Introduction to Introduction to BiomechanicsBiomechanics

IE497BIE497BDr. R. A. WyskDr. R. A. Wysk

The human skeletonThe human skeleton

Bone componentsBone components

Cortical BoneCortical Bone

Osteonal BoneOsteonal Bone

JointsJoints

• FibrousFibrous• Fibrous joints connect bones without allowing any movement. The Fibrous joints connect bones without allowing any movement. The

bones of your skull and pelvis are held together by fibrous joints. bones of your skull and pelvis are held together by fibrous joints. The union of the spinous processes and vertebrae are fibrous The union of the spinous processes and vertebrae are fibrous joints. joints.

• CartilaginousCartilaginous• Cartilaginous joints are joints in which the bones are attached by Cartilaginous joints are joints in which the bones are attached by

cartilage. These joints allow for only a little movment, such as in cartilage. These joints allow for only a little movment, such as in the spine or the spine or ribs.ribs.

• SynovialSynovial• Synovial joints allow for much more movement than cartilaginous Synovial joints allow for much more movement than cartilaginous

joints. Cavaties between bones in synovial joints are filled with joints. Cavaties between bones in synovial joints are filled with synovial fluid. This fluid helps lubricate and protect the bones. synovial fluid. This fluid helps lubricate and protect the bones. Bursa sacks contain* the synovial fluid. Bursa sacks contain* the synovial fluid.

Synovial JointsSynovial Joints• Synovial joints allow for Synovial joints allow for

much more movement much more movement than cartilaginous joints. than cartilaginous joints. Cavaties between bones Cavaties between bones in synovial joints are in synovial joints are filled with synovial fluid. filled with synovial fluid. This fluid helps lubricate This fluid helps lubricate and protect the bones. and protect the bones. Bursa sacks contain* the Bursa sacks contain* the synovial fluid. synovial fluid.

Ball and socket JointsBall and socket Joints• A ball and socket A ball and socket

joint allows for joint allows for radial movment in radial movment in almost any almost any direction. They are direction. They are found in the hips found in the hips and shoulders. and shoulders.

Ellipsoid JointsEllipsoid Joints• Similar to a ball and Similar to a ball and

socket joint -- allow the socket joint -- allow the same type of movement same type of movement to a lesser magnitude. to a lesser magnitude. The wrist is an ellipsoid The wrist is an ellipsoid joint.joint.

Saddle JointsSaddle Joints• A saddle joint A saddle joint

allows movement allows movement back and forth back and forth and up and down, and up and down, but does not but does not allow for rotation allow for rotation like a ball and like a ball and socket joint. socket joint.

Pivot JointsPivot Joints• Pivot joints allow rotation around Pivot joints allow rotation around

an axis. The neck and forearms an axis. The neck and forearms have pivot joints. In the neck the have pivot joints. In the neck the occipital bone spins over the top occipital bone spins over the top of the axis. In the forearms the of the axis. In the forearms the radius and ulna twist around each radius and ulna twist around each other. other.

GlidingGliding• In a gliding or In a gliding or

plane joint plane joint bones slide past bones slide past each other. each other. Metacarpal and Metacarpal and metatarsal metatarsal joints are gliding joints are gliding joints joints

The kneeThe knee

A bad joint?!?A bad joint?!?• 30-50% of all sports injuries30-50% of all sports injuries• 0.2% of the general population per 0.2% of the general population per

year for knee ligament problemsyear for knee ligament problems• ACL and MCL are 90% of all sport ACL and MCL are 90% of all sport

injuriesinjuries• Women are 2-8 times greater riskWomen are 2-8 times greater risk

Long boneLong bone

Long bone cont’dLong bone cont’d

SummarySummary

• Human body is a very complex Human body is a very complex systemsystem

• Bones are very strong mechanical Bones are very strong mechanical membersmembers

• Self healingSelf healing• Can be very slipperyCan be very slippery