Skeletal System Made up of bones In an

Skeletal System

• Made up of bones • In an adult there are 206 bones

Functions of the Bone 1. Framework: support body’s muscles, fat, and skin • 2. Protection a. surrounds vital organs to protect them • examples: skull surrounding brain; ribs to protect heart • 3. Levers: attach to muscles to help provide movement • 4. Production of blood cells: red and white blood cells and platelets

Formation of bones • Initially collagen fibers secreted by fibroblasts then cartilage deposits between fibers • Skeleton fully formed by 2 nd month of fetal development – all cartilage

Formation continued… • 8 th week of fetal development – ossification begins - which is mineral matter being deposited and cartilage is replaced

Formation continued… • During childhood and adolescence, ossification exceeds bone loss • During adulthood and middle age, ossification equals bone loss • After age 35, bone loss exceeds ossification

Bone Growth • Grows in length at the epiphyseal line • Grows in width by addition of bone to the surface

• Controlled by anterior pituitary gland (growth hormone)

Four major types of bones • long • short • flat • irregular

Two sections of skeleton • Axial – forms main trunk of body; composed of the skull, spinal column, ribs, and sternum

• Appendicular - forms extremities (arms and legs); composed of shoulder girdle, arm bones, pelvic girdle, and leg bones

Axial skeleton • Skull • Composed of cranial and facial bones • Cranium • Surrounds and protects the brain • Made of eight bones • • • Frontal Two parietal Two temporal Occipital Ethmoid Sphenoid

• At birth the cranium is not solid bone • Spaces called fontanels or “soft spots” allow for enlargement of skull as brain growth occurs • Fontanels are made of membrane and cartilage • Turn into solid bone by about 18 months of age

Facial Bones • Fourteen facial bones 1). Main bones a). Mandible: lower jaw b). Maxilla: two bones forming upper jaw c). Zygomatic: two cheek bones d). Nasal: five bones in upper part of nose e). Lacrimal: two bones at inner aspect of eyes f). Palatine: two bones of hard palate or roof of mouth

Sutures • areas where cranial bones have joined together

Sinuses • a. Air spaces in the bones of the skull • b. Provide strength with less weight • c. Act as resonating chambers for the voice • d. Lined with mucous membranes

Foramina • a. Openings in bones • b. Allow nerves and blood vessels to enter or leave bone

Vertebrae • Spinal column made 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 chest, attach to ribs • Lumbar: 5 vertebrae by waist • Sacrum: 5 fused bones, triangular in shape, forms dorsal part of pelvis • Coccyx: 3 -4 fused bones, called tailbone, slightly moveable

Intervertebral Disks • 1) Pads of cartilage tissue that separate vertebrae • 2) Act as shock absorbers • 3) Permit bending and twisting movements of vertebral column

Ribs • 1) 12 pairs of long slender bones • 2) Attach to thoracic vertebrae on dorsal surface of body • a) True ribs: First 7 pairs of ribs; Attach directly to sternum on front of body • b) False ribs: Next 5 pairs of ribs; first 3 pairs attach to cartilage of rib above • c) Floating ribs: last two pairs of false ribs; no attachment on front of body

Ribs continued…

Sternum • Breastbone 1) Consists of three parts a) Manubrium: upper region b) Gladiolus: body or center area c) Xiphoid process: small piece of cartilage at bottom 2. Two clavicles attach to the manubrium by ligaments 3. Ribs attach to sternum with costal cartilages to form a cage that protects the heart and lungs

Appendicular Skeleton

Shoulder Girdle (aka Pectoral Girdle) • Two clavicles • Two scapula's (scapulae)

Upper Extremities • Humorous: upper arm • Radius: thumb side of forearm • Ulna: Little finger side of forearm • Carpals (8): wrist bones • Metacarpals (5): hand bones • Phalanges (14): finger bones

