Anatomy Physiology Chapter 10 Articulations Mosby items and

Introduction Articulation—point of contact between bones Joints are mostly very movable, but some are immovable or allow only limited motion Movable joints allow complex, highly coordinated, and purposeful movements to be executed Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc. , an affiliate of Elsevier Inc. 2

Classification of Joints may be classified by using a structural or functional scheme (Table 101) Structural classification—joints are named according to: Type of connective tissue that joins bones together (fibrous or cartilaginous joints) Presence of a fluid-filled joint capsule (synovial joint) Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc. , an affiliate of Elsevier Inc. 3

Classification of Joints (cont) Functional classification—joints are named according to the degree of movement allowed Synarthroses—immovable joint Amphiarthroses—slightly movable Diarthroses—freely movable Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc. , an affiliate of Elsevier Inc. 4

Classification of Joints Fibrous joints (synarthroses)—bones of joints fit together closely, thereby allowing little or no movement (Figure 10 -1) Syndesmoses—joints in which ligaments connect two bones Sutures—found only in the skull; teethlike projections from adjacent bones interlock with each other Gomphoses—between the root of a tooth and the alveolar process of the mandible or maxilla Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc. , an affiliate of Elsevier Inc. 5

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Classification of Joints Cartilaginous joints (amphiarthroses) —bones of joints are joined together by hyaline cartilage or fibrocartilage; allow very little motion (Figure 10 -2) Synchondroses—hyaline cartilage present between articulating bones Symphyses—joints in which a pad or disk of fibrocartilage connects two bones Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc. , an affiliate of Elsevier Inc. 7

Classification of Joints Synovial joints (diarthroses) —freely movable joints (Figure 10 -3) Structures of synovial joints Joint capsule—sleevelike casing around the ends of the bones that binds them together Synovial membrane—membrane that lines the joint capsule and also secretes synovial fluid Articular cartilage—hyaline cartilage covering the articular surfaces of bones Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc. , an affiliate of Elsevier Inc. 9

Classification of Joints Structures of synovial joints (cont) Joint cavity—small space between the articulating surfaces of the two bones of the joint Menisci (articular disks)—pads of fibrocartilage located between articulating bones Ligaments—strong cords of dense white fibrous tissue that hold the bones of a synovial joint more firmly together Bursae—synovial membranes filled with synovial fluid; cushion joints and facilitate movement of tendons Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc. , an affiliate of Elsevier Inc. 11

Classification of Joints Synovial joints (cont) Types of synovial joints (Figure 10 -4) Uniaxial joints—synovial joints that permit movement around only one axis and in only one plane Hinge joints—articulating ends of bones form a hinge-shaped unity that allows only flexion and extension Pivot joints—a projection of one bone articulates with a ring or notch of another bone Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc. , an affiliate of Elsevier Inc. 12

Classification of Joints Types of synovial joints (cont) Biaxial joints—synovial joints that permit movements around two perpendicular axes in two perpendicular planes Saddle joints—synovial joints in which the articulating ends of the bones resemble reciprocally shaped miniature saddles; only example in the body is in the thumbs Condyloid (ellipsoidal) joints—synovial joints in which a condyle fits into an elliptical socket Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc. , an affiliate of Elsevier Inc. 14

Classification of Joints Types of synovial joints (cont) Multiaxial joints—synovial joints that permit movements around three or more axes in three or more planes Ball-and-socket (spheroid) joints— most movable joints; the ball-shaped head of one bone fits into a concave depression Gliding joints—relatively flat articulating surfaces that allow limited gliding movements along various axes Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc. , an affiliate of Elsevier Inc. 15

Representative Synovial Joints Humeroscapular joint (Figure 10 -5) Shoulder joint Most mobile joint because of the shallowness of the glenoid cavity Glenoid labrum—narrow rim of fibrocartilage around the glenoid cavity that lends depth to the glenoid cavity Structures that strengthen the shoulder joint are ligaments, muscles, tendons, and bursae Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc. , an affiliate of Elsevier Inc. 16

