The Skeletal The Skeletal System:System:

Structure, Function, Structure, Function, and Diseasesand Diseases

of the bones and of the bones and jointsjoints

Is this the correct anatomical position?

The Skeletal SystemThe Skeletal System

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Parts of the skeletal system Bones (skeleton) Joints Cartilages Ligaments (bone to bone)(tendon=bone to

muscle)

Divided into two divisions Axial skeleton- skull, spinal column Appendicular skeleton – limbs and girdle

Functions of BonesFunctions of Bones

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Support of the body

Protection of soft organs

Movement due to attached skeletal muscles

Storage of minerals and fats

Blood cell formation

Bones of the Human BodyBones of the Human Body

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The skeleton has 206 bones Two basic types of bone tissue

Compact bone Homogeneous

Spongy bone Small needle-like

pieces of bone Many open spaces

Figure 5.2b

Bones are classified by their shape:

1.Long- bones are longer than they are wide (arms, legs)

2.Short- usually square in shape, cube like (wrist, ankle)

3.Flat- flat , curved (skull, Sternum)

4.Irregular- odd shapes (vertebrae, pelvis)

Classification of Bones on the Classification of Bones on the Basis of ShapeBasis of Shape

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Figure 5.1

Types of Bone CellsTypes of Bone Cells

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Osteocytes Mature bone cells

Osteoblasts Bone-forming cells

Osteoclasts Bone-destroying cells Break down bone matrix for remodeling and

release of calcium Bone remodeling is a process by both

osteoblasts and osteoclasts

Changes in the Human SkeletonChanges in the Human Skeleton

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In embryos, the skeleton is primarily hyaline cartilage

During development, much of this cartilage is replaced by bone

Cartilage remains in isolated areas Bridge of the nose

Parts of ribs

Joints

Bone FracturesBone Fractures

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A break in a bone Types of bone fractures

Closed (simple) fracture – break that does not penetrate the skin

Open (compound) fracture – broken bone penetrates through the skin

Greenstick- frays, hard to repair, breaks like a green twig

Bone fractures are treated by reduction and immobilization Realignment of the bone

Axial skeleton supports and protects organs of head, neck and trunk Axial skeleton:

skull (cranium and facial bones) hyoid bone (anchors tongue and muscles associated with

swallowing) vertebral column (vertebrae and disks) bony thorax (ribs and sternum)

Appendicular skeleton includes bones of limbs and

bones that anchor them to the axial skeletonAppendicular skeleton:

pectoral girdle (clavicle, scapula)

upper limbs (arms)pelvic girdle (sacrum, coccyx)lower limbs (legs)

Articulation- where joints meet, connect, and are formed.

The Axial SkeletonThe Axial Skeleton

Slide 5.20a

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Forms the longitudinal part of the body Divided into three parts

Skull Vertebral Column Rib Cage

The Axial SkeletonThe Axial Skeleton

Slide 5.20b

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Figure 5.6

The Skull•8 sutured bones in cranium•Facial bones: 13 sutured bones 1 mandible

Craniumencases brainattachments for musclessinuses

Bones of the SkullBones of the Skull

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Figure 5.11

Allows forgrowth

Paranasal SinusesParanasal Sinuses

Slide 5.25a

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Hollow portions of bones surrounding the nasal cavity

Figure 5.10

The Hyoid BoneThe Hyoid Bone

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The only bone that does not articulate with another bone

Serves as a moveable base for the tongue, and other muscle attachments

Figure 5.12

The Vertebral ColumnThe Vertebral Column

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Vertebrae separated by intervertebral discs made of cartilage

The spine has a normal S curvature

Each vertebrae is given a name according to its location Figure 5.14

Thoracic cageribsthoracic

Vertebraesternumcostal cartilages

•True ribs are directly attached to the sternum(first seven pairs)•Three false ribs are joined to the 7th rib•Two pairs of floating ribs

JointsA joint, or articulation, is the place where two

bones come together.

• Fibrous- Immovable:connect bones, no movement. (skull and pelvis).

• Cartilaginous- slightly movable, bones are attached by cartilage, a little movement (spine or ribs).

• Synovial- freely movable, much more movement than cartilaginous joints. Cavities between bones are filled with synovial fluid. This fluid helps lubricate and protect the bones.

The Synovial JointThe Synovial Joint

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Figure 5.28

Types of Synovial Joints Based on Types of Synovial Joints Based on ShapeShape

Slide 5.52a

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Figure 5.29a–c

Types of Synovial Joints Based on Types of Synovial Joints Based on ShapeShape

Slide 5.52b

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Figure 5.29d–f

Types of JointsHinge- A hinge joint allows extension and

retraction of an appendage. (Elbow, Knee)

Ball and Socket- A ball and socket joint allows for radial movement in almost any direction. They are found in the hips and shoulders. (Hip, Shoulder)

Gliding- In a gliding or plane joint bones slide past each other. Mid-carpal and mid-tarsal joints are gliding joints. (Hands, Feet)

Saddle- This type of joint occurs when the touching surfaces of two bones have both concave and convex regions with the shapes of the two bones complementing one other and allowing a wide range of movement. (Thumb)

Bones of the Cranium• Some are thicker than others!!!

Cranium BonesFrontal Bone

Occipital Bone

Temporal Bone

Parietal Bone

Parietal Bone

Maxilla and Mandible

Maxilla

Mandible

?

Clavicle or Collarbone• The clavicle, or

collar bone, holds the shoulder joint away from the rest of the upper body and is only as thick as your little finger.

Scapula• The scapula is

located on the back side of the ribcage and helps provide part of the shoulder joint and movement for the arms.

Vertebral Column or Spinal Cord

1) The cervical region (neck bones) 

 2) The thorasic region (what

the ribs attach to)

3) The lumbar region (the lower part of the back) 

Coccyx and Sacrum

Humerus (Upper Arm Bone)

Radius and Ulna• Radius on Top

• Ulna on Bottom

Carpals or (Wrist Bones)

Metacarpals (Top of Hands)

Phalanges (Little Fingers)

Rib Cage

Sternum (Breastbone)

Pelvis (Dancing Bone)

Femur (Largest Bone in the Body)

The Tibia and Fibula

Tarsals

Metatarsals

Phalanges

Calcaneous

Skeletal System ReviewMy Videos\wholebodyskeleton.mov

Joints of the Body• Ball and Socket

Joint: Round end of bone fitting snuggly within another bone.– Ex. Shoulder and

Hip

Joints of the Body• Hinge Joint:

Movement at joint in one direction like a door.– Ex. Knee and

Elbow

Joints of the Body• Pivot Joint: Bone

resting atop another bone permitting free movement.– Ex. Neck, Wrist

and Ankles

Joints of the Body• Fixed Immovable:

Joint does not move– Ex. Skull

• Gliding Joint: Bones slipping over other bones with a free flowing movement.– Ex. Knuckles

The Connectors of the Body

• Ligaments: Connect bone to bone

The Connectors of the Body!!

• Tendon: Attaches muscles to bones

The Connectors of the Body

• Cartilage: It acts as a cushion between bones at a joint and protects the bones.