Pelvic Girdle • Two os coxae: contains the acetabulum (hip socket) • Join with sacrum on dorsal part of body • Join together at a joint called the pubic symphysis on ventral part of body

• Each os coxae made of three bones that are fused or joined • Ilium • Ischium • Pubis

Obturator foramen • 1) Opening between the ischium and pubis • 2) Allows for passage of nerves and blood vessels to and from the legs

Lower Extremities • Femur: thigh bone • Patella: kneecap • Tibia: medial bone in lower leg, shin bone • Fibula: Lateral bone of lower leg, small than tibia • Tarsals (7): ankle bones (calcaneous is heel bone) • Metatarsals (5): bones forming instep of foot • Phalanges (14): toe bones

Joints (a. k. a. Articulations) • Synarthrotic • Immovable • Cranium • Amphiarthrotic • 1)Limited movement • 2)pubic symphysis, vertebral joints, sacroiliac joint • Diarthrotic • Freely movable • Gliding: wrist • Pivot: between radius and ulna • Ball and socket: hip, shoulder • Hinge: elbow

Bone Composition, Shape & Bone Marrow Types of Bone Based on Composition 1. Compact Bone • Very dense • Stress bearing • Femur, tibia, humorous

2. Cancellous Bone • Light, spongy. • Low stress areas where weight of bone would be a problem. • Found at ends of long bones, ribs, sternum, hips, vertebrae, cranium.

Classification of Bones According to Shape Long Bones (extremities): levers 1. Parts of long bones: • Epiphysis: at ends, cancellous bone • Diaphysis: shaft, compact bone • Medullary Canal: • Cavity in diaphysis • Filled with yellow marrow

4. Endosteum: • Membrane that lines medullary canal • Keeps yellow marrow intact • Produces some bone growth

5. Periosteum: • Tough membrane covering outside of bones • Contains blood and lymph vessels • Contains osteoblasts: special cells that form new bone tissue • Necessary for bone growth, repair, and nutrition

6. Articular cartilage: • Thin layer covers the epiphysis • Acts as a shock absorber when two bones meet to form a joint

7. Long bones include: Femur Tibia Fibula Humorous Ulna Radius Clavicle

Short Bones • Cubed shaped • Allow flexible movement • Cancellous bone covered by compact bone

Short Bones include:

Flat Bones • Flat plates • Protect vital organs • Provide broad surface area for muscle attachment

Flat bones include: Facial Bones Scapula Cranial Bones Sternum

Irregular Bones • Peculiarly shaped to provide support & protection • Allows flexibility Vertebra Ribs Hip bones Ear bones Hyoid bone

Sesamoid Bone • Extra bones found in certain tendons. Patella

Bone Growth • Grow in length at epiphyseal line • Grow in width by addition of bone to surface • Controlled by anterior pituitary (growth hormone)

Growth Hormone Dysfunction • Dwarfism: hypofunction • Giantism: hyperfunction • Acromegaly: hyperfunction after puberty; enlarges bones of hands, feet, and face.

Bone Marrow • Yellow Marrow • Inside medullary canal • Mainly fat cells

Bone Marrow continued… • Red Marrow 1. Found in certain bones such as: 1. Vertebrae 2. Ribs 3. Sternum 4. Cranium 5. Proximal ends of humorous & femur 2. Produces RBC, platelets & some WBC 3. Important in the manufacture of blood & is involved with the body’s immune response 4. Used in diagnosing blood diseases 5. Given as transplants to people with defective immune systems

Diseases & Disorders of the Skeletal System

Arthritis • Inflammation of the bones at the joints; usually with pain and changes in bone structure. Two Main Types of Arthritis: • Osteoarthritis • Rheumatoid Arthritis

Osteoarthritis • Chronic disease that occurs with aging • Symptoms: joint pain, stiffness, aching, limited ROM • Rx: Rest, heat/cold applications, aspirin, anti-inflammatory medications, steroid injections, special exercises

