The skeletal System
Skeletal System
 An anatomical reference system called directional
terms is used to identify the location of bones.
 The starting point assumes that the body is in the
Anatomical position; that is, a reference position
where the subject is standing erect, facing front on and
with palms facing forward. (Diagram next slide)
 This enables us to locate a bone in reference to how it
is relative to another part of the body.
Anatomical Position
Transverse
Plane
Sagittal Plane
Frontal (Coronal)
Plane
Directional Terms Defined
 Superior-towards the head; for example, the chest is superior to the
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hips.
Inferior- towards the feet; for example, the foot is inferior to the leg.
Anterior-towards the front; for example, the nose is anterior to the
ear.
Posterior-towards the back; for example, the backbone is posterior to
the heart.
Medial-towards the midline of the body; for example, the big toe is
on the medial side of the foot.
Lateral-towards the side of the body; for example, the little toe is on
the lateral side of the foot.
Proximal- towards the body’s mass; for example, the shoulder is
proximal to the elbow.
Distal- away from the body’s mass; for example, the elbow is distal to
the shoulder.
Skeletal System Introduction
 The adult human skeleton has 206 bones. They range
in shape and size, a feature that allows them to
perform specialised functions.
 Functions of bones:
1. Protection to vital organs, for example the cranium
and ribs.
2. Support framework for the body
3. Movement-site of muscle attachment
4. Storage- minerals, for example calcium
5. Production of Red Blood Cells and White Blood Cells
Skeletal System Introduction
 The skeleton is divided into two (2) major portions: The
axial skeleton and the appendicular skeleton.
1. Axial skeleton-consists of the bones of the skull, the
vertebral column and the rib cage.
Skeletal System Introduction
2. Appendicular skeleton-consists of the bones of the
upper and lower limbs and the bony girdles that support
them on the body trunk.
Pectoral girdle
Types of Bone
 There are five (5) types of bone-long, short, flat, irregular and
sesamoid.
1. Long Bones- are hollow, tubular in shape and have along shaft. The
ends of long bones form the articulating or connecting surfaces at joints.
- these bones can withstand heavy stress and are important in weight
bearing.
- examples: humerus, femur, radius, tibia, ulna and phalanges.
2. Short Bones- are shaped like a cube and almost equal in length and
width.
- examples: bones in the wrist (carpals) and ankle bones (tarsals)
3. Flat Bones- generally thin with a layer of spongy bone in their centre.
- they are usually broad in shape and have a smooth surface allowing a
large area for muscle attachment.
-examples: scapula, cranial bones, sternum and ribs
Types of Bone
4. Irregular Bones- complex shapes, for example vertebrae
5. Sesamoid Bones- this type of bone is small and found in special tissue
called tendons, where there can be more than usual pressure applied.
- examples: the patella
Overview of skeletal bones
Overview of skeletal bones
Vertebral Column
Joint Types (page 133-Outcomes)
Joint Classification
Fibrous
Cartilaginous
Synovial
Definition
Movement actions
allowed
Examples
Types of synovial joints
Type of synovial joint
Definition
Examples
Hinge joint
Hinge joints are
UNIAXIAL like a door
hinge.
-movement restricted to
flexion and extension
• Knee Joint
• Elbow Joint
Consists of a head that
fits into a cup like
depression.
-Most flexible joint
-MULTIAXIAL joint
• Shoulder
• Hip
Convex condyle that fits
into a concave surface.
-BIAXIAL
• Metacarpophalangeal
joint (Knuckles)
• Flexion, Extension,
Abduction, Adduction
and Circumduction
(Uniaxial)
Ball and socket joint
(Multiaxial)
Condyloid/ellipsoidal
joint
(Biaxial)
Types of synovial joints
Type of synovial joint
Definition
Examples
Pivot Joint
Consist of a bony pivot
projection with a
osteoligamentous.
• C1 and C2-move head
from side to side.
• Radius and ulna joint at
proximal end.
(supination/pronation)
-Only example of a nonaxial joint. Articular
surfaces are flat and only
allow slipping or gliding
movements.
• Carpals
• Tarsals
(Uniaxial)
Plane/gliding Joint
(Non-Axial)
Saddle Joint
(Biaxial)
Each articular surface has • Carpometacarpal joints
both a concave and convex
of the thumbs.
areas that fit together. It is • Flexion, Extension,
shaped like a saddle.
Abduction, Adduction
and Circumduction
Function and structure of the knee
joint
Feature of synovial joints
Write notes on features from page 133-134 outcomes
textbook. (Ligaments, tendons, synovial fluid and
hyaline cartilage).