By the end of this section, you will be able to:
Discuss both functional and structural classifications for body joints
- Distinguish between the functional and structural classifications for joints
- Describe the three functional types of joints and give an example of each
- Describe the three structuraltypes of joints and give an example of each
- Describe the planes of movement possible indiarthrodial joints
A joint, also called an articulation, is any place where adjacent bones or bone and cartilage come together (articulate with each other) to form a connection. Joints are classified both structurally and functionally. Structural classifications of joints take into account whether the adjacent bones are strongly anchored to each other by fibrous connective tissue or cartilage, or whether the adjacent bones articulate with each other within a fluid-filled space called a joint cavity. Functional classifications describe the degree of movement available between the bones, ranging from immobile, to slightly mobile, to freely moveable joints. The amount of movement available at a particular joint of the body is related to the functional requirements for that joint. Thus immobile or slightly moveable joints serve to protect internal organs, give stability to the body, and allow for limited body movement. In contrast, freely moveable joints allow for much more extensive movements of the body and limbs.
The structural classification of joints is based on whether the articulating surfaces of the adjacent bones are directly connected by fibrous connective tissue or cartilage, or whether the articulating surfaces contact each other within a fluid-filled joint cavity. These differences serve to divide the joints of the body into three structural classifications. A fibrous joint is where the adjacent bones are united by fibrous connective tissue. At a cartilaginous joint, the bones are joined by hyaline cartilage or fibrocartilage. At a synovial joint, the articulating surfaces of the bones are not directly connected, but instead come into contact with each other within a joint cavity that is filled with a lubricating fluid. Synovial joints allow for free movement between the bones and are the most common joints of the body.
The functional classification of joints is determined by the amount of mobility found between the adjacent bones. Joints are thus functionally classified as a synarthrosis or immobile joint, an amphiarthrosis or slightly moveable joint, or as a diarthrosis, which is a freely moveable joint (arthroun = “to fasten by a joint”). Depending on their location, fibrous joints may be functionally classified as a synarthrosis (immobile joint) or an amphiarthrosis (slightly mobile joint). Cartilaginous joints are also functionally classified as either a synarthrosis or an amphiarthrosis joint. All synovial joints are functionally classified as a diarthrosis joint.
An immobile or nearly immobile joint is called a synarthrosis (plural = synarthroses). The immobile nature of these joints provide for a strong union between the articulating bones. This is important at locations where the bones provide protection for internal organs. Examples include sutures, the fibrous joints between the bones of the skull that surround and protect the brain (Figure 9.1.1), and the epiphyseal growth plate, acartilaginous joint that unites the epiphyses and diaphysis of a growing long bone like the femur.
An amphiarthrosis (plural = amphiarthroses) is a joint that has limited mobility. An example of this type of joint is the cartilaginous joint that unites the bodies of adjacent vertebrae. Filling the gap between the vertebrae is a thick pad of fibrocartilage called an intervertebral disc (Figure 9.1.2). Each intervertebral disc strongly unites the vertebrae but still allows for a limited amount of movement between them. However, the small movements available between adjacent vertebrae can sum together along the length of the vertebral column to provide for large ranges of body movements.
Another example of an amphiarthrosis is the pubic symphysis of the pelvis. This is a cartilaginous joint in which the pubic regions of the right and left hip bones are strongly anchored to each other by fibrocartilage. This joint normally has very little mobility. The strength of the pubic symphysis is important in conferring weight-bearing stability to the pelvis. During pregnancy, increased levels of the hormone relaxin lead to increased mobility at the pubic symphysis which allows for expansion of the pelvic cavity during childbirth.
A freely mobile joint is classified as a diarthrosis(plural = diarthroses). This functional classification ofjoints describesall synovial joints of the body, which provide the majority of body movements. Most diarthrotic joints are found in the appendicular skeleton and give the limbs a wide range of motion. These joints are divided into three categories, based on the number of axes of motion provided by each. An axis in anatomy is described as the movements in reference to the three anatomical planes: transverse, frontal, and sagittal. Thus, diarthroses are classified as uniaxial,biaxial, or multiaxial joints.
