Skeletal System and Joints

• Proximal radioulnar joints include the ulna and radius.
• Knuckle joints and wrist joints are examples of condylar joints.
• Ball-and-socket joints have a cup (socket) and spherical head (ball), allowing for flexion/extension, adduction/abduction, rotation, and multiaxial movement.
• Shoulder joints and hip joints are examples of ball-and-socket joints.
• Knuckle joints of the thumbs are examples of saddle joints.
• Saddle joints have concave and convex articular surfaces, allowing for flexion/extension, adduction/abduction, and biaxial movement.
• Condylar joints have oval articular surfaces, allowing for flexion/extension, adduction/abduction, and biaxial movement.
• Examples of cartilaginous joints include the knee joint.
• A joint (articulation) is a site where two or more bones meet, functioning to give the skeleton mobility and hold it together.
• Fibrous joints are formed by dense fibrous connective tissue, have no joint cavity, and are mostly immovable.
• Cartilaginous joints are formed by hyaline cartilage, have a joint cavity, are mostly movable, and have three types: knee, elbow, and ankle.
• Synovial joints are formed by synovial membrane, have a joint cavity, are mostly movable, and have three types: knee, elbow, and ankle.
• Examples of synovial joints include the knee joint.
• Cartilaginous: formed by hyaline cartilage, have a joint cavity; most are movable; three types (knee, elbow, ankle); example: knee joint.

  Synovial: formed by synovial membrane, have a joint cavity; most are movable; three types (knee, elbow, ankle); example: knee joint.
• Examples of fibrous joints include distal articulation between the tibia and fibula.
• C2 (axis) has no body processes like other vertebrae, has major knoblike dens that project superiorly into the anterior arch of the atlas; dens pivot for rotation and allow side-to-side rotation, “no” bone.
• Coccyx: also fused bones (4) that from the terminus of column, “tailbone”.
• Sternum: also known as the breastbone, consists of three fused bones manubrium (articulates ribs 1-2), body (articulates ribs 2-7), and xiphoid process (site of muscle attachment).
• Reinforcing ligaments include capsular (thickened part of fibrous layer), extracapsular (outside the capsule), and intracapsular (deep to capsule and covered by synovial membrane).
• Lumbar vertebrae: consists of 5 vertebrae, concave, L1-L5 “small of the back”; receives most stress so the vertebral bodies are large; have short, thick pedicles and laminae, flat hatchet-shaped spinous processes point posteriorly, the vertebral foramen is triangular, the orientation of articular facets locks lumbar vertebrae together to prevent rotation.
• Depression is lowering a part of the body (ex
• Kyphosis: hunchback, the abnormal dorsal thoracic curvature common in people with osteoporosis, tuberculosis of the spine, rickets, or osteomalacia; treatments include physical therapy, bracing, and surgery if severe.
• Nerves and blood vessels detect pain and monitor joint position/stretch, capillary beds supply filtrate for synovial fluid.
• False (vertebrochondral) ribs: pairs 8-10, attach indirectly to the sternum by joining costal cartilage of the rib above.
• Articular cartilage is hyaline cartilage that covers the ends of bones and prevents damage.
• Bursae and tendon sheaths are bags of synovial fluid that act as a lubricant, “ball bearing”.
• Ribs: 12 pairs form sides of the thoracic cage and attach posteriorly to bodies and transverse processes of the thoracic vertebrae; categorized into true (vertebrosternal), false (vertebrochondral), and vertebral (floating).
• Synovial fluid is viscous, slippery filtrate of plasma and hyaluronic acid; lubricates and nourishes articular cartilage, contains phagocytic cells to remove microbes and debris.
• Lordosis: swayback, accentuated lumbar curvature that can result from disease but is also seen in
• Special movements include Eversion/Inversion; protraction/retraction; elevation/depression, etc.
• Thoracic vertebrae: consists of 12 vertebrae, convex, T1-T12 increase in size and articulate with the ribs; the body is heart shaped with two small demi facets to articulate with ribs (T10-T12 only have one facet, not two), the vertebral foramen is circular with long, sharp spinous processes that have transverse costal facets; location of articular facets allow for rotation of this area.
• Rotation is a type of movement in synovial joints, where the bone turns around its own long axis, toward the midline or away from it; example: rotation between the C1 and C2 vertebrae, rotation of humerus and femur.
• Main parts of the ribs: the shaft (bone that makes up most of rib), head (posterior end that articulates with facets on bodies of two adjacent vertebrae), neck (constricted portion beyond head), and tubercle (knoblike structure lateral to neck, articulates posteriorly to transverse costal facet of same-numbered thoracic vertebrae).
• Eversion and inversion of the foot are special movements, where eversion is when the sole of the foot faces laterally, inversion is when the sole of the foot faces medially.
• Gliding is one type of movement in synovial joints, where one flat bone surface glides or slips over another similar surface; example: intercarpal joints, intertarsal joints, between vertebrae.
• Angular movement is another type of movement in synovial joints, which involves increasing or decreasing the angle between two bones, and is a movement along a sagittal plane; examples: moving the neck forward or backward, flexing or extending the arm or leg.
• Foramen magnum: The opening for the spinal cord, arteries, and veins into/out of the skull, part of the occipital bone.
• Inversion and eversion of the foot are special movements, where inversion is when the sole of the foot faces medially, eversion is when the sole of the foot faces laterally.
• Protraction and retraction of the mandible are special movements, where protraction is when the mandible juts out, retraction is when the mandible is pulled towards the neck.
• Bursae reduce friction where ligaments, muscles, skin, tendons, or bones rub together.