Introduction to Biomechanics ISE789 Dr. R. A. Wysk Spring 2010

Musculoskeletal System Bones Passive soft tissue Muscles Nerves

Functions of the skeleton Support and motion Protect vital organs Mineral storage Hematopoiesis

A little bit of anatomy Major mechanical functions of the body – Purpose(s) Medical related issues – Injuries – Treatments Engineering issues – Replacement

Anatomy terms Superior - toward the head Inferior - away from the head Anterior - the front of the body or body part Posterior - the back of the body or body part Medial - toward the midline that divides left and right Lateral - to the side away from the midline Proximal - closer to the torso Distal - farther away from the torso Anatomical position - standing erect, facing the observer, arms are at the sides with palms facing forward.

Sectioning Read Medical Terms doc

Basic types of bone tissue Cortical bone – Compact bone – Central shaft of long bone Cancellous/trabecular bone – Spongy bone – Found inside ends of long bone and inside vertebral bodies Trabecular or spongy metal

The Human skeleton There are 206 bones in the human body that make up our skeleton – 80 bones in the axial skeleton – 126 bones - appendicular skeleton 60 bones – upper limbs 60 bones – lower limbs – 4 bones – pectoral girdle – 2 bones – pelvic girdle

Groups of bones Long bones – Long in one direction – Ends are expanded and covered – Femurs, tibias, fibulas, humeri, radii, ulnas, metacarpals, metatarsals, phalanges, and clavicles Short bones – Same dimensions in all directions – Thin cordices; filled with trabecular bone – The entire vertebral column, carpal bones, and tarsal bones. Flat bones – Skull – Pelvis – The ribs, scapula, sternum, and ilium

The human skeleton

Bone components

Cortical Bone

Osteonal Bone

Joints of the Body Synovial Joints – Large range of motion joint – Cartilaginous joints – Between the ribs and sternum Fibrocartilage pad Between adjacent vertebral bodies

Joints Fibrous Fibrous joints connect bones without allowing any movement. The bones of your skull and pelvis are held together by fibrous joints. The union of the spinous processes and vertebrae are fibrous joints. Cartilaginous Cartilaginous joints are joints in which the bones are attached by cartilage. These joints allow for only a little movment, such as in the spine or ribs.ribs. Synovial Synovial joints allow for much more movement than cartilaginous joints. Cavaties between bones in synovial joints are filled with synovial fluid. This fluid helps lubricate and protect the bones. Bursa sacks contain* the synovial fluid.

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

Ball and socket Joints A ball and socket joint allows for radial movment in almost any direction. They are found in the hips and shoulders.

Ellipsoid Joints Similar to a ball and socket joint -- allow the same type of movement to a lesser magnitude. The wrist is an ellipsoid joint.

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

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

Gliding In a gliding or plane joint bones slide past each other. Metacarpal and metatarsal joints are gliding joints

The knee

A bad joint?!? 30-50% of all sports injuries 0.2% of the general population per year for knee ligament problems ACL and MCL are 90% of all sport injuries Women are 2-8 times greater risk

Long bone

Long bone cont’d

Coefficients of Friction Joint /materialCoefficient of friction Human knee – 0.02 Human hip 0.01 – 0.04 Gold on gold 2.8 Steel on steel 0.6 – 0.8 Glass on glass 0.9 Ice on ice at 0 o C 0.01 – 0.1 J. Charnley 1960 A. Unsworth 1975

Synovial Joints Ball and socket Joints – Hip and shoulder Bicondylar Joints – Knee joints Multiple bone joints – Wrist and ankle joints