Chapter 7:2
Skeletal System
Key Terms (Vocabulary)
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Appendicular skeleton
Axial skeleton
Carpals
Clavicles
Cranium
Diaphysis
Endosteum
Epiphysis
Femur
Fibula
Fontanels
Foramina
Humerus
Joints
Ligaments
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Medullary canal
Metacarpals
Metatarsals
Os coxae
Patella
Periosteum
Phalanges
Radius
Red marrow
Ribs
Scapula
Sinuses
Skeletal system
Sternum
Sutures
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Tarsals
Tibia
Ulna
Vertebrae
Yellow marrow
• Human skeletal system is made up of 206 bones
• Bone Functions:
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• 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
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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
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Axial Skeleton
Skull
Spinal Column
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 Bones
14 facial bones
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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 discs
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
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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
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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: 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