A&P Exam 3 Pt.2

Articulation

-Where a bone meets another bone, cartilage, or teeth

Mobility vs. Stability

More mobility = less stability

More stability = less mobility

Ex. Shoulder (glenohumeral) ver mobile, less stable

Hip (coxal) more stable, less mobile

Fibrous

-Bones held by collagen fibers

-No joint cavity

-Example: skull sutures

Cartilaginous

-Bones held by cartilage

-No joint cavity

-Example: intervertebral discs

Synovial

-Bones separated by fluid

-Has joint cavity + capsule

-Most movable

-Example: knee, shoulder

Fiborus Joint Subtypes

-Sutures: short fibers between skull bones, Ex. skull & no motion

-Gomphoses: tooth in socket, Ex. teeth & no motion

-Syndesmoses: ligament between bones Ex. radius/ulna & some motion

Cartilaginous Joint Subtypes

-Synchondroses: Hyaline cartilage, Ex. Growth plates & no motion

-Symphyses: Fibrocartilage pad, Ex. Intervertebral discs & some motion

Synovial Joint Structures

-Fibrous layer (outer capsule)

-Synovial membrane

-Joint cavity (with synovial fluid)

-Articular capsule

-Articular cartilage

-Ligaments

Fibrous Layer

-Strengthens joint

Synovial Membrane

-Produces synovial fluid

Joint Cavity

-Allows space between bones

Synovial Fluid

-Reduces friction

-Absorbs shock

-Transports nutrients/waste

Articular Cartilage

-Prevents bone rubbing

Ligaments

-Connect bone to bone, stabilize

Nerves

-Detect pain/stretch

Blood Vessels

-Nourish Tissues

Synovial Joint Subtypes

-Plane: gliding, Ex. carpals

-Hinge: flexion, extension, Ex. elbow & knee

-Pivot: rotation, Ex. atlantoaxial

-Condylar: biaxial, Ex. knuckles

-Saddle: biaxial, Ex. thumb

-Ball & Socket: multiaxial, Ex. shoulder & hip

Functional Classification (movement)

-Plane: nonaxial

-Hinge: uniaxial

-Pivot: uniaxial

-Condylar: biaxial

-Saddle: biaxial

-Ball & socket: multiaxial

Angular (body movement)

-Flexion: decreases angle

-Extension: increases angle

-Hyperextension: beyond normal

-Lateral flexion: side bending

-Abduction: away from midline

-Adduction: toward midline

-Circumduction: circular motion

Roatational (body movement)

-Medial rotation: toward midline

-Lateral rotation: away from midline

-Pronation: palm down

-Supination: palm up

Special Motions (body movement)

-Depression/Elevation: down/up

-Protraction/Retraction: forward/back

-Inversion/Eversion: sole inward/outward

-Opposition/Reposition: thumb touch/return

-Dorsiflexion: toes up

-Plantarflexion: toes down

Tibiofemoral Joint

-Description: Joint between femur (thigh bone) and tibia (shin bone)

-Function: Main weight-bearing joint; allows flexion & extension

Patellofemoral Joint

-Description: Joint between patella (kneecap) and femur

-Function: Helps knee extension by improving leverage of quadriceps

Tendon

-Description: Connects muscle to bone

-Function: Transfers force to move the joint

Medial Meniscus

-Description: C-shaped fibrocartilage pad on inner knee

-Function: Shock absorption, improves fit between femur & tibia

Lateral Meniscus

-Description: Fibrocartilage pad on outer knee

-Function: Same as medial meniscus (shock absorption, stability)

Patellar Ligament

-Description: Connects patella → tibia

-Function: Transfers force for knee extension

Anterior Cruciate Ligament (ACL)

-Description: Ligament inside the knee running diagonally

-Function: Prevents hyperextension and forward movement of tibia-

Posterior Cruciate Ligament (PCL)

-Description: Crosses ACL in opposite direction

-Function: Prevents tibia from sliding backward

Tibial Collateral Ligament (MCL)

-Description: Ligament on medial (inner) side

-Function: Resists forces pushing knee inward

Fibular Collateral Ligament (LCL)

-Description: Ligament on lateral (outer) side

-Function: Resists forces pushing knee outward

Bursa

-Description: Small fluid-filled sacs

-Function: Reduce friction between tissues (ligaments, tendons, bones)

Joint cavity

-Description: Space inside joint filled with synovial fluid

-Function: Reduces friction & allows smooth movement

Femur

-Description: Thigh bone (upper bone)

-Function: Forms top of knee joint; weight-bearing

Tibia

-Description: Main shin bone

-Function: Bears most body weight

Fibula

-Description: Smaller bone next to tibia

-Function: Stabilization (not major weight-bearing)

Unhappy Triad

-Caused by lateral or posterior blow to knee

-Damages: ACL, MCL, Medial meniscus

Glenohumeral vs. Coxal

-Similarities: Both ball-and-socket, multiaxial movement

-Differences:

Glenohumeral (shoulder): More mobile, less stable

Coxal (hip): More stable, less mobile, has acetabular labrum (improves fit)

Humeroulnar Joint

-Bones: trochlea (humerus) + trochlear notch (ulna)

-Type: hinge

-Motion: flexion/extension

Humeroradial Joint

-Bones: capitulum (humerus) + radial head

-Type: hinge

-Motion: flexion/extension

Proximal Radioulnar Joint

-Bones: radial head + radial notch of ulna

-Type: pivot

-Motion: pronation/supination