Skeletal System

5 Functions of the Skeletal System 1. Movement: Skeletal system provides points of attachment for muscles. Your legs and arms move when the muscles pull on the bones. 2. Support: The backbone is the main support center for the upper body. It holds your head up and protects your spinal cord. Muscle attached to bones!!

5 Functions of the Skeletal System 3. Protection: The bones of your skull protect your brain. Your ribs protect your lungs and heart from injury. 4. Makes Blood: Red and white blood cells are formed by tissue called marrow, which is in the center of the bone.

5 Functions of the Skeletal System 5. Storage: Bones store minerals, such as calcium and phosphorus, for use by the body

Two Major Skeletal System Parts Axial Skeleton: The axial skeleton includes the skull, spine, ribs and sternum. Appendicular Skeleton: The appendicular skeleton includes the appendages of the body, which are the shoulders, arms, hips, and legs.

Skeletal System Bones Four basic bone shapes 1. Long- longer than they are wide Ex. arms, legs and fingers Humerus 2. Short- fairly equal in width and length, similar to a cube Ex. wrist and ankles Tarsals 3. Flat- thinner bones that can be flat or curved, platelike in nature Ex. skull, sternum, scapula 4. Irregular- like parts of a jigsaw puzzle, odd- shaped, need to connect to other bones Ex. spine (vertebrae) and hip bones

Basic Bone Anatomy Each bone end is called at epiphysis. Proximal epiphysis – the proximal end of the bone (closer to the point of attachment) Distal epiphysis – the distal end of the bone (farther from the point of attachment) The region between or “running through” the two ends is called the diaphysis

Bone Structure Typical Four Layers: Periosteum: Covers Bones Compact Bone: Dense, hard tissue, lies beneath the periosteum Spongy Bone: Helps make bones light weight and provides a space for red bone marrow, lies beneath the compact bone Bone Marrow: Fills the gaps between the spongy bone

Ossification This is the formation of bone in the body. Bones grow longitudinally to lengthen, and they grow wider and thicker so they can more efficiently support body weight and any other weight we support when we work or play.

Joints -Need for movement -Connected by ligaments, ligaments hold bone to bone -Joints are classified by function or structure -Function: joints can be immobile, move a little, or move freely -Structure: divided based on the type of connective tissue that links the bones -1. Fibrous joints: held together by short connective tissue strands, immobile or slightly movable. Ex – Skull bones held together by fibrous joints -2. Cartilaginous joints: held together by cartilage, immobile or slightly movable. Ex – joints between ribs and sternum -3. Synovial joints: held together by a joint cavity with a synovial membrane and filled with fluid, freely moving. Ex - knee

Joints Gliding Joints – flat, or slightly curved, platelike bones found in your wrists and ankles. Gliding joints slide back and forth. Hinge Joints – found in knees and elbows. Typically one bone is in the shape of a cylinder and the other a trough. They can either open or close. Saddle Joints – have a bone shaped just like a saddle and another bone similar to a horse’s back. This joint is found in the base of your thumb. Saddle joints rock up and down and side to side.

Joints Ellipsoidal Joints – formed by oval shaped bone fitted into a depression and provide two axes of movement, like the joint formed at the wrist with both the radius and ulna. Pivot Joints – have a circular portion of one bone that spins inside a ring-shaped portion of the other. Pivot joints are the type of joint found in your neck and forearm. They can partially rotate. Ball-and-socket Joints – consist of a spherical articulation with a cup-shaped socket on the other bone. Ball-and-socket joints are located in your hips and shoulders and can perform all types of movement, including rotation.

Movement Classification Flexion – occurs when a joint is bent, decreasing the angle between the involved bones Extension – is a result of straightening a joint so the angle between the involved bones increase, as occurs with a kicking motion Dorsiflexion – occurs when the foot us bent up toward the leg Hyperextension – if the joint is forced to straighten beyond its normal limits

Movement Classification Abduction and Adduction – ABduction: to move away from the body’s midline “BE GONE” ADDuction: to move towards the midline of the body Think of “aDDress”, where mail comes TOWARD your house

Movement Classification Inversion and Eversion– Inversion – when the sole of one foot is turned inward so it points to the other foot. Eversion – opposite of inversion, sole of foot is turned outward

Movement Classification Supination and Pronation– Supination – when the hand is turned to the point where the palm faces upward. Pronation – turns the palm downwards

Movement Classification Supination and Pronation– Supination – when the hand is turned to the point where the palm faces upward. Pronation – turns the palm downwards

Movement Classification Protraction and Retraction– Protraction – the motion of drawing a part forward Retraction – the motion of drawing a part backwards Think of a turtle sticking its head out and drawing it back into its shell.

Movement Classification Rotation – is when a bone “spins” on its axis Circumduction – movement of the end of a limb in a circle

Bones of the Skull

The skull protects and houses the brain and has openings needed for our sensory organs, such as the eyes, nose and ears. The skull contains fibrous connective tissue joints called sutures that hold the bony plates of the skull together.

Thoracic “Cage” Bones of the chest provides support and protection for the heart, lungs, and great blood vessels. The cage is flexible because of cartilaginous connections that allow for movement during the process of breathing.

The sternum is composed of three distinct structures: 1.Manubrium – superior portion 2.Body – largest, central portion 3.Xiphoid – final and inferior portion that hardens by the age of 25

Clavicle or Collarbone The clavicle, or collar bone, holds the shoulder joint away from the rest of the upper body and is only as thick as your little finger.

Scapula The scapula is located on the back side of the ribcage and helps provide part of the shoulder joint and movement for the arms.

Humerus (Upper Arm Bone)

Radius and Ulna Radius on Top Ulna on Bottom

Carpals or (Wrist Bones)

Metacarpals (Top of Hands)

Phalanges (Little Fingers)

Rib Cage

Sternum (Breastbone)

Pelvis (Dancing Bone)

Femur (Largest Bone in the Body)

The Tibia and Fibula

Tarsals

Metatarsals

Phalanges