Skeletal System

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Skeletal System
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Functions of the Skeleton

• The skeletal system is a living, dynamic system,
  with networks of infiltrating blood vessels.
• Living mature bone is about 60 calcium compounds
  and about 40 collagen.
• All humans were born with over 300 bones but some
  bones, such as those in the skull and lower
  spine, fuse during growth, thereby reducing the
  number.
• Although mature bones consist largely of calcium,
  most bones in the skeleton of vertebrates,
  including humans, began as cartilage.

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Support

• The skeleton is the framework of the body, it
  supports the softer tissues and provides points
  of attachment for most skeletal muscles.

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Protection

• The skeleton provides mechanical protection for
  many of the body's internal organs, reducing risk
  of injury to them.

• For example, cranial bones protect the brain,
  vertebrae protect the spinal cord, and the
  ribcage protects the heart and lungs.

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Assisting in Movement

• Skeletal muscles are attached to bones, therefore
  when the associated muscles contract they cause
  bones to move.

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Storage of Minerals

• Bone tissues store several minerals, including
  calcium and phosphorus. When required, bone
  releases minerals into the blood - facilitating
  the balance of minerals in the body.

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Production of Blood Cells

• The red bone marrow inside some larger bones
  produces blood cells.

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Storage of Chemical Energy

• With increasing age some bone marrow changes from
  'red bone marrow' to 'yellow bone marrow'.
• Yellow bone marrow consists mainly of adipose
  cells, and a few blood cells. It is an important
  chemical energy reserve.

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Connections with other systems

• Skeletal System holds the structure of body
  which allows the muscular system to move the
  body.
• Skeletal System has bone marrow which forms
  blood. This complements the cardiovascular
  system.
• The Nervous System sends messages for movement or
  reactions in the body which relates back to the
  skeletal and muscular system for movement.
• The Respiratory System is related because oxygen
  is needed to the cardiovascular system for
  movement in the body. This relates back to the
  muscular and skeletal system.
• The Immune System is related because white blood
  cells and T cells with immunity functions are
  sent made and released in the bone marrow.
• The Digestive System is related because minerals
  like calcium and vitamin D are separated through
  digestion and sent throughout the body through
  the cardiovascular system. These minerals will
  reach the skeletal system.
• The Lymphatic System is related because bone
  marrow is considered a lymph organ. Also many
  immunity cells released from the marrow will rest
  in the thymus which is also part of the lymphatic
  system.

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Axial Skeleton
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Skull

• Cranium (8)
• Frontal bone (1) forms forehead and superior
  surface of orbits
• Parietal bones (2) found on both sides of the
  skull, posterior to the frontal bone
• Occipital bone (1) forms the posterior and
  inferior portions of the cranium
• Temporal bones (2) found below the parietal
  bones, contributing to the sides and base of the
  cranium
• Sphenoid bone (1) forms part of the floor of
  the cranium
• Ethmoid bone (1) found anterior to the sphenoid
  bone, consisting of two honeycombed masses of
  bone

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Skull

• Facial (14)
• Maxillary bones (2) forms the floor and medial
  portion of the orbit rim, walls of the nasal
  cavity, and the anterior roof of the mouth (hard
  palate)
• Zygomatic bones (2) found on each side of the
  skull, articulating with the frontal bone and the
  maxilla to complete the lateral wall of the
  orbit. Along the lateral margin, each gives rise
  to a slender bony extension that curves laterally
  and posteriorly to meet a process from the
  temporal bone, together forming the zygomatic
  arch.
• Palatine bones (2) form the posterior surface
  of the hard palate. The superior surfaces of each
  horizontal portion contribute to the floor of the
  nasal cavity. The superior tip of the vertical
  portion of each forms a small portion of the
  inferior wall of the orbit.
• Mandible (1) forms the lower jaw.
• Lacrimal bones (2) located within the orbit on
  its medial surface and articulate with the
  frontal, ethmoid, and maxillary bones.
• Nasal bones (2) form the bridge of the nose and
  articulate with the superior frontal bone and the
  maxillary bones.
• Inferior nasal conchae (2) project from the
  lateral walls of the nasal cavity.
• Vomer (1) The inferior margin articulates with
  the paired palatine bones and, with the ethmoid
  bone, supports a prominent partition that forms
  part of the nasal septum.

