The Skeletal System. How many bones are in the body? 206

The Skeletal System

How many bones are in the body?

206

There are 5 main functions of bones

1. Framework- support muscles

2. Protection- surrounds vital organs, etc.

3. Levers- attach to muscles to provide movement

4. Produce blood cells- red, white, and platelets

5. Storage- calcium

Parts of long bones

• Long bones are bones of extremities

• Periosteum-tough membrane covering outside of bones

»Contains osteoblasts which are special cells that form new bone tissue

Spongy Bone

• Located at the ends of long bones

• Has many small, open spaces that make bones lightweight

• Filled with a substance called marrow – yellow composed of fat cells – red produces red blood cells

Cartilage

• Smooth, slippery, thick layer of tissue

• Covers the ends of bones

• Does not contain blood vessels or minerals

• Flexible and acts as a shock absorber

• Makes movement easier by reducing friction

Two sections of a skeleton

1. Axial Skeleton

2. Appendicular Skeleton

Axial Skeleton

• Forms main trunk of the body

• Composed of the skull, spinal column, ribs, and sternum

Appendicular Skeleton

• Forms extremities (arms and legs)

• Composed of 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

• At birth, the cranium is not solid bone– Spaces are called

fontanels “soft spots” that allow for brain growth

– Turns into solid bone by 18 months

• Composed of 8 bones

1.Frontal

2.Two parietal

3.Two temporal

4.Occipital

5.Ethmoid

6.Sphenoid

Facial bones

• Fourteen facial bones– Main bones of the face

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

Sutures

• Areas where cranial bones have joined together

Sinuses

• Air spaces in the bones of the skull

• Act as a resonating chamber for the voice

• Lined with mucous membranes

Foramina (Foramen)

• Openings in the bones

• Allow nerves and blood vessels to enter or leave bone

Vertebrae

Spinal column is composed of 26 bones called vertebrae

• Protects the spinal cord

• Provides support for head and trunk

Main sections of vertebral column:

• Cervical: 7 neck vertebrae

• Thoracic: 12 vertebrae in back of chest, attached to ribs

• Lumbar: 5 vertebrae by waist

• Sacrum: 1 large vertebra on back of pelvic girdle

• Coccyx: 1 fused vertebra called “tailbone”

Intervertebral disks

• Pads of cartilage tissue that separate vertebrae

• Act as shock absorbers

• Permit bending and twisting movements of vertebral column

Ribs (costae)

• 12 pairs of long, slender bones

• Attach to thoracic vertebrae on dorsal surface of body

• True ribs– First 7 pairs of ribs– Attach directly to sternum on front of body

• False ribs– Next 5 pairs of ribs– First three pairs attach to cartilage of rib

above

• Floating ribs– Last 2 pairs of false ribs– No attachment on front of body

Sternum

• “Breastbone”• Consists of three parts

– Manubrium or upper region– Gladiolus: body or center area– Xiphoid process: small piece of cartilage at

bottom (landmark for chest compressions)

• Two clavicles attach to the manubrium by ligaments

• Ribs attach to sternum with cartilage

Shoulder or pectoral girdle

• Two clavicles or “collarbones”• Two scapulas 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 ulna to allow the hand to turn freely

• Ulna: larger bone of lower arm that contains a projection called the olecranon process at upper end, forming “elbow”

Wrist and hands

• Carpals: 8 wrist bones on each hand

• Metacarpals: 5 bones on each hand to form palm

• Phalanges:– 14 bones on each hand to form a thumb and

fingers– 3 on each finger– 2 on each thumb

Pelvic Girdle

• Made of two os coxae or “hip bones”

• Join with sacrum on dorsal part of body

• Join together at a joint called the symphysis pubis on ventral part of body

• Each os coxae is made of three bones that are fused or joined– Ilium

– Ischium

– Pubis

• Contains 2 recessed areas or sockets called acetabulum that provide for attachment of smooth rounded head of the femur

• Obturator foramen– Opening between the ischium and pubis

– Allows for passage of nerves and blood vessels to and from the legs

Bones of the legs

• Femur: Thigh bone

• Patella: Knee cap

• Tibia: Larger weight bearing bone of lower leg. Commonly called the “shin bone”

• Fibula: slender smaller bone of the lower leg that attaches to the proximal end of the tibia

