By the end of this section, you will be able to:
- Distinguish between the functional and structural classifications for joints
- Describe the three functional types of joints and give an example of each
- List the three types of diarthrodial 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. 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 ([link]), and the manubriosternal joint, the cartilaginous joint that unites the manubrium and body of the sternum for protection of the heart.
Suture Joints of Skull
The suture joints of the skull are an example of a synarthrosis, an immobile or essentially immobile joint.
An amphiarthrosis 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 ([link]). 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.
An intervertebral disc unites the bodies of adjacent vertebrae within the vertebral column. Each disc allows for limited movement between the vertebrae and thus functionally forms an amphiarthrosis type of joint. Intervertebral discs are made of fibrocartilage and thereby structurally form a symphysis type of cartilaginous joint.
A freely mobile joint is classified as a diarthrosis. These types of joints include all synovial joints of the body, which provide the majority of body movements. Most diarthrotic joints are found in the appendicular skeleton and thus 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 (for movement in one plane), biaxial (for movement in two planes), or multiaxial joints (for movement in all three anatomical planes).
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 (polyaxial or triaxial joint). This type of diarthrotic joint allows for movement along three axes ([link]). 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.
A multiaxial joint, such as the hip joint, allows for three types of movement: anterior-posterior, medial-lateral, and rotational.
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 within a 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 manubriosternal joint. 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 an amphiarthrosis type of joint. Thus, based on their movement ability, both fibrous and cartilaginous joints are functionally classified as a synarthrosis or amphiarthrosis.
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.
The joint between adjacent vertebrae that includes an invertebral disc is classified as which type of joint?
Which of these joints is classified as a synarthrosis?
- the pubic symphysis
- the manubriosternal joint
- an invertebral disc
- the shoulder joint
Which of these joints is classified as a biaxial diarthrosis?
- the metacarpophalangeal joint
- the hip joint
- the elbow joint
- the pubic symphysis
Synovial joints ________.
- may be functionally classified as a synarthrosis
- are joints where the bones are connected to each other by hyaline cartilage
- may be functionally classified as a amphiarthrosis
- are joints where the bones articulate with each other within a fluid-filled joint cavity
Define how joints are classified based on function. Describe and give an example for each functional type of joint.
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. 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.
Explain the reasons for why joints differ in their degree of mobility.
The functional needs of joints vary and thus joints differ in their degree of mobility. 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, which in the vertebral column can add together to yield a much larger overall movement. The freedom of movement provided by a diarthrosis can allow for large movements, such as is seen with most joints of the limbs.
- 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)
Joints are thus functionally classified as a synarthrosis or immobile joint, an
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 3 classifications of joints? ›
Histologically the three joints in the body are fibrous, cartilaginous, and synovial. Functionally the three types of joints are synarthrosis (immovable), amphiarthrosis (slightly moveable), and diarthrosis (freely moveable).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.
- 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.
Functional classification of joints is based on: the amount of movement allowed by the 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.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).What is the functional classification of joints the intervertebral joint? ›
The structural classification of the intervertebral disc joint is a fused, fibrocartilaginous symphysis. However, functionally, it is considered an amphiarthrosis which permits a limited amount of movement.
There are three categories of joints classified in a functional classification: synarthroses, amphiarthroses, and diarthrosis. In fibrous joints, connective tissue holds the bones in place.What are the 3 main functions of joints? ›
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 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 most common types of joints? ›
Synovial joints are the most common joint in the body and are the type of joint that most people are familiar with.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.
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.How many main joints are there? ›
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.How many structural classifications of joints are there? ›
Structural classification of joints categorizes them based on the type of tissue involved in formation. There are three structural classifications of joints: 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 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.
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. An amphiarthrosis is a slightly moveable joint, such as the pubic symphysis or an intervertebral cartilaginous joint. A diarthrosis is a freely moveable joint.How are joints classified structural vs functional? ›
Joints are primarily divided into structural and functional categories . Functional classification is based on the amount of movement between the articulating bones, whereas structural classification is based on how the bones are connected to one another.How does classifying joints according to their structure and function help to describe human movement? ›
Joints are classified based on the mobility allowed (functional classification) and the type of material uniting the bones (structural classification). It is important to know the classification of the joint to have an idea of the range of motion allowed by that joint. Any abnormalities may need further assessment.What is the term for a joint that is no longer articulating? ›
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 joints also called? ›
Joints are also called. articulations which are functional junctions between bones.What is the most common functional classification of synovial joints? ›
Synovial joints are the most common type of joint in the body (see image 1). These joints are termed diarthroses, meaning they are freely mobile. A key structural characteristic for a synovial joint that is not seen at fibrous or cartilaginous joints is the presence of a joint cavity.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.What are the classification of joints and their functions? ›
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”).How many different types of joint classification are there? ›
There are three types of joints in the structural classification: fibrous, cartilaginous, and synovial joints.
Joints are primarily divided into structural and functional categories . Functional classification is based on the amount of movement between the articulating bones, whereas structural classification is based on how the bones are connected to one another.What are immovable joints classified as? ›
Synarthroses. Synarthroses are immovable joints. The singular form is synarthrosis. In these joints, the bones come in very close contact and are separated only by a thin layer of fibrous connective tissue.Which of the following are the main functions of joints? ›
A joint has two main functions: to allow mobility of the skeletal system and to provide a protective enclosure for vital organs.What are the two systems for classifying joints? ›
There are two ways to classify joints: on the basis of their structure or on the basis of their function.