{"id":4215,"date":"2017-03-28T18:01:38","date_gmt":"2017-03-28T18:01:38","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/wm-biology2\/?post_type=chapter&p=4215"},"modified":"2017-07-05T17:42:10","modified_gmt":"2017-07-05T17:42:10","slug":"joints-and-skeletal-movement","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/suny-wmopen-biology2\/chapter\/joints-and-skeletal-movement\/","title":{"raw":"Joints and Skeletal Movement","rendered":"Joints and Skeletal Movement"},"content":{"raw":"

Classify the different types of joints on the basis of structure<\/h2>\r\nThe point at which two or more bones meet is called a joint<\/b>, or articulation<\/b>. Joints are responsible for movement, such as the movement of limbs, and stability, such as the stability found in the bones of the skull.\r\n
\r\n

Learning Objectives<\/h3>\r\n
    \r\n \t
  • Classify the different types of joints on the basis of structure<\/li>\r\n \t
  • Identify the six types of synovial joints<\/li>\r\n \t
  • Explain the role of joints in skeletal movement<\/li>\r\n<\/ul>\r\n<\/div>\r\n

    Classification of Joints on the Basis of Structure<\/h2>\r\nThere are two ways to classify joints: on the basis of their structure or on the basis of their function. The structural classification divides joints into bony, fibrous, cartilaginous, and synovial joints depending on the material composing the joint and the presence or absence of a cavity in the joint.\r\n

    Fibrous Joints<\/h3>\r\nThe bones of fibrous joints<\/b> are held together by fibrous connective tissue. There is no cavity, or space, present between the bones and so most fibrous joints do not move at all, or are only capable of minor movements. There are three types of fibrous joints: sutures, syndesmoses, and gomphoses. Sutures<\/b> are found only in the skull and possess short fibers of connective tissue that hold the skull bones tightly in place (Figure\u00a01a).\r\n\r\nSyndesmoses<\/b> are joints in which the bones are connected by a band of connective tissue, allowing for more movement than in a suture. An example of a syndesmosis is the joint of the tibia and fibula in the ankle. The amount of movement in these types of joints is determined by the length of the connective tissue fibers. Gomphoses<\/b> occur between teeth and their sockets; the term refers to the way the tooth fits into the socket like a peg (Figure\u00a01b). The tooth is connected to the socket by a connective tissue referred to as the periodontal ligament.\r\n\r\n[caption id=\"attachment_2794\" align=\"aligncenter\" width=\"1024\"]\"Part Figure\u00a01.\u00a0(a) Sutures are fibrous joints found only in the skull. (b) Gomphoses are fibrous joints between the teeth and their sockets. (b credit: modification of work by Gray's Anatomy)[\/caption]\r\n

    Cartilaginous Joints<\/h3>\r\n[caption id=\"attachment_2795\" align=\"alignright\" width=\"350\"]\"Illustration Figure\u00a02.\u00a0Synovial joints are the only joints that have a space or \u201csynovial cavity\u201d in the joint.[\/caption]\r\n\r\nCartilaginous joints<\/b> are joints in which the bones are connected by cartilage. There are two types of cartilaginous joints: synchondroses and symphyses. In a synchondrosis<\/b>, the bones are joined by hyaline cartilage. Synchondroses are found in the epiphyseal plates of growing bones in children. In symphyses<\/b>, hyaline cartilage covers the end of the bone but the connection between bones occurs through fibrocartilage. Symphyses are found at the joints between vertebrae. Either type of cartilaginous joint allows for very little movement.\r\n

    Synovial Joints<\/h3>\r\nSynovial joints<\/b> are the only joints that have a space between the adjoining bones (Figure\u00a02). This space is referred to as the synovial (or joint) cavity and is filled with synovial fluid. Synovial fluid lubricates the joint, reducing friction between the bones and allowing for greater movement. The ends of the bones are covered with articular cartilage, a hyaline cartilage, and the entire joint is surrounded by an articular capsule composed of connective tissue that allows movement of the joint while resisting dislocation. Articular capsules may also possess ligaments that hold the bones together. 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.\r\n

