Skeletal System - Human Anatomy (Bone structure)

Skeletal System - Human Anatomy

1. Skeletal System

2. 21-2
Introduction
•Bones provide the
body with structure
and support
•206 bones with joints
and connective tissue
•Divisions
–Axial – 80 bones
•Skull
•Vertebral column
•Rib cage
–Appendicular – 126
bones
•Arms and legs
•Pectoral girdle
•Pelvic girdle

3. 21-3
The Skeletal System

4. 21-4
Bone Structure
•Bones contain various
kinds of tissues,
including
–Osseous tissue
–Blood vessels
–Nerves
•Osseous tissue can
appear compact or
spongy
Compact Bone
Spongy
Bone

5. 21-5
Bone Structure
•Compact bone looks
solid
–Structures can be
observed with a
microscope
•All bones are made
up of both compact
and spongy bone

6. 21-6
Bone Structure

7. 21-7
Bone Structure
•Flat bones – located in the skull and rib
cage
–Ribs
–Frontal bone
•Irregular bones
–Vertebrae
–Bones of the pelvic girdle

8. 21-8
Gender Differences
•Male Skull
–Larger and heavier
–Forehead shorter
–Face less round
–Jaw larger
–Mastoid processes
more prominent
•Male pelvic bones
–Heavier and thicker
–Obturator foramina
and acetabula are
larger and closer
together

9. 21-9
Gender Differences
•Male pelvic cavity
–Narrower and longer
–Less roomy and more
funnel shaped
•Male sacrum
–Narrower
–Sacral promontory
projects forward
–Sacral curvature is
less sharp posteriorly
•Male coccyx
–Less movable

10. 21-10
Functions of Bones
•Give shape to body parts
•Support and protect soft structures
– Examples – brain, lungs, heart
•Allow body movement, because skeletal muscles attach
to them
–Allow for voluntary movement

11. 21-11
Functions of Bones
•Red bone marrow of
bone produces new
blood cells –
hematopoiesis
•Store calcium

12. 21-12
Apply Your Knowledge
ANSWER: Every cell in the body needs calcium, so the
body must have a large supply readily available.
Why is it important for the bones to store calcium?

13. 21-13
Bone Growth
•Ossification – process
of bone growth
•Intramembranous
ossification
–Bones begin as tough,
fibrous membrane
–Bone-forming cells called
osteoblasts turn the
membrane to bone
(located in skull)

14. 21-14
Bone Growth (cont.)
•Endochondral ossification
–Bones begin as cartilage
models
–Primary ossification center
•Bone formed in the diaphysis
–Secondary ossification center
•Epiphyses turn to bone
•Bones with some cartilage between an epiphysis and the
diaphysis will continue to grow
–Medullary cavity and spaces in cancellous bone
form
•Cells that form holes in bone are called osteoclasts

15. 21-15
Building Better Bones
•Teach healthy behaviors
–Bone-healthy diet with calcium and
vitamin D
–Bone-health exercises
 Weight-bearing
 Strength training
–Bone-healthy lifestyle
 Avoid smoking
 Avoid alcohol

16. 21-16
Bone Tests
•Bone density
•Bone scans
•Diagnose causes of
 Bone pain
 Arthritis
 Bone infections
 Bone cancers

17. 21-18
Bony Structures
•Rigid foundation
•Projections and processes for muscle and
ligament attachment
•Depressions and hollows for articulations
– the connection of bones at joints
•Openings for blood vessels and nerves

18. 21-19
Bony Structures
Term Definition
Condyle A rounded process that usually articulates
with another bone
Crest A narrow, ridge-like projection
EpicondyleA projection situated above a condyle
Foramen An opening through a bone that is usually
a passageway for blood vessels, nerves,
or ligaments
Fossa A relatively deep pit or depression

19. 21-20
Bony Structures
Term Definition
Head An enlargement on the end of a bone
Process A prominent projection on a bone
Suture An interlocking line of union between
bones
TrochanterA relatively large process
Tubercle A small, knoblike process
TuberosityA knoblike process, usually larger than a
tubercle

