Human skeleton pptx. Punjab cuvas bhawalpur

1. SKELETAL SYSTEM
Dr. Muhammad Sajid
Department of Anatomy & Histology
CUVAS, Bahawalpur

2. Outline
Definition of Skeleton
Function of Skeleton
Skeleton System
Classification of Bone
Markings of Bones
Bone Surface Description

3. SKELETON
The framework of hard structures of body which supports and protects the soft tissues and organs of the
human.
It consist of mainly the:
 Bones.
 Supplemented by cartilage in many places and,
 The binding tissue called the ligament (Joint).
FUNCTION:
 It gives strength and proper shape to human body.
 Support and furnishes attachment to the soft tissues.
 Provide protection to delicate tissues/organs.
 Help in locomotion, act as a levers.
 Production of Blood cells (RBC, WBC & Platellets)
 Storage of minerals and growth factors
 Triglyceride (Fat) storage: Fat is stored in internal cavities of bones.
 Hormone production: bone is an endocrine organ. One hormone secreted by the osteoblasts, the bone-
forming cells, osteocalcin affects glucose homeostasis, energy expenditure and male fertility.

4. Functions of Bones

9. SKELETAL SYSTEM
Types of Skeleton
1. Appendicular Skeleton:
includes the bones of the thoracic girdle and forelimbs and the pelvic girdle and hind limbs.
2. Axial Skeleton:
consists of the bones of the skull, ear bones, hyoid apparatus and bones of the vertebral column, ribs, and
sternum.
Cervical, Thoracic, Lumbar, Sacral, and Caudal (formerly coccygeal).
Human Vertebral Column Formula: C7 T12 L5 S5 Cd4.

10. Upper Limb (1.Appendicular Skeleton) Lower Limb
1)Thoracic/Shoulder Girdle 1) Pelvic Girdle (1)
a) Scapula (1) a) Ilium
b) Clavicle (1) b) Ischium
2) Arm/ Brachium: Humerus (1) c) Pubis
3) Fore-arm/ Antibrachium: 2) Thigh: a) Femur(1)
Radius & Ulna(2) b) Patella(1)
4) Hand 3) Leg: Tibia & Fibula(2)
a) Carpals (8) 4) Foot: a) Tarsal (7)
b) Metacarpals (5) b) Metatarsals (5)
c) Phalanges (14) c) Phalanges (14)
(Total Bones in Upper Limb: 32x2:=64 bones) (Total Bones in Lower Limb: 31x2:=62 bones)

11. 2.Axial Skeleton
Axial skeleton forms the axis of human body. It consists of
1) Skull & Mandible : 22 bones,
2) Ossicles of the Middle Ear (Ear Bones): 3x2=6
3) Hyoid Bone: 1
4) Vertebral Column: 26 bones (5 sacral and 4 coccygeal bones are considered 1 bone
separately).
5) Thoracic Cage: a) Ribs (24) …….7 sternal, 3 asternal , 2 floating=12 pair
b) Sternum (1)

12. Classification of Bones
Classification of Bones on the basis of Structure: There are five types of bones.
1) Long Bones: These are greater in one dimension than the other.
Function: act as levers and aid in support, locomotion and prehension.
Examples: The bones of the limbs e.g. humerus, radius & ulna, femur and tibia & fibula etc.
2) Short Bones: These are somewhat cuboidal in shape.
Function: absorbing concussion
Examples: carpal and tarsal bones

13. Classification of Bones
3) Flat Bones: These are relatively thin and expanded in two dimensions.
Function: These are used for the protection of vital organs e.g. brain, heart, lungs, pelvic viscera
and provide large surface area for muscle attachment.
Examples: Scapula, frontal bone and ilium.
4) Irregular Bone: These are unpaired bones.
Function: These are important for protection, support and muscle attachment.
Examples: vertebrae and sternebrae.
5) Sesamoid Bones: These are like sesame seed.
Function: These are developed along the course of tendons to reduce friction or change the course
of tendons. Sesamoids act like pulleys, providing a smooth surface for tendons to slide over,
increasing the tendon's ability to transmit muscular forces.
Examples: Patella (knee cap).

14. Marking on the Bones
Process: Any prominent and roughened projection on a bone e.g. tuberosity,
tubercle, trochanter, spine and crest etc. coracoid process in scapula.
Tuberosