Notes: Joints

(1) How are bones hinged together? Joints: Connection between two bones. Filled with cartilage (padding) Types of Joints: Pivot Condyloid Plane Hinge Saddle Ball-and-socket

(2) What is the purpose of Joints? Allow for wider range of movement. Circular Angular Reduce rigidity of bone structure.

(3) Pivot Joint Rounded end of one bone, protrudes into a sleeve of another bone. Movement = Uniaxial Rotation of one bone Location = Vertebral Column (allowing head movement side to side “no”) and between the radius and ulna.

(4) Condyloid Joint Rotation along two axes (x and y) Oval surface of one bone fits into the depression of another bone Movement = Angular motion (flexion, extension, abduction, adduction, circumduction) Location = Wrist and knuckles

(5) Plane Joint Straight gliding along 2 horizontal axes Movement = short gliding Location = Intercarpal and Intertarsal joints and vertebral

(6) Hinge Joint One bone is cylindrical, and fits into the trough shape of the other bone Movement = uniaxial hinge (flexion and extension) Location = elbow and interphalangeal joints

(7) Saddle Joint Similar to condyloid, but with greater freedom of movement. Both bone surfaces are shaped like a saddle. Movement = angular motions (flexion, extension, abduction, adduction, circumduction) Location = thumbs and metacarpal joints

(8) Ball and Socket Joint Rotation along 3 different axes. One bone is spherical and fits into the cuplike socket of the other bone. Movement = Universal (all types) Location = shoulder and hips

(9) Injuring Joints Sprains: Dislocations: Ligaments reinforcing a joint are stretched or torn If torn badly, can be replaced with muscle Usually result from inflexibility or irregular movement Dislocations: Bones are forced out of alignment Usually result from serious falls and contact sports Results in stretching of joint ligaments, leading to future dislocations