20. http://slideplayer.com/slide/4445808/

22. 21-23
The Skull
•Two bone types:
–Cranial – form the top, sides, and back of the
skull
–Facial – form the face
“Soft spots” felt on an infant's skull are actually
fontanels
➢Tough membranes that connect the incompletely
developed bones

23. 21-24
Cranial Bones
•Frontal – anterior
•Parietal – top and
most of the sides
•Occipital – back
•Temporal – form the
lower sides of the
skull
•Sphenoid and
ethmoid bones –
floor
•Ear ossicles are the
smallest bones of the
body
–Malleus
–Incus
–Stapes

24. 21-25
The Skull (cont.)
•Mandible – forms the
lower jawbone
•Maxillae – form the upper
jawbone
•Zygomatic – form the
prominence of the cheeks
•Nasal bones – fuse
together to form the
bridge of the nose
•Palatine – form the
anterior portion of the
palate
•Vomer – a thin bone that
divides the nasal cavity
Click to see
Skull

25. 21-27
The Spinal Column
•7 cervical vertebrae
•12 thoracic vertebrae
• 5 lumbar vertebrae
•Sacrum
•Coccyx

26. 21-28
The Spinal Column (cont.)
•Cervical vertebrae
–Smallest and lightest
–Located in the neck
region
–First one is atlas
–Second one is axis
•Thoracic vertebrae
–Join the 12 pairs of
ribs
•Lumbar vertebrae
–Have very sturdy
structures

27. 21-29
The Spinal Column (cont.)
•Sacrum
–A triangular-shaped bone that consists of five
fused vertebrae
•Coccyx
–A small, triangular-shaped bone made up of 3
to 5 fused vertebrae
–Considered unnecessary
–More commonly called the tailbone

28. 21-30
Apply Your Knowledge
Identify the sections
of the spinal column
and give the
number of
vertebrae for each.
Thoracic – 12
Lumbar – 5
Sacrum –
5 fused
Coccyx –
3 to 5 fused
Cervical – 7
ANSWER:

29. 21-31
The Rib Cage
•Sternum
–Breastplate
–Forms the front
middle portion of
the rib cage
–Joins with the
clavicles and
most ribs
–Xiphoid process
•Cartilaginous tip

30. 21-32
The Rib Cage (cont.)
•12 pairs of ribs
–All are attached
posteriorly to
thoracic vertebrae
–True
•First seven pairs of
ribs
•Attach to sternum
by costal cartilage
–False
•Rib pairs 8, 9, and
10
•Attach to the costal
cartilage of rib pair
7
–Floating
•Rib pairs 11 and 12
•Do not attach
anteriorly to any
structure

31. 21-33
Bones of the Shoulders, Arms, and Hands
•Shoulders – pectoral
girdles
–Clavicles
–Scapulae
•Upper limb or arm
bones
–Humerus
–Radius
–Ulna

32. 21-34
Bones of the Shoulders, Arms, and Hands
(cont.)
•Hand
–8 carpals per hand
–5 metacarpals per
hand
–14 phalanges per
hand
•3 in each finger
•2 in each thumb

33. 21-35
Bones of the Hips, Legs, and Feet
•Hipbones
–Coxal bones form
the pelvic girdle
•Ilium
•Ischium
•Pubis

34. 21-36
Bones of the Hips, Legs, and Feet (cont.)
•Bones of leg
–Femur
–Patella
–Tibia
–Fibula

35. 21-37
Bones of the Hips, Legs, and Feet (cont.)
•Bones of the foot
–Tarsals
–Metatarsals
–Phalanges

36. 21-38
Joints
•Junctions between bones
•Classification based on
structure
–Fibrous joints
•Connected together with
short fibers
•Between cranial bones and
facial bones
•Sutures – fibrous joints in the
skull

37. 21-39
Joints
–Cartilaginous
joints
•Connected
together with
a disc of
cartilage
•Between
vertebrae

38. 21-40
Joints
–Synovial joints
•Covered with hyaline cartilage
•Held together by a fibrous joint
capsulelined with synovial
membrane
–Secretes synovial fluid so bones
move easily against each other
•Freely movable
•Bones are also held together through
tough, cord-like structures called ligaments

