An overview of the human skeleton

1. ANATOMY OF THE HUMAN
SKELETON
PRESENTED
BY
CHIOMA GOODNESS EZEH

2. OUTLINE
• INTRODUCTION
• SKELETAL SYSTEM ( MEANING )
• GROSS ANATOMY OF THE SKELETAL SYSTEM
• TYPES OF BONES
• JOINTS
• MICROSCOPIC STRUCTURE OF BONES
• THE SKULL
• VERTEBRAE
• RIBS AND STERNUM
• PECTORAL GIRDLE AND UPPER LIMB
• PELVIC GIRDLE AND LOWER LIMB
• FACTS ABOUT THE SKELETAL SYSTEM
• FUNTIONS OF THE SKELETON
• COMMON CONDITIONS THAT AFFECTS THE SKELETAL SYSTEM
• TIPS FOR A HEALTHY SKELETAL SYSTEM
• SUMMARY
• REFERENCES

3. INTRODUCTION
• The human skeleton is a unique structure that has adapted to the needs of
bipedal locomotion and erect posture. The structural peculiarities of the human
skeleton gives humans their characteristic appearance and facial geometry.
• The bony structure provides the shape and framework on which the human
body is designed and functions. It houses and protects vital organs, it contains
bone marrow which is the functional unit of the hematopoiesis system and it
provides attachments and anchorage to muscles, ligaments and joint capsules.
Bone often acts as levers which in conjunction with muscular contraction
initiate and sustain movements.

4. WHAT IS SKELETAL SYSTEM?
• The skeletal system is your body’s framework .
• It consists of bones and connective tissues including
cartilages, tendons and ligaments.
• It’s also called MUSCULOSKELETAL SYSTEM.

5. GROSS ANATOMY OF THE SKELETAL
SYSTEM
• The bony skeleton is divided into 2 parts;
• The Axial Skeleton: This is the central core unit
consisting of the skull, vertebrae, ribs and sternum.
• The Appendicular Skeleton: The appendicular skeleton
comprises of the bones at the extremities.
•

6. •The adult human skeleton consists of 206
bones of which 126 are part of the
appendicular skeleton, 74 are parts of the
axial skeleton and 6 are parts of the auditory
ossicles (bones in the middle ear).
•Bone is a solid organ that appears pinkish
white externally and deep red internally
when in a fresh state.

7. • Essentially, bone is of 2 types:
• The Compact or Cortical Bone: These are well-packed and densely organized
bones, they appear ivory-like and is very strong. This type of bone is mainly
found in the diaphysis of long bones.
• The Cancellous or Woven Bones: These bones on the other hand has loosely
woven lattices with relatively less dense organization of the bone tissue. This
type of bone is found in the epiphyses and metaphysis of long bones among
other locations.
• NOTE: The relative quantities of compact and cancellous bone vary in
different locations depending on the relative requirements for strength and
flexibility, respectively at a given site.

8. TYPES OF BONES
• Anatomically, the different types of bones are traditionally grouped into the
following;
• Long Bones: This includes; Clavicles, Humerus, Radius, Ulna,
Metacarpals, Femur, Tibia, Fibula, Metatarsals, and Phalanges.
• NOTE: Metacarpals, metatarsals and phalanges are sometimes referred to
as short-long bones.
• Flat Bones: This includes; the skull, mandible, scapula, sternum and ribs.
• Short Bones: This includes; Carpals, Tarsals, and Patella.
• Sesamoid (Irregular Bones): This includes; vertebrae, Sacrum, Coccyx and
hyoid bone.

9. • The long bone itself has different parts as follows;
• Diaphysis: This is the central and cortical shaft of a long bone; the narrowest
part of diaphysis is often referred to as the ISTHMUS of the long bone.
• Metaphysis: The diaphysis flares on either sides to form the metaphysis
which is essentially cancellous bones.
• Epiphysis: This lies on either ends of the long bone. In adults, it is the
remnant of the growing end of the bone, whereas in a child, the ends of the
long bone possess the growth plate and the epiphysis.
• Medullary Cavity: This is the cavity within the long bone, it contains bone
marrow and it’s constituents.

10. • Bone is covered by a membrane called the
PERIOSTEUM. The inner medullary cavity is lined
with a membrane called the ENDOSTEUM.

