skeletal system. made up of bones in an adult there are 206 bones
TRANSCRIPT
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. Protectiona. 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 2nd month of fetal development – all cartilage
Formation continued…
• 8th 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 jawb). Maxilla: two bones forming upper jawc). Zygomatic: two cheek bonesd). Nasal: five bones in upper part of nosee). Lacrimal: two bones at inner aspect of eyesf). 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 bottom2. Two clavicles attach to the manubrium by ligaments3.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): levers1. 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 FibulaTibia
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
Ear bones
RibsVertebra
Hyoid bone
Hip bones
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. Vertebrae2. Ribs3. Sternum4. Cranium5. Proximal ends of humorous & femur
2. Produces RBC, platelets & some WBC3. Important in the manufacture of blood & is involved with the body’s immune response4. Used in diagnosing blood diseases5. 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--CompoundBreak 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-SpiralSevere twisting of a bone causes one or more breaks; common in skiing and skating accidents
Fractures-DepressedBroken piece of skull bone moves inward; common with severe head injuries
Fracture-CollesBreaking 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