    Classification of Joints on the Basis of Function<\/h2>\r\nThe functional classification divides joints into three categories: synarthroses, amphiarthroses, and diarthroses:\r\n
      \r\n \t
    • Synarthroses\u00a0are a joints that are\u00a0immovable. This includes sutures, gomphoses, and synchondroses.<\/li>\r\n \t
    • Amphiarthroses are joints that allow slight movement, including syndesmoses and symphyses.<\/li>\r\n \t
    • Diarthroses are joints that allow for free movement of the joint, as in synovial joints.<\/li>\r\n<\/ul>\r\n

      Types of Synovial Joints<\/h2>\r\nSynovial joints are further classified into six different categories on the basis of the shape and structure of the joint. The shape of the joint affects the type of movement permitted by the joint (Figure\u00a03). These joints can be described as planar, hinge, pivot, condyloid, saddle, or ball-and-socket joints.\r\n\r\n[caption id=\"attachment_2796\" align=\"aligncenter\" width=\"600\"]\" Figure\u00a03.\u00a0Different types of joints allow different types of movement. Planar, hinge, pivot, condyloid, saddle, and ball-and-socket are all types of synovial joints.[\/caption]\r\n

      Planar Joints<\/h3>\r\nPlanar joints<\/b> have bones with articulating surfaces that are flat or slightly curved faces. These joints allow for gliding movements, and so the joints are sometimes referred to as gliding joints. The range of motion is limited in these joints and does not involve rotation. Planar joints are found in the carpal bones in the hand and the tarsal bones of the foot, as well as between vertebrae (Figure\u00a04).\r\n\r\n[caption id=\"attachment_2797\" align=\"aligncenter\" width=\"1024\"]\"Photo Figure\u00a04.\u00a0The joints of the carpal bones in the wrist are examples of planar joints. (credit: modification of work by Brian C. Goss)[\/caption]\r\n

      Hinge Joints<\/h3>\r\nIn hinge joints<\/b>, the slightly rounded end of one bone fits into the slightly hollow end of the other bone. In this way, one bone moves while the other remains stationary, like the hinge of a door. The elbow is an example of a hinge joint. The knee is sometimes classified as a modified hinge joint (Figure\u00a05).\r\n\r\n[caption id=\"attachment_2798\" align=\"aligncenter\" width=\"1024\"]\"Photo Figure\u00a05.\u00a0The elbow joint, where the radius articulates with the humerus, is an example of a hinge joint. (credit: modification of work by Brian C. Goss)[\/caption]\r\n

      Pivot Joints<\/h3>\r\n[caption id=\"attachment_2799\" align=\"alignright\" width=\"350\"]\"Illustration Figure\u00a06.\u00a0The joint in the neck that allows the head to move back and forth is an example of a pivot joint.[\/caption]\r\n\r\nPivot joints<\/b> consist of the rounded end of one bone fitting into a ring formed by the other bone. This structure allows rotational movement, as the rounded bone moves around its own axis. An example of a pivot joint is the joint of the first and second vertebrae of the neck that allows the head to move back and forth (Figure\u00a06). The joint of the wrist that allows the palm of the hand to be turned up and down is also a pivot joint.\r\n

      Condyloid Joints<\/h3>\r\nCondyloid joints<\/b> consist of an oval-shaped end of one bone fitting into a similarly oval-shaped hollow of another bone (Figure\u00a07). This is also sometimes called an ellipsoidal joint. This type of joint allows angular movement along two axes, as seen in the joints of the wrist and fingers, which can move both side to side and up and down.\r\n\r\n[caption id=\"attachment_2800\" align=\"aligncenter\" width=\"544\"]\"Illustration Figure\u00a07.\u00a0The metacarpophalangeal joints in the finger are examples of condyloid joints. (credit: modification of work by Gray's Anatomy)[\/caption]\r\n

      Saddle Joints<\/h3>\r\nSaddle joints<\/b> are so named because the ends of each bone resemble a saddle, with concave and convex portions that fit together. Saddle joints allow angular movements similar to condyloid joints but with a greater range of motion. An example of a saddle joint is the thumb joint, which can move back and forth and up and down, but more freely than the wrist or fingers (Figure\u00a08).\r\n\r\n[caption id=\"attachment_2801\" align=\"aligncenter\" width=\"1024\"]\"Photo Figure\u00a08.\u00a0The carpometacarpal joints in the thumb are examples of saddle joints. (credit: modification of work by Brian C. Goss)[\/caption]\r\n