A uniaxial joint only allows for a motion in a single plane (around a single axis). The elbow joint, which only allows for bending or straightening, is an example of a uniaxial joint. A biaxial joint allows for motions within two planes. An example of a biaxial joint is a metacarpophalangeal joint (knuckle joint) of the hand. The joint allows for movement along one axis to produce bending or straightening of the finger, and movement along a second axis, which allows for spreading of the fingers away from each other and bringing them together. A joint that allows for the several directions of movement is called a multiaxial joint (sometimes called polyaxial or triaxial joint). This type of diarthrotic joint allows for movement along three axes (Figure 9.1.3). The shoulder and hip joints are multiaxial joints. They allow the upper or lower limb to move in an anterior-posterior direction and a medial-lateral direction. In addition, the limb can also be rotated around its long axis. This third movement results in rotation of the limb so that its anterior surface is moved either toward or away from the midline of the body.
Structural classifications of the body joints are based on how the bones are held together and articulate with each other. At fibrous joints, the adjacent bones are directly united to each other by fibrous connective tissue. Similarly, at a cartilaginous joint, the adjacent bones are united by cartilage. In contrast, at a synovial joint, the articulating bone surfaces are not directly united to each other, but come together ata fluid-filled joint cavity.
The functional classification of body joints is based on the degree of movement found at each joint. A synarthrosis is a joint that is essentially immobile. This type of joint provides for a strong connection between the adjacent bones, which serves to protect internal structures such as the brain or heart. Examples include the fibrous joints of the skull sutures and the cartilaginous epiphysealplate. A joint that allows for limited movement is an amphiarthrosis. An example is the pubic symphysis of the pelvis, the cartilaginous joint that strongly unites the right and left hip bones of the pelvis. The cartilaginous joints in which vertebrae are united by intervertebral discs provide for small movements between the adjacent vertebrae and are also amphiarthroticjoints. Thus, based on their movement ability, somefibrous and cartilaginous joints are functionally classified as synarthroses while others areamphiarthroses.
The most common type of joint is the diarthrosis, which is a freely moveable joint. All synovial joints are functionally classified as diarthroses. A uniaxial diarthrosis, such as the elbow, is a joint that only allows for movement within a single anatomical plane. Joints that allow for movements in two planes are biaxial joints, such as the metacarpophalangeal joints of the fingers. A multiaxial joint, such as the shoulder or hip joint, allows for three planes of motions.
Critical Thinking Questions
1. Define how joints are classified based on function. Describe and give an example for each functional type of joint.
2. Explain how degree of mobility is related to joint strength.
- slightly mobile joint
- joint of the body
- biaxial joint
- type of diarthrosis; a joint that allows for movements within two planes (two axes)
- cartilaginous joint
- joint at which the bones are united by hyaline cartilage (synchondrosis) or fibrocartilage (symphysis)
- freely mobile joint
- fibrous joint
- joint where the articulating areas of the adjacent bones are connected by fibrous connective tissue
- site at which two or more bones or bone and cartilage come together (articulate)
- joint cavity
- space enclosed by the articular capsule of a synovial joint that is filled with synovial fluid and contains the articulating surfaces of the adjacent bones
- multiaxial joint
- type of diarthrosis; a joint that allows for movements within three planes (three axes)
- immobile or nearly immobile joint
- synovial joint
- joint at which the articulating surfaces of the bones are located within a joint cavity formed by an articular capsule
- uniaxial joint
- type of diarthrosis; joint that allows for motion within only one plane (one axis)
Answers for Critical Thinking Questions
- Functional classification of joints is based on the degree of mobility exhibited by the joint. A synarthrosis is an immobile or nearly immobile joint. An example is the epiphyseal plateor the joints between the skull bones surrounding the brain. An amphiarthrosis is a slightly moveable joint, such as the pubic symphysis or an intervertebral cartilaginous joint. A diarthrosis is a freely moveable joint. These are subdivided into three categories. A uniaxial diarthrosis allows movement within a single anatomical plane or axis of motion. The elbow joint is an example. A biaxial diarthrosis, such as the metacarpophalangeal joint, allows for movement along two planes or axes. The hip and shoulder joints are examples of a multiaxial diarthrosis. These allow movements along three planes or axes.
- Joint mobility is inversely related to joint strength. A synarthrosis, which is an immobile joint, serves to strongly connect bones thus protecting internal organs such as the heart or brain. A slightly moveable amphiarthrosis provides for small movements while maintaining stability between adjacent bones asin the vertebral column. The freedom of movement provided by a diarthrosis can allow for large movements, such as is seen with most joints of the limbs. However, these joints are the most frequently injured due to their looserarticulations at the joint cavity.