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Skull

• Middle Ear (Auditory Ossicles)
• Malleus (2) attaches at three points to the
  interior surface of the tympanum (tympanic
  membrane)
• Incus (2) attaches the malleus to the inner
  bone (stapes)
• Stapes (2) seated within the "oval window."

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• Hyoid Bone U-shaped and hangs below the skull,
  suspended by ligaments from the styloid processes
  of the temporal bones, and serves as a base for
  muscles associated with the tongue and larynx.

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Vertebral Column

• Cervical vertebrae (7) extend from the head to
  the thorax
• Thoracic vertebrae (12) extend from the
  cervical portion to the lumbar section
• Lumbar vertebrae (5) continues from the
  thoracic vertebrae to the sacrum
• Sacrum (1) forms the posterior wall of the
  pelvis
• Coccyx (1) is one mass of four to five small
  coccygeal vertebrae that have fused into one,
  commonly called the tailbone

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Thoracic Cage

• True ribs (14) consist of 7 pairs of bone that
  reaches the anterior body wall. They are
  connected to the sternum by separate
  cartilaginous extensions (costal cartilages).
• False ribs (10) consist of ribs 8-12 that do
  not attach directly to the sternum. The last two
  pairs are floating ribs because they have no
  connection with the sternum.
• Sternum (1) has three parts in the adult. The
  manubrium articulates with the clavicles of the
  appendicular skeleton and with the cartilages of
  the first pair of ribs. The body, or gladiolus,
  ends at the xiphoid process.

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Appendicular Skeleton
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Pectoral Girdle

• Scapula (2) is commonly called the shoulder
  blade. It is supported and positioned by the
  skeletal muscles. The scapula has no bony or
  ligamentous bonds to the thoracic cage, but it is
  extremely important for muscle attachment.
• Clavicle (2) is commonly called the collarbone.
  It articulates with the manubrium of the sternum,
  and is the only direct connection between the
  pectoral girdle and the axial skeleton.

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Upper Limbs

• Humerus (2) extends from the scapula to the
  elbow.
• Radius (2) lies along the lateral side (or thumb
  side) of the forearm.
• Ulna (2) forms the medial support of the forearm.
  
• Carpals (16) consist of 8 pairs of bones of the
  wrist and, composed of
• four proximal bones (scaphoid, lunate, triangular
  or triquetral, and pisiform)
• four distal bones (trapezium, trapezoid,
  capitate, and hamate).
• Metacarpals (10) consist of 5 pairs of bones that
  articulate with the distal carpal bones forming
  the palm of the hand.
• Phalanges (28) consist of 14 pairs of finger
  bones. Four fingers contain three phalanges while
  the pollex (thumb) has only two.

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Pelvic Girdle

• Os coxae (2) is commonly called the hip bone. It
  is formed from a fusion of three bones (ilium,
  ischium, and pubis).

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Lower Limbs

• Femur (2) is commonly called the thigh bone. It
  is the longest, strongest, and heaviest bone in
  the body. Distally, it articulates with the tibia
  at the knee joint. The head (epiphysis)
  articulates with the pelvis at the acetabulum.
• Tibia (2) is commonly called the shinbone. It is
  the large medial bone of the leg, attached to the
  patella by a ligament.
• Fibula (2) parallels the lateral border of the
  tibia.
• Patella (2) is the knee cap.
• Tarsals (14) consist of 7 pairs of bones (talus,
  calcaneus, navicular, cuboid, and the 1st, 2nd,
  and 3rd cuneiform bones). Only the talus
  articulates with the tibia and fibula.
• Metatarsals (10) support the sole of the foot and
  numbers I to V from medial to lateral with the
  distal ends forming the ball of the foot.
• Phalanges (28) have the same arrangement as with
  the fingers and thumb only with the toes and
  great toe (hallux)

