Download skeletal system

SKELETAL SYSTEM
• The bodily system that consists of
the bones, their associated
tendons, ligaments, and
cartilages. Teeth are also
considered part of the skeletal
system.
•
206 BONES IN HUMAN BODY
FUNCTIONS OF BONES
SUPPORTS THE BODY
PROTECTS THE BODY
PRODUCES BLOOD CELLS
STORES MINERALS
SKULL
28 skull bones (8 cranial, 14 facial, and 6
ear bones)
the horseshoe-shaped hyoid bone of the
neck
VERTEBRAL (spinal) COLUMN
The spinal column (or vertebral column) extends from the
skull to the pelvis and is made up of 26 individual bones
termed vertebrae. The vertebrae are stacked on top of
each other group into four regions:
Cervical Vertebrae : 7 Vertebrae nearest neck.
Atlas (C1) supports the skull and Axis (C2)
Thoracic Vertebrae : 12 Vertebrae nearest chest
– Ribcage is attached to thoracic vertebrae
Lumbar Vertebrae : 5 Vertebrae – responsible for
most weight bearing and biomechanical stress.
Sacral Spine : Sacrum – 1 (5 fused bones)
Coccyx – 1 (5 fused bones)
Cervical Vertebrae (C1 – C7)
The cervical spine is further divided into two parts; the
upper cervical region (C1 and C2), and the lower cervical
region (C3 through C7). C1 is termed the Atlas and C2 the
Axis.
Atlas (C1)
The Atlas is the first cervical vertebra and therefore
abbreviated C1. This vertebra supports the skull. Its
appearance is different from the other spinal vertebrae.
The atlas is a ring of bone made up of two lateral masses
joined at the front and back by the anterior arch and the
posterior
arch.
Axis (C2)
The Axis is the second cervical vertebra or C2. It is a blunt
tooth–like process that projects upward. It is also referred
to as the ‘dens’ (Latin for ‘tooth’) or odontoid process. The
dens provides a type of pivot and collar allowing the head
and atlas to rotate around the dens.
Thoracic Vertebrae (T1 – T12)
The thoracic vertebrae increase
in size from T1 through T12
The rib cage is joined to the thoracic
vertebrae. At T11 and T12, the ribs do
not attach and are so are called "floating
ribs." The thoracic spine's range of
motion is limited due to the many
rib/vertebrae connections
Lumbar Vertebrae (L1 – L5)
The lumbar vertebrae graduate in size
from L1 through L5. These vertebrae
bear much of the body's weight and
related biomechanical stress
Sacral Spine
The Sacrum is located behind the
pelvis. Five bones (abbreviated S1
through S5) fused into a triangular
shape, form the sacrum. The sacrum fits
between the two hipbones connecting
the spine to the pelvis. The last lumbar
vertebra (L5) articulates (moves) with
the sacrum. Immediately below the
sacrum are five additional bones, fused
together to form the Coccyx (tailbone).
RIBS
A bony framework that protects the heart, lungs, and
other underlying organs. The rib-cage is made up of
three groups of bones – the sternum (breastbone), 12
pairs of ribs, and 12 thoracic vertebrae.
All of the ribs are attached to the spinal column, but
only the top seven pairs connect to the sternum.
These are called true ribs and are joined to the
sternum by strips of cartilage known as costal
cartilage. The next three pairs of ribs are known as
false ribs. Instead of attaching directly to the sternum,
they all attach to the lowest true rib. The last two pairs
of ribs are called floating ribs and attach only to the
spine.
CLAVICLE AND SCAPULA
(pectoral girdle)
The pectoral girdle is the set of
bones which connect the upper
limb to the axial skeleton on
each side. It consists of the
clavicle and scapula in humans
CLAVICLE – “collarbone”
SCAPULA – “shoulder blade”
HUMERUS, RADIUS, ULNA
• The humerus is the (upper) arm bone. It
joins with the scapula above at the
shoulder joint (or glenohumeral joint) and
with the ulna and radius below at the
elbow joint. **The ULNA is the bone that
runs from the point of elbow to point
outside of wrist.
CARPALS, METACARPALS, AND
PHALANGES
• The hand has 27 bones
PELVIS
• The pelvis is a basin shaped cavity
bordered by the pelvic girdle and sacrum,
containing and protecting the bladder,
rectum and reproductive organs. Pelvic, as
pertains to the pelvis. The structure of the
vertebrate skeleton supporting the lower
limbs in humans and the hind limbs or
corresponding parts in other vertebrates.
FEMUR, TIBIA, FIBULA
• Femur – Largest Bone in Body (Weight
Bearing)
• Tibia – “Shin Bone” (Weight Bearing)
• Fibula – Helps muscles and tendons
attach – non-weight bearing
• Patella – “knee cap”
TARSALS, METATARSALS,
PHALANGES
• The foot has 26 bones
THE WHOLE PICTURE
INTERESTING FACTS
The hand has 27 bones, the foot has 26 and the face
has 14.
The longest bone in your body, the femur (thigh
bone), is about 1/4 of your height. The smallest is the
stapes (or stirrup) in the ear which is about 1/10 of
an inch.
Humans and giraffes have the same number of
bones in their necks.
Most of the bones in the body are in the hands.