Joints can be classified: Histologically, on the dominant type of connective tissue. ie fibrous, cartilaginous, and synovial. Functionally, based on the amount of movement permitted.How do you classify the joints in anatomy? ›
Classification Of Joints - Fibrous Joints - Cartilaginous Joints - Synovial joints - TeachMeAnatomy.What are the 4 major categories of joints? ›
- Ball-and-socket joints. Ball-and-socket joints, such as the shoulder and hip joints, allow backward, forward, sideways, and rotating movements.
- Hinge joints. ...
- Pivot joints. ...
- Ellipsoidal joints.
Answer and Explanation: The following is not a functional classification of joints D. Arthrofibrosis.What is the classification of joints based on quizlet? ›
Functional classification of joints is based on: the amount of movement allowed by the joint.What are the 8 major joints of the body? ›
- Fibrous Joints. Fixed joints, also called immovable joints, are found where bones are not flexible. ...
- Cartilaginous Joints. ...
- Synovial Joints. ...
- Ball and Socket Joints. ...
- Pivotal Joints. ...
- Hinge Joints. ...
- Saddle Joints. ...
- Condyloid Joints.
Joints are thus functionally classified as a synarthrosis or immobile joint, an amphiarthrosis or slightly moveable joint, or as a diarthrosis, which is a freely moveable joint (arthroun = “to fasten by a joint”).What are the types of joints definitions? ›
A joint is the part of the body where two or more bones meet to allow movement. Generally speaking, the greater the range of movement, the higher the risk of injury because the strength of the joint is reduced. The six types of freely movable joint include ball and socket, saddle, hinge, condyloid, pivot and gliding.What is the functional classification of joints based on? ›
Functional classification of joints is based on the degree of mobility exhibited by the joint. A synarthrosis is an immobile or nearly immobile joint. An example is the manubriosternal joint or the joints between the skull bones surrounding the brain.What are the 9 types of joints? ›
- Ball and socket joint. Permitting movement in all directions, the ball and socket joint features the rounded head of one bone sitting in the cup of another bone. ...
- Hinge joint. ...
- Condyloid joint. ...
- Pivot joint. ...
- Gliding joint. ...
- Saddle joint.
Some of the functions of joints include providing flexibility to the skeleton, making different types of movements possible, providing stability to specific structures such as the skull and pelvis, and directing the motion of a specific bone or set of bones.What are the 3 main types of joints? ›
Functionally the three types of joints are synarthrosis (immovable), amphiarthrosis (slightly moveable), and diarthrosis (freely moveable).How many different types of joint classification are there? ›
There are three types of joints in the structural classification: fibrous, cartilaginous, and synovial joints.Which type of joints move the most? ›
Synovial joints are capable of the greatest movement of the three structural joint types; however, the more mobile a joint, the weaker the joint. Knees, elbows, and shoulders are examples of synovial joints.What are the 6 synovial joints? ›
Synovial joints are often further classified by the type of movements they permit. There are six such classifications: hinge (elbow), saddle (carpometacarpal joint), planar (acromioclavicular joint), pivot (atlantoaxial joint), condyloid (metacarpophalangeal joint), and ball and socket (hip joint).What are the four types of immovable joints? ›
Immovable joints (called synarthroses) include skull sutures, the articulations between the teeth and the mandible, and the joint found between the first pair of ribs and the sternum.Is the classification of joints which of the following is true? ›
Answer and Explanation: The correct answer to this question is B) All synovial joints are freely movable. There are three different ways to classify joints in both type of tissue and movement. The options when categorized by type of tissue includes fibrous, cartilaginous, and synovial.What is an immobile joint classified as? ›
Synarthrosis. An immobile or nearly immobile joint is called a synarthrosis. The immobile nature of these joints provide for a strong union between the articulating bones.What are the 4 functions of joints? ›
Abduction: The ability to lift your arm away from your body. Flexion: The ability to extend your arm over your head. Adduction: Moving your arm to your sides. Internal rotation and external rotation: Twisting your arm forward and back from your shoulder.Which type of joints do not show any movement? ›
Joints which do not allow any movement of bones are called fibrous or fixed joints. These joints bind the bones closely and tightly. On the other hand, the ball and socket joint, hinge joint and pivot joint allow partial or free movement of bones. Fixed joints are present between various bones of the skull.
