Untitled Flashcards Set

• Joints, also called articulations: where bones connect

• Functions of joints: enable movement and provide stability

Two classifications:

• Structural: three types depending on the connective material and whether a cavity is present

  • Fibrous - three subtypes based on fiber alignment

• Functional - Movement based

• Functional classifications: three types based on movement joint allows

– Synarthroses: immovable joints

–Amphiarthrosis: slightly movable joints

– Diarthroses: freely movable joints

• Structural classifications are more clear cut

Bones joined by dense fibrous connective tissue

• Lack a joint cavity 

• Most are immovable

• Depends on length of connective tissue fibers

• Three types of fibrous joints: 

  • Sutures

  • Syndesmosis

  • Gomphose
    Sutures

    
    Rigid, interlocking joints of skull

  • Permit growth in early life

  • Contain short connective tissue fibers that allow for expansion

  • In middle age, sutures ossify and fuse

    • Once sutures are closed, immovable, referred to as synostoses

  • Immovable joints join skull into one unit that protects brain

  • Fontanels are soft, membranous gaps between the bones of an infant’s skull. These are areas where the bones have not yet fused, allowing for flexibility during birth and rapid brain growth after.

    syndesmosis Two parallel 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

  Distal tibiofibular joint – minimal movement

  Interosseous membrane between the radius and ulna – allows more movement

  Gomphoses

  • Peg-in-socket joints

  • Only examples are the teeth in alveolar sockets

  • Fibrous connection is the periodontal ligament

  • Holds tooth in socket

  Cartilaginous joints are joints where bones are united by cartilage, not by fibrous tissue or a fluid-filled cavity. These joints typically allow little to no movement, depending on their type.

  • Bones united by cartilage

  • Like fibrous joints, have no joint cavity

  • Not highly movable

  • Two types

    • Synchondroses

    • Symphyses
      Synchondroses

      • Bar or plate of hyaline cartilage connects bones

      • Almost all are synarthrotic (immovable)
        Epiphyseal plates in growing bones

      • First rib’s connection to the sternum (manubrium)

      • Costochondral joints – between the ribs and costal cartilage (these are technically synchondroses, although often categorized differently depending on the source)
        
        
        Symphyses

        Fibrocartilage connects bones in symphysis joint

        •Hyaline cartilage also present as articular cartilage on bony surfaces

        •Symphyses are slightly movable and strong (slightly movable) joints

        •Examples

        Intervertebral joints

        • Bones are joined by fibrocartilage, with hyaline cartilage on bone surfaces

        • Allow limited movement (amphiarthrotic)
          
          synovial joints

        • Bones separated by fluid-filled joint cavity

        • All are diarthrotic (freely movable)

        • Include almost all limb joints

        • Characteristics of synovial joints

        • Have six general features
          
          Articular Cartilage:

          • Covers the ends of bones

          • Made of hyaline cartilage

          • Prevents bones from crashing against each other

          
          joint (Synovial) Cavity

          • A small fluid-filled space / potential space

          • Unique to synovial joints

          • Allows for free movement
            

Articular Capsule

• Two-layered structure surrounding the joint

• Outer fibrous layer: Dense irregular connective tissue

• Inner synovial membrane: Produces synovial fluid

Synovial Fluid

• A slippery, viscous fluid made from plasma and hyaluronic acid

• Lubricates and nourishes cartilage

• Contains phagocytes to clean up debris

Reinforcing Ligaments

• Stabilizes the joint

• Capsular (part of the capsule)

• Extracapsular (outside the capsule)

•  Intracapsular (inside, covered by synovial membrane)

Nerves and Blood Vessels

• Nerves detect pain, stretch, and joint position

• Capillaries in the synovial membrane supply the fluid components

Six characteristics of synovial joints

1. Articular Cartilage

2. Articular Capsule

3. Joint Cavity

4. Synovial Fluid

5. Reinforcing Ligaments

6. Nerves and Capillaries

Fatty Pads

• Cushioning between the joint capsule and synovial membrane or bone

Articular Discs (Menisci)

