Download Human Movement Systems: Skeletal System

Human Movement Systems:
Skeletal System
Objectives
• After this presentation, the participant will be able to
explain the basic structure and function of:
– Skeletal System Organization
– Types of bones
– Bone remodeling
– Joints (including stability vs. mobility)
– Connective Tissue
– Role of Exercise
The Skeletal System
 Provides:
– Structure
– Protection of vital organs
– Levers for movement
– Storage for mineral
 Bones form junctions that
are connected by
muscles and connective
tissue known as joints.
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
Vertebral Column
 Series of irregularly shaped
bones called vertebrae.
 Houses the spinal cord.
– Cervical spine has 7 (concave curve) vertebrae.
– Thoracic spine has 12 (convex curve).
– Lumbar spine has 5 (concave curve).
– Sacrum is fused triangle attached to pelvis.
– Coccyx is tail bone.
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
Divisions of the Skeletal System
 Axial skeleton:
•
Skull
•
Rib cage
•
Vertebral column
 Appendicular skeleton:
•
Upper and lower extremities
•
Shoulder and pelvic girdles
Types of Bones
Long bones: Long
cylindrical shaft and irregular
or widened ends
 Epiphysis: End of long bone
 Diaphysis: Shaft of long bone;
 Epiphyseal plate: growth plate
 Periosteum: Hard membrane
 Medullary cavity: marrow
 Articular cartilage: Covers
articular surfaces of bones
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
Types of bone tissue
Types of bone tissue:
 Compact Bone (a.k.a.
cortical bone)
– Dense bone found primarily in
shaft of long bones.
 Cancellous Bone (a.k.a.
spongy or trabecular bone)
– Found at end of long bones and
in irregularly shaped bones.
– Less dense, more flexible
– Prone to effects of osteoporosis
– Site of red blood cell production
•
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
Types of bones
Short bones:
Irregular bones:
Flat bones:
• Similar in length and
• Unique shape
• Thin, protective
width and appear
somewhat cubical in
shape
Copyright © 2012 Wolters Kluwer Health | Lippincott
Williams & Wilkins
and function
Copyright © 2012 Wolters Kluwer
Health | Lippincott Williams & Wilkins
Copyright © 2012 Wolters Kluwer
Health | Lippincott Williams & Wilkins
Bone Markings
Depressions:
Processes:
• Flattened or
• Projections protruding
from the bone to which
muscles, tendons, and
ligaments attach
indented portions
of the bone
• Common
depressions:
• Common processes:
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
•
Condyle
•
Fossa
•
Epicondyle
•
Sulcus
•
Tubercle
•
Trochanter
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
Bone Growth & Remodeling
Bones under go remodeling throughout life cycle:
 Osteoblasts build up new bone tissue.
 Osteoclasts chew up old bone tissue.
 Remodeling is the constant process building up and
breaking down of these cells.
 In children, osteoblasts are more active; as we age,
osteoclasts become more active.
Bone Growth & Remodeling
Wolff’s Law: Bone will adapt to the loads under which it is
placed.
– Sensitive to direction and amount of force.
 Importance of weight bearing exercise:
– Exercise that forces the body to work against gravity appear to
stimulate bone growth the best:
– Running, lifting weights, calisthenics are weight bearing
– Swimming and cycling are not, so less bone stimulation than land
training.
Aging and Bone Density
Osteoporosis Fracture
 Kyphosis of the upper back
due to osteoporotic
fractures of the thoracic
vertebrae.
Dowager’s Hump
Low Bone Density Risk Factors
Hormones
Menopause
Premature
Race:
Caucasian
Medication:
Asian
Corticosteroids
menopause
Amenorrhea
Hyperthyroidism
Low testosterone
in men
Diet:
Low Calcium
Low Vitamin D
Inactivity
Osteoporosis
Size:
Small Frame
Low weight
Smoking
Advanced Age
Alcohol & Caffeine
Joints
 One bone that articulates with another bone.
 Joint motion is referred to as arthrokinematics.
 Typical joint motions seen in the human articular
system include:
• Roll: Rolling on joint surface on another such as femoral
condyles rolling over the tibial condyles during a squat
•
Slide: Sliding of a joint surface across another such as
tibial condyles moving (sliding) across the femoral
condyles during a knee extension
•
Spin: Rotation of one joint surface on another such as
head of the radius rotating on the end of the humerus
during pronation and supination of the forearm
Classifications of Joints
 Synovial joints:
– Produce synovial fluid
– Have a joint cavity and fibrous connective tissue
– Example: Knee
 Non-synovial joints:
– No joint cavity and fibrous connective tissue
– Little or no movement
– Example: Sutures of the skull
Connective Tissue anatomy
 Connective tissue —serves to connect,
support, and anchor various body parts.
Characterized by poor vascularity and
do not repair or adapt as easily as other
tissues in the body
– Fascia —a sheet or band of fibrous tissue
that lies deep to the skin or forms an
attachment for muscles and organs
– Tendon —when a muscle contracts to
produce movement, it pulls on a tendon,
which attaches the muscle to the bone
– Ligaments —supportive structures found at
joints that connect bones to other bones
– Cartilage —serves as padding between the
bones at a joint and functions to provide
cushioning and the smooth gliding of joint
movement
16
Connective Tissue
 Davis’s Law - Soft tissue models
along the lines of stress.
– If muscle is in a constant shortened state
(such as when you sit all day), your
connective tissue remodels to adapt to the
shorter length, resulting in:
• Relative flexibility (seeking the path of least
resistance)
• Poor neuromuscular efficiency (altered
length-tension relationship, and forcecouple relationships.
• Synergistic Dominance (muscles other than
prime movers help too much)
Myofascial Release


Myofascial release applies pressure to tight, restricted areas of fascia and
underlying muscle in an attempt to relieve tension and improve flexibility
–
It is thought that sustained pressure to a tight area can inhibit tension in a
muscle by stimulating the GTO to bring about autogenic inhibition.
–
Trigger points can be diminished through the application of pressure followed by
static stretching of the tight area.
In the fitness setting, a foam roller is used, allowing the exerciser to control
his or her own intensity and duration of pressure.
Summary
 Structure & function of the skeletal system
 Bone growth and remodeling
 Joints
 Connective Tissue
 Role of Exercise