Apuntes sobre articulaciones

• Study notes about articulations

Arthrology

• Arthrology is the study of articulations which is the junction of hard and soft tissues that allow bones to not sound
• Graphy refers to the area of tomography, or radiograph

Articulations

• Articulations are where two or more bone structures or cartilaginous structures meet
• The principle function of articulations is to permit movement

Classification of Articulations

• Classified according to their mobility:
  • Synarthrosis: Immovable, examples include the cranium and costal arches with the column
  • Amphiarthrosis: Slightly movable
  • Diarthrosis: Freely movable, examples include the shoulder and hip

Classification by Type

• Classified according to the type of tissue that unites the bones:
  • Fibrous, cartilage or synovial

Fibrous Joints

• Fibrous joints unite bones with dense fibrous connective tissue
  • Sutures are connected by Sutural ligament in the cranium
  • Gomphosis connects teeth to the jaw with periodontal ligament
  • Syndesmosis, connected by interosseous membrane, connects the radius to the ulna

Cartilaginous Joints

• The bones are united by cartilage, which serves as a shock absorber
  • Synchondrosis made of hyaline cartilage
  • Symphysis made of fibrocartilage

Synovial Joints

• Characterized by specific components:
  • Synovial cavity with synovial fluid
  • Articular cartilage (hyaline)
  • Articular capsule
• Structures that can be present:
  • Fibrocartilaginous structures
  • Menisci or articular discs
  • Ligaments or tendons to help stabilize and facilitate movement

Types

• Plane
• Hinge or Ginglymus
• Pivot or Trochoid
• Condyloid or Ellipsoidal
• Saddle or Reciprocal Engagement
• Spheroid or Enarthrosis

Planar Joints

• Nonaxial (flexion and extension)
• Allows gliding or sliding movements with limited mobility
• Example: Acromioclavicular joint, articular processes of vertebrae, and between carpal bones

Trochlear (Ginglymus or Hinge) Joints

• Uniaxial for extension and flexion
• Have lax capsules and strong collateral ligaments
• Example: Humeroulnar joint and interphalangeal joints

Sellar (Saddle) Joints

• Biaxial. Provides flexion, extension, adduction, abduction and rotation
• Concave surface articulating with a convex surface
• Example: Carpometacarpal joint of the thumb.

Trochoid (Pivot) Joints

• Monoaxial permitting rotation
• bony pivot surrounded by an osteoarticular ring
• Example: Atlantoaxial joint and radioulnar joint.

Condyloid (Ellipsoidal) Joints

• Biaxial: permit flexion, extension, abduction, adduction, and slight circumduction
• Example: Radiocarpal joints, metacarpophalangeal joints, and the knee.

Spheroid (Ball and Socket)

• Multiaxial with a sphere fitting into the cavity of another bone
• Allows flexion, extension, adduction, abduction, internal and external rotation, and circumduction
• Examples: Coxofemoral (hip) and glenohumeral (shoulder) articulations.

Extremity Articulations

• Superior:
  • Shoulder: Spheroid
  • Elbow: Hinge
  • Wrist: Condyloid
• Inferior:
  • Hip: Spheroid
  • Knee: Hinge
  • Ankle: Hinge

Movements

• Flexion: Reducing the angle (90° or less)
• Extension: Increasing the angle (90° or more)
• Abduction: Movement away from the midline/center
• Adduction: Movement toward the midline/center
• Circumduction: Imperfect circular movement
• Rotation: Turning a segment around its long axis

Common Movements

• Flexion
• Extension
• Radial deviation (abduction)
• Ulnar deviation (adduction)
• Pronation (down)
• Supination (up)
• Plantar flexion
• Dorsiflexion
• Inversion
• Version
• External rotation
• Internal rotation
• Abduction