ARTICULATIONS OF THE SPINE AND THORAX Pages 8 -12, 42 and 57

Arthrology joint, articulation or union between two or more bones Classification by degree of movement or tissue that bind the bones together

By Degree of Movement synarthrodial joint - allows no movement; flat bones of the skull amphiarthrodial joint - partially movable diarthrodial joint - freely movable By Joint Tissues fibrous connective tissue cartilage combination of connective tissue and cartilage cartilage and joint cavity

The Fibrous Joint suture - between bones of the skull syndesmosis - partially movable; two bones connected by a fibrous interosseous membrane gomphosis - articulation between the teeth and the alveolar processes The Synchondroses primary cartilaginous joint plate of hyaline cartilage between apposing surfaces = area of growth between bones sphenooccipital synchondrosis in the young → fuses after adolescence

The Symphyses secondary cartilaginous joint partially movable apposing bony surfaces are covered with cartilage but separated by intervening fibrous tissue or fibrocartilage intervertebral discs, symphysis pubis The Synovial Joint freely movable surfaces of the opposing bones are covered by articular cartil. the inner aspect of articular cavity is lined with a synovial membrane (not articular surfaces of the cartilage) → produces intervening film of synovial fluid

some joints contain discs or meniscus interposed between articular surfaces reinforcing ligaments bursae - flattened sacs that contain synovial fluid and reduce friction tendon sheath - bursa that wraps around a tendon that is subject to friction

The Multiaxial Joint provides the greatest degree of movement in three planes Ball-and-Socket and Saddle/Ellipsoid joint The Biaxial Joint allows movement in two planes the shape of the joint surfaces prevents rotation around a vertical axis Condyloid joint membrane The Uniaxial Joint allows movements in one plane only Plane, Hinge/Ginglymus and Pivot joint

Articulation of Spine

Joints of the Vertebral Bodies intervertebral disc anulus fibrosis - concentric layers of fibrocartilaginous fibers pulpal nucleus - fibrogelatinous material anterior longitudinal ligament posterior longitudinal ligament

Joints of the Vertebral Arches between the superior and inferior articular processes of adjacent vertebrae - zygapophysial/facet joints angulations of the articular facets determine types of movements the cervical vertebrae allow a range of flexion, lateroflexion and rotation coupled with lateroflexion the thoracic should be particularly mobile in rotation (is limited by the attachment of ribs) in the lumbar region - flexion, extension and little rotation

Accessory Ligaments of the Intervertebral Joints ligamenta flava (yellow) interspinous and supraspinous ligaments nuchal ligament intertransverse ligament

Craniovertebral Joints atlanto-occipital joints anterior and posterior atlanto-occipital membranes atlanto-axial joint lateral atlanto-axial joints median atlanto-axial joint cruciate ligament of atlas transverse ligaments longitudinal bands alar ligaments tectorial membrane ligamentum apicis dentis

Articulation of Thorax costovertebral joints costochondral joints and interchondral joints sternocostal joints

Costovertebral Joints head of the rib articulates with the inferior and superior costal facets of two adjacent vertebral bodies and the intervening intervertebral disc allow elevation and depression of the ribs Costotransverse Joints costotransverse ligaments - limit movements to slight gliding radiate ligament (ligamentum capitis costae radiatum) Costochondral Joints Interchondral Joints (6th-9th) Sternocostal Joints sternocostal radiate ligaments membrana sterni externa et interna

Movements of the thoracic wall during inspiration produce increases in the intrathoracic volume and diameters of the thorax