Representative Synovial Joints Elbow joint (Figure 10 -6) Humeroradial joint—lateral articulation of the capitulum of the humerus with the head of the radius Humeroulnar joint—medial articulation of the trochlea of the humerus with the trochlear notch of the ulna Both components of the elbow joint surrounded by a single joint capsule and stabilized by collateral ligaments Classic hinge joint Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc. , an affiliate of Elsevier Inc. 18

Representative Synovial Joints Elbow joint (cont) Medial and lateral epicondyles are externally palpable bony landmarks Olecranon bursa independent of elbow joint space Inflammation called olecranon bursitis Trauma to nerve results in unpleasant sensations in the fingers and part of the hand supplied by the nerve Severe injury may cause paralysis of hand muscles or reduction in wrist movements Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc. , an affiliate of Elsevier Inc. 20

Representative Synovial Joints Proximal radioulnar joint—between the head of the radius and the medial notch of the ulna Stabilized by the annular ligament Permits rotation of the forearm Dislocation of the radial head called a “pulled elbow” Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc. , an affiliate of Elsevier Inc. 21

Representative Synovial Joints Distal radioulnar joint—point of articulation between the ulnar notch of the radius and the head of the ulna Acts with the proximal radioulnar joint Permits pronation and supination of the forearm Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc. , an affiliate of Elsevier Inc. 22

Representative Synovial Joints Radiocarpal (wrist) joints (Figure 10 -7) Only the radius articulates directly with the carpal bones distally (scaphoid and lunate) Joints are synovial Scaphoid bone is fractured frequently Portion of the fractured scaphoid may become avascular Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc. , an affiliate of Elsevier Inc. 23

Representative Synovial Joints Carpometacarpal joints—total of three joints One joint for the thumb—wide range of movements Two joints for the fingers— movements largely gliding type Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc. , an affiliate of Elsevier Inc. 25

Representative Synovial Joints Carpometacarpal joints (cont) Thumb carpometacarpal joint is unique and important functionally Loose-fitting joint capsule Saddle-shaped articular surface Movements—extension, adduction, abduction, circumduction, and opposition Opposition—ability to touch the tip of the thumb to the tip of other fingers— movement of great functional significance Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc. , an affiliate of Elsevier Inc. 26

Representative Synovial Joints Metacarpophalangeal joints (Figure 10 -8) Rounded heads of metacarpal bones articulate with concave bases of the proximal phalanges Capsule surrounding joints strengthened by collateral ligaments Primary movements are flexion and extension Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc. , an affiliate of Elsevier Inc. 27

Representative Synovial Joints Interphalangeal joints Typical diarthrotic, hinge-type, synovial joints Exist between heads of phalanges and bases of more distal phalanges Two categories: PIP joints—proximal interphalangeal joints (between proximal and middle phalanges) DIP joints—distal interphalangeal joints (between middle and distal phalanges) Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc. , an affiliate of Elsevier Inc. 29

Representative Synovial Joints Hip joint (Figure 10 -9) Stable joint because of the shape of the head of the femur and the acetabulum A joint capsule and ligaments contribute to the joint’s stability Knee joint (Figures 10 -10 and 10 -11) Largest and one of the most complex and most frequently injured joints Tibiofemoral joint is supported by a joint capsule, cartilage, and numerous ligaments and muscle tendons Permits flexion, extension, and with the knee flexed, some internal and external rotation Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc. , an affiliate of Elsevier Inc. 30

Representative Synovial Joints Ankle joint (Figure 10 -12) Synovial-type hinge joint Articulation between the lower ends of the tibia and fibula and the upper part of the talus Joint is “mortise” or wedge shaped Lateral malleolus lower than medial malleolus Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc. , an affiliate of Elsevier Inc. 34

Representative Synovial Joints Ankle joint (cont) Internal rotation injury results in common “sprained ankle” Involves anterior talofibular ligament Other ankle ligaments also may be involved in sprain injuries—example is deltoid ligament Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc. , an affiliate of Elsevier Inc. 36

$Representative Synovial Joints Ankle joint (cont) External ankle rotation injuries generally involve bone fractures$