• Made of fibrocartilage

•  Improve the fit between bone ends

• Help stabilize the joint

• Reduce friction and wear

bursae and tendon sheaths

• Both structures are small, fluid-filled sacs that reduce friction — like tiny ball bearings

• Not technically part of the joint, but closely associated with synovial joints

Bursae

• Cushion and reduce friction where ligaments, muscles, tendons, skin, or bones rub together

Tendon Sheaths

• Elongated bursae that wrap around tendons

• Found where tendons experience a lot of friction

• The role of the bursae is to limit friction between points of contact between tendons, ligaments, bone, connective tissue, and skin. 

• High friction areas can lead to overuse in

• Stability = how well a joint stays together during movement

• Depends on the shape of bones, strength of ligaments, and muscle tone

• Muscle tone is often the most important factor, especially in active joints

Articular Surface Shape

• Shallow or poorly fitting surfaces = less stable

• Deep sockets (like the hip) = more stable

Ligaments

• More ligaments = more stability

• However, ligaments can stretch and aren’t the main stabilizer

• Most important factor influencing overall joint stability

• Keeps tendons tight across joints

• Especially important in shoulder, knee, and foot joints

• Most movable and common type of joint in the body

• Structural Features:

  • Articular cartilage – covers bone ends, reduces friction

  • Joint (synovial) cavity – space filled with synovial fluid

  • Articular capsule – two-layered enclosure surrounding the joint

  • Synovial fluid – lubricates and nourishes joint tissues

  • Ligaments – reinforce and stabilize the joint

  • Nerves and blood vessels – support joint health and function

• Functional Characteristic:

  • All synovial joints are diarthroses → freely movable

Bursae

• Flattened sacs filled with synovial fluid

•  Found where ligaments, tendons, muscles, skin, or bones rub together

• Act as cushions to reduce friction and pressure

Tendon Sheaths

• Elongated bursae that wrap around tendons

• Common in wrist and ankle tendons

• Help prevent tendon friction during movement

meniscus

• Made of fibrocartilage

• Wedge-shaped pads that sit between the articular surfaces of bones

• Help improve the fit between bone ends

• Distribute weight evenly across the joint

• Increase joint stability

• Help absorb shock and reduce wear and tear

synovial joint movement types

Movement Types

• Gliding: Sliding (intercarpal, intertarsal joints)

• Angular: Flexion, extension, abduction, adduction

• Rotation: Bone turns around its own axis (e.g., atlantoaxial joint)

Based on Axes of Movement

• Nonaxial: Slipping/gliding (e.g., intercarpal joints)

• Uniaxial: Movement in 1 plane (e.g., elbow – hinge joint)

• Biaxial: Movement in 2 planes (e.g., wrist – condylar)

• Multiaxial: Movement in all planes (e.g., shoulder – ball-and-socket)

gliding movement

One flat bone surface glides or slips over another similar surface 

Examples

• Intercarpal joints

• Intertarsal joints

• Between articular processes of vertebrae

angular movements

• Increase or decrease angle between two bones

• A change in the angle between two bones

• Can occur in multiple planes

• Movement depends on the type of movement and joint involved
  

• Flexion: decreases the angle of the joint

• Extension: increases the angle of the joint

• Hyperextension: movement beyond the anatomical position

Movement Along the Frontal Plane

• Abduction: away from the midline

• Adduction: movement along frontal plane, toward the midline

circumduction

• Involves flexion, abduction, extension, and adduction of limb

• Limb describes cone in space
  

Rotation: turning of bone around its own long axis, toward midline or away from it 

• Medial: rotation toward midline

• Lateral: rotation away from midline

Examples

• Rotation between C₁ and C₂ vertebrae

• Rotation of humerus and femur

• Supination: palms face anteriorly / Up (like holding soup)

