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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.
Support
The skeleton is the
framework of the
body, it supports
the softer tissues
and provides points
of attachment for
most skeletal
muscles.
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.
Assisting in
Movement
Skeletal
muscles are
attached to
bones, therefore
when the
associated
muscles contract
they cause
bones to move.
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.
Production of
Blood Cells
The red
bone
marrow
inside some
larger
bones
produces
blood cells.
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.
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.
Axial Skeleton
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
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.
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."
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.
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
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.
Appendicular
Skeleton
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.
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.
Pelvic Girdle
Os coxae (2) is
commonly called
the hip bone. It is
formed from a
fusion of three
bones (ilium,
ischium, and
pubis).
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)
Ossification
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.
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.
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.
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.
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.
Osteoporosis
“porous bones”
Over time, bone mass, and therefore bone
strength, is decreased
Bones become fragile and break easily
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.
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
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.
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.
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.
Enchondromas
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.
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.
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
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
Osteomyelitis
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.
Osteomyelitis
Osteomyelitis is a serious
condition, requiring aggressive
treatment to prevent spread of
your infection and to save the
affected bone
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.
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
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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