The document provides an overview of the skeletal system, including: 1. Bones are made of tissues like osseous tissue, cartilage, and connective tissue. The skeletal system framework includes bones and cartilages. 2. There are 206 bones in the adult human skeleton, divided into the axial skeleton (skull, vertebral column, ribs, sternum) and appendicular skeleton (limbs and their attachments). 3. Key bones include the skull, vertebrae, ribs, sternum, clavicles, and bones of the upper and lower limbs. The skull has 28 bones including cranial and facial bones.

1. SKELETAL SYSTEM
MRS BINCY VARGHESE
CLINICAL INSTRUCTOR
KGMU INSTITUTE OF NURSING
LUCKNOW, INDIA

2. INTRODUCTION
1. BONES: Structure, function, types,
histology, bone formation, bone
growth.
2. SKELETAL SYSTEM: Divisions,
skull, facial bones, hyoid bone,
vertebral column.

3. BONE
Bone is made up of Osseous tissue,
cartilage, dense connective tissue,
epithelium, adipose tissue.
The entire framework of bones and
cartilages constitute the “Skeletal
System”.

4.  The bones, muscles and joints
together form “Musculoskeletal
system”
 The branch of medical science
concerned with the prevention or
correction of disorders of the
musculoskeletal system is called
“Orthopedics”

5. FUNCTIONS OF BONE
 Support
 Protection
 Assists movement
 Mineral storage
 Hematopoesis

6. STRUCTURE OF BONE

9. TYPES OF BONES
LONG BONES
SHORT BONES
FLAT BONES
IRREGULAR BONES
SESAMOID BONES

12. TYPES OF BONE TISSUE
 Compact bone tissue
 Spongy bone tissue

14. MICROSCOPIC STRUCTURE OF
BONE
Bone may be Compact or Spongy.
1. Compact Bone
 Strongest form of bone tissue with few
spaces.
 Found beneath the periosteum.
 Provides protection, support, resists the
pressure produced by weight and
movement.

15. COMPACT BONE
 Few spaces, found beneath the Periostuem
 Consist of:
1. The main structural unit is called
OSTEON.
2. Each Osteon consist of a CONCENTRIC
LAMELLAE arranged around CENTRAL
CANAL.
3. Radiating from lacunae are tiny
projections called CANALICULI.

16. 4. Blood vessels, nerves, lymphatic vessels
from periosteum penetrate the Compact
bone through VOLKMANN’S CANAL/
PERFORATING CANALS.
5. Arranged around the entire outer and
inner circumference of bone are
CIRCUMFERENTIAL LAMELLAE.

17. Spongy or Cancellous Bone
 Makes the bone light.
 Short, flat and irregularly shaped bone
contain spongy bone tissue.
 Consist of lamellae arranged in irregular
pattern called TRABECULAE.
 Between these Trabeculae are spaces filled
with yellow and red bone marrow.
 The trabeculae consist of concentric
lamellae, lacunae and canliculi

18. HISTOLOGY OF BONE TISSUE
Called Osseous Tissue.
It contains extracellular matrix or bone
matrix which is composed of 25% water,
25% collagen fibers and 50% crystallized
mineral salts.
As these mineral salts are deposited in
the extracellular matrix, they crystallize
and the tissue hardens. This process is
known as Calcification.

19. BONE CELLS
Four types of cells:
 Osteogenic cells
 Osteoblasts
 Osteocytes
 Osteoclasts

20. BLOOD SUPPLY
1. Periosteal arteries
2. Nutrient artery
3. Metaphyseal arteries
4. Epiphyseal arteries

21. DIVISIONS OF THE SKELETAL SYSTEM
 The human skeleton consists of 206
named bones.
 Bones of the skeleton are grouped into
two principal divisions:
I) Axial skeleton
II) Appendicular skeleton

22. I) Axial skeleton
 Consists of the bones that lie around
the longitudinal axis of the human body
 Skull bones, hyoid bone, ribs, sternum
and bones of the vertebral column

