Skeletal system
- 1. Introduction to the Skeletal System Yoga Life Asanas and Meditation
- 2. Humans are vertebrates, animals having a vertebral column or backbone. They rely on a sturdy internal frame that is centered on a prominent spine. The human skeletal system consists of bones, cartilage, ligaments and tendons and accounts for about 20 percent of the body weight.
- 3. Introduction to the Skeletal System • Bones provide a rigid framework, known as the skeleton, that support and protect the soft organs of the body. • The skeleton supports the body against the pull of gravity. The large bones of the lower limbs support the trunk when standing. • The fused bones of the cranium surround the brain to make it less vulnerable to injury. Vertebrae surround and protect the spinal cord and bones of the rib cage help protect the heart and lungs of the thorax. • The skeleton makes up about 20% of the human mass. • Your nose and ears are not made of bone; they are made of cartilages
- 4. Introduction to the Skeletal System • Bones contain more calcium than any other organ. The intercellular matrix of bone contains large amounts of calcium salts, the most important being calcium phosphate. When blood calcium levels decrease below normal, calcium is released from the bones so that there will be an adequate supply for metabolic needs. When blood calcium levels are increased, the excess calcium is stored in the bone matrix. The dynamic process of releasing and storing calcium goes on almost continuously. • The outside of a bone is hard, but the inside is softer, made of marrow. Young children have soft bones which keep on growing, once we reach twenty years old our bones stop growing.
- 5. Introduction to the Skeletal System
- 6. Fun Facts of Skeletal System • The living bones in our bodies use oxygen and give off waste products in metabolism. They contain active tissues that consume nutrients, require a blood supply and change shape or remodel in response to variations in mechanical stress. • Bones contain more calcium than any other organ. The intercellular matrix of bone contains large amounts of calcium salts, the most important being calcium phosphate. • Bones work together with muscles as simple mechanical lever systems to produce body movement. • The skeleton also protects the soft body parts. • It is composed of around 270 bones at birth – this total decrease to around 206 bones by adulthood after some bones get fused together. The bone mass in the skeleton reaches maximum density around age 21.
- 7. Structure of Bone Tissue • There are two types of bone tissue: compact and spongy. • Osteoblasts are bone-forming cell, osteoclasts resorb or break down bone, and osteocytes are mature bone cells. An equilibrium between osteoblasts and osteoclasts maintains bone tissue. Compact Bone, Compact bone, have a denser material used to create much of the hard structure of the skeleton. As seen in the image below, compact bone forms the cortex, or hard outer shell of most bones in the body.
- 8. Structure of Bone Tissue Spongy (Cancellous) Bone, • Spongy (cancellous) bone is lighter and less dense than compact bone. • Spongy bone is usually located at the ends of the long bones (the epiphyses), with the harder compact bone surrounding it. • Spongy bone provides balance to the dense and heavy compact bone by making bones lighter so that muscles can move them more easily. In addition, the spaces in some spongy bones contain red bone marrow,
- 9. Bone Development & Growth • The terms osteogenesis and ossification are often used synonymously to indicate the process of bone formation. • Bone development continues throughout adulthood. Even after adult stature is attained, bone development continues for repair of fractures and for remodeling to meet changing lifestyles. Osteoblasts, osteocytes and osteoclasts are the three cell types involved in the development, growth and remodeling of bones. Osteoblasts are bone-forming cells, osteocytes are mature bone cells and osteoclasts break down and reabsorb bone.
- 10. Classification of Bones, • The four principal types of bones are long, short, flat and irregular.
- 11. Classification of Bones, • Long Bones, Bones that are longer than they are wide are called long bones. They consist of a long shaft with two bulky ends or extremities. They are primarily compact bone but may have a large amount of spongy bone at the ends or extremities. Long bones include bones of the thigh, leg, arm, and forearm.
- 12. Classification of Bones, Short Bone, Short bones are roughly cube shaped with vertical and horizontal dimensions approximately equal. They consist primarily of spongy bone, which is covered by a thin layer of compact bone. Short bones include the bones of the wrist and ankle.
- 13. Classification of Bones, Flat Bone, Flat bones are thin, flattened, and usually curved. Most of the bones of the cranium are flat bones.