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Ossification
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Ossification

• The ossification process is divided into two main
  phases.
• In the first stage of ossification, the cartilage
  is covered with a layer of cells called
  osteoblasts, which form other bone cells. Once
  this encasement of osteoblasts has formed, the
  cartilage is slowly eaten away and the bone cells
  replace the cartilage. These bone cells are
  arranged in concentric circles, which causes the
  bone to be very hard. The mature cells, called
  osteocytes, store the calcium of the body which
  can be released or extracted from the bloodstream
  as needed. After the bone completes its formation
  process, the mature bone is encased in a membrane
  of connective tissue called the periosteum.

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Long Bone

• This bone is much longer than it is wide.
• consists of a long shaft, the diaphysis, with two
  ends or extremities, the epiphyses.
• The outer part of a long bone is made of compact
  bone.
• medullary cavity is in the interior part of the
  long bone. This is the central cavity of bone
  shafts where red bone marrow and yellow bone
  marrow, adipose tissue, is stored.
• The functions of the long bone include strength,
  structure, and mobility. They are very strong
  dense bones.

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Joint Articulation

• A joint is the location at which two or more
  bones make contact.
• There functions include movement and mechanical
  support.
• joints can also be classified functionally, by
  the degree of mobility they allow.

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Joint Articulation

• Examples of classifications
• Synarthrosis - permits little or no mobility.
  Example Skull
• Amphiarthrosis - permits slight mobility. Example
  vertebrae
• Diarthrosis - permits a variety of movements.
  Example shoulder, hip knee, elbow.

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Orthopaedic Surgery

• Orthopaedics is a medical specialty that deals
  with the musculoskeletal system and uses medical,
  physical, and surgical methods to restore
  function lost as a result of injury or disease.
  An orthopaedist, also called an orthopaedic
  surgeon, is a highly skilled physician trained in
  a variety of medical and surgical techniques that
  will be used during your surgery.

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Osteoporosis
porous bones

• Over time, bone mass, and therefore bone
  strength, is decreased
• Bones become fragile and break easily

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Types of Osteoporosis

• Primary osteoporosis is from an acceleration of
  the normal aging process.
• Secondary osteoporosis is caused by other disease
  processes or prolonged use of certain medications
  that result in bone loss.

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Who is Affected?

• Most often, older people and women after
  menopause are affected by osteoporosis.
• Women are five times more likely than men to
  develop the disease.
• Women have smaller, thinner bones than men and
  they lose bone mass more rapidly after menopause
  when they stop producing the bone-protecting
  hormone, estrogen

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Symptoms of Osteoporosis

• People cannot feel their bones getting weaker.
  They may not know that they have osteoporosis
  until they actually break a bone.
• Women can lose up to 20 of their bone mass in
  the five to seven years after menopause, making
  them more susceptible to osteoporosis.

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Treatments of Osteoporosis

• There is no cure for osteoporosis, but there are
  medications to prevent or treat it
• Fosamax / Boniva / Actonel Alendronate,
  Ibandronate and Risedronate are approved for the
  prevention and treatment of osteoporosis in
  postmenopausal women and for the treatment of
  osteoporosis in men.

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Five Steps to Bone Health Osteoporosis
Prevention

• Eat healthy
• Get your daily recommended amounts of Calcium and
  Vitamin D
• Exercise
• Engage in regular weight-bearing and muscle
  strengthening exercise.
• Maintain a healthy lifestyle
• Avoid smoking and excessive alcohol consumption.
• Talk to your healthcare provider
• Talk to your healthcare provider about bone
  health.
• Get tested
• Have a bone density test and take medication when
  appropriate.

