Chapter 6 Skeletal System
Synarthroses
(immovable) joints
1 ethmoid
(located between the eyes) forms the principal part of the nasal cavity and helps form part of the eye orbit.
Diarthroses
(movable) joint
Amphiarthroses
(partially movable) joints
1 sphenoid
(which resembles a bat) is considered the key bone of the cranium; all other bones of the cranium connect to it.
5 nasal bones
2 bridge of the nose [your glasses sit on this bone]; 1 is the vomer bone, 2 inferior concha bone
Axial skeleton
22 bones of the skull, 14 facial bones, Spinal column (vertebra), Cervical 7 vertebrae, Thoracic 12 vertebrae, Lumbar 5 vertebrae, Sacrum 5 fused bones, Coccyx 4 fused bones, Ribs (12) and sternum
Bone is made up of
35% organic material, 65% inorganic mineral salts, and water.
transverse processes
Above the foramen protrude two winglike bony structures called
osteocytes (from the Greek word osteon, meaning "bone")
Bones are formed of microscopic cells called, mature bone cell
Joints
Called articulations Points of contact between two bones
Bursa sacs
Closed sacs with a synovial lining
Periosteum
Covering on the outside of the bone Necessary for bone growth, repair and nutrition
ossification
During the eighth week of embryonic development blank begins, mineral matter starts to replace previously formed cartilage, creating bone
Red marrow
Ends of long bones Manufactures red blood cells and some white blood cells
shaft, or diaphysis
Hollow cylinder of compact bone
Skeletal System Function
It allows movement and anchorage of muscles. Muscles that are attached to the skeleton are called skeletal muscles. Upon contraction, these muscles exert a pull on a bone and so move it. In this manner, bones play a vital part in body movement, serving as passively operated levers. Ligaments are fibrous bands that connect bones to bones and cartilage and serve as support for muscles. Joints are also bound together by ligaments. Tendons are fibrous cords that connect muscles to bone.
Skeletal System Function
It is the site for hematopoiesis (hem-ah-toe-poy-EE-sis), that is, the formation of blood cells. Stem cells in the red marrow tissue of the bone differentiate into red blood cells, white blood cells, and platelets. In an adult, the ribs, sternum, and bones of the pelvis contain red marrow. Red bone marrow at the ends of the humerus and femur are plentiful at birth but gradually decrease as we age.
Skeletal System Function
It protects the soft and delicate internal organs. For example, the cranium protects the brain, the inner ear, and parts of the eye. The ribs and breastbone protect the heart and lungs; the vertebral column encases and protects the spinal cord.
Skeletal System Function
It provides mineral storage. Bones are a storage depot for minerals such as calcium and phosphorus. In case of inadequate nutrition, the body is able to draw upon these reserves. For example, if the body's blood calcium level dips below normal, the bone releases the necessary amount of stored calcium into the bloodstream. When calcium levels exceed normal, calcium release from the skeletal system is inhibited. In this way the skeletal system helps maintain blood calcium homeostasis.
Skeletal System Function
It supports body structures and provides shape to the body.
Bone types
Long bones Flat bones Irregular bones Short bones
Appendicular skeleton lower extremities
Pelvic girdle: Ilium, ischium and pubis, Upper leg: Femur, Lower leg: Tibia, fibula and patella Ankle: 7 tarsal bones, Foot: Metatarsal and phalanges (toes)
gradually decrease as we age
Red bone marrow
Appendicular skeleton upper extremities
Shoulder girdle, 2 clavicles and 2 scapulae, Arm, Humerus, radius, ulna, Hand, Carpals, metacarpals, and phalanges (fingers)
Axial skeleton
Skull, spinal column, ribs, sternum, and hyoid bone
5 functions of the skeletal system
Support, Protect, Movement, Storing, Acting
Articular capsule
Synovial membrane (lining), Synovial fluid, Synovial cavity (area between 2 articular, cartilages
C1 through C7.
The cervical vertebrae are also known as
1 mandible
is the lower jaw, the only movable bone in the face
Arthritis
The joint pain and stiffness associated with arthritis is most noticeable in the morning, after a period of rest. There are at least 20 different types, the most common being rheumatoid arthritis, osteoarthritis, and gout
the body
The large, solid part of the vertebra is known as
fracture, or break
The most common traumatic injury to a bone, there is swelling due to injury and bleeding tissues
bone collagen
The organic part derives from a protein, a fibrous material
the spinous process (spine) and the articular processes
The roof of the foramen contains
paranasal sinuses
The skull contains large spaces within the facial bones
vertebrae
The spine consists of small bones
Appendicular skeleton
Upper and lower extremities
Cartilage,
a connective tissue, is also found at the ends of certain bones in adults, providing a smooth surface for adjacent bones to move against each other
Traction
a pulling force is used to hold the bones in place (used for fractures of the long bone).
Ball-and-socket joints
allow the greatest freedom of movement. Here, one bone has a ball-shaped head that nestles into a concave socket of the second bone. Our shoulders and hips have ball-and-socket joints.
Lumbar vertebrae
are located in the back. They have large bodies that bear most of the body's weight. They are also known as L1 through L5.
Thoracic vertebrae
are located in the chest area. They articulate with the ribs. The thoracic vertebrae are also known as T1 through T12.
Cervical vertebrae
are located in the neck area
Gliding joints
are those in which nearly flat surfaces glide across each other, as in the vertebrae of the spine. These joints enable the torso to bend forward, backward, and sideways, as well as rotate.
Pivot joints
are those with an extension rotating in a second, arch-shaped bone. The radius and ulna are pivot joints. Another example is the joint between the atlas that supports the head, and the axis that allows the head to rotate.
ossification
blank due to mineral deposits continues through childhood. As bones ossify, they become hard and more capable of bearing weight.
