ARTICULATIONS
WHAT IS A JOINT? A site where two or more bones meet. Provides mobility Weakest point of skeleton
Fibrous connective membranes Joint Structure Fibrous connective membranes Sutures – connected by short fibers from the periosteum (becomes synostosis in adult) Syndesmoses – connected by ligaments (distal end of tibia & fibula) Gomphoses -- “peg in sockets” (tooth sockets)
Cartilaginous - hyaline cartilage holding joint together Joint Structure Cartilaginous - hyaline cartilage holding joint together Synchondroses– cartilage unites bones (epiphyseal plates & costal joints) Symphyses – connected by fibrocartilage (pubic symphysis, vertebral joints)
Synovial joints – separated by a fluid containing joint cavity Joint Structure Synovial joints – separated by a fluid containing joint cavity Diarthroses - freely moveable joints such as shoulder, knee, hip, and most others
Joints classified by function Synarthroses NO MOVEMENT (sutures, gomphoses, synchondroses, some syndesmoses) Amphiarthroses – SLIGHT MOVEMENT (symphyses, some syndesmoses
Diarthroses - FREELY MOVABLE Joints by function Diarthroses - FREELY MOVABLE Plane (gliding) - tarsals and carpals Condyloid (ellipsoid) – metacarpophalangeal joints Pivot - Atlas/Axis; Radius/Capitulum Saddle - Thumbs Hinge – Elbow, Knee Ball and socket – Shoulders, Hips
Suture
Synchrondroses
Syndesmosis
Symphyses
Synovial Joint
Ball & Socket Joint
Condyloid Joint
Hinge Joint
Pivot Joint
Saddle Joint
Plane (Gliding) Joint
Structure of Diarthrotic Joint Two or more opposing bones Joint capsule of connective tissue surrounds joint cavity Joint cavity lined with synovial membrane Articular cartilage – covers ends of bone Menisci (articular disks) - cartilage pads (knee) Bursae – flattened sacs filled with synovial fluid Ligaments – attach bone to bone Tendons – attach muscle to bone
Synovial Joint
Types of Movement Flexion/Extension Abduction/Adduction Circumduction Rotation Protraction/Retraction
Protraction / Retraction
Types of Movement Elevation/Depression Inversion/Eversion Pronation/Supination Dorsiflexion/Plantar flexion
Supination / Pronation
Elevation / Depression
Inversion / Eversion
Joint Injuries Sprains - ligaments stretched or torn Cartilage Injuries - torn cartilage rarely repairs because it’s avascular) Dislocations (luxation) - bones moved out of alignment
Knee Joint
Inflammatory/Degenerative Conditions Bursitis - inflammation of a bursa caused by blow or friction Tendonitis - inflammation of tendons caused by overuse Arthritis
>100 different types; affecting 1 out of 7 Arthritis >100 different types; affecting 1 out of 7 Osteoarthritis - Wear & Tear; affects 85% Rheumatoid Arthritis - Autoimmune May occur at any age; Most common around 40-50; Affects 1-2% of Americans Immune cells attack joint tissue causing scarring & ossification Ankylosis = stiff deformed joints Gouty Arthritis (Gout) Caused by build up of Uric Acid
Other Bone Disorders Rickets - soft bones; lack of calcium due to vitamin D deficiency Osteoporosis - excessive bone loss Paget’s disease - excessive bone formation Osteomyelitis - Inflammation caused by pus-forming bacteria Achondroplasia - defective endochondral bone growth; form of dwarfism
Osteosarcoma - form of bone cancer Scoliosis - abnormal lateral curvature of the spine Kyphosis - abnormal thoracic curvature Lordosis - abnormal lumbar curvature Herniated Disk (Ruptured or Slipped Disk) - compression on intervertebral disk presses on nerves