Ankles and Feet

• Tarsals: 7 bones of ankles

• Calcaneous- Heel bone

• Metatarsals: 5 bones forming instep of foot

• Phalanges1. 14 bones on each foot

2. Form the toes

3. 2 on each great toe

4. 3 on each of other toes

Joints

• Joints – areas where 2 or more bones

join together

• Ligaments:– connective tissue bands that

hold long bones together

3 Main Types of Joints

1. Diarthrosis or synovial

• Freely movable• Ex: “Ball-and-

socket joints” of the shoulder and hip

• Ex: Hinge joints of the elbow and knee

2. Amphiarthrosis• Slightly movable• Ex: is the attachment of the ribs to the thoracic

vertebrae• Ex: symphysis pubis or joint between two pelvic

bones

3. Synarthrosis• Immovable• Examples are the suture joints of the cranium

Diseases and Abnormal Conditions

ArthritisGroup of diseases involving an

inflammation of the joints

Two main types:

1. Osteoarthritis

– Chronic disease that occurs with aging

– Symptoms: Joint pain, stiffness, aching, limited range of motion

– Treatment: rest, heat/cold applications, ASA, anti-inflammatory medications, steroid injections, special exercises

2. Rheumatoid – Chronic inflammatory disease of joints– Three times more common in women– Often begins between age 35-45– Scar tissue forms and atrophy of bone and

muscle occurs– Permanent deformity and immobility Treatment:

» Rest and prescribed exercise» Anti-inflammatory medications: ASA and

steroids» Surgery, or arthroplasty to replace damaged

joints such as hips or knees

Bursitis

Inflammation of bursae, (small fluid-

filled sacs surrounding joints)

• Bursitis frequently affects shoulders, elbows, hips, or knees

• Symptoms:• Severe pain, limited movement, accumulation of

fluid in joint

• Treatment:• Pain medications and rest• Injections of steroids and anesthetics into joint• Aspiration of joint• Physical therapy to preserve joint motion

Fractures

A crack or break in a bone

Types of fractures:

• Greenstick: bone is bent and splits, causing a crack or an incomplete break: common in children

• Simple: complete break with no damage to skin

• Compound: break in bone that ruptures through skin; increased chance of infection

Types of fractures, cont…• Impacted: broken fragments; or splinters into

more than two pieces• Spiral: severe twisting of a bone causing one

or more breaks: common in skiing and skating accidents

• Depressed: broken piece of skull bone moves inward

• Colles: breaking and dislocation of the distal radius that causes a characteristic bulge at the wrist, caused by falling with outstretched hand.

Compound Fracture

Greenstick

Simple Fracture

Spiral Fracture

Impacted Fracture

Depressed

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, at times, insertion of pins, plates, and other devices.

ORIF (Open Reduction Internal Fixation)

Disclocation

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

• Treatment: rest and elevations, 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

• Treatment: antibiotics for infection

Osteoporosis

Metabolic disorder with increased porosity or softening of bones

• Causes– Deficiency of hormones, especially estrogen in

females– Prolonged lack of calcium in diet– Sedentary lifestyle

• Tx: Increased intake of Ca and Vit D, exercise, medications such as Fosamax and Citracel, Estrogen replacement

Ruptured disk (herniated)

Interbertebral disk ruptures or protrudes out of place and causes pressure on the

spinal nerve

Most common site is lumbrosacral area: can occur anywhere on spinal column

• Symptoms: severe pain, muscle spasm, impaired movement, and/or numbness

• Treatment: – Pain, anti-inflammatory, and muscle relaxant

medications– Rest and traction– Physical and Massage therapy– Chiropractic treatment– Heat or cold applications– Laminectomy: surgical removal of the protruding

disk for severe cases– Severe cases, spinal fusion can be performed to

insert a screw/rod

Abnormal curvatures of spinal column

• Kyphosis: “hunchback” bowing of thoracic area

• Scoliosis: side to side, or lateral curvature of spine

• Lordosis: swayback, inward curvature of lumbar spine

Kyphosis

Scoliosis

Lordosis

• Causes of abnormal curvatures of spine:• Poor posture• Congenital defects• Structural defects• Malnutrition

• Treatment:• Therapeutic exercises, firm mattresses,

and braces• Surgical repair for severe deformities