Skeleton includes bones and cartilages.It forms the main supporting framework
hape and supportMuscular attachment Act as leversProtection of organsErythropoiesisStorage of minerals
Introduction to Human Skeletal System
For the students of Gulf Medical University, Ajman,
Dr. Seyed Morteza Mahmoudi,
Gulf Medical University, Ajman
At the end of the session students should be able to:
1) Name the parts of human skeleton
2) Identify and explain the purpose of some bones in
the human skeleton
3) List the bones forming every part
4) Classify bones according to origin, shape and
Skeleton is a system made up of bones and cartilages
and supported and supplemented by ligaments,
tendons and muscles.
It serves as a scaffold which supports organs, anchors
muscles, and protects organs.
What are Bones (Oss)?
What are their functions?
Bone is a specialized connective tissue, consisting of cells, fibers
and extracellular matrix. It’s a hard clacific, with adynamic
Acid base balance
6 ear bones
26 vertebrae (7 cervical, 12 thorax, 5 lumbar, the sacrum
which is five fused vertebrae, and the coccyx which is four
24 ribs plus the sternum
The shoulder girdle (2 clavicles and 2 scapulae)
The pelvic girdle (2 fused bones)
30 bones in our arms and legs (a total of 120);
Total No. 206
Classification of bones
Shaft with two ends
Develop by intracartilagenous ossification
Three centers of ossification
Central medullary cavity
E.g. humerus, ulna, femur etc.
Short long bones:
Shaft with one end
Have two centers of ossification
E.g. metacarpal and metatarsal bones
Modified long bones:
No medullary cavity
Have no shaft or ends
Shape is cuboid, trapizoid or cuniform.
Carpal and tarsl bones
Bony nodules embedded in tendons/ joints
No periosteum and ossify after birth
E.g. Patella, pisiform
Classification of bones
All bones: mesodermal origin.
Process of bone formation: ossification
Formed in a hyaline cartilage model. Results in
the formation of the long bones,
Bone laid dawn directly in fibrous mesenchymal
connective tissue. Results in the formation of the
cranial bones and the clavicles.
Bone marrow (yellow/red)
Diaphysis: shaft of a long bone which ossifies from primary
Epiphysis: ends and tips of bone which ossify from
Pressure epiphysis: articular and takes part in
transmission of weight. Eg. Head of femur, lower end of
Traction epiphysis: non articular- provides attachment of
one or more tendons which exert a traction on epiphysis.
These ossify later than the pressure epiphysis.
Atavistic epiphysis: independent bone- which in man is
fused to another bone- coracoid process of scapula
Aberrant epiphysis: not always present- head of the 1st
metacarpal and base of the other metacarpals
Epiphyseal plate of cartilage: separates epiphysis from
metaphysis. Proliferation of cells
lengthwise growth of a long bone
Metaphysis: ends of diaphysis merging into the
epiphysis. Zone of active growth. Richly supplied by
blood vessels. Common site for osteomyelitis because
of entrapment of bacteria and emboli in the bend of
the blood vessels
Covering the long bone in all area, except the articular
surfaces is periosteum.
Deep to the periosteum is a layer of compact bone
This layer is thicker in the diaphysis than the epiphysis
Covering the articular surfaces is articular cartilage, or
In the diaphysis of the long bone deep to the compact bone
is the medullary cavity.
In the adult it is full of yellow bone marrow.
The medullary cavity is lined with endosteom.
In the epyphysis deep to the layer of compact bone is
Between the trabacula of the spongy bone is red bone