HSI 1.02 Skeletal System...The Skeletal system is made of organs that are called bones THERE ARE 206 BONES IN THE ADULT SKELETON. Bone Types Long Bones-found in the arms and legs Flat

Skeletal System

BONESInternet resource site:

http://www.innerbody.com/htm/body.html

Unit Objectives

� A. List five functions of bones� B. Label the main parts of a bone on a diagram of a

long bone� C. Name the two divisions of the skeletal system and

the main groups of bones in each division� D. Identify the main bones of the skeleton� E. Compare the three classifications of joints by

describing the type allowed by each� F. Describe at least four diseases of the skeletal

system

Reference

Diversified Health Occupations, 6th edition, Unit 6:4

Body Structures & Functions, 10th edition, chapter 5

Skeletal System

� The Skeletal system is made of organs that are called bones

� THERE ARE 206 BONES IN THE ADULT SKELETON

Bone Types

� Long Bones-found in the arms and legs

� Flat Bones-examples are the bones of the skull and the ribs

� Irregular bones-represented by the bones of the spinal column

� Short Bones-appear cubelike in shape such as bones of the wrist and ankle

Parts of long bones

� Definition: Long bones are bones of the extremities (arms & legs)

� Diaphysis: shaft of long bone that is a hollow cylinder of hard, compact bone.

� Epiphysis: at each end of the diaphysis

� Medullary canal: cavity in diaphysis that is filled with yellow marrow

� Yellow Marrow: inside medullary canal; mainly fat cells

Parts of long bones

� Endosteum� Membrane that lines medullary canal� Keeps the yellow marrow intact� Produces some bone growth

� Red marrow� Found in certain bones such as vertebrae, ribs, sternum,

cranium, and proximal ends of humerous and femur� Produces red blood cells, platelets, and some white blood

cells� Bone marrow is important in the manufacture of blood and is

involved with the body’s immune response� Used in diagnosing blood diseases� Given as transplants to people with defective immune systems

Parts of the long bones

� Periosteum� Tough membrane covering outside of bones� Contains blood and lymph vessels� Contains osteoblasts: special cells that form new bone

tissue� Necessary for bone growth, repair and nutrition

� Articular cartilage� Thin layer covers the epiphysis� Acts as a shock absorber when two bones meet to

form a joint

Parts of the long bone

� Spongy Bone� The medullary canal is

surrounded by compact or hard bone. Where less strength is needed in the bone, some of the hard bone is dissolved away leaving spongy bone

Two sections of skeleton

� Axial skeleton� Forms the main trunk

of the body� Composed of the skull,

spinal column, ribs and sternum

Two sections of skeleton

� Appendicular skeleton� Forms extremities

(arms and legs)� Composed of shoulder

girdle, arm bones, pelvic girdle, and leg bones

Parts of the skeleton

� Axial skeleton

� Appendicular Skeleton

Skull

� Composed of cranium and facial bones

� Collectively, there are 22 bones in the skull

� Cranium� Spherical structure that

surrounds and protects the brain

� Made of eight bones� Frontal-forms the forehead� Two Parietal-form the roof

and sides of the skull� Two temporal-house the ears� Occipital-forms the base of

the skull and contains the foramen magnum

� Ethmoid-forms the nasal septum

� Sphenoid-all other bones connect to it (considered the key bone of the skull)

Skull

� Cranium continued� At birth, the cranium is

not solid bone� Spaces called

fontanels or “soft spots” allow for the enlargement of the skull as brain growth occurs

� Fontanels are made of membrane and cartilage

� Turn into solid bone by about 18 months of age

Skull

� Cranial bones are thin and slightly curved. During infancy, these bones are held snugly together by an irregular band of connective tissue called a suture. As a child grows, this connective tissues ossifies and turns into hard bone.