- 14. Classification of Bones, Irregular Bone, Bones that are not in any of the above three categories are classified as irregular bones. They are primarily spongy bone that is covered with a thin layer of compact bone. The vertebrae and some of the bones in the skull are irregular bones.
- 15. Classification of Bones, All bones have surface markings and characteristics that make a specific bone unique. There are holes, depressions, smooth facets, lines, projections and other markings.
- 16. Divisions of the Skeleton • The adult human skeleton usually consists of 206 named bones. These bones can be grouped in two divisions: axial skeleton and appendicular skeleton. • The 80 bones of the axial skeleton form the vertical axis of the body. They include the bones of the head, vertebral column, ribs and breastbone or sternum. • The appendicular skeleton consists of 126 bones and includes the free appendages and their attachments to the axial skeleton. The free appendages are the upper and lower extremities, or limbs, and their attachments which are called girdles. The named bones of the body are listed below by category.
- 17. Divisions of the Skeleton
- 18. Divisions of the Skeleton APPENICULAR SKELETON The Appendicular Skeleton consists of 126 bones of different shapes & sizes. This includes the bones of upper extremities & lower extremities. The bones of the upper extremities consist of the clavicle, scapula, humerus, radius, ulna, bones of the wrist and hand (8 carpal bones, 5 metacarpal & 14 phalanges) The bones of the lower extremities consist of the pelvic bones, femur, patella, tibia, fibula, and bones of the ankle & feet (7 tarsal bones, 5 mata tarsal & 14 phalanges
- 19. Divisions of the Skeleton AXIAL SKELETON Skull: It consists of 8 cranial bones and 14 facial bones Ribs: Also known as the thoracic cage or rib cage and consists of 24 ribs. The first seven ribs are attached with the costal cartilage and the 8th, 9th and 10th ribs are connected to the 7th rib. The 11th and 12th ribs are floating ribs. The rib cage protects the heart, lungs, and kidneys. It also provides attachment sites for inter-coastal muscles and muscles of the arms. These 24 ribs are attached to the 12 thoracic vertebras from the back, and with the sternum (breastbone) from the front.
- 20. Divisions of the Skeleton AXIAL SKELETON The Vertebral Column: A total of 26 vertebrae for an adult. •The Cervical Spine: Consists of 7 vertebral bodies (C1 through C7). These vertebrae are the smallest in the spinal column, and they support the skull. •The Thoracic Spine: Consists of 12 vertebral bodies (upper back - T1 through T12). This part of the spine has very little motion as they are attached to the ribs & sternum. However, because there is little motion in this region, it is usually not a source of chronic pain. •The Lumbar Spine: Consists of 5 vertebral bodies (lower back - L1through L5). This part extends from the lower thoracic spine to the sacrum. The vertebral bodies stack on top of each other with a disc in between each one. These vertebrae are the largest in the spinal column and they transmit the weight down to the sacrum. These take the most strain during lifting. •The Sacrum Spine: The 5 sacrum vertebrae are fused together to become one vertebra when a child grows up. The sacrum is housed within the bones of the pelvis and it transmits the weight sideways from the spine into the pelvic girdle. •The Coccyx Spine: The 4 coccyx vertebrae are fused together to become one vertebra known as the ‘tailbone’ when a child grows up and it moves only during pregnancy.
- 21. Divisions of the Skeleton There are inter-vertebral discs between each vertebra. These discs consist of semi fluid and thick cartilage and act as shock absorbers. Once the disc is injured or starts to degenerate due to age, it can become painful for the spine and back. Injury, stress, and poor postural habits can cause progressive weakness in these discs and the muscles in the spine. It is recommended that you develop habits that reduce the pressure placed on the back. Spinal exercise, when performed correctly, is one of the best measures to prevent spinal problems and back pain and should be an important part of your fitness routine. Successful and appropriate back strengthening exercises can build stability in weak muscles and are more effective if they are easy to perform, and do not aggravate other problems or worsen a current condition. Always consult your doctor/therapist before beginning an exercise program if you have specific spine or back problems. The intervertebral discs are fibro cartilaginous cushions serving as the spine’s shock absorbing system, which protect the vertebrae, brain, and other structures (i.e., nerves). The discs allow some vertebral motion: extension and flexion. Individual disc movement is very limited – however, considerable motion is possible when several discs combine forces.
