This document provides an overview of the human skeleton for students of Gulf Medical University. It begins by stating the learning objectives, which are to name parts of the skeleton, identify bones and explain their purposes, list bones by body part, and classify bones by origin, shape and structure. The document then defines the skeleton and its functions. It proceeds to describe bones in more detail, covering their composition, functions, classification by shape, development, body region, and microscopic and macroscopic structure. Diagrams are included to illustrate bone structures like the diaphysis, epiphysis, growth plate, and bone tissues.

2. For the students of Gulf Medical University, Ajman,
DMD
Dr. Seyed Morteza Mahmoudi,
MBBS
Gulf Medical University, Ajman

3.  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
structure

7.  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.

8. What are Bones (Oss)?
What are their functions?

9.  Bone is a specialized connective tissue, consisting of cells, fibers
and extracellular matrix. It’s a hard clacific, with adynamic
structure.
 Functions:
 Mechanical




Protection
Movement
Structure
Sound transduction
 Synthetic,
 Hematopoiesis
 Metabolic
 Mineral storage
 Acid base balance
 Endocrine function

10.  8 cranial
 14 facial
 6 ear bones
 Hyoid bone
 26 vertebrae (7 cervical, 12 thorax, 5 lumbar, the sacrum
which is five fused vertebrae, and the coccyx which is four
fused vertebrae)
 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

12. How do we classify bones?

13. Contents
Classification of bones
Shape
Development
Region
Structure

14. Shape
Long bones
Short bones
Flat bones
Irregular bones
Pneumatic bones
Sesamoid bones
Accessory bones

15.  Long bones:
 Shaft with two ends
 Develop by intracartilagenous ossification
 Three centers of ossification
 Central medullary cavity
 Nutrient foramina
 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
 E.g. clavicle

16.  Have no shaft or ends
 Shape is cuboid, trapizoid or cuniform.
 Carpal and tarsl bones

17.  Skull
 Ribs
 Sternum
 Scapula

19.  Bone that contain air-filled spaces

20.  Bony nodules embedded in tendons/ joints
 No periosteum and ossify after birth
 E.g. Patella, pisiform

22. Contents
Classification of bones
Shape
Development
Region
Structure

23. Development
Crtilaginous bones
Membraneous bones
Membrano-cartilaginous bones

24.  All bones: mesodermal origin.
 Process of bone formation: ossification
Endochondral
Formed in a hyaline cartilage model. Results in
the formation of the long bones,
Intramembraneous
Bone laid dawn directly in fibrous mesenchymal
connective tissue. Results in the formation of the
cranial bones and the clavicles.

25. Osteoblasts
Osteocytes
Osteoclasts

27.  Cartilaginous bones: ossify over a cartilagenous
tissue: bones of limbs, vertebral column
 Membraneous bones: ossify over mesenchymal
tissue: vault, facial bones
 Membrano-cartilaginous bones: partly from
cartilage and partly from mesenchymal ossification:
clavicle, mandible

28. Contents
Classification of bones
Shape
Development
Region
Structure

29. Region
Axial Skeleton
Appendicular Skeleton

31. Contents
Classification of bones
Shape
Development
Region
Structure

32. Structure
Macroscopic
Microscopic
• Compact:
dense, cortex
of long bones
• Cancellous:
meshwork of
trabeculae
• Lamellar :
mature
human bones
• Fibrous:
young fetal
bones

37. Diaphysis
Epiphysis
Epiphyseal growth plate
Metaphysis

38. Periosteum
Endosteum
Bone marrow (yellow/red)
Hyaline cartilage

39.  Diaphysis: shaft of a long bone which ossifies from primary





center
Epiphysis: ends and tips of bone which ossify from
secondary centre
Pressure epiphysis: articular and takes part in
transmission of weight. Eg. Head of femur, lower end of
radius
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

40.  Epiphyseal plate of cartilage: separates epiphysis from
metaphysis. Proliferation of cells
lengthwise growth of a long bone
in
cartilage-
 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

42.  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
hyaline cartilage.

43.  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
spongy bone.
 Between the trabacula of the spongy bone is red bone
marrow.

44.  Nutrient artery
 Periosteal artery
 Epiphyseal artery
 Metaphyseal artery