Representative Synovial Joints Ankle joint (cont) External ankle rotation injuries generally involve bone fractures rather than ligament tears First-degree ankle injury—lateral malleolus fractured Second-degree ankle injury—both malleoli fractured Third-degree ankle injury—fracture of both malleoli and articular surface of tibia Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc. , an affiliate of Elsevier Inc. 37

Representative Synovial Joints Vertebral joints (Figures 10 -13 and 10 -14) Vertebrae are connected to one another by several joints to form a strong flexible column Bodies of adjacent vertebrae are connected by intervertebral disks and ligaments Intervertebral disks are made up of two parts Annulus fibrosus—disk’s outer rim, made of fibrous tissue and fibrocartilage Nucleus pulposus—disk’s central core, made of a pulpy, elastic substance Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc. , an affiliate of Elsevier Inc. 38

Types and Range of Movement at Synovial Joints Measuring range of motion (Figure 10 -15) Range of motion (ROM) assessment used to determine extent of joint injury ROM can be measured actively or passively; both are generally about equal ROM measured by instrument called a goniometer Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc. , an affiliate of Elsevier Inc. 41

Types and Range of Movement at Synovial Joints Angular movements—change the size of the angle between articulating bones Flexion—decreases the angle between bones; bends or folds one part on another (Figures 10 -16, A; 1018; and 10 -19) Extension and hyperextension (Figure 10 -18) Extension—increases the angle between bones, returns a part from its flexed position to its anatomical position Hyperextension—stretching or extending a part beyond its anatomical position (Figures 10 -19, 10 -21, and 10 -23) Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc. , an affiliate of Elsevier Inc. 43

Types and Range of Movement at Synovial Joints Angular movements (cont) Plantar flexion and dorsiflexion (Figure 10 -25) Plantar flexion—increases the angle between the top of the foot and the front of the leg Dorsiflexion—decreases the angle between the top of the foot and the front of the leg Abduction and adduction (Figures 10 -19 and 10 -23) Abduction—moves a part away from the median plane of the body Adduction—moves a part toward the median plane of the body Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc. , an affiliate of Elsevier Inc. 49

Types and Range of Movement at Synovial Joints Circular movements Rotation and circumduction Rotation—pivoting a bone on its own axis (Figure 10 -16, D) Circumduction—moves a part so that its distal end moves in a circle Supination and pronation (Figure 10 -20, B) Supination—turns the hand palm side up Pronation—turns the hand palm side down Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc. , an affiliate of Elsevier Inc. 51

Types and Range of Movement at Synovial Joints Gliding movements—simplest of all movements; articular surface of one bone moves over the articular surface of another without any angular or circular movement Special movements Inversion and eversion (Figure 10 -25, B) Inversion—turning the sole of the foot inward Eversion—turning the sole of the foot outward Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc. , an affiliate of Elsevier Inc. 53

Types and Range of Movement at Synovial Joints Special movements (cont) Protraction and retraction (Figure 10 -17, A) Protraction—moves a part forward Retraction—moves a part backward Elevation and depression (Figure 10 -17, B) Elevation—moves a part up Depression—lowers a part Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc. , an affiliate of Elsevier Inc. 54

Cycle of Life: Articulations Bone development and the sequence of ossification between birth and skeletal maturity affect joints Fontanels between cranial bones disappear Epiphysial plates ossify at maturity Older adults ROM decreases Changes in gait Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc. , an affiliate of Elsevier Inc. 56

Cycle of Life: Articulations Skeletal diseases manifested as joint problems Abnormal bone growth (lipping)— influences joint motion Disease conditions can be associated with specific developmental periods Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc. , an affiliate of Elsevier Inc. 57

Cycle of Life: Articulations Hand—“reason for the upper extremity”; thumb—“reason for the hand” Examples of “big picture” thinking when used in functional context Mobility of the upper extremity is extensive because of the following: Arrangement of bones in the shoulder girdle, arms, forearm, wrist, and hand Location and method of attachment of muscles to bones Proper functioning of joints Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc. , an affiliate of Elsevier Inc. 58

Cycle of Life: Articulations Mobility and extensive ROM needed to position upper extremity and hand to permit grasping and manipulation of objects, thus enabling effective interaction with objects in the external environment Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc. , an affiliate of Elsevier Inc. 59