39. 21-41
Common Diseases and Disorders
•Arthritis – general term meaning
joint inflammation
–Osteoarthritis – degenerative joint
disease, primarily of weight-bearing
joints
–Rheumatoid arthritis – chronic
systemic inflammatory disease of
smaller joints and surrounding tissues

40. 21-42
Common Diseases and Disorders (cont.)
•Bursitis – inflammation of a bursa (fluid-
filled sac that cushions tendons)
•Carpal tunnel syndrome – overuse of
wrist; the median nerve in the wrist
becomes compressed
•Ewing’s family of tumors (EFT) – a group
of tumors that affect different tissue types;
primarily bone
•Gout – a type of arthritis; deposits of uric
acid crystals in the joints

41. 21-43
Common Diseases and Disorders (cont.)
•Kyphosis – abnormal curvature of the
spine (humpback)
•Lordosis – exaggerated inward curvature
of the lumbar spine (swayback)
•Osteogenesis imperfecta – brittle-bone
disease
•Osteoporosis – a condition in which
bones thin (become porous) over time

42. 21-44
Common Diseases and Disorders (cont.)
•Osteosarcoma – a type of bone cancer that
originates from osteoblasts, the cells that make
bony tissue
•Paget’s disease – causes bones to
enlarge and become deformed
and weak

•Scoliosis – an abnormal
S-shaped curvature of
the spine

43. 21-46
In Summary
21.1 Bones consist of the following substances: Osteons or
Haversian systems, bone matrix between osteocytes
(bone cells), collagen fibers and proteins, the lamella,
and canaliculi.
21.2 Diaphysis is the shaft of a long bone. Epiphysis is an
end of a long bone. Articular cartilage covers the end
of long bones. The medullary cavity is lined by the
endosteum. The periosteum is the membrane
surrounding the diaphysis.
21.3 Bone functions include giving shape to body parts,
protecting the soft structures of the body, and
assisting in movement. The red bone marrow is
responsible for hematopoiesis. Bones also store
calcium.

44. 21-47
In Summary (cont.)
21.4 Long bones include the femur and humerus; short
bones include the carpals and tarsals; flat bones
include the ribs and frontal bone; irregular bones
include the vertebrae and bones of the pelvic girdle.
21.5 Bones grow through the two types of ossification:
intramembranous ossification and endochondral
ossification. The cartilage plate between the diaphysis
and epiphysis allows for growth of the long bone.
21.6 Skeletal structures include the following: Condyles,
crests, epicondyles, foramens, fossas, heads,
processes, sutures, trochanters, tubercles and
tuberosities.

45. 21-48
In Summary (cont.)
21.7 The major bones of the skull are the frontal, parietal,
temporal, and occipital bones. Within the skull are the
mastoid processes, sphenoid, ethmoid, and ear
ossicles. The facial bones include mandible, maxilla,
zygomatic, nasal and palatine bones, and vomer. The
spinal column includes cervical, thoracic, and lumbar
vertebrae and the sacrum and coccyx. There are12
pair of ribs, a sternum, and xiphoid process. An upper
extremity includes the clavicle, scapula, humerus,
radius, ulna, carpals, metacarpals, and phalanges.
The bones of the hip, leg, and foot include the coxal
bones, femur, patella, tibia, fibula, metatarsals,
tarsals, and phalanges.

46. 21-49
In Summary (cont.)
21.8 The fontanels are the membranous structures that
connect the incompletely developed cranial bones.
21.9 The three joint types are fibrous joints, cartilaginous
joints, and synovial joints.
21.10 A synovial joint consists of hyaline-covered bones
held together by a fibrous joint capsule, which is
lined by a synovial membrane that secretes synovial
fluid. Ligaments hold the bones of these joints
together.

47. 21-50
In Summary (cont.)
21.11 There are many diseases and disorders of bones
and skeletal system with varied signs, symptoms,
and treatments found in the Pathophysiology section
of this chapter. Some of the common diseases and
disorders discussed include arthritis, bursitis, carpal
tunnel syndrome, EFT, gout, kyphosis, lordosis, and
scoliosis, as well as osteoporosis and osteosarcoma.

48. 21-51
Rigid, the skeleton of
habit alone upholds the
human frame.
~ Virginia Woolf