Rheumatoid Arthritis Chronic inflammatory disease of connective tissues and joints Three times more common in women Often begins between ages 35 -45 Progressive attacks cause scar tissue formation and atrophy of bone and muscle tissue resulting in permanent deformity and immobility • Rx: Rest and prescribed exercise • Anti-inflammatory medications: aspirin and steroids • Surgery or arthroplasty to replace damaged joints such as hips or knees • •

Bursitis • Inflammation of bursae (small fluid-filled sacs surrounding joints) • Frequently affects shoulders, elbows, hips, or knees • Symptoms: severe pain, limited movement, accumulation of fluid in joint • Rx: • Pain medications and rest • Injections of steroids and anesthetics into joint • Aspiration (withdrawal of fluid with a needle) of joint • Physical Therapy to preserve joint motion

Fractures • Involve a crack or break in a bone • Several Types of Fractures

Fractures--Greenstick Bone is bent and splits causing a crack or incomplete break; common in children

Fractures-Simple Complete break with no damage to skin

Fractures--Compound Break in bone that ruptures through skin; increased chance of infection

Fractures--Impacted Broken bone ends jam into each other

Fractures-Comminuted Bone fragments or splinters into more than two pieces

Fractures-Spiral Severe twisting of a bone causes one or more breaks; common in skiing and skating accidents

Fractures-Depressed Broken piece of skull bone moves inward; common with severe head injuries

Fracture-Colles Breaking and dislocation of the distal radius that causes a characteristic bulge at the wrist; caused by falling on an outstretched hand

Reduction: • Process by which bone is put back into proper alignment • Closed reduction: position bone in alignment, usually with traction, and apply cast or splint to maintain position • Open reduction: surgical repair of bone, and sometimes the insertion of pins, plates, and other devices

Dislocation • Bone is forcibly displaced from a joint • Frequently occurs in shoulders, fingers, knees, and hips • Reduced and immobilized with splint, cast, or traction

Sprain • Twisting action tears ligaments at a joint • Common sites are wrists and ankles • Symptoms: pain, swelling, discoloration, limited movement • Rx: Rest and elevation • Immobilization with elastic bandage or splint • Cold applications

Osteomyelitis • Inflammation of bone usually caused by pathogenic organism • Pathogen causes formation of abscess within bone and accumulation of pus in medullary canal • Symptoms: pain at site, swelling, chills, fever • Rx: antibiotics for infection

Osteoporosis • Metabolic disorder with increased porosity or softening of bones • Etiology • Deficiency of hormones, especially estrogen in females • Prolonged lack of calcium in diet • Sedentary lifestyle • Loss of calcium and phosphate causes bones to become porous, brittle, and prone to fracture • Bone density tests lead to early detection and preventative treatment • Rx: • • Increased intake of calcium and vitamin D Exercise Medications to increase bone mass Estrogen replacement

Ruptured Disk • Also called a herniated or slipped disk • Intervertebral disk ruptures or protrudes out of place and causes pressure on the spinal nerve • Most common site is lumbar-sacral area; can occur anywhere on spinal column • Symptoms: severe pain, muscle spasm, impaired movement and/or numbness • Rx: • • • Pain, anti-inflammatory, and muscle relaxant medications Rest and traction Physical therapy and massage therapy Chiropractic treatment Heat or cold applications Laminectomy: surgical removal of the protruding disk for severe cases

Spina Bifida • Congenital defect in which the vertebrae fail to unite in midline • May require surgery • Severity may cause paralysis

Abnormal curvatures of spinal column • 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 or abnormal curvatures: • poor posture • congenital defects • structural defects of vertebrae • malnutrition • degeneration of vertebrae • Rx: • Therapeutic exercises, firm mattresses and braces • Surgical repair for severe deformities

Growth Hormone Disorders • Dwarfism: hypofunction • Gigantism: hyperfunction

Acromegaly: hyperfunction after puberty; enlarges bones of hands, feet, face