Joints - NEED TO ADD MOVEMENTS ALLOWED BY SYNOVIAL JOINTS

Anatomy Exam 1

Joints (articulations) definition and function

• connections between two or more bones

• mobility, holding skeleton together

Classification: structural

• fibrous

• cartilaginous

• synovial

Classification: functional

• synarthroses (immovable joints)

• amphiarthroses (slightly movable)

• diarthroses (freely moving)

Fibrous joints (what connects them? joint cavity? what is their functional classification? what are the three types?)

• connected by dense fibrous CT

• no joint cavity

• connected by short fibers making them primarily synarthrotic

fibrous joints:

• sutures

• syndesmosis

• gomphosis

Fibrous joints: sutures

• skull bones - connected by short fibers

• allows for growth in adolescence

• in middle age, sutures ossify and fuse into one unit protecting brain

  • fused unit: synostoses

fibrous joints: syndesmoses

• connected by ligaments (bands of fibrous tissue)

  • short fibers = little to no movement, long fibers = more movement

syndesmoses in interosseous membrane connecting radius and ulna

fibrous joints: gomphoses

• peg-in sockets

• teeth

• fibrous connection: periodontal ligament

Cartilaginous joints

• connected by cartilage

• not highly movable (most are amphiarthrotic)

• no joint cavity
  

types:

• synchondroses

• symphyses

Cartilaginous joints: Synchondroses

• connected by hyaline cartilage

• almost all are synarthrotic

examples: epiphyseal plate joints

• cartilage of 1st rib w manubrium of sternum

Cartilaginous joints: symphyses

• connected by fibrocartilage

• amphiathrotic

ex:

• pubic symphysis

• intervertebral joints

Synovial joints

• articular cartilage (hyaline cartilage covering ends of bones to prevent crushing of bone ends)

• have synovial (joint) cavities

• synovial fluid to nourish/lubricate articular cartilage

• articular (joint) capsule: two layers thick

  • external fibrous layer: dense irregular CT

  • inner synovial membrane: loose CT makes synovial fluid

• reinforcing ligaments

  • capsular: thickened part of fibrous layer

  • extracapsular: outside capsule

  • intracapsular: deep to capsule, covered by synovial membrane

• nerves & blood vessels