilage or hyaline cartilage.

What are the key terms for classifying joints based on their mobility?

The key terms are diarthrosis for freely mobile joints, amphiarthrosis for slightly mobile joints, and synarthrosis for immobile joints.

How are joints classified according to their range of motion?

Joints are classified as uniaxial, biaxial, or polyaxial based on the number of axes they can move along.

What is the only polyaxial joint in the human body?

The ball-and-socket joint is the only polyaxial joint in the human body.

What are the factors that contribute to joint stability?

The degree of contact between articulating surfaces, the presence of ligaments, and the tone of the surrounding muscles are the factors that contribute to joint stability.

Why are some joints more susceptible to dislocation or injury?

Some joints are more susceptible to dislocation or injury because there is a trade-off between mobility and stability; the more mobile a joint is, the less stable it will be.

What are the movements allowed by the different types of synovial joints?

Ball-and-socket joints allow flexion/extension, adduction/abduction, and internal/external rotation. Hinge joints allow flexion/extension. Pivot joints allow rotation. Condylar joints allow radial/ulnar deviation and flexion/extension. Saddle joints allow abduction/adduction, flexion/extension, and circumduction. Plane joints allow sliding or gliding movements.