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Enchondromas
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Enchondromas

• One type of benign cartilage tumor that appears
  on the inside of the bone
• These tumors usually begin and grow in
  childhood, then stop growing but remain present
  throughout adulthood.
• They are often found in patients between 10 and
  20 years of age.

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Enchondromas

• These tumors are very common and often occur in
  the small bones of the hand and feet.
• They are the most common tumor of the hand.
• They also occur in the long bones of the upper
  arm and thigh.

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Symptoms of Enchondromas

• These tumors are usually painless.
• They are usually found during an X-ray evaluation
  of another problem in the same area.
• When these tumors appear in the hands or feet, or
  in multiple lesions, they can deform the bone.
• Symptoms enlarged fingers, pathologic fracture,
  or deformities.
• On an X-ray, they appear as a dark hole in the
  bone

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Treatments of Enchondromas

• Nonsurgical Treatment
• Most enchondromas require no treatment at all
• Some surgeons think that tumors without symptoms
  do not need to be removed
• Surgical Treatment
• When enchondromas are treated surgically, it is
  usually with scraping out and filling of the
  cavity with bone graft or other filling
  substances. Although they can come back, most of
  them will not

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Osteomyelitis
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Osteomyelitis

• Osteomyelitis is the medical term for an
  infection in a bone.
• Infections can reach a bone by traveling through
  your bloodstream or spreading from nearby tissue.
  
• Infections can also begin in the bone itself if
  trauma exposes your bone to germs.
• Bone infections commonly affect the long bones of
  your body, such as your leg bones and upper arm
  bone, as well as your spine and pelvis.

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Osteomyelitis

• Osteomyelitis is a serious condition, requiring
  aggressive treatment to prevent spread of your
  infection and to save the affected bone

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Types of Osteomyelitis

• Osteomyelitis is divided into several types
  depending on where an infection begins and where
  it occurs.
• Infections that travel through the bloodstream.
  Infections that travel through the bloodstream
  affect only a small portion of adults, but affect
  the majority of children with osteomyelitis.
  Infections may begin as a urinary tract
  infection, and spread through the blood to a
  bone.
• Infections that occur after injury or surgery.
  Bone infections can occur after trauma such as
  broken bones that break the skin or open wounds
  to the surrounding skin and muscles.
• Infections in people with poor circulation.
  Osteomyelitis that occurs in people with poor
  circulation, such as those with diabetes, usually
  begins with minor scrapes or cuts on the feet.
  Poor circulation impairs the body's response to
  infection.
• Infection in the bones of the spine.
  Osteomyelitis that occurs in the spine most
  commonly affects older adults and usually starts
  with an infection in the bloodstream, though it
  can also occur from trauma or surgery. A number
  of infections can cause vertebral osteomyelitis,
  including skin infections, respiratory tract
  infections, urinary tract infections, infections
  in the mouth, and infections in areas where you
  receive drug injections.

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Symptoms of Osteomyelitis

• Acute Osteomyelitis
• Fever that may be abrupt
• Irritability or lethargy in young children
• Pain in the area of the infection
• Swelling, warmth and redness over the area of the
  infection
• Chronic Osteomyelitis
• Warmth, swelling and redness over the area of the
  infection
• Pain or tenderness in the affected area
• Chronic fatigue
• Drainage from an open wound near the area of the
  infection
• Fever, sometimes

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Treatments of Osteomyelitis

• Surgery
• Drain the infected area.
• Remove diseased bone and tissue.
• Restore blood flow to the bone.
• In order to stabilize the affected bone and the
  new graft, you may need to have metal plates,
  rods or screws inserted into the bone.
• Antibiotics
• If your doctor suspects you have chronic
  osteomyelitis, he or she works to determine
  exactly what microorganism is causing the
  infection before prescribing antibiotics. Your
  doctor uses a bone biopsy or a piece of bone
  removed during surgical treatment to determine
  what's causing the infection.

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Worksheet Answers
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The End