BONES AND JOINTS

1. BONES AND JOINTS Basic Anatomy

2. The Skeleton • The average human adult skeleton has 206 bones joined to ligaments and tendons • Forms a protective and supportive framework for the attached muscles and the soft tissues which underlie it. • Minor differences between male and female skeletons: men's bones tend to be larger and heavier than corresponding women's bones, and a woman's pelvic cavity is wider to accommodate childbirth.

3. SKELETAL FUNCTION • The skeleton plays an important part in movement by providing a series of independently movable levers, which the muscles can pull to move different parts of the body • It supports and protects the internal body organs • It is an efficient factory which produces red blood cells from the bone marrow of certain bones and white cells from the marrow of other bones • The bones are also a storehouse for minerals - calcium, for example - which can be supplied to other parts of the body

4. JOINTS • Joints permit bodily movement and are held together by fibres called "ligaments". • Some joints, like those in the skull, allow no movement. • Others may permit only limited movement: for example the joints in the spine allow some movement in several directions. • Moveable joints are continuously lubricated to prevent friction. These joints have a variable range of movement, and these are called "synovial" joints.

5. JOINTS • Joints are sturdy enough to hold the skeleton together while permitting a range of motions. • Joints are lubricated by "synovial" fluid. • The ends of these joints are coated with articular (or hyaline) cartilage, which reduces friction and cushions against jolts. • Between the bones, in a narrow space, is the joint "cavity," which gives us freedom of movement. • Ligaments then bind these bones to prevent dislocations and limit the joint's movements.

6. Joint Types1: Ball and Socket • The greatest range of joint movement is provided by a "ball-and- socket" joint, in which the spherical head of one bone lodges in the spherical cavity of another

7. Joint Types2: Hinge • The simplest type of joint is the "hinge," as found in the elbows and the joints of the fingers and toes. • Hinge joints allow movement in only one direction. Elbow

8. Joint Types3: Pivot • A pivot joint allows two bones to move in a rotational motion by twisting against each other • The radio-ulnar joint in the elbow, or atlas/axis in the neck do this

9. Joint Types4: Gliding • Gliding" joints permit a wide range of mostly sideways movements - as well as movements in one direction • The bones in the wrists and ankles slide against each other in a gliding motion • The spine is a series of gliding joints

11. Joint movement: Extension • When two bones move away from each other, the action is known as EXTENSION • This would occur for example with straightening of the elbow or knee

12. Joint movement: Abduction • When a joint moves away from the vertical centreline of the body, it is known as abduction. • This movement occurs when the arm is raised to one side

13. Joint movement: Adduction • When a joint moves towards the vertical centreline of the body, it is known as adduction. • This movement occurs when the arm is lowered

14. Joint movement: Rotation • This occurs when a bone rotates, either in a socket or relative to another bone. • It can occur at ball & socket or gliding type joints Lowering (blue arrow) is internal rotation. Raising is external

15. Forward movement is flexion Rearward movement is extension Joint movement: General For all joints except the knee and elbow