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