Skull

� 14 facial bones� Nasal

� 5 bones total� 2 are nasal bones that

form the bridge of your nose

� 1 is the volmer bone which forms the lower part of the nasal septum

� 2 are inferior concha bones which make up the side walls of the nasal cavity

SkullFacial Bones continued

� Maxilla (2)� Make up the upper jaw

� Lacrimal (2)� In the inner aspect of the

eyes; contain tear ducts� Zygomatic (2)

� Form the prominence of the cheek

� Palatine (2)� Form the hard palate of

the mouth� Mandible (1)

� Is the lower jaw and the only movable bone in the face

Skull

� Sinuses are air spaces in the bones of the skull. They are lined with mucous membranes

� Foramina are openings in bones that allow nerves and blood vessels to enter or leave the bone

Spinal Column/vertebra

� The spine, or vertebral column, is strong and flexible.

� It supports the head and provides for the attachment of the ribs.

� The spine also encloses the spinal cord of the nervous system.

Spinal Column/vertebra

� The spine consist of small bones called vertebrae.� Vertebrae are separated from each other by pads of

cartilage called intervertebral disks.� The disk serve as cushions between the vertebrae

and act as shock absorbers.� During our lifetime, these disk become thinner, which

is why we lose height as we age.� The vertebral column is divided into 5 sections

Spinal Column/vertebrae

� 1) Cervical vertebrae are located in the neck area.� There are 7 cervical vertebrae� The atlas is the first cervical vertebrae

� The atlas articulates (is jointed) with the occipital bones of the skull

� The atlas permits us to nod our head

� The axis is the second cervical vertebrae� The axis is the odontoid process which forms a

pivot on which the atlas rotates; this permits us to turn our heads


� 2) Thoracic vertebrae are located in the chest area� There are 12 thoracic vertebrae

� 3) Lumbar vertebrae� There are 5 lumbar vertebrae

� 4) Sacrum� Wedge shaped vertebrae formed by 5 fused bones.

Forms the posterior pelvic girdle and serves as an articulation point for the hips

� 5) Coccyx� The tailbone. It is formed by 4 four bones


� The spinal nerves enter and leave the spinal cord through the openings (foramen) between the vertebrae.

� The spine is curved, not straight. A curved spine has more strength than a straight one would have.

� Before birth, the thoracic and sacral region are convex curves. Once the infant learns to hold his head up, the cervical region become concave. When a child learns to walk, the lumbar region also becomes concave. This completes the 4 normal curves of the adult spine.


A typical vertebra contains three basic parts:

Bodyforamenprocesses

The large, solid part of the vertebrae is known as the body; the central opening is known as the foramen.


� Above the foramen protrude two wing like bony structures called transverse processes.

� The roof of the foramen contains the spinal process (spine) and the articular process.

Ribs and sternum

� The thoracic area of the body is protected and supported by thoracic vertebrae, ribs and sternum.

Ribs and Sternum

� The sternum (breastbone) is divided into three parts:� The upper region (manubrium)� The body� Xiphoid process which is the lower

cartilaginous part

Attached to each side of the upper region of the sternum are the two clavicles (collar bones). These are attached by ligaments

Ribs and sternum

� Seven pairs of costal cartilages join 7 pairs of ribs directly to the sternum.

� These are known as True Ribs� The next 3 pairs are false ribs because they

are attached by costal cartilage to the seventh rib instead of the sternum.

� The last 2 pairs of ribs are floating ribs because they are not connected to costal cartilage nor the sternum.

Appendicular Skeleton

� Includes the upper extremities: shoulder girdles, arms, wrists, and hands

� Includes the lower extremities: hip girdle, legs, ankles, and feet.

� There are 126 bones in the Appendicular skeleton

Shoulder Girdle

� Also called the pectoral girdle

� Consists of 4 bones: two curved clavicles (collar bones) and two triangular scapulae (shoulder bones)

� The scapulae permit the attachment of muscles that assist in arm movement and serve as a place of attachment for the arms.

� The clavicles help brace the shoulders and prevent excessive forward motion

Arm

� The bones in the arms consist of the humerus, radius and the ulna.

