Bones - Skeleton
Early Life
• During development of the embryo, the
human skeleton is made up of cartilage and
fibrous membranes, but most of these early
supports are soon replaced by bone.
• Think about the body position in utero during development,
and the first few years of child’s life.
• Most bones stop growing during adolescence.
• Some facial bones, especially those of the
nose and lower jaw, continue to grow almost
to no end throughout life.
(example of change of facial structure in elderly)
Skeleton
• divided into the axial and appendicular
• Together comprise 206 bones in the human
body
axial skeleton
• These bones form the vertical axis of the body.
They function in protection and support of the
body and body parts.
• skull bones
• vertebral column
• rib cage
Axial Skeleton
Appendicular Skeleton
• These bones comprise the upper and lower limbs
of the body, and the bones that connect limbs to
the axial skeleton. They function in movement.
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clavicles
pelvis
Arms and hands
Legs and feet
Appendicular Skeleton
Function of Bones
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-Protection of vital organs
-Support & maintenance of posture
-Providing attachment points for muscles
-Storage & release of minerals (calcium &
phosphorus)
• -Blood cell production (haemopoiesis)
• -Storage of energy (lipids in yellow bone
marrow)
bone classifications (types)
Long bones: longer than they are wide; have a
shaft with 2 ends. Movement bones: including
femur, metatarsals & clavicle
Short bones: small & cube-shaped. Include
carpals & tarsals
Flat bones: thin, flat and often curved. Including
the sternum, scapula, ribs and skull bones
Irregular bones: have specialized & complicated
shapes, including sacrum, coccyx & vertebrae
Bone classifications
Bone Textures
• Bones are made up of 2 layers that differ in
texture and function:
• - Compact bone: external layer of the bone
that is very dense, filled with passageways for
nerves, blood vessels, and lymphatic vessels.
• - Cancellous bone: internal layer of the bone
that looks spongy; has an irregular latticework
structure.
Long Bone: structure
• Long bones are mainly comprised of a shaft, 2
ends and membranes.
Diaphysis: the shaft; constructed of
compact bone and envelopes a marrow cavity.
In adults, this cavity stores yellow marrow (fat)
Epiphyses: the bone ends of a long bone;
constructed of compact bone externally and
spongy bone internally. Blood cell production
occurs here
Con’t
• Articular Cartilage: thin layer of cartilage covering
the ends of the bone where joints are formed.
They reduce friction & absorb shock
• - Periosteum; thin shiny white membrane;
important for bone growth, repair, nutrition and
attachment of ligaments/tendons.
• - Medullary Cavity: space within the diaphysis
where yellow bone marrow is stored.
• -Nutrient Foramen: where blood vessels pass into
the bone.
Diagram of Long Bone
Vertebral column
• 33 Vertebrae in the body
• Strong and flexible
• Cervical: 7 vertebrae; the smallest & have the
most movement
• Thoracic: 12 vertebrae; less mobile due to the
ribs attached to them
• Lumbar: 5 vertebrae; biggest & strongest; weight
bearing
• Sacral: 5 vertebrae (fused); transmit weight to the
legs/pelvis
• Coccygeal: 4 vertebrae (fused)
Vertebrae
Vertebrae
• The vertebral foramen; (hole) in each
vertebrae line up to house the spinal cord.
• -Intervertebral discs: located between the
body of each vertebrae; fibrocartilage on the
outside & gel like in the middle; give the
vertebral column flexibility; shock absorbers
Spinal column
4 curves of the spine increase strength, help
maintain upright balance & absorb shock
Sources
“Human Anatomy & Physiology, Pearson International Edition, Eighth Edition.” Marieb and Hoehn.
2010
McGraw-Hill Companies. www.mcgraw-hill.com/
National Library of Medicine and International Osteoporosis Foundation.
www.nlm.nih.gov/
Nucleus Communications, Inc. 2003.
www.nucleusinc.com
Visual Dictionary Online. www.visualdictionaryonline.com
http://tw.aisj-jhb.com/dslattery/files/2013/05/bones.pdf