      Ball-and-Socket Joints<\/h3>\r\nBall-and-socket joints<\/b> possess a rounded, ball-like end of one bone fitting into a cuplike socket of another bone. This organization allows the greatest range of motion, as all movement types are possible in all directions. Examples of ball-and-socket joints are the shoulder and hip joints (Figure\u00a09).\r\n\r\n[caption id=\"attachment_2802\" align=\"aligncenter\" width=\"544\"]\"Illustration Figure\u00a09.\u00a0The shoulder joint is an example of a ball-and-socket joint.[\/caption]\r\n\r\n
      \r\n\r\nWatch this animation showing the six types of synovial joints.\r\n\r\nhttps:\/\/youtu.be\/zWo9-3GJpr8\r\n\r\n<\/div>\r\n

      Movement at Synovial Joints<\/h2>\r\nThe wide range of movement allowed by synovial joints produces different types of movements. The movement of synovial joints can be classified as one of four different types: gliding, angular, rotational, or special movement.\r\n

      Gliding Movement<\/h3>\r\nGliding movements<\/b> occur as relatively flat bone surfaces move past each other. Gliding movements produce very little rotation or angular movement of the bones. The joints of the carpal and tarsal bones are examples of joints that produce gliding movements.\r\n

      Angular Movement<\/h3>\r\nAngular movements<\/b> are produced when the angle between the bones of a joint changes. There are several different types of angular movements, including flexion, extension, hyperextension, abduction, adduction, and circumduction. Flexion<\/b>, or bending, occurs when the angle between the bones decreases. Moving the forearm upward at the elbow or moving the wrist to move the hand toward the forearm are examples of flexion. Extension<\/b> is the opposite of flexion in that the angle between the bones of a joint increases. Straightening a limb after flexion is an example of extension. Extension past the regular anatomical position is referred to as hyperextension<\/b>. This includes moving the neck back to look upward, or bending the wrist so that the hand moves away from the forearm.\r\n\r\nAbduction<\/b> occurs when a bone moves away from the midline of the body. Examples of abduction are moving the arms or legs laterally to lift them straight out to the side. Adduction<\/b> is the movement of a bone toward the midline of the body. Movement of the limbs inward after abduction is an example of adduction. Circumduction<\/b> is the movement of a limb in a circular motion, as in moving the arm in a circular motion.\r\n

      Rotational Movement<\/h3>\r\nRotational movement<\/b> is the movement of a bone as it rotates around its longitudinal axis. Rotation can be toward the midline of the body, which is referred to as medial rotation<\/b>, or away from the midline of the body, which is referred to as lateral rotation<\/b>. Movement of the head from side to side is an example of rotation.\r\n

      Special Movements<\/h3>\r\nSome movements that cannot be classified as gliding, angular, or rotational are called special movements. Inversion<\/b> involves the soles of the feet moving inward, toward the midline of the body. Eversion<\/b> is the opposite of inversion, movement of the sole of the foot outward, away from the midline of the body. Protraction<\/b> is the anterior movement of a bone in the horizontal plane. Retraction<\/b> occurs as a joint moves back into position after protraction. Protraction and retraction can be seen in the movement of the mandible as the jaw is thrust outwards and then back inwards. Elevation<\/b> is the movement of a bone upward, such as when the shoulders are shrugged, lifting the scapulae. Depression<\/b> is the opposite of elevation\u2014movement downward of a bone, such as after the shoulders are shrugged and the scapulae return to their normal position from an elevated position. Dorsiflexion<\/b> is a bending at the ankle such that the toes are lifted toward the knee. Plantar flexion<\/b> is a bending at the ankle when the heel is lifted, such as when standing on the toes. Supination<\/b> is the movement of the radius and ulna bones of the forearm so that the palm faces forward. Pronation<\/b> is the opposite movement, in which the palm faces backward. Opposition<\/b> is the movement of the thumb toward the fingers of the same hand, making it possible to grasp and hold objects.\r\n