11. JOINTS
• The ends of bones articulates to form mobile units termed JOINTS. These
are essentially the connections between the bony elements of the skeleton. In
terms of the type of tissue that bridges them, joints may be described as
synovial or fibrous, cartilage or bony.

12. MICROSCOPIC STRUCTURE OF BONES
• The skeleton makes up about 30-40% of an adult’s body mass. The skeleton’s mass
is made up of bone matrix and many tiny bone cells. Roughly half of the bone
matrix’s mass is water while the other half is collagen protein and solid crystals of
calcium carbonate and calcium phosphate.
• Living bones cells are found on the edges of bones and in small cavities inside of
the bone matrix. Although these cells make up very little of the total bone mass, they
have several very important roles in the functions of the skeletal system. The bone
cells allow bones to;
1. Grow and develop.
2. Be repaired following an injury or daily wear.
3. Be broken down to release their stored minerals.

13. THE SKULL
• The skull is composed of 23 bones in the skull. Including the bones of
the middle ear and the hyoid bone, the head contains 29 bones. They are
fused together except for the mandible. These bones are separate In
children to allow the skull and brain grow but fuse to give added strength
and protection as an adult. The mandible remains as a movable jaw bone
and forms the only movable joint in the skull with the temporal bone.
The skull is divided into three parts; namely;
• CRANIAL BONES
• FACIAL BONES
• MIDDLE EARS BONES

14. CRANIAL BONES
• They are the bones of the superior potion of the skull and they protect the brain
from damage.
It consists of 8 bones namely;
• Occipital bone
• Parietal bone- 2
• Frontal bone
• Temporal bone-2
• Sphenoid bone (sometimes counted as facial)
• Ethmoid bone (sometimes counted as facial)

15. FACIAL BONES
• They are the bones of the inferior and anterior portion of the skull known as the facial bones
and support the eyes, nose and mouth.
It consists of 15 bones namely;
• Nasal bones-2
• Maxilae(upper jaw)-2
• Lacrimal bone-2
• Zygomatic bone (check bone)-2
• Palatine bone -2
• Inferior nasal concha-2
• Vomer - 1
• Hyoid bone -1
• Mandible-1

16. MIDDLE EARS BONES
It consists of 6 bones namely;
• Malleus-2
• Incus-2
• Stapes-2

17. VERTEBRAE
26 Vertebrae forms the vertebral column of the human body. They are named by
region;
• Cervical(Neck)-7 vertebrae
• Thoracic(Chest)- 12 vertebrae
• Lumbar(Lower back)-5 vertebrae
• Sacrum- 1 vertebrae
• Coccyx(Tailbone)- 1 vertebrae

18. RIBS AND STERNUM
• The sternum or breastbone is a thin knife-shaped bone located along the midline of
the anterior side of the thoracic region of the skeleton. The sternum connects to the
ribs by thin bands of cartilage called the costal cartilage.
• There are 12 pairs of ribs that together with the sternum forms the because they
connect the thoracic vertebrae directly to the sternum through their own band of
costal cartilage.
• Ribs 8, 9 and 10 are connected to the sternum through cartilage that is connected to
the cartilage of the seventh rib, so we consider these to be “ FALSE RIBS”.
• Ribs 11 and 12 are also false ribs but are also considered to be “FLOATING RIBS”
because they don’t have any cartilage attachments to the sternum at all.

19. PECTORAL GIRDLE AND UPPER LIMB
• The pectoral girdle connects the upper limb (arm) bone to the axial skeleton and
consists of the left and right clavicles (collar bone) and scapulae (pair of large
triangular bones).
• The humerus is the bone of the upper arm. It forms the ball and socket joints of the
shoulder with the scapula and forms the elbow joint with the lower arm bones.
• The radius and ulna are the 2 bones of the forearm.
• The ulna is on the medial side of the forearm and forms a hinge joint with the
humerus at the elbow.
• The radius allows the forearm and hand to turn over at the wrist joint.
• The lower arm bones form the wrist joints with carpals, a group of 8 small bones
that gives added flexibility to the wrist.
• The carpals are connected to the 5 metacarpals that forms the bones of the hand and
connects to each of the fingers. Each fingers have 3 bones known as phalanges,
except for the thumb which only has 2 phalanges.

