Support, movement Support, movement and locomotionand locomotion

INTRODUCTIONINTRODUCTION

Objectives:Objectives:

• List and describe the major functions List and describe the major functions of the skeletal system.of the skeletal system.

• List, describe and give specific List, describe and give specific examples of the types of bones.examples of the types of bones.

• List and describe the two major List and describe the two major divisions of the skeletal system and the divisions of the skeletal system and the bones which compose each.bones which compose each.

• Describe the process of bone Describe the process of bone formation.formation.

• List and describe the various types of List and describe the various types of joints.joints.

Functions of the Skeletal Functions of the Skeletal SystemSystem

• Support of the bodySupport of the body• Protection of soft organsProtection of soft organs• Movement due to attached Movement due to attached

skeletal musclesskeletal muscles• Storage of minerals and fatsStorage of minerals and fats• Blood cell formationBlood cell formation

Classification of Bones Classification of Bones by Shapeby Shape• Long bones

– Typically longer than wide– Have a shaft (long, central cylinder) with heads at both ends– Contain mostly compact bone

• Examples: Femur, humerus• Short bones

– Generally cube-shape– Contain mostly spongy bone

• Examples: Carpals, tarsals• Flat bones

– Thin and flattened– Usually curved– Thin layers of compact bone around a layer of spongy bone

• Examples: Skull, ribs, sternum• Irregular bones

– Irregular shape– Usually with projections (processes) or openings (foramen)– Do not fit into other bone classification categories

• Example: Vertebrae and hip• Sesamoid bones: These are bones that are imbedded in ligaments and are not

directly attached to other bones. Example: Patella

Classification of Bones Classification of Bones by Shapeby Shape

Divisions of the SkeletonDivisions of the Skeleton• The Skeleton is divided into two major regions:The Skeleton is divided into two major regions:

a. Axial Skeletona. Axial Skeletonb. Appendicular Skeletonb. Appendicular Skeleton

• The Axial Skeleton forms the longitudinal part The Axial Skeleton forms the longitudinal part of the bodyof the body

• Divided into three partsDivided into three parts– SkullSkull– Vertebral columnVertebral column– Bony thoraxBony thorax

• The Appendicular skeleton is composed of the The Appendicular skeleton is composed of the appendages and the joints which attach them to appendages and the joints which attach them to the axial skeletonthe axial skeleton

Limbs (appendages)Limbs (appendages) Pectoral girdle (shoulder, scapula, and Pectoral girdle (shoulder, scapula, and

clavicle)clavicle) Pelvic girdle (pelvis)Pelvic girdle (pelvis)

Divisions of the SkeletonDivisions of the Skeleton

Axial Skeleton: The SkullAxial Skeleton: The Skull

• Two sets of bonesTwo sets of bones– CraniumCranium– Facial bonesFacial bones

• Bones are joined by sutures Bones are joined by sutures (fixed, non-movable joints)(fixed, non-movable joints)

• Only the mandible is attached by Only the mandible is attached by a freely movable jointa freely movable joint

Axial Skeleton: The SkullAxial Skeleton: The Skull

Axial Skeleton: The Axial Skeleton: The SkullSkull

Axial Skeleton: Hyoid Axial Skeleton: Hyoid BoneBone

The only bone The only bone that does not that does not articulate with articulate with another boneanother bone

Serves as a Serves as a moveable base moveable base for the tonguefor the tongue

Figure 5.12

Axial Skeleton: Vertebral Axial Skeleton: Vertebral ColumnColumn Vertebrae are Vertebrae are

separated by separated by intervertebral intervertebral discs composed discs composed of fibrocartilageof fibrocartilage

The spine has a The spine has a normal curvaturenormal curvature

Each vertebrae is Each vertebrae is given a name given a name according to its according to its locationlocation

