BIO 169 Chapter 9: Articulations

Overview: function in connecting bones, skeletal stability and movement

Synarthroses

-located where movement is prevented

-immovable

-can be fibrous, cartilaginous, or bony

Fibrous Synarthroses: Sutures

-found between bones of the skull

Fibrous Synarthroses: Gomphoses

-binds teeth in mandible/maxilla

Cartilaginous Synarthroses: Synchondroses

-cartilage bridge between articulating bones (ribs/sternum)

Bony Synarthroses: Syntoses

-rigid joint where bones fuse (mandible)

Amphiarthroses

-allow slight movement

-can be fibrous or cartilaginous

Fibrous Amphiarthroses: Syndesmosis

-bones connected by ligament (tibia/fibula)

Cartilaginous Amphiarthroses: Symphysis

-bones with fibrocartilage between them (intervertebral disks)

Diarthroses (freely movable)

-freely moveable joint

-will be a synovial joint (knee)

Synovial Joint

-covers articulating surfaces and prevents bone to bone friction

Synovial Joint Components: Joint Capsule

-provides strength and stability to the joint

-inner synovial membrane produces synovial fluid

-outer layer of dense collagen fibers

Synovial Joint Components: Synovial Fluid

-viscous fluid that lubricates, absorbs shocks, and provides nutrients

Synovial Joint Components: Articular Cartilage

-cartilage covers bone ends

Synovial Joint Components: Articular Discs (Meniscus)

-cushioning fibrocartilaginous pad between bones

Synovial Joint Components: Fat Pad

-mass of adipose that protects the joint

Synovial Joint Components: Ligaments

-hold bones together

Synovial Joint Components: Tendons

-hold muscles to bones

Synovial Joint Components: Bursae

-fluid filled sacs reduce friction/shock

Joint Stabilization

-muscles, collagen, and fat pads provide support

-meniscus, tendons, and surface shape limit movement

Representative Synovial Joints: Hip Joint

-high stability/low motion, has increased amount of ligaments,           tendons, cartilage, and muscles

Representative Synovial Joints: Elbow Joint

-mid stability mid motion, has ligaments and interlocking articulation

Representative Synovial Joints: Shoulder Joint

-low stability/high motion, has muscles, ligaments, and tendons

Dislocation

-articulating bone surfaces forced out of alignment

-tears ligaments and cartilage

Range of Motion of Synovial Joints: Nonaxial Joints

-bones glide past one another (e.g. vertebrocostal joint)

Range of Motion of Synovial Joints: Uniaxial Joint (Monaxial)

-allows motion in one plane around single axis of motion (e.g. elbow)

Range of Motion of Synovial Joints: Biaxial Joint

-allows motion in two planes around two axes of motion (wrist)

Range of Motion of Synovial Joints: Triaxial Joint

-allows motion in multiple planes around all three axes of motion (e.g. shoulder)

Synovial Joint Classes: Plane (Gliding) Joint

-flat articular surfaces slide across one another slightly (nonaxial)

Synovial Joint Classes: Hinge Joint

-permit angular motion in a single plane (monaxial)

Synovial Joint Classes: Pivot Joint

-permits rotation (monaxial)

Synovial Joint Classes: Condylar Joint

-oval condyle fits into ellipsoidal depression (biaxial)

Synovial Joint Classes: Saddle Joint

-saddle-shaped articular face fits on convex surface (biaxial)

Synovial Joint Classes: Ball and Socket Joint

-ball-shaped head fits in cuplike depression (triaxial)

Synovial Joint Movements: Gliding Movement

-two surfaces slide across one another (e.g. carpal bones)

Synovial Joint Movements: Angular Movement, Flexion/Extension

-movement in anterior/posterior plane that reduces/increases angle             between articulating bones

Synovial Joint Movements: Angular Movement, Hyperextension

-extension past anatomical position

Synovial Joint Movements: Angular Movement, Abduction/Adduction

-movement in frontal plane away from/toward the long axis of body

Synovial Joint Movements: Angular Movement, Circumduction

-moving arm in a loop

Synovial Joint Movements: Rotational Movement, Left/Right Rotation

-rotate head left or right

Synovial Joint Movements: Rotational Movement, Medial/Lateral Rotation

-rotate anterior limb surface toward/away from long axis of the trunk

Synovial Joint Movements: Rotational Movement, Pronation/Supination

-turns wrist//hand from palm up to palm down OR palm down to palm up

Synovial Joint Movements: Special Movements, Opposition/Reposition

-movement of the thumb toward/away from palm surface

Synovial Joint Movements: Special Movements, Protraction/Retraction

-moving body part anteriorly/posteriorly in horizontal plane

Synovial Joint Movements: Special Movements, Elevation/Depression

-moving body part superiorly/inferiorly

Synovial Joint Movements: Special Movements, Lateral Flexion

-bending vertebral column to the side

Synovial Joint Movements: Special Movements, Inversion/Eversion

-twisting movement of foot turning sole inward or outward

Synovial Joint Movements: Special Movements, Dorsiflexion/Plantar Flexion

-flexion of ankle joint (digging in heel) and extension of ankle joint (on tip toes)

Aging and Joints

-joints are subject to considerable wear and tear over a lifetime

-rheumatism (pain/stiffness) and arthritis (inflammation) are common