DEVELOPMENT CLASSES
THE SKELETAL SYSTEM
Hand-Out
2009
THE SKELETAL SYSTEM
THE SKELETON
The skeleton is a bony framework made up 206 bones in the adult and 350 in a baby.
THE FUNCTIONS OF THE SKELETON
The skeleton performs several important functions:-
· Support – For soft tissue, gives body shape, attachment for muscles to work
· Protection – Of vital organs
· Movement – To act as levers for muscles to work
· Mineral storage – Calcium and phosphorous are stored in bones
· Production - Of blood cells
· Storage of energy – Fat in yellow marrow is an important source of energy
COMPOSITION OF BONE
THE SKELETAL SYSTEM
Bones are made up of two types of bone tissue,
COMPACT BONE
Compact bone is the hard outer covering of every bone. Dense tissue containing few spaces, which has high stress bearing capabilities.
CANCELLOUS BONE
Lighter bone tissue characterized by many spaces, which contain Red Marrow, Red bone marrow produces Blood Cells, (red blood cells, white blood cells and platelets)
PERIOSTEUM
Bones are covered in a dense fibrous membrane called the Periosteum. This contributes to bone growth and repair and contains blood vessels, which nourish the cells of the bone tissue. It also provides attachments for ligaments and tendons
CARTILAGE
This covers the ends of the bones in place of the periostium at a joint with another bone. It reduces friction and acts as a shock absorber.
OSSEOUS is the name given to bone tissue.
TYPES OF BONES
The bones of the skeleton are classified according to their shape:-
· LONG
· SHORT
· FLAT
· IRREGULAR
· SEASAMOID
LONG BONES - femur, tibia, Humerus, Radius, Ulna and Phalanges
SHORT BONES - Carpals and Tarsals
FLAT BONES - Pelvis, Cranium and Scapula
IRREGULAR BONES - Vertebrae and some facial bones
SESAMOID BONES - Patella
THE SKELETAL SYSTEM
DIVISIONS OF THE SKELETON
The human skeleton is divided into two major divisions:-
AXIAL SKELETON APPENDICULAR SKELETON
THE AXIAL SKELETON
THE SKELETAL SYSTEM
The Axial Skeleton follows the line of the axis of the body and includes, The Skull, Spinal Column and Thoracic Cage.
THE SKULL
THE CRANIUM THE FACE
THE AXIAL SKELETON
THE SKULL
CRANIAL BONES (8 bones)
* TEMPORAL (2) * FRONTAL (1)
* PARIETAL (2) * OCCIPITAL (1)
* SPHENOID (1) * ETHMOID (1)
THE SKELETAL SYSTEM
THE FACIAL BONES (14 Bones)
* MANDIBLE (1) * LACRAMAL (2)
* MAXILLA (2) * PALATINE (2)
* ZYGOMATIC (2) * NASAL (2)
* NASAL CONCHAE (2) * VOMER (1)
The mandible is the only moveable bone in the face.
NOTE
The PALATINE bone cannot be seen in this diagram as it makes up the roof of the mouth.
THE SKELETAL SYSTEM
THE SPINAL COLUMN (33 Bones)
The spine supports the skull and gives attachment to the ribs. The bones in the spine are called Vertebrae.
The Spine is divided into five groups,
7 CERVICAL (Neck – 1st Atlas, 2nd Axis)
12 THORACIC (Chest – rib attachment)
5 LUMBAR (small of the back)
5 SACRAL (Fused- part of the pelvis)
4 COCCYX (Fused- remnant of a tail at base of spine)
INTERVERTEBRAL DISCS – Cartilage between the vertebrae, which act as shock absorbers.
THE SKELETAL SYSTEM
THE THORACIC CAGE
The rib cage contains 25 bones (12 Pairs Ribs (24) + 1 Sternum).
STERNUM
A long flat bone down the centre of the chest known as the Breastbone.
THE RIBS
7 Pairs TRUE Ribs (attached at the spine and sternum)
3 Pairs FALSE Ribs (attached at spine and the rib above)
2 Pairs FLOATING Ribs (attached only at the spine)
The INTERCOASTAL MUSCLES are located between the ribs. They work with the diaphragm during breathing, and known as the Principal Muscles of Respiration.)
THE APPENDICULAR SKELETON
The appendicular skeleton is made up of the ‘Bones of the upper and lower limbs and the pelvis’, all of which are attached or appended to the Axial Skeleton.
THE SKELETAL SYSTEM
UPPER LIMBS and SHOULDER GIRDLE
SCAPULA (2) (shoulder blades) CLAVICALS (2) (collar bones)
HUMERUS (2) (upper arms) RADIUS and ULNA (2x2) (forearms)
CARPALS (2x8) wrists METACARPLES (2x5) palm of hands
PHALANGES (2X14) fingers
PELVIS
The Pelvic Girdle consists of four bones
R/L HIP BONES SACRUM COCCYX
LOWER LIMBS
FEMUR (2) thigh bone TARSALS (2X7) ankles
PATELLA (2) knee bones PHALANGES (2X14) toes
TIBIA and FIBULA (2x2) METATASALS (2x5) instep
lower leg and shin bone
THE SKELETAL SYSTEM
TYPES OF JOINTS
A joint is a junction of two or more bones. There are three types:-
- IMMOVABLE or FIBROUS JOINT (Skull and Pelvis)
- SLIGHTLY MOVABLE JOINTS (Pubis and intervertebral)
- FREELY MOVEABLE or SYNOVIAL JOINTS (elbow, Hip and Knee)
SYNOVIAL JOINTS
BALL AND SOCKET JOINT (Hip and Shoulder) moves freely in all directions
HINGE JOINTS (Knees and Elbows) move in only one direction
GLIDING JOINT (Wrists and Ankles) bones glide over one another
PIVOT JOINT (Radius and Ulna) which allows rotation
LIGAMENTS, TENDONS AND MUSCLES
LIGAMENTS
Ligaments are composed of dense fibrous connective tissue. They attach one bone to another.
TENDONS
Tendons are also composed of dense fibrous tissue, which is continuous with the fibrous sheath covering each muscle, and attaches to the periostium of a bone, another muscle or skin.
MUSCLE
Muscle tissue is highly specialized to generate force.
THE SKELETAL SYSTEM
STUDY OUTLINES
YOU MUST KNOW:-
How many bones make up the adult and baby skeletons.
How a bone is composed
The different types of bones and they position in the body
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