23. Skull
Sternum
Ribs
VertebralColumn
Axial Skeleton

24. I) Appendicular skeleton
 Consists of the bones of the limbs
including the bones of the pectoral and
pelvic girdle.

25. APPENDICULAR SKELETON
PECTORAL/SHOULDER GIRDLE
CLAVICLE
SCAPULA
BONES OF UPPER LIMB
PELVIC GIRDLE
BONES OF LOWER LIMB

27. AXIAL SKELETON
1. SKULL: Cranium and facial bones
2. HYOID BONE
3. RIBS AND STERNUM
4. VERTEBRAL COLUMN

28. BONES OF AXIAL SKELETON
 SKULL: 28 BONES
 HYOID BONE: 01
 VERTEBRAL COLUMN: 26
 STERNUM AND RIBS: 25

29. SKULL
28 irregularly shaped bones form
the skull.
 Cranium: 8 bones
 Facial bones: 14
 Auditory Ossicles: 6

30. SKULL
Divided into two parts:
a) Calvaria/ Cranium
b) Face

31. CRANIAL BONES
 Enclose the cranial cavity
 Which contains the brain and its
fluids, blood vessels, nerves, and
membranes

32. THE CRANIAL BONES
 Occipital bone
 Frontal bone
 Sphenoid
 Ethmoid
 Parietal bones: Paired
 Temporal bones: Paired

33. A) CALVARIA/CRANIUM
Frontal Bone
Parietal Bone
Temporal Bone
Occipital Bone

35. THE 4 MAJOR SUTURES
“The immovable joints of the skull”
1. Coronal suture
2. Sagittal suture
3. Lambdoid suture
4. Squamous suture

36. SUTURES
Figure 7–3a, b

37. CORONAL SUTURE
Attaches frontal bone to parietal
bones

38. SAGITTAL SUTURE
Between the parietal bones.

39. LAMBDOID SUTURE
Separates occipital from parietal
bones

40. SQUAMOUS SUTURES
Form boundaries between
temporal bones and parietal
bones

41. WHAT ARE THE BONES OF THE CRANIUM?

42. THE FRONTAL BONE
Figure 7–6

43. SKULL

44. THE PARIETAL BONES
Figure 7–5b

45. THE OCCIPITAL BONE
Figure 7–5a

46. THE TEMPORAL BONES
Figure 7–7

47. THE SPHENOID
Figure 7–8

48. THE ETHMOID
Figure 7–9

49. THE INFANT SKULL
Figure 7–15

50. THE 4 FONTANELS
 Anterior/Frontal fontanel
 Posterior/Occipital fontanel
 Sphenoid fontanel
 Mastoid fontanel

51. FACIAL BONES
Nasal Bones (2)
Form the bridge of the nose
Maxillae (2)
 Form the upper jawbone
 Form most of the hard palate
 Separates the nasal cavity from the oral
cavity. Contains maxillary sinus.

52. Figure 7–11

53. MAXILLAE

54. Zygomatic Bones (2)
 Commonly called cheekbones, form the
prominences of the cheeks
Lacrimal Bones (2)
 Resemble finger nail in size and shape.
They are posterior to nasal bone. Form
a part of the medial wall of each orbit

55. Palatine Bones (2)
 L shaped, form the posterior portion of
the hard palate, part of the floor of nasal
cavity
Inferior Nasal Conchae (2)
 Form a part of the inferior lateral wall of
the nasal cavity. Helps to filter the air in
nasal cavity.

56. Vomer (1)
 Roughly triangular bone, forms the
inferior portion of the nasal septum
Mandible (1)
 Lower jawbone, largest and strongest
facial bone, only movable skull bone

57. MANDIBLE

58. THE HYOID BONE
Figure 7–12c

59. THE HYOID BONE
 “U” shaped, does not articulate with
any other bone. It is suspended by
ligaments and muscles.
 Located in the anterior neck between
mandible and larynx.
 It supports tongue, provides attachment
site for tongue muscles and muscles of
neck and pharynx.
Figure 7–12c

60. WHAT ARE THE VERTEBRAL REGIONS,
THE CURVATURES OF THE VERTEBRAL
COLUMN, AND THEIR FUNCTIONS?

61. THE VERTEBRAL COLUMN
The spine, spinal column or vertebral
column:
 protects the spinal cord
 supports the head and body
It is composed of series of bones called
as Vertebrae.

