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Skeletal System. HST III Spring 2009. The skeletal system :. Is made up of organs called bones Provides a framework that supports the body’s muscles, fat, and skin Provides protection by surrounding vital organs Forms levers where muscles attach to provide movement
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Skeletal System HST III Spring 2009
The skeletal system: • Is made up of organs called bones • Provides aframeworkthat supports the body’s muscles, fat, and skin • Provides protectionby surrounding vital organs • Forms leverswhere muscles attach to provide movement • Produces red and white blood cellsand platelets (hemopoiesis or hematopoiesis) • Storesmost of the calcium supply of the body in addition to phosphorus and fats
Long Bones • Refers to the bones of the arms and legs, or extremities
Parts ofLong Bones • Diaphysis– long shaft • Epiphysis– the extremity or end • Medullary canal– cavity within the diaphysis, • Yellow marrow– fills the medullary cavity; storage area for fat cells; contains cells that form leukocytes or white blood cells
Parts ofLong Bones • Endosteum – membrane that lines the medullary canal and keeps the yellow marrow intact; produces some bone growth • Red marrow – found in certain bones, such as the vertebrae, ribs, sternum, cranium, and the proximal ends of the humerus and femur; produceserythrocytes(red blood cells),thrombocytes(platelets), andsomeleukocytes(white bloodcells).
Red Marrow • Because it is important in the manufacturing of blood cells, and is involved with the body’s immune response, it is used to diagnose blood diseases (ex. leukemia), and is sometimes transplanted in people with defective immune systems.
Parts of Long Bones • Periosteum – tough membrane that covers the outside of bone; contains blood vessels, lymph vessels, and osteoblasts (special cells that form new bone tissue); necessary for bone growth, repair and nutrition • Articular cartilage – covers the epiphysis and acts as a shock absorber when two bones meet to form a joint
The Skeletal System is divided into two sections: • Axial skeleton – forms the main trunk of the body and is composed of the skull, spinal column, ribs, and breastbone • Appendicular skeleton – forms the extremities and is composed of the shoulder girdle, arm bones, pelvic girdle, and leg bones
The Skull: • Composed of the cranial and facial bones • Spherical structure that surrounds and protects the brain
The Skull: • Made of eight bones • Frontal (1) • Parietal (2) • Temporal (2) • Occipital (1) • Ethmoid (1) • Sphenoid (1)
Fontanels • Soft spaces (soft spots), present at birth, that allow for the enlargement of the skull as brain growth occurs • Made up of membrane and cartilage, and turn into solid bone by approximately 18 months of age.
There are 14 Facial Bones • Mandible (lower jaw); (1) • Maxilla (upper jaw); (2) • Zygomatic (cheek); (2) • Lacrimal (inner aspect of eyes); (2) • Nasal (5) • Palantine (hard palate or roof of mouth); (2)
Sutures • Are areas where the cranial bones have joined together
Sinuses • Air spaces in bones of the skull that act as resonating chambers for the voice; lined with mucous membranes
Foramina • Openings in bones that allow nerves and blood vessels to enter or leave the bone
Vertebrae • Compose the spinal column (26-vertebrae) • Protects the spinal cord and provides support for the head and trunk • Divided into 5 sections: 1) cervical, 2) thoracic, 3) lumbar, 4) sacral, and 5) coccyx
Vertebrae • Cervical (neck); (7) • Thoracic (chest); (12) • Lumbar (waist); (5) • Sacrum (back of pelvic girdle); (1) • Coccyx (tailbone); (1)
Intervertebral Disks • Pads of cartilage tissue that separate the vertebrae • Act as shock absorbers and permit bending and twisting movements of the vertebral column
Ribs (Costae) • 12 pairs of ribs • Attach to the thoracic vertebrae on the dorsal surface of the body • The first 7 pairs are calledtrue ribsbecause they attach directly to the sternum, or breastbone, on the front of the body • The next 5 pair are calledfalse ribs, and attach to cartilage extending from the rib above • The last 2 pairs of ribs are calledfloating ribsbecause they have no attachment on the front of the body
Sternum • Breastbone • Consist of 3 parts: 1)Manubrium( upper region), 2)Gladiolus(body), and theXiphoidprocess (a small piece of cartilage at the bottom)
Two collarbones, orclaviclesare attached to the manubrium by ligaments. Theribsare attached to the sternum with costal cartilages to form a “cage” that protects the heart an lungs.