Axial Skeleton: Vertebral Axial Skeleton: Vertebral ColumnColumn

Axial Skeleton: Anterior Axial Skeleton: Anterior ThoraxThorax

Forms a cage Forms a cage to protect to protect major organsmajor organs

Made-up Made-up of two of two partsparts

1. 1. SternumSternum

2. Ribs2. Ribs

Appendicular Skeleton: Appendicular Skeleton: Pectoral GirdlePectoral Girdle

• Composed of two bonesComposed of two bones– Clavicle – collarboneClavicle – collarbone– Scapula – shoulder bladeScapula – shoulder blade

• These bones allow the upper limb These bones allow the upper limb to have exceptionally free to have exceptionally free movementmovement

Appendicular Skeleton: Appendicular Skeleton: Pectoral Girdle (Shoulder)Pectoral Girdle (Shoulder)

Appendicular Skeleton: Appendicular Skeleton: Brachium RegionBrachium Region

The arm is The arm is formed by a formed by a single bonesingle bone

HumerusHumerus

Appendicular Skeleton: Appendicular Skeleton: Antebrachium RegionAntebrachium Region

• The forearm has The forearm has two bonestwo bones

• Ulna (side Ulna (side adjacent to little adjacent to little finger)finger)

• Radius (side Radius (side adjacent to adjacent to thumb)thumb)

Appendicular Skeleton: Appendicular Skeleton: Carpus, Manus, and Digits Carpus, Manus, and Digits

RegionRegion The hand

Carpals – wrist

Metacarpals – palm

Phalanges – fingers

Articulations: JointsArticulations: Joints

• A joint is a location where two or more bones meet.

• Functions of joints– Hold bones together– Allow for mobility

• Ways joints are classified– Functionally– Structurally

Types of JointsTypes of Joints

• Fibrous jointsFibrous joints– Generally immovable (sutures of skull)Generally immovable (sutures of skull)

• Cartilaginous jointsCartilaginous joints– Immovable or slightly moveable (vertebral Immovable or slightly moveable (vertebral

disc)disc)

• Synovial jointsSynovial joints– Freely moveable (shoulder, pelvis, knee, Freely moveable (shoulder, pelvis, knee,

elbow, digits)elbow, digits)– Articulating bones are separated by a joint Articulating bones are separated by a joint

cavitycavity– Synovial fluid is found in the joint cavitySynovial fluid is found in the joint cavity

Structure of a Synovial Structure of a Synovial JointJoint

Figure 5.28

Type of Synovial JointsType of Synovial Joints

Types of Synovial JointsTypes of Synovial Joints

Diseases and Disorders of Diseases and Disorders of the Skeletal Systemthe Skeletal System

• A fracture is 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

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

Diseases and Disorders of Diseases and Disorders of the Skeletal System: the Skeletal System:

FracturesFractures

SimpleGreenstick radius

SimpleComplete fibula

CompoundFracture tibia and fibula

ComminutedFracture radius

Diseases and Disorders of Diseases and Disorders of the Skeletal Systemthe Skeletal System

• Osteoporosis:Osteoporosis: This This illness afflict both illness afflict both men and women but men and women but it is most common it is most common in post menopausal in post menopausal women. The bone women. The bone tissue becomes tissue becomes brittle and breaks brittle and breaks easily with little easily with little applied stress. Due applied stress. Due to loss of calcium to loss of calcium from the bone from the bone matrix.matrix.

Diseases and Disorders of Diseases and Disorders of the Skeletal Systemthe Skeletal System

• Rickets: Rickets is a Rickets: Rickets is a disease associated with disease associated with a deficiency of vitamin a deficiency of vitamin D in the diet. It D in the diet. It prevents the body from prevents the body from absorbing calcium absorbing calcium needed for the needed for the formation of strong, formation of strong, bone matrix. Typically bone matrix. Typically the long bones are soft the long bones are soft and bend under the and bend under the stress from the weight stress from the weight of the body. It results of the body. It results in “bowed legs”. This in “bowed legs”. This disease often affects disease often affects children who are children who are undernourished. undernourished.