- 22. Divisions of the Skeleton
- 24. Part of skeleton system • Ligaments are the stretchy bands which bind the bones to prevent dislocations and limit the joint’s movements. The bones are hence held in position and controlled in movement by the ligaments. • Tendons are the fibrous structures which connect the muscle to the bone. • Cartilages are the tough, smooth shiny substances which cover the end of each bone. They help reduce friction and cushion the bones against jolts. The cartilage - coated bone-ends are kept apart by a thin film of slippery fluid (called synovial fluid) which works like a lubricant. Between the bones, in a narrow space, is the joint “cavity,” which gives us freedom of movement.
- 25. Articulations An articulation, or joint, is where two bones come together. In terms of the amount of movement they allow, there are three types of joints: immovable, slightly movable and freely movable.
- 26. Articulations Immovable joints, In these joints, the bones come in very close contact and are separated only by a thin layer of fibrous connective tissue. The sutures in the skull are examples of immovable joints
- 27. Articulations Slightly movable joints, A slightly movable joint (amphiarthrosis) is an articulation between bones in which the motion is limited due to either fibrous tissue or cartilage. Slightly movable joints, have a cushion of cartilage in between the bones, with the bones resting on these beds of cartilage. This cushion of cartilage stops the bones from rubbing together.
- 28. Articulations Freely movable joints, Also known as synovial joints, these joints have synovial fluid enabling all parts of the joint to smoothly move against each other. These are the most prevalent joints in your body. Examples include joints like the knee and shoulder.
- 29. Articulations, Types of freely movable joint There are six types of freely movable diarthrosis (synovial) joints: 1. Ball and socket joint, Permitting movement in all directions, the ball and socket joint features the rounded head of one bone sitting in the cup of another bone. Examples include your shoulder joint and your hip joint. 2. Hinge joint. The hinge joint is like a door, opening and closing in one direction, along one plane. Examples include your elbow joint and your knee joint. 3. Condyloid joint. The condyloid joint allows movement, but no rotation. Examples include your finger joints and your jaw.
- 30. Articulations, Types of freely movable joint 4. Pivot joint. The pivot joint, also called the rotary joint or trochoid joint, is characterized by one bone that can swivel in a ring formed from a second bone. Examples are the joints between your ulna and radius bones that rotate your forearm, and the joint between the first and second vertebrae in your neck. 5. Gliding joint. The gliding joint is also called the plane join. Although it only permits limited movement, it’s characterized by smooth surfaces that can slip over one another. An example is the joint in your wrist. 6. Saddle joint. Although the saddle joint does not allow rotation, it does enable movement back and forth and side to side. An example is the joint at the base of your thumb.
- 31. Articulations, Types of freely movable joint
- 32. Review: Introduction to the Skeletal System • The human skeleton is well -adapted for the functions it must perform. Functions of bones include support, protection, movement, mineral storage, and formation of blood cells. • There are two types of bone tissue: compact and spongy. Compact bone consists of closely packed osteons, or haversian system. Spongy bone consists of plates of bone, called trabeculae, around irregular spaces that contain red bone marrow. • Osteogenesis is the process of bone formation. Three types of cells, osteoblasts, osteocytes, and osteoclasts, are involved i n bone formation and remodeling. • In intramembranous ossification, connective tissue membranes are replaced by bone. This process occurs in the flat bones of the skull. In endochondral ossification, bone tissue replaces hyaline cartilage models. Most bones are formed in this manner. • Bones grow in length at the epiphyseal plate between the diaphysis and the epiphysis. When the epiphyseal plate completely ossifies, bones no longer increase in length. • Bones may be classified as long, short, flat, or irregular. The diaphysis of a long bone is the central shaft. There is an ep iphysis at each end of the diaphysis. • The adult human skeleton usually consists of 206 named bones and these bones can be grouped in two divisions: axial skeleton and appendicular skeleton. • The bones of the skeleton are grouped in two divisions: axial skeleton and appendicular skeleton. • There are three types of joints in terms of the amount of movement they allow: synarthroses (immovable), amphiarthroses (slightly movable), and diarthroses (freely movable).