� The humerus is the only bone in the upper arm.� It is the second largest bone in the body� The upper end of the humerus has a smooth,

round surface called the head, which articulates with the scapula.

Arm

� The forearm consists of two bones, the radius and the ulna

� The radius is the bone that runs up the thumb side of the forearm. � Its name derives from

the fact that it can rotate around the ulna.

� This allows the hand to rotate freely and with great flexibility

Arm

� The ulna is the largest bone in the forearm. � It is far more limited than the radius� At its upper end, it produces a projection

called the olecranon process, forming the elbow

� The olecranon process is known as the “funny bone”.

� The olecranon process articulates with the humerus

Hand

� The hand is a remarkable piece of skeletal engineering

� Contains more bones per size than any other part of the body

� Collectively, the hand has 27 bones

Hand

� Wrist bones (carpals)� Consist of eight small bones arranged in two

rows held together by ligaments � There is only slight lateral movement of the

carpals

Hand

� The hand consist of two parts: the palmer surface and the fingers

� The palmer surface had 5 metacarpal bones� The fingers have 14 phalanges (singular,

phalanx)� Each finger has three phalanges except for

the thumb which only has two� There are hinge joints between each phalanx,

allowing the fingers to be bent easily� The thumb is the most flexible finger.

Pelvic Girdle

� Made up of two os coxae (coxal or hip bones)

� Join with sacrum on the dorsal part of the body

� Join together at a joint called the symphysis pubis

� Serves as an area of attachment for the bones and muscles of the legs

Pelvic Girdle

� Each os coxa made of three bones that are fused or joined� Ilium� Ischium� Pubis

The female pelvis is much wider than the male pelvis for childbirth

Pelvic Girdle

� Contains two recessed areas or sockets called acetabulums that provide for attachment of bones of the leg

� Obturator foramen� Opening between the Ischium and pubis� Allows for passage of nerves and blood

vessels to and from the legs

Legs

� Femur-thigh bone� Longest & strongest

bone in the body� Patella-kneecap

� Flat, triangular bone found in front of the knee joint

� Tibia-long supporting bone of lower leg medial surface

� Fibula-smaller bone of the lower leg, lateral surface

Ankle & Foot

� Tarsals� 7 bones in ankle� Calcaneous is the heel

bone and the largest of the ankle bones

� Metatarsals� 5 bones forming the

instep (arch) of the foot

� Phalanges� 14 bones on each foot� Form the toes

Joints

� Defined as areas where two or more bones join together

� Ligaments: connective tissue bands that hold long bones together

� Joints (articulations)

Joints

� Arthroscopy: examination of a joint using arthroscope with fiber optic lens. Most knee injuries are treated with arthroscopy

Joints

� Three main types of joints:� 1) Diarthroses (comprise most of the joints)

� Freely moveable� Ball-and-socket joints of the shoulder & hip� Hinge joints of the elbow and knee� Pivot joints of the radius and ulna, atlas and axis� Gliding joints of the vertebrae

� 2) Amphiarthroses� Slightly moveable� Ex: attachment of ribs to the spine & the symphysis pubis

� 3)Synarthroses� Immoveable� Example is the cranium; the suture is an immovable skull

joint

Joints

� When two movable bones meet at a joint, their surfaces do not touch one another

� Movable joints (diarthroses) tend to have the same structure consisting of 3 main parts:� Articular cartilage� A bursa (joint capsule)� A synovial joint cavity

Diseases and abnormal conditions

� Arthritis� Group of diseases involving inflammation of

the joints� Two main types: Osteoarthritis and

rheumatoid arthritis� Osteoarthritis

� Chronic disease that occurs with aging� Symptoms: joint pain, stiffness, aching, limited

range of motion (ROM)� Treatment: rest, heat/cold applications, ASA,

NSAIDs, steroids, special exercises


� Rheumatoid Arthritis� Chronic inflammatory disease of connective

tissue and joints, results in permanent deformity and immobility

� Three times more common in women� Often begins between ages of 35-45� Treatment: Rest and prescribed exercise,

medications and surgery to replace joint


� Ricketts� Usually found in children� Caused by lack of vitamin D� Bones become soft due to lack of calcification,

causing deformities such as bowlegs.� Preventable with sufficient quantities of

calcium, Vitamin D, and sunlight


� Fractures� Involve a crack or break

in the bone� Types of fractures� 1) Greenstick

Bone is bent and splits causing a crack or incomplete break

Common in children

Fractures

� 2) Simple� Complete break with no damage to skin

� 3) Compound� Break in bone that ruptures through skin� Increased risk of infection

