Musculoskeletal System Module 4

Skeletal system Part 1 of 2 The skeletal system is the internal framework of the body. Skeletal system

Skeletal System at a Glance Functions of Skeletal System Internal framework of body Supports body Protects internal organs Point of attachment for muscles Produces blood cells Stores minerals Organs of Skeletal System Bones of the skeleton Joints The skeleton supports the body; protects internal organs; serves as a point of attachment for skeletal muscles for body movement; produces blood cells and stores minerals. The primary structures of the skeletal systems are bones and joints.

Anatomy and Physiology Bones are body organs with blood supply, nerves, and lymphatic vessels Bones are connected to each other to form skeleton Framework for the body 206 bones Each bone in the human body is a unique organ that carries its own blood supply, nerves, and lymphatic vessels.

Anatomy and Physiology Red bone marrow within bones produces blood cells Bones also: Protect vital organs Store minerals Joint Place where two bones meet Held together by ligaments Gives flexibility to skeleton Bone marrow is the site of blood cell production. A ligament holds together the joint where 2 bones meet.

Bones Also called osseous tissue One of hardest materials in body Formed from gradual process before birth called ossification Fetal skeleton is formed from a cartilage model Flexible tissue is gradually replaced by osteoblasts (immature bone cells) In adult bones osteoblasts mature into osteocytes Formation of strong bones depends on adequate supply of minerals Ossification is the gradual process of bone formation, beginning before birth. Osteoblasts are immature bone cells.

Four Shapes of Bones Long bones Short bones Flat bones Irregular bones Longer than wide Example: femur humerus Roughly as long as wide carpals tarsals Plate- shaped sternum scapula pelvis Shape very irregular vertebrae

Classification of bones by shape.

Long Bones Majority of bones in body Divided into: Diaphysis Epiphysis The majority of all the bones in a human body are long bones. Long bones are divided into the DIAPHYSIS and EPIPHYSIS

Diaphysis Central shaft Medullary cavity Open canal within diaphysis Contains yellow bone marrow Mostly fat The center of the diaphysis contains an open canal- the medullary cavity. *early in life this cavity also contains RED BONE MARROW, but as we age the Red marrow in the medullary cavity gradually convert to YELLOW BONE MARROW.

Epiphysis Wide ends of long bone Articular cartilage Covers epiphysis Distal epiphysis Proximal epiphysis Articular cartilage Covers epiphysis Prevents bone rubbing on bone The widened out ends of long bones is called the EPIPHYSYS. The distal epiphysis is at the end of the bone furthest from point of attachment. The proximal epiphysis is end of bone closest to point of attachment.

Periosteum Covers surface of bone not covered by articular cartilage Thin connective tissue membrane Contains numerous nerve and lymphatic vessels

Compact Bone Also called cortical bone Very dense and hard Outer layer of bone Found in both epiphysis and diaphysis

Cancellous Bone Also called spongy bone Found inside bone Has spaces containing red bone marrow Manufactures blood cells CAN sell us or spongy bone is found inside the bone. Spongy bone has spaces in it, giving it a sponge like appearance. These spaces contain RED BONE MARROW which manufacture most of the body's blood cells.

Components of a long bone.

Bony Processes Projection from the surface of a bone Rough processes provide place for muscle attachment Smooth rounded processes articulate with another bone in a joint Named for shape and location

Common Bony Processes Head Large smooth ball-shaped end of a long bone Condyle Smooth rounded portion at end of bone Epicondyle Projection above or on a condyle Trochanter Large rough process Tubercle Small rough process Tuberosity Read table

Bony Depressions Sinus Foramen Fossa Fissure Hollow cavity within bone Smooth opening for nerves and blood vessels Fossa Shallow cavity or depression within a bone Fissure Deep groove or slit-like opening Read table

The Skeleton Skeleton has two divisions Axial skeleton Appendicular skeleton The skeleton is divided into 2 sections the AXIAL and the APPENDICULAR skeletons.

Axial Skeleton Includes bones in: Head Neck Spine Chest Trunk The bones of the axial skeleton for the central axis foe the whole body and protects many internal organs like the heart, lungs and brain.

