Skeletal System 7.4 Skeletal system is made of organs that are called bones In the adult, there are 206 bones

Function of Bones 1. Framework: support body’s muscles, fat, and skin 2. Protection: surround vital organs, for example, skull surrounds the brain and the ribs protect the heart and lungs 3. Levers: attach to muscle to help provide movement 4. Produce blood cells: produce red and white blood cells and platelets, a process called hemopoiesis or hematopoiesis 5. Storage: store most of calcium supply of the body in addition to phosphorus and fats

Parts of Long Bones Long bones are bones of the extremities, the arms and legs Diaphysis- long shaft Epiphysis- two extremities or ends Medullary canal is a cavity within the diaphysis filled with yellow marrow, mainly a storage area for fat cells, contains cells that form leukocytes (white blood cells) Red Marrow is found in certain bones such as vertebrae, ribs, sternum, cranium, and proximal ends of humerus and femur; produces erythrocytes (red blood cells) thrombocytes (platelets), and some leukocytes Bone marrow is important in the manufacture of blood and is involved with the body’s immune response

Two Sections of the Skeleton 1. Axial skeleton Forms the main trunk of the body Composed of the skull, spinal column, ribs, and sternum 2. Appendicular skeleton Forms extremities, arms and legs Composed of the shoulder girdle, arm bones, pelvic girdle,and leg bones

Skull Composed of cranial and facial bones Cranium- spherical structure that surrounds and protects the brain Made of Eight bones: 1 frontal bone, 2 parietal bones, 2 temporal bones, 1 occipital bone, 1 ethmoid bone, and 1 sphenoid bone At birth the cranium is not solid bone, spaces called Fontanels or soft spots, allow for enlargement of the skull as brain growth occurs Fontanels are made of membrane and cartilage and turn into solid bone by about 18 months

Facial Bones Mandible; lower jaw Maxilla; two bones forming upper jaw Zygomatic; two cheek bones Nasal; five bones in upper part of nose Lacrimal; two bone at inner aspect of eyes Palatine; two bone of hard palate or roof of mouth

Sutures; areas where cranial bones have joined together Sinuses; air spaces in the bones of the skull; provide strength and act as resonating chamber for the voice, lined with mucus membranes Foramina; openings in bones that allow nerves and blood vessels to enter or leave bones

Vertebrae Spinal column composed of 26 bones called vertebrae Protect the spinal cord Provide support for head and trunk Main Sections: Cervical; 7 neck vertebrae Thoracic; 12 vertebrae in back of the chest attach to ribs Lumbar; 5 vertebrae near waist Sacrum; 1 large vertebra on back of pelvic girdle Coccyx; 1 fused vertebra called the tail bone Intervertebral Discs; pads of cartilage tissue that separates vertebrae, acts as shock absorbers, permits bending and twisting movement of vertebral column

Ribs of costae 12 pairs of long slender bones Attach to thoracic vertebrae on dorsal surface of body True Ribs; first 7 pairs of ribs that attach directly to sternum on front of body False Ribs; next 5 pairs of ribs; first 3 pairs attach to cartilage of rib above them (#7); lat 2 pairs are called floating ribs because they have no attachment on the front of the body

Sternum Commonly called the breastbone Consist of three parts Manubrium or upper region Gladiolus; body or center region Xiphoid process; small piece of cartilage at bottom 2 clavicles attach to the manubrium by ligaments Ribs attach to sternum with costal cartilages to form a cage that protects the heart and lungs

Shoulder or Pectoral Girdle 2 clavicles or collar bones 2 scapular or shoulder bones Scapula provides for attachment of upper arm bone

Bones of the Arm Humerus; upper arm bone Radius; lower arm bone on thumb side that rotates around the ulna to allow the hand to turn freely Ulna; larger bone of lower arm that contains a projection called the olecranon process at the upper end forming the elbow Carpals; 8 wrist bones on each hand Metacarpals; 5 bones one each hand to form palm Phalanges; 14 bones on each hand to form a thumb and fingers, 3 on each finger and 2 on each thumb

Bones of Pelvic Girdle Made of 2 os coxae (coxal or hip bones) that join with sacrum on dorsal part of body Joined together at a joint called the symphysis pubis on the ventral part of the body Each os coxae is made of 3 bones that are fused of joined Ilium, Ischium, Pubis

Bones of the Legs Femur; thigh bone Patella; kneecap Tibia; larger weight bearing bone of lower leg commonly called the shin bone, medial surface Fibula; slender smaller bone of the lower leg that attaches to the proximal end of the tibia, lateral surface Tarsals; 7 bones of ankles, calcaneous is the heel bone Metatarsals; 5 bones forming the instep of foot Phalanges; 14 bones on each foot, form the toes, 2 on each great toe and 3 on each of other toes

Joints Areas where 2 or more bones join together Ligaments; connective tissue banks that hold long bones together There are 3 main types of joints 1. Diarthrosis or synovial; freely movable, ball and socket joints of the shoulder and hip, hinge joints of the elbow and knee 2. Amphiarthrosis; slightly movable, attachment of ribs to thoracic vertebrae and symphysis pubis, the joint between the 2 pelvic bones 3. Synarthrosis; immovable, suture joints of the cranium

Diseases 1. Arthritis- inflammation of the joints 2 main types Osteoarthritis; chronic disease that occurs with aging, symptoms include joint pain, stiffness, aching, limited range of motion, treatment; rest, heat/cold, aspirin, anti inflammatory medications Rheumatoid: chronic inflammatory disease of connective tissue and joints, 3 times more common in women, progressive attacks cause scar tissue formation and atrophy of bone and muscle which results in permanent deformity and immobility, treatment ; rest, anti inflammatory medication, aspirin, surgery

2. Bursitis; inflammation of the bursae, small fluid filled sacs surrounding joints Frequently affects shoulder, elbow, hip, knees Severe pain and limited movement with accumulation of fluid in joints Treatment includes pain medication and rest, steroids, aspiration of fluid, physical therapy to preserve joint motion

Fractures Involves a crack or break in a bone 1. greenstick; bone is bent and splits causing a crack or incomplete break, common in children 2. simple; complete break with no damage to the skin 3. compound; break in bone that ruptures through the skin 4. impacted; broken bone ends jam into each other 5. comminuted; bone fragments or splinters into more than 2 pieces

Dislocation- bone is forcibly displaced from a joint, immobilized with splint, cast, or traction Sprain- twisting action tears ligament at a joint, rest and elevation, immobilize with bandage or splint

Abnormal Curvatures Kyphosis- hunchback or rounded bowing of the back at the thoracic area Scoliosis- side to side or lateral curvature of spine Lordosis- swayback or abnormal inward curvature of lumbar vertebrae Causes are poor posture, congenital defects, structural defects of vertebrae, malnutrition