      Check Your Understanding<\/strong><\/h2>\r\nAnswer the question(s) below to see how well you understand the topics covered in the previous section. This short quiz does\u00a0not<\/strong>\u00a0count toward your grade in the class, and you can retake it an unlimited number of times.\r\n\r\nUse this quiz to check your understanding and decide whether to (1) study the previous section further or (2) move on to the next section.\r\n\r\nhttps:\/\/assessments.lumenlearning.com\/assessments\/5056","rendered":"

      Classify the different types of joints on the basis of structure<\/h2>\n

      The point at which two or more bones meet is called a joint<\/b>, or articulation<\/b>. Joints are responsible for movement, such as the movement of limbs, and stability, such as the stability found in the bones of the skull.<\/p>\n

      \n

      Learning Objectives<\/h3>\n
        \n
      • Classify the different types of joints on the basis of structure<\/li>\n
      • Identify the six types of synovial joints<\/li>\n
      • Explain the role of joints in skeletal movement<\/li>\n<\/ul>\n<\/div>\n

        Classification of Joints on the Basis of Structure<\/h2>\n

        There are two ways to classify joints: on the basis of their structure or on the basis of their function. The structural classification divides joints into bony, fibrous, cartilaginous, and synovial joints depending on the material composing the joint and the presence or absence of a cavity in the joint.<\/p>\n

        Fibrous Joints<\/h3>\n

        The bones of fibrous joints<\/b> are held together by fibrous connective tissue. There is no cavity, or space, present between the bones and so most fibrous joints do not move at all, or are only capable of minor movements. There are three types of fibrous joints: sutures, syndesmoses, and gomphoses. Sutures<\/b> are found only in the skull and possess short fibers of connective tissue that hold the skull bones tightly in place (Figure\u00a01a).<\/p>\n

        Syndesmoses<\/b> are joints in which the bones are connected by a band of connective tissue, allowing for more movement than in a suture. An example of a syndesmosis is the joint of the tibia and fibula in the ankle. The amount of movement in these types of joints is determined by the length of the connective tissue fibers. Gomphoses<\/b> occur between teeth and their sockets; the term refers to the way the tooth fits into the socket like a peg (Figure\u00a01b). The tooth is connected to the socket by a connective tissue referred to as the periodontal ligament.<\/p>\n

        \"Part<\/p>\n

        Figure\u00a01.\u00a0(a) Sutures are fibrous joints found only in the skull. (b) Gomphoses are fibrous joints between the teeth and their sockets. (b credit: modification of work by Gray’s Anatomy)<\/p>\n<\/div>\n

        Cartilaginous Joints<\/h3>\n
        \"Illustration<\/p>\n

        Figure\u00a02.\u00a0Synovial joints are the only joints that have a space or \u201csynovial cavity\u201d in the joint.<\/p>\n<\/div>\n

        Cartilaginous joints<\/b> are joints in which the bones are connected by cartilage. There are two types of cartilaginous joints: synchondroses and symphyses. In a synchondrosis<\/b>, the bones are joined by hyaline cartilage. Synchondroses are found in the epiphyseal plates of growing bones in children. In symphyses<\/b>, hyaline cartilage covers the end of the bone but the connection between bones occurs through fibrocartilage. Symphyses are found at the joints between vertebrae. Either type of cartilaginous joint allows for very little movement.<\/p>\n

        Synovial Joints<\/h3>\n

        Synovial joints<\/b> are the only joints that have a space between the adjoining bones (Figure\u00a02). This space is referred to as the synovial (or joint) cavity and is filled with synovial fluid. Synovial fluid lubricates the joint, reducing friction between the bones and allowing for greater movement. The ends of the bones are covered with articular cartilage, a hyaline cartilage, and the entire joint is surrounded by an articular capsule composed of connective tissue that allows movement of the joint while resisting dislocation. Articular capsules may also possess ligaments that hold the bones together. 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.<\/p>\n

        Classification of Joints on the Basis of Function<\/h2>\n

        The functional classification divides joints into three categories: synarthroses, amphiarthroses, and diarthroses:<\/p>\n

          \n
        • Synarthroses\u00a0are a joints that are\u00a0immovable. This includes sutures, gomphoses, and synchondroses.<\/li>\n
        • Amphiarthroses are joints that allow slight movement, including syndesmoses and symphyses.<\/li>\n
        • Diarthroses are joints that allow for free movement of the joint, as in synovial joints.<\/li>\n<\/ul>\n