  • Radius and ulna are parallel

• Pronation: palms face posteriorly

  • Radius rotates over ulna

• Dorsiflexion: bending foot toward shin

• Plantar flexion: pointing toes

• Inversion: sole of foot faces medially

• Eversion: sole of foot faces laterally

• Protraction: mandible juts out

• Retraction: mandible is pulled toward neck

• Elevation: lifting body part superiorly

  • Example: shrugging shoulders

• Depression: lowering body part

  • Example: opening jaw

Nonaxial – No rotation, only sliding

• Uniaxial – Movement in 1 plane

• Biaxial – Movement in 2 planes

• Multiaxial – Movement in 3 planes

tendoitinis Inflammation of tendon sheaths, typically caused by overuse

• Symptoms and treatment similar to those of bursitis

bursitis Inflammation of bursa, usually caused by blow or friction

• Treated with rest and ice and, if severe, anti-inflammatory drugs

degenerative joints disease

• Progressive degeneration of articular cartilage

• Most common type of arthritis 

• Scene in people 60+, obesity, or trauma to the joint

• Common in hips, spine, knees, DIP, and PIP

Clinical Features

• Fragments of Cartilage floating in joint space

• Osteophyte - outgrowth of bones in joint space

arititis General term for a group of joint disorders that involve inflammation of one or more joints, leading to 

• Pain

• Swelling

• Stiffness

• Reduced mobility.

• It can affect any joint in the body

Common types include:

• Osteoarthritis: Degeneration of cartilage due to wear and tear

• Rheumatoid arthritis: Autoimmune disorder causing chronic inflammation

• Gouty arthritis: Caused by the buildup of uric acid crystals in joints

ball and socket joint Movement: Flexion/extension, abduction/adduction, rotation (multiaxial)

• Example: Shoulder and hip joints
  

saddle joint

• Movement: Like condylar, but with greater freedom (biaxial)

• Example: Carpometacarpal joint of the thumb

  condylar joint

• Movement: Flexion/extension, abduction/adduction (biaxial)

• Example: Metacarpophalangeal joints (knuckles), wrist

pivot joint Movement: Rotation around a single axis (uniaxial)

• Example: Atlantoaxial joint (neck), proximal radioulnar joint
  

hinge joint Movement: Flexion and extension (uniaxial)

• Example: Elbow, knee, interphalangeal joints

plane joint Movement: Gliding (nonaxial)

• Example: Intercarpal joints (wrist), intertarsal joints (ankle)

nonaxial movement Movement does not occur around an axis

Type of Motion:

• Slipping or gliding only

Example:

• Intercarpal joints (wrist bones)

• Intertarsal joints (ankle bones)

Joint Type:

• Plane joints

Uniaxial Joints

• Movement in one plane, around one axis

Examples:

• Elbow (hinge joint – flexion/extension)

• Proximal radioulnar (pivot joint – rotation)
  

Biaxial Joints

• Movement in two planes, around two axes

Examples:

• Wrist (condylar joint – flexion/extension + abduction/adduction)

• Knuckles (metacarpophalangeal joints)

multiaxial movement Movement in or around all three planes

• Sagittal, frontal, and transverse

Type of Motion:

• Flexion/extension, abduction/adduction, rotation

Examples:

• Shoulder joint

• Hip joint

Joint Type:

• Ball-and-socket

Fatty Pads

• Cushioning between the joint capsule and synovial membrane or bone

Articular Discs (Menisci)

• Made of fibrocartilage

•  Improve the fit between bone ends

• Help stabilize the joint

• Reduce friction and wear

• Protraction: mandible juts out

• Retraction: mandible is pulled toward neck

• Inversion: sole of foot faces medially

• Eversion: sole of foot faces laterally

Dorsiflexion: bending foot toward shin

• Plantar flexion: pointing toes

• Supination: palms face anteriorly / Up (like holding soup)

  • Radius and ulna are parallel

• Pronation: palms face posteriorly

  • Radius rotates over ulna

Rotation: turning of bone around its own long axis, toward midline or away from it 

• Medial: rotation toward midline

• Lateral: rotation away from midline

Examples

• Rotation between C₁ and C₂ vertebrae

• Rotation of humerus and femur