ANAT337-L Articulations

Axial skeleton

central skeleton; skull, spinal column, and ribs

Appendicular skeleton

part of skeleton including upper and lower limbs; pectoral girdle and pelvic girdle

Articulations

aka joints; where a bone meets another bone, cartilage, or teeth

vary in stability and motility

increases; decreases

As motility ____, stability ____.

1. Articular surfaces - shape influences movements possible and stability

2. Ligaments - capsules and ligaments prevent excessive motions; increase in ligaments = increase in stability

3. Muscle tone - helps stabilize joints by keeping tension on tendons

Factors that influence joint stability:

synarthrosis

functional joint classification; immobile or nearly immobile joint

ex: suture

Amphiarthrosis

functional joint classification; a joint with limited mobility

ex: syndesmosis, intervertebral disc

Diarthroses

functional joint classification; freely mobile joints

ex: synovial joints

Synovial joint

diarthrotic joint that articulates bones separated by fluid filled joint cavity

Articular cartilage

found on synovial joints

hyaline cartilage that reduces friction and acts as a shock absorber

Osteoarthritis

aging and stress result in breakdown of the articular cartilage

Articular capsule

found on synovial joints

has two layers

• outer fibrous made of dense regular CT that serves to provide structural stability to joint

• inner synovial membrane that serves to secrete fluid into joint

Joint cavity

contains synovial fluid and filtrate of blood

nourishes and lubricates joint/cartilage

Ligament

found on synovial joints

connects bone to bone, comprised of dense regular CT, strengthens and reinforces capsule, can be intrinsic/extrinsic

Articular disc

present in some synovial joints with articulating bones of different shapes

Bursae

accessory structure of synovial joints

sacs containing synovial fluid that reduce friction between tendons passing over joints

Tendon sheaths

accessory structure of synovial joints

elongated bursae around tendons passing over bone

Fat pads

accessory structure of synovial joints

fill in spaces of synovial joints, also provide some protection

Gliding

Movement of synovial joints

occurs in plane joints

Angular motions

Movement of synovial joints; change in joint angle

flexion/extension, abduction/adduction, circumduction

Rotational motions

Movement of synovial joints

medial-lateral rotation, supination/pronation

Nonaxial

classification of synovial joint by movement

gliding movements

ex: plane joint

Uniaxial

classification of synovial joint by movement

rotation or angular motion

ex: pivot/hinge joint

Biaxial

classification of synovial joint by movement

angular motion only

ex: saddle joint/condylar joint

Multiaxial

classification of synovial joint by movement

rotation, angular motion, circumduction

ex: ball and socket joint

transverse

Movement along the sagittal plane occurs on the ___ axis.

anteroposterior

Movement along the coronal plane occurs on the ___ axis.

vertical

Movement along the transverse plane occurs on the ___ axis.