Chapter 7:2

Skeletal System

Key Terms (Vocabulary)• Appendicular skeleton• Axial skeleton• Carpals• Clavicles• Cranium• Diaphysis• Endosteum• Epiphysis• Femur• Fibula• Fontanels• Foramina• Humerus• Joints• Ligaments

• Medullary canal• Metacarpals• Metatarsals• Os coxae• Patella• Periosteum• Phalanges• Radius• Red marrow• Ribs• Scapula• Sinuses• Skeletal system• Sternum• Sutures

• Tarsals• Tibia• Ulna• Vertebrae• Yellow marrow

• Human skeletal system is made up of 206 bones• Bone Functions:

• Framework: bones form a framework to support the body’s muscles, fat, and skin

• Protection: bones surround vital organs to protect them• Levers: muscles attach to bones to help provide movement• Production of blood cells: bones help produce red and white

blood cells and platelets• Storage: bones store most of the calcium supply of the body

in addition to phosphorus and fats• Bones vary in shapes and sizes depending on where they are

located in the body• Bones in the extremities (arms and legs) are called long bones

Parts of a bone• The long shaft is called the diaphysis• The two end of a bone are called the

epiphysis• The medullary cavity (canal) is

located within the diaphysis• The medullary cavity is filled with

yellow marrow, which is mainly the storage for fat cells

• The endosteum is a membrane that lines the medullary cavity and keeps the marrow intact

• Red marrow is found in certain bones and it produces red blood cells, platelets, and some white blood cells

• Red marrow is used to diagnose blood diseases

• The outside of the bone is covered with a tough membrane called the periosteum

• The periosteum is necessary for bone growth because it contains blood vessels, lymph vessels, and osteoblasts

Axial Skeleton• Skull• Spinal Columns• Ribs• Breastbone

Appendicular Skeleton• Shoulder girdle• Arm bones• Pelvic girdle• Leg bones

The Skull• The cranium is a spherical structure that surrounds and

protects the brain• 8 cranial bones:

• 1 frontal• 2 parietal• 2 temporal• 1 occipital• 1 ethmoid• 1 sphenoid

• Sutures

Facial Bones14 facial bones

• 1 mandible (lower jaw)• 2 maxilla (upper jaw)• 2 zygomatic (cheek)• 2 lacrimal (inner aspects

of the eyes)• 5 nasal• 2 palatine (roof of the

mouth)

Spinal Column• Spinal column is composed

of 26 bones called vertebrae• 7 cervical (neck)• 12 thoracic (chest)• 5 lumbar (waist)• 1 sacrum (back of pelvic

girdle)• 1 coccyx (tailbone)

• Pads of cartilage tissue called intervertebral disks separate the vertebrae

Thoracic Cavity• 12 pairs of ribs

• 7 true ribs• 5 false ribs (last 2

are “floating” ribs• Sternum is also called

the breastbone• 2 clavicles are

attached to the sternum by ligaments

Bones of the upper body

• 2 clavicles (collarbones)• 2 scapulas (shoulder blades)• 1 humerus (upper arm)• 1 radius (lower arm, thumb

side)• 1 ulna (larger bone in lower

arm)• 8 carpals (wrist bones)• 5 metacarpals (palm of the

hand)• 14 phalanges (3 on each

finger and 2 on the thumb)

Bones of the lower body

• 2 os coxae (hip bones)• 1 femur (thigh)• 1 patella (kneecap)• 1 tibia (shin bone)• 1 fibula (smaller bone)• 7 tarsals (ankle)• 5 metatarsals (instep of

foot)• 14 phalanges (2 on the big

toe, 3 on the rest)

Joints• Joints are where 2 or more bones

come together• Ligaments help hold long bones

together at the joint• 3 main types of joints:

• Synovial Joint: freely moveable (ball-and-socket and hinge joints)

• Amphiarthrosis: slightly moveable (ribs to thoracic vertebrae and joint between the 2 pelvic bones)

• Synarthrosis: immovable (suture joints in the cranium)

Disease and Abnormal Conditions

• Arthritis• Osteoarthritis: most common, chronic disease that

usually occurs as a result of aging• Most frequently affects the hips and knees• Symptoms include joint pain, stiffness, aching,

limited range of motion• Rheumatoid arthritis: chronic inflammatory disease

that affects the connective tissues and joints• Scar tissue and atrophy of bone and muscle tissue

Disease and Abnormal Conditions

• Bursitis• Inflammation of the bursae• Bursae are small fluid filled sacs surrounding the

joints• Symptoms include severe pain, limited movement,

and fluid accumulation in the joint

Disease and Abnormal Conditions

• Fractures• Greenstick: bone is bent and splits• Closed: complete break of bone with no damage to

the skin• Compound (open): bone breaks and ruptures the skin• Impacted: broken bone ends jam into each other• Comminuted: bone fragments into more than 2 pieces• Spiral: bone twists and breaks• Depressed: piece of skull bone moved inward• Colles: breaking and dislocation of the distal radius

• **PICTURES TO COME**

Disease and Abnormal Conditions

• Osteomyelitis• Bone inflammation

• Osteoporosis• Softening of the bones

• Ruptured Disk• The intervertebral disk ruptures or protrudes out of

place• Spinal Curvatures

• Kyphosis• Lordosis• Scoliosis