Listen to pronunciation. (TEN-dun) Tough, fibrous, cord-like tissue that connects muscle to bone or another structure, such as an eyeball. Tendons help the bone or structure to move.Why are joints important in the human body? ›
Joints connect bones. They provide stability to the skeleton, and allow movement. There are different types of joints.How many joints are in the human body? ›
The joints connect bone to bone, and there are 360 joints in our bodies. Bone mass reaches maximum density in our late 20's and early 30's. As we age, our bones may weaken causing them to be more prone to fractures, so taking care of our bone and joint health is vital.What are the three classifications of joints based on movement quizlet? ›
The functional classification joint is based on the degree of movement that they allow. The three functional classes are: 1) synarthroses, which are totally immovable, 2) amphiarthroses, which have slight movement, and 3) diarthroses, which are freely moveable joints.What are the components of the joints? ›
Joints, particularly hinge joints like the elbow and the knee, are complex structures made up of bone, muscles, synovium, cartilage, and ligaments that are designed to bear weight and move the body through space.What are the classification of joints Class 11? ›
There are three types of joints: Fibrous joints. Cartilaginous joints. Synovial joints.What are the different types of joint movement? ›
- Flexion – bending a joint. ...
- Extension – straightening a joint. ...
- Abduction – movement away from the midline of the body. ...
- Rotation – this is where the limb moves in a circular movement around a fixed joint towards or away from the midline of the body.
The main joints of the body — such as those found at the hip, shoulders, elbows, knees, wrists, and ankles — are freely movable. They are filled with synovial fluid, which acts as a lubricant to help the joints move easily.What is cartilage called? ›
There are three types of cartilage in your body: Hyaline cartilage. Elastic cartilage. Fibrocartilage.Why are joints called joints? ›
The noun joint came into English through the French word joindre, meaning “to join.” Use joint to describe the point where two things connect, or join. A joint on your body allows for movement — you can look at your finger to see how that works.
Functional joints are classified by their degrees of movement. These include synarthrosis joints, amphiarthrosis joints, and diarthrosis joints. Synarthrosis joints are immobile while diarthrosis joints are the most mobile.What connects muscle to muscle? ›
Because tendons connect every muscle in your body, a wide range of injuries and disorders can cause tendon problems. Tendon issues are more common with age.Where are the 3 types of joints located? ›
- Fibrous joints hold skull bones together to protect the brain. ...
- Intervertebral discs are cartilaginous joints, composed of thick fibrocartilage, that support bones while allowing limited movement. ...
- Synovial joints are freely movable and provide the greatest degree of mobility. ...
- OpenStax College/Wikimedia Commons/CC BY 3.0.
|Common Joint Name||Bones of the Joint|
|Wrist||Radius, ulna and carpals|
|Sacroiliac||Sacrum and ilium|
|Hip||Femur and pelvis|
|Knee||Femur, patella, tibia and fibula|
The shoulder joint is the body's most flexible joint, as well as its most complex. Three bones, nearly a dozen different muscles and many ligaments and tendons meet in the shoulder.What is a pivot joint? ›
pivot joint, also called rotary joint, or trochoid joint, in vertebrate anatomy, a freely moveable joint (diarthrosis) that allows only rotary movement around a single axis. The moving bone rotates within a ring that is formed from a second bone and adjoining ligament.What are the classification of joints based on articulation? ›
Articulations vary in the amounts of movement they allow as well as their structures. Joints are classified based on function, the amount of movement they allow, into three categories: synarthrosis, amphiarthrosis, and diarthrosis.What are the functions of joints in anatomy and physiology? ›
The main function of a joint is to facilitate the movement of the human body. Some additional functions of joints include providing stability to the head and pelvis, providing flexibility to the skeleton, and directing the movement of muscles at a joint.How are joints classified by both structure and function quizlet? ›
Structurally (by the tissue type that binds the junction bones) joints are classified as fibrous, cartilaginous and synovial joints. This classification is the most commonly used. Functionally joints are classified as synarthrotic (immovable), amphiarthrotic (slightly movable), and diarthrotic (freely movable).