          Types of Synovial Joints<\/h2>\n

          Synovial joints are further classified into six different categories on the basis of the shape and structure of the joint. The shape of the joint affects the type of movement permitted by the joint (Figure\u00a03). These joints can be described as planar, hinge, pivot, condyloid, saddle, or ball-and-socket joints.<\/p>\n

          \"Illustration<\/p>\n

          Figure\u00a03.\u00a0Different types of joints allow different types of movement. Planar, hinge, pivot, condyloid, saddle, and ball-and-socket are all types of synovial joints.<\/p>\n<\/div>\n

          Planar Joints<\/h3>\n

          Planar joints<\/b> have bones with articulating surfaces that are flat or slightly curved faces. These joints allow for gliding movements, and so the joints are sometimes referred to as gliding joints. The range of motion is limited in these joints and does not involve rotation. Planar joints are found in the carpal bones in the hand and the tarsal bones of the foot, as well as between vertebrae (Figure\u00a04).<\/p>\n

          \"Photo<\/p>\n

          Figure\u00a04.\u00a0The joints of the carpal bones in the wrist are examples of planar joints. (credit: modification of work by Brian C. Goss)<\/p>\n<\/div>\n

          Hinge Joints<\/h3>\n

          In hinge joints<\/b>, the slightly rounded end of one bone fits into the slightly hollow end of the other bone. In this way, one bone moves while the other remains stationary, like the hinge of a door. The elbow is an example of a hinge joint. The knee is sometimes classified as a modified hinge joint (Figure\u00a05).<\/p>\n

          \"Photo<\/p>\n

          Figure\u00a05.\u00a0The elbow joint, where the radius articulates with the humerus, is an example of a hinge joint. (credit: modification of work by Brian C. Goss)<\/p>\n<\/div>\n

          Pivot Joints<\/h3>\n
          \"Illustration<\/p>\n

          Figure\u00a06.\u00a0The joint in the neck that allows the head to move back and forth is an example of a pivot joint.<\/p>\n<\/div>\n

          Pivot joints<\/b> consist of the rounded end of one bone fitting into a ring formed by the other bone. This structure allows rotational movement, as the rounded bone moves around its own axis. An example of a pivot joint is the joint of the first and second vertebrae of the neck that allows the head to move back and forth (Figure\u00a06). The joint of the wrist that allows the palm of the hand to be turned up and down is also a pivot joint.<\/p>\n

          Condyloid Joints<\/h3>\n

          Condyloid joints<\/b> consist of an oval-shaped end of one bone fitting into a similarly oval-shaped hollow of another bone (Figure\u00a07). This is also sometimes called an ellipsoidal joint. This type of joint allows angular movement along two axes, as seen in the joints of the wrist and fingers, which can move both side to side and up and down.<\/p>\n

          \"Illustration<\/p>\n

          Figure\u00a07.\u00a0The metacarpophalangeal joints in the finger are examples of condyloid joints. (credit: modification of work by Gray’s Anatomy)<\/p>\n<\/div>\n

          Saddle Joints<\/h3>\n

          Saddle joints<\/b> are so named because the ends of each bone resemble a saddle, with concave and convex portions that fit together. Saddle joints allow angular movements similar to condyloid joints but with a greater range of motion. An example of a saddle joint is the thumb joint, which can move back and forth and up and down, but more freely than the wrist or fingers (Figure\u00a08).<\/p>\n

          \"Photo<\/p>\n

          Figure\u00a08.\u00a0The carpometacarpal joints in the thumb are examples of saddle joints. (credit: modification of work by Brian C. Goss)<\/p>\n<\/div>\n

          Ball-and-Socket Joints<\/h3>\n

          Ball-and-socket joints<\/b> possess a rounded, ball-like end of one bone fitting into a cuplike socket of another bone. This organization allows the greatest range of motion, as all movement types are possible in all directions. Examples of ball-and-socket joints are the shoulder and hip joints (Figure\u00a09).<\/p>\n

          \"Illustration<\/p>\n

          Figure\u00a09.\u00a0The shoulder joint is an example of a ball-and-socket joint.<\/p>\n<\/div>\n

          \n

          Watch this animation showing the six types of synovial joints.<\/p>\n