The Pectoral (Shoulder) Girdle Is made up of: • 2 clavicles (collarbones) and 2 scapulas (shoulder bones) • The scapula is utilized in the attachment of the upper arm bones
Bones of each arm include: • 1humerus(upper arm) • 1radius(lower arm on thumb side) that rotates around theulnato allow the hand to turn freely • 1ulna(larger bone of lower arm)with a projection called theolecranon processat its upper end, forming the elbow
Bones of each arm include: • 8 carpals (wrist) • 5 metacarpals (palm of hand) • 14 phalanges (three on each finger, and two on the thumb)
The Pelvic Girdle is: • Made up of 2 os coxae (coxal, or hip bones) • Join the sacrum on the dorsal part of the body • Fuse together a joint called the symphysis pubis on the ventral part of the body
Pelvic Girdle • Each coxae is made up of 3 fused sections: 1) ilium, 2) ischium, and 3) the pubis • Contains 2 recessed areas or sockets called acetabula, which provide for the attachment of the smooth rounded head of the femur (upper leg bone)
Pelvic Girdle • An opening between the ischium and pubis, called the obturator foramen, allows for the passage of nerves and blood vessels to and from the legs
Each leg consists of: • 1 femur (thigh bone) • 1 patella (kneecap) • 1 tibia (larger weight bearing bone of the lower leg; shin bone) • 1 fibula (slender, smaller bone of the lower leg that attaches to the proximal end of the tibia
Each leg consists of: • 7 tarsals (ankle bones) • 5 metatarsals (instep of foot) • 14 phalanges (2 on the great toe and 3 on each of the other 4 toes) • The heel is formed by the large tarsal bone called the calcaneous
Joints • Areas where two or more bones join together • Connective tissue bands, called ligaments, help hold long bones together at joints • There are 3 main types of joints: 1) Diarthrosis or synovial, 2) Amphiarthrosis, and 3) Synarthrosis
Diarthrosis or Synovial Joints • Freely movable • Examples include the ball and socket joints of the shoulder, hip, or the hinge joints of the elbow and knee
AmphiarthrosisJoints • Slightly movable • Examples include the attachment of the ribs to the thoracic vertebrae and the symphysis pubis
SynarthrosisJoints • Immovable • Examples include the suture joints in the cranium
Arthritis • A group of diseases involving inflammation of the joints • 2 main types: 1) Osteoarthritis and 2) Rheumatoid arthritis
Osteoarthritis • The most common form of arthritis • Chronic disease • Usually occurs as a result of aging • Frequently affects the hips and knees
Rheumatoid Arthritis • Chronic inflammatory disease • Affects the connective tissues and joints • 3 times more common in women than in men • Onset often occurs between ages 35-45 • Progressive attacks can cause scar formation and atrophy of bone and muscle tissue which result in permanent deformity and immobility
Bursitis • Inflammation of the bursae, which are small, fluid-filled sacs surrounding the joints • Frequently affects the shoulders, elbows, hips, or knees
Fracture • Is a crack or break in a bone • There are 8 types of bone fractures
Greenstick Fracture • The bone is bent and splits • Causes a crack or incomplete break • Common in children
Simple or Closed Fracture • Complete break of the bone with no damage to the skin
CompoundorOpen Fracture • Bone breaks and ruptures through the skin • Increased chance of infection
Impacted Fracture • Broken bone ends jam into each other
Comminuted Fracture • Bone fragments or splinters into more than two pieces
Spiral Fracture • Bone twist, resulting in one or more breaks • Common in skiing and skating accidents
Depressed Fracture • A broken piece of skull bone moves inward; • Common in severe head injuries
Colles Fracture • Breaking and dislocation of the distal radius that causes a characteristic bulge at the wrist • Caused by falling on an outstretched hand
Before a fracture can heal, the bone must be put back into its proper alignment. This process is called reduction.
Closed Reduction • Positioning the bone in correct alignment, usually with traction, and applying a cast or splint to maintain the position until the fracture heals
Open Reduction • Involves surgical repair of the bone • In some cases special pins, plates, or other devices are surgically implanted to maintain correct position of the bone