20. Bones of the carpals includes:
• Scaphoid bone
• Lunate bone
• Triquetral bone
• Pisiform bone
• Trapezium bone
• Trapezoid bone
• Capitate bone
• Hamate bone

21. Bones of the metacarpals incudes;
• Proximal phalanges - 5 on each fingers.
• Intermediate phalanges - 4 on each fingers.
• Distal phalanges – 5 on both fingers.

22. PELVIC GIRDLE AND LOWER LIMB
• Formed by the left and right hip bone, the pelvic girdle connects the lower limbs (leg) bones to
the axial skeleton.
• The femur is the largest bone in the body and the only bone of the thigh (femoral) region. The
femur forms the ball and socket hip joint with the hip bone and forms the knee joint with the
tibia and patella.
• Commonly called the kneecap, the patella is special because it is one of the few bones that are
not present at birth. The patella forms in early childhood to support the knee for walking and
crawling.
• The tibia and fibula are the bones of the lower leg. The tibia are much longer than the fibula and
bears almost all of the body’s weight.
• The fibula is mainly a muscle attachment point and its used to help maintain balance. The tibia
and fibula form the ankle joint with the talus, one of the 7 tarsal bones in the foot.
• The tarsals are a group of 7 small bones that form the posterior end of the foot and heel. The
tarsals form joints with the 5 long metatarsals of the foot. Then each of the metatarsals form a
joint with one set of phalanges in the toes. Each toe has three phalanges, except for the big toe
which has only 2 phalanges.

23. Bones of the tarsals includes
• Calcaneus or heel bone.
• Talus.
• Navicular bone.
• Medial cuneiform bone
• Intermediate cuneiform bone
• Lateral cuneiform bone
• Cuboid bone.

24. FACTS ABOUT THE SKELETAL
SYSTEM
• The hand contains more bones (27 individual bones).
• Most red and white blood cells are created in the bone marrow.
• The stapes, a stirrup – shaped bone located deep in the ear is the body’s
smallest bone.
• Bone stores about 99% of the calcium in your body and are composed of
about 25% water.
• Your skeleton completely replaces itself every 10 years or there about
through remodeling.

25. FUNCTIONS OF THE SKELETON
• The human skeleton performs 6 major functions;
• Support
• Movement
• Protection
• Production of blood cells
• Storage of minerals
• Endocrine regulation

26. COMMON CONDITIONS THAT AFFECTS
THE SKELETAL SYSTEM
• ARTHRITIS: Age, injury and medical conditions can lead to arthritis , a painful wearing
down of joints.
• FRACTURE: Disease, tumor or trauma can put stress on a bone causing it to break.
• OSTEOSARCOMA: Cancer that forms in the bone can cause tumors that may weaken
and break bones.
• OSTEOPOROSIS: Bone loss caused by not getting enough calcium can lead to fragile
and brittle bones known as osteoporosis.
• SPRAIN AND TEARS: Age, disease, and trauma can cause connective tissues to
overstretch and tear.
• SPINAL CURVATURES: This is when the spine doesn’t curve in it’s usual shape.
Typically, the spine follows gentle forward or backward curves.

27. SPINAL CURVATURES
• There are three main types of spinal curvatures:
• Kyphosis: Creates a rounding in the upper back.
• Lordosis: Causes the lower back to curve inwards.
• Scoliosis: Causes an S- or C- shaped curve in the spine.

28. TIPS FOR HEALTHY SKELETAL
SYSTEM
• Consume calcium
• Get enough vitamin D
• Do weight- bearing exercises
• Wear protective gears

29. SUMMARY
• The skeletal system is your body’s framework.
• The skeletal system Is divided into axial and appendicular skeleton.
• The skull is composed of 29 bones in general.
• The vertebral column has 26 bones in total.
• There are 12 pairs of ribs that forms the rib cage with the sternum in the thoracic
region.
• The hand has 54 bones
• The foot has 52 bones
• Wearing of protective gears can help maintain a healthy skeletal system

30. REFERENCES
• HUMAN BODY (206) – RENSSELAER POLYTECHNIC INSTITUTE
• MAMMAL ANATOMY – AN ILLUSTRATED GUIDE