� 4) Comminuted� Bone is broken into many pieces (shattered)

Fractures

� Reductions� Process by which bone is put back into proper

alignment� Closed reduction: position bone in alignment,

usually with traction or force, and apply cast or splint to maintain position

� Open reduction: surgical repair of bone, and, at times, insertion of pins, plates, rods and other devices. AKA ORIF (open reduction internal fixation)


� Dislocation� Bone is forcibly displaced from a joint� Reduced and immobilized with splint, traction, or cast

� Sprain� Twisting action tears ligaments at a joint� Common sites are wrists and ankles� Symptoms: pain, swelling, discoloration, limited

movement� Treatment: rest & elevation; Immobilization with elastic

bandage or splint; Cold applications


� Strains� Overstretching or tearing of muscle


� Osteomyelitis� Inflammation of bone usually caused by a

pathogen � Symptoms: pain at site, swelling, chills, fever� Treatment is antibiotics (usually IV) for

infection


� Osteoporosis� Affect 25 million Americans, 80% which are

women� Etiology

� Deficiency of hormones, especially estrogen if female (By age 55, the average postmenopausal woman has lost 35% of her bone mass)

� Prolonged lack of calcium in diet� Sedentary lifestyle

Osteoporosis con’t

� Loss of calcium and phosphate causes bones to become porous, brittle, and prone to fracture

� Treatment� Increased intake of calcium and Vitamin D� Exercise� Medications to increase bone mass� Estrogen replacement


� Abnormal curvatures of the spinal column� Kyphosis: “Hunchback” or rounded bowing of

the back at the thoracic area� Scoliosis: Side to side or lateral curvature of

the spine� Lordosis: “swayback” or abnormal inward

curvature of the lumbar vertebrae


� Osteosarcoma� Bone cancer� May occur in younger people� The most common site of affliction is just

above the knee

Functions of bones

� 1. Framework: support body’s muscles, fat, and skin� 2. Protection: surround vital organs to protect them

� Examples: Skull that surrounds the brain and the ribs that protect the heart and lungs

� 3. Movement and anchorage of muscles.� 4. Produce blood cells: produce red & white blood

cells and platelets, a process called hemopoiesis or hematopoiesis

� 5. Mineral Storage: stores most of the calcium supply of body. Also stores phosphorus

Bone Formation

� Bones consist of microscopic cells called osteocytes. An osteocyte is a mature bone cell

� Embryo skeleton starts as osteoblasts, then change to cartilage.

� Ossification (bone replaces cartilage) starts at 8 weeks

� Infant’s bones are very soft and pliable because of incomplete ossification at birth

� (Fontanels are an example of this)

Motions

� Joints can move in may directions

� Flexion: Brings two bones closer together which decreases the angle between the two bones

� Extension: increasing the angle between two bones which results in a straightening motion

Motions

� Abduction� The movement of an

extremity away from the midline

� Adduction� The movement of an

extremity towards the midline

Motions

� Pronation� The forearm turns the

hand so the palm is downward or backward

� Supination� The palm is forward or

upward

Motions

� Circumduction� Includes flexion,

extension, abduction, and adduction

� Rotation� Movement allows the

bone to move around one central axis

Documents

HSI 1.02 Skeletal System...The Skeletal system is made of organs that are called bones THERE ARE 206 BONES IN THE ADULT SKELETON. Bone Types Long Bones-found in the arms and legs Flat