Anatomical Position Used to help describe the location of one body part with respect to another. Standing erect Facing forward Legs slightly apart Palms forward Terms Superior – above, upper Inferior – below, lower Example: The head is superior to the waist. Anterior (Ventral) – towards the front Posterior (Dorsal) – towards the back Example: Your nose is on the anterior surface of the head. Medial – closer to the imaginary midline Think medial is middle Lateral – further from the midline Think towards the outside Example: The ears are lateral to the eyes. Referring just to arms and legs: Proximal – near the joint (point of attachment) Distal – further from the joint (point of attachment) Think distal is more distance Example: The thigh is more proximal to the knee, than the foot. Parts of a Bone Periosteum The layer that covers a bone. Membrane that controls the development of bone Two Tissues: Compact Bone The hardest part of a bone. Spongy Bone Lighter, full of tiny holes. Contains many blood vessels. Bone Marrow The center of bones. Responsible for making red and white blood cells. Types of Bones Flat Bones Provide protection for soft tissues. Are points for muscle attachment. Example: bones of the skull. Long Bones Provide strength and support. Example: bones of the arms and legs. Short Bones Not much longer than they are wide. Provide flexibility. Example: bones of the wrists and ankles. Irregular Bones Have shapes related to a specialized function. Examples: Bone of middle ear, backbone. Functions of Bones Supports the body (framework). Protects internal organs. Stores calcium. Produces new red and white blood cells. In the bone marrow. Helps with movement, attachment of muscles. Bones and muscles work together. Joints The point (place) where the bones meet. There are five types of joints. Immoveable Bones fit tightly together. Example: skull. Hinge Allow back and forth movement. Example: elbow and knee. Ball and Socket Allow movements in all direction. Example: hip and shoulder. Pivot Allow side to side and up and down movements. Example: base of skull with neck. Gliding or Ellipsoidal Allow some bending and twisting movements. Examples: wrists, vertebra Ligaments A band of tough, fibrous, elastic tissue. Made up of collagen. Keeps the bones of a joint in place. Supports the joint. Injury to a ligament is called a sprain. Facts There are 206 bones in the adult skeleton. Babies are born with over 350 bones. Some eventually fuse together. The Skeletal System is made of bone and cartilage and does include joints. Bone is not dead. It is constantly growing, changing, and developing. Over half your bones are in your hands and feet.