The Skull Is divided into two parts Cranium Facial bones Protects brain, eyes, ears, nasal cavity, and oral cavity Attachment for muscles of chewing and turning the head The skull protects the brain, eyes, ears, nasal cavity and oral cavity. The skull is the point of attachment for the muscles of chewing and turning the head.

Bones of the Skull Cranium- 1 frontal bone; 2 parietal bones; 2 temporal bones; 1 ethmoid bone; 1 sphenoid bone; 1 occipital bone Facial- 1 mandible bone; 1 maxilla bone; 2 zygomatic bones; 1 vomer bone; 1 palatine bone; 2 nasal bones; lacrimal bones Read bone names

Hyoid Bone Single U-shaped bone In neck between mandible and larynx Attachment point for swallowing and speech muscles

The Trunk Vertebral column Sternum Rib cage

The Vertebral Column Divided into five sections Cervical - 7 vertebrae of neck Thoracic - 12 vertebrae of chest Lumbar - 5 vertebrae of low back Sacrum - 5 fused vertebrae at base of spine Coccyx - 3–5 small vertebrae attached to sacrum Read table

The Rib Cage 12 pairs of ribs Attached to vertebral column at back Provides support for organs, such as heart and lungs True ribs 10 pairs attached to sternum in front Floating ribs Inferior 2 pairs No attachment in front All ribs attach to the vertebral column, but only 10 of the 12 pair attach in front to the sternum.

Appendicular Skeleton Includes bones of: Pectoral girdle Upper extremities Pelvic girdle Lower extremities The APPENDICULAR skeleton is responsible for movement. These are the bones for our lower extremities and muscles to attach to.

Upper Extremities Arm Each Arm Consists of: Humerus – upper arm Ulna – part of forearm Radius – part of forearm Carpals – wrist bones Metacarpals – hand bones Phalanges – finger bones Read list

Pelvic Girdle Also called os coxae, innominate bone, or hipbone Attaches lower extremity to axial skeleton Articulates with sacrum posteriorly Consists of: Ilium Ischium Pubis The PELVIC GIRDLE consists of the ilium, ischium, and pubis. The Pelvic girdle attaches the legs to the axial skeleton.

Lower Extremity Leg Consists of: Femur – thigh bone Patella – knee cap Tibia – shin bone Fibula – lower leg bone Tarsals – ankle bones Metatarsals – foot bones Phalanges – toe bones Read list

Joints Formed where two bones meet Also called an articulation Three types based on movement allowed between the 2 bones: Synovial Cartilaginous Fibrous Synovial Joints- Freely moving joints Most common type of joint Example is ball-and-socket joint Bones held together by ligaments Strong bands of connective tissue Some contain a bursa Sac-like structure lined with synovial membrane Joints are formed when 2 bones meet, this is also called an ARTICULATION. * Synovial joints are the most numerous in our bodies. Synovial joints are free moving.

Synovial Joints Enclosed in an elastic joint capsule Contains synovial fluid Lubricant secreted by synovial membrane Ends of bones are covered with articular cartilage The elastic joint capsule is lined with a SYNOVIAL MEMBRANE that secretes SYNOVIAL FLUID.

Cartilaginous Joints Allow slight movement Hold bones firmly in place by solid piece of cartilage Example Pubic symphysis An example of a CARTILAGINOUS JOINT is the pubic symphysis- where the left and right pubic bones meet in front of the lower abdomen. There are held in place by cartilage.

Fibrous Joints Allow almost no movement Joined by thick fibrous tissue Example Sutures of the skull Fibrous joints allow for almost no movement since the ends of the bones are joined by a think fibrous tissue which may even fuse into solid bone.

Examples of three types of joints found in the body

ASK YOURSELF …If you are practicing the terms introduced in chapter 4 in our text. ..If you are practicing the terms that will be on your pronunciation test.

REMEMBER There will be a pronunciation test due at the end of week 7 (see the course calendar for due date) practice the terms. Practice the use of the audio board in Blackboard, we will use to submit the pronunciation test- detailed directions on the syllabus.

CAUTION This PowerPoint included only half of the information for this module.

UP NEXT- Muscular system