Anatomy Unit 6 test

Wolford

Structural classification of joints based on 2 criteria

* presence/absence of a space b/t the articulating bones (synovial cavity)
* type of connective tissue that binds the bones together

What are the 3 functional classifications for joints?

\-synarthrosis

\-amphiarthrosis

\-diarthrosis

synarthroasis

immovable joint

diarthrosis

Freely movable joints; also known as synovial joints

What are the 3 major structural categories for joints?

\-fibrous joints

* cartilaginous joints
* synovial joints

fibrous joints

held together by fibrous connective tissue; collagen fibers; no synovial cavity, so little/no movement

cartilaginous joint

held together by cartilage; no synovial cavity, so little/no movement

synovial joint

joined by dense irregular connective tissue; often have accessory ligaments; have synovial cavity

3 types of fibrous joints

sutures, syndesmoses, gomphoses

suture

fibrous joint that has thin layer of dense fibrous connective tissue; interlocking edges decrease chance of breaking; e.g. your cranium

syndemosis

a fibrous joint at which two bones are bound by long collagen fibers; greater space b/t 2 articulating bones; e.g. fibula and tibia

Gomphosis

a fibrous joint in which a cone-shaped peg fits into a socket; e.g. teeth and their socket

2 types of cartilaginous joints

synchondrosis and symphysis

synchondrosis

an almost immovable joint between bones bound by a layer of hyaline cartilage; e.g. rib and sternum

symphesis

Bones cover with hyaline cartilage that is fused to a middle plate of fibrocartilage; e.g. pelvic

where are symphesyes found in the body?

ALl occur at the midline (vertebral joints and pelvic)

Extracapsular ligaments

stabilizing ligaments located outside joint capsule; e.g. MCL

Intracapsular ligaments

stabilizing ligaments located inside joint capsule; e.g. ACL and PCL

Composition of articular cartliage

articular discs are pads of fibrocartilage that are b/t the meeting surfaces of the bones and attached to fibrous capsule

Functions of articular cartliage

direct flow of synovial fluid--> cushions and reduces friction of movement, protects bone ends; allows bones of different shapes to fit together more securely

Types of synovial joints

plane, hinge, pivot, condyloid, saddle, ball and socket

Plane (planar)

articular surfaces are flat or slightly curved; usually permit side-to-side and back-and-forth gliding movements

condyloid

convex oval-shaped projection of one bone fits into a corresponding depression in another bone; minimal circumduction, side-to-side, flexion/extension

Hinge

convex surface of one bone fits into the concave surface of another bone; usually allow motion around a single axis

Saddle

articular surface of one bone is saddle-shaped; articular surface of other bone "sits" in saddle; bi-axial: side-to-side and up-and-down

Pivot

rounded surface of one bone articulated with a ring of the other bone and a ligament; allows rotation around the longitudinal axis

Ball and socket

ball-shaped head of one bone articulates (fits) with cup-shaped cavity of another; multi-axial

What are the 2 layers of the articular capsule

fibrous layer and synovial membrane

Fibrous layer

outer layer of articular capsule consisting of dense irregular connective tissue that attaches to articulating bones

Synovial membrane

inner layer of the articular capsule; composed of areolar connective tissue containing elastic fibers and adipocytes

What are the functions of the synovial fluid

secreted by the synovial membrane, thin film over surfaces; Lubrication, provides nutrients, protects articular cartilages, and absorbs shock.

Gliding

nearly flat bone surfaces slide or glide over each other; occurs at planar joints; e.g. wrist

Flexion and joint it uses

decrease in the angle between articulating bones; e.g. elbow.

Hinge joint

Extension

increase in angle b/t articulating bones; e.g. elbow

Hyperextension

continuation of extension beyond the anatomical position; e.g. moving head back

Abduction and joint it uses

movement away from the midline; ball and socket

Adduction and joint it uses

Movement toward the midline of the body; ball and socket

Circumduction and what joint it uses

the circular movement at the far end of a limb; continuous flexion, abduction, extension, and adduction; ball and socket and condyloid joints

Rotation (medial and lateral)

inward and outward rotation around the axis; e.g. ankles

Elevation and the joint it uses

Raising a body part; TMJ

Depression and the joint it uses

Lowering a body part; TMJ

Protraction and the joint it uses

inward and outward rotation around the axis; TMJ

Retraction and the joint it uses

moving a body part backward and parallel to the ground; TMJ

Inversion

Turning the soles of the foot inward

Eversion

Turning the sole of the foot outward

Dorsiflexion

Bending the foot or toes upward

Plantar flexion

bending of the sole of the foot by curling the toes toward the ground

Supination

Turn palms up

Pronation

Turns palms of hands down

Opposition

Movement of the thumb to touch the fingertips

What motion does the radium cross the ulna, taking the body out of anatomical position

Pronation

What affects the degree of motion at a joint

soft tissues surrounding the joints, muscles, ligaments, tendons, skin, and capsules; shape of articulating bones

What are the 2 intrascapular ligaments of the knee

ACL and PCL

ACL

anterior cruciate ligament, a ligament that stabilizes the knee joint (prevents sliding b/t tibia and femur)

PCL

Posterior Cruciate Ligament; prevents backward placement of the tibia along the femur

What is the rotator cuff?

Group of four tendons and other muscles in the shoulder, connecting the humerus to the scapula

Glenoid labrum

fibrocartilage ring that deepens glenoid cavity

What is the ligament that the radius rotates in?

annular ligament

What provides stability for the hip

deep socket (acetabulum), large head of the femur, and many ligaments

2 main movements with the TMJ (temporomandibular joint)

protraction and retraction, elevation and depression

What affects the range of motion at a synovial joint?

* structure or shape of articulating bone
* strength or tension of joint ligaments
* arrangement and tension of muscles
* apposition of soft parts
* disuse

Sprains

ligaments reinforcing a joint are stretched or torn; if torn, repairs slowly and is very painful/immobilizing

Cartilage injuries

tearing knee menisci or articular cartilage due to high stress exercises

Dislocation

displacement of a bone from its joint

What does it mean for a bone to be reduced

bone is moved back to proper position after dislocation

What are the general tendencies seen with joints as one ages?

* by 80, some degeneration in elbows, hips, knees, shoulders
* men tend to develop degenerative changes in vertebral column

Osteoarthritis

Inflammation of bone and joints (actually degeneration of joint tissue). Cartilage is worn away, bone tissue thickens and forms spurs; joint movement is restricted causing stiffness; slow and irreversible

Rheumatoid arthritis

Chronic inflammatory disease of connective tissues and joints; autoimmune disease; inflammatory cells flood certain joints and release large quantities of inflammatory chemicals