62.  71 cm in adult male and 61 cm in adult
female.
 The adult vertebral column typically
contains 26 vertebrae.

63. 7 Cervical Vertebrae
(C1-C7)
12 Thoracic Vertebrae
(T1-T12)
5 Lumbar Vertebrae
(L1-L5)
1 Sacrum (consist of 5
fused sacral vertebrae)
1 Coccyx (4 fused
coccygeal vertebrae)

64. NORMAL CURVES OF THE VERTEBRAL
COLUMN

67. PRIMARY CURVES
Thoracic and sacral curves:
 are called primary curves (present
during fetal development)
SECONDARY CURVE
Lumbar and cervical curves:
 are called secondary curves (appear
after birth)

68. ABNORMAL CURVES

69. INTERVERTEBRAL DISCS
 Found between the bodies of adjacent
vertebrae from C2 to Sacrum. They are
pads of fibrocartilage.
 Absorb shocks, form strong joints and
permit various movements of the
vertebral column.

70. INTERVERTEBRAL
DISC

72. PARTS OF VERTEBRAE
 VERTEBRAL BODY
 VERTEBRAL ARCH
 PROCESSES

76. VERTEBRAL COLUMN (REGIONS)
Cervical Region
 Cervical vertebrae (C1–C7)
 The atlas (C1) is the first cervical vertebra
 The axis (C2) is the second cervical vertebra
Thoracic Region
 Thoracic vertebrae (T1–T12)
 Articulate with the ribs
Lumbar Region
 Lumbar vertebrae (L1–L5)
 Provide for the attachment of the large back muscles
Sacrum
 The sacrum is a triangular bone formed by the union of five sacral
vertebrae (S1–S5)
 Serves as a strong foundation for the pelvic girdle
Coccyx
 The coccyx, like the sacrum, is triangular in shape
 It is formed by the fusion of usually four coccygeal vertebrae

77. THE CERVICAL VERTEBRAE

78. Cervical Vertebrae

80. THORACIC VERTEBRAE

82. LUMBAR VERTEBRAE

84. SACRUM

85. THORAX
Thoracic cage is formed by the:
 Sternum
 Ribs
 Costal cartilages
 Thoracic vertebrae
Functions to:
 Enclose and protect the organs in the thoracic
cavity.
 Provide support for the bones of the upper
limbs
 Play a role in breathing

86. Sternum
 “Breastbone” located in the center of the
thoracic wall
 Consists of the manubrium, body, xiphoid
process
Ribs
 Twelve pairs of ribs give structural support to
the sides of the thoracic cavity
Costal cartilages
 Costal cartilages contribute to the elasticity of
the thoracic cage

89. RIBS

92. Sternum
True Ribs (7)
False Ribs (3)
Floating Ribs (2)

93. APPENDICULAR
SKELETON

94. BONES OF THE PECTORAL GIRDLE

95. ACROMION
CORACOID
PROCESS
GLENOID
CAVITY
LATERAL
(AXILLARY)
BORDER
MEDIAL
(VERTEBRAL)
BORDER
SUBSCAPULAR
FOSSA

96. Humerus
Ulna
Radius
Carpals
Metacarpals
Phalanges
The Upper Limb
(Forelimb)

101. PELVIS

102. Ischium
Ilium
Acetabulum
Pubis
Ischium
Obturator
foramen
Pelvis (lateral view)

103. Femur
Patella
Tibia
Fibula
Tarsals
Metatarsals
Phalanges
The Lower Limb

107. metatarsals
phelangies
tarsals
metatarsals
phelangies
tarsals

112. THANK
YOU