A typical vertebra contains three basic parts:
body, foramen, and (several) processes
When pressure is applied to a bone, the flexible organic material prevents
bone damage
during embryonic development
cartilage is deposited between the fibers
mineral elements of bones resist
crushing or bending under pressure
epiphysis
each end of the long bone, Covered by articular cartilage
2 palatines
form the hard palate of the mouth.
2 zygomatics
form the prominence of the cheek.
2 parietals
form the roof and sides of the cranium.
2 temporals
form the sides of the cranium and house the ears.
1 frontal
forms the forehead, the roof of the nasal cavity, and the eye orbits of the cranium.
vomer bone
forms the lower part, or midline, of the nasal septum
1 occipital
forms the posterior or base of the cranium and contains the foramen (faw-RAY-men) magnum. The foramen magnum is the large opening on the inferior portion of the occipital bone where the spinal cord passes through to connect to the brain.
medullary canal
in the center Yellow bone marrow Endosteum (lining of the marrow canal) Haversian canal: carries blood vessels that nourish bone cells
Circumduction
includes flexion, extension, abduction, and adduction
embryonic skeleton
initially consists of collagenous protein fibers secreted by the osteoblasts (primitive embryonic cells)
A stress or hairline fracture
is a tiny crack in the bone that typically occurs from overuse. This fracture can be quite painful but usually heals itself.
Hammertoe
is a toe that is curled (flexed) due to a bend in the middle joint of one or more toes. It may be caused by shoes that are too tight or heels too high. The longest of the four smaller toes may be forced against the front of the shoe, resulting in an unnatural bending of the toe with pain and pressure in the affected area. Proper footwear with a deep toe box and flexible material covering the toes may be helpful, as can using a special device ordered by a physician to wear in the shoe to help position the toe.
sacrum
is a wedge-shaped bone formed by five fused bones. It forms the posterior pelvic girdle and serves as an articulation point for the hips.
coccyx
is also known as the tailbone. It is formed by four fused bones.
Sprain
is an injury to a joint caused by any sudden or unusual motion, such as "turning the ankle." The ligaments are either torn from their attachments to the bones or torn across, but the joint is not dislocated. A common athletic injury is to the ligament of the knee, sometimes called an anterior cruciate ligament (ACL) injury.
Adduction
is movement toward the midline
A closed/simple fracture
is one in which the bone is broken, but the broken ends do not pierce through the skin to form an external wound
RICE
is the acronym for rest, ice, compression, and elevation, the recommended immediate treatment for bone, joint, and muscle injuries
Flexion
is the act of bringing two bones closer together, which decreases the angle between the two bones
Extension
is the act of increasing the angle between two bones, which results in a straightening motion
Skeletal System
is the bone framework within the body. It is composed of 206 bones
The atlas
is the first cervical vertebra, It articulates, or is jointed, with the occipital bone of the skull. This permits us to nod our heads
An open/compound fracture
is the most serious type of fracture, where the broken bone ends pierce and protrude through the skin. This can provide a site for infection of the bone and neighboring tissues
Abduction
is the movement of an extremity away from the midline (an imaginary line that divides the body from head to toe)
A greenstick fracture
is the simplest type of fracture. The bone is partly bent, but it never completely separates. The break is similar to that of a young, sap-filled woodstick, where the fibers separate lengthwise when bent. Such fractures are common among children because their bones contain flexible cartilage
Whiplash injury
is trauma to the cervical vertebrae, usually the result of an automobile accident. The force generated by a car's abrupt change in speed or direction whips the head, putting tremendous strain on the cervical spine and neck muscles. Treatment depends on the extent of the injury.
2 lacrimals
make up part of the eye orbit at the inner angle of the eye; they contain the tear ducts.
inferior concha bone
make up the side walls of the nasal cavity).
2 maxillae
make up the upper jaw.
inorganic portion of bone is made from
mineral salts such as calcium phosphate, calcium carbonate, calcium fluoride, magnesium phosphate, sodium oxide, and sodium chloride. These minerals give bone its hardness and durability.
Hinge joints
move in one direction or plane, as in the knees, elbows, and outer joints of the fingers.
rotation
movement allows a bone to move around one central axis. This type of pivot motion occurs when you turn your head from side to side (just say no)
Dislocation
occurs when a bone is displaced from its proper position in a joint. This may result in the tearing and stretching of the ligaments. Reduction or return of the bone to its proper position is necessary, along with rest to allow the ligaments to heal.
A comminuted fracture
occurs when the bone is splintered or broken into many pieces that can become embedded in the surrounding tissue
Closed reduction
the bony fragments are brought into alignment by manipulation, and a cast or splint is applied.
foramen
the central opening for the spinal cord is
pronation
the forearm turns the hand so the palm is downward or backward
hematopoiesis
the formation of blood cells
supination
the palm is forward or upward
in adults
the ribs, sternum, and bones of the pelvis contain red marrow.
axis
the second cervical vertebra is the odontoid process, which forms a pivot on which the atlas rotates; this permits us to turn our heads.
fontanel
the soft spot on a baby's head
Open reduction
through surgical intervention, devices such as wires, metal plates, or screws are used to hold the bone in alignment and a cast or splint may be applied.
Females bones grow
until about 18 years of age
Males bones grow
until about 20-21 years of age
intervertebral discs
vertebrae are are separated from each other by pads of cartilage tissue called, also these discs serve as cushions between the vertebrae and act as shock absorbers. These discs become thinner as we age, which accounts for a loss in height.
Growth stops
when all the epiphyseal cartilage (also known as the growth plate) is ossified