Which joint in the figure is capable of multiaxial movement

prepared by

Karen Dunbar Kareiva

Ivy Tech Community College

© Annie Leibovitz/Contact Press Images

Chapter 8 Part A

Joints

Why This Matters

Understanding the nature of joints will help you treat patients with injuries such as ankle sprains

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8.1 Classification of Joints

Joints, also called articulations: sites where two or more bones meet

Functions of joints: give skeleton mobility and hold skeleton together

Two classifications:

Structural: three types based on what material binds the joints and whether a cavity is present

Fibrous

Cartilaginous

Synovial

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8.1 Classification of Joints

Functional classifications: three types based on movement joint allows

Synarthroses: immovable joints

Amphiarthroses: slightly movable joints

Diarthroses: freely movable joints

Structural classifications are more clear cut, so these will be used here

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8.2 Fibrous Joints

Bones joined by dense fibrous connective tissue

No joint cavity

Most are immovable

Depends on length of connective tissue fibers

Three types of fibrous joints

Sutures

Syndesmoses

Gomphoses

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Sutures

Rigid, interlocking joints of skull

Allow for growth during youth

Contain short connective tissue fibers that allow for expansion

In middle age, sutures ossify and fuse

Immovable joints join skull into one unit that protects brain

Closed, immovable sutures referred to as synostoses

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Figure 8.1a Fibrous joints.

Suture

Joint held together with very short,

interconnecting fibers, and bone

edges interlock. Found only in

the skull.

Suture

line

Fibrous

connective

tissue

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Syndesmoses

Bones connected by ligaments, bands of fibrous tissue

Fiber length varies, so movement varies

Short fibers offer little to no movement

Example: inferior tibiofibular joint

Longer fibers offer a larger amount of movement

Example: interosseous membrane connecting radius and ulna

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Figure 8.1b Fibrous joints.

Syndesmosis

Joint held together by a ligament.

Fibrous tissue can vary in length,

but is longer than in sutures.

Fibula

Tibia

Ligament

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Gomphoses

Peg-in-socket joints

Only examples are the teeth in alveolar sockets

Fibrous connection is the periodontal ligament

Holds tooth in socket

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Figure 8.1c Fibrous joints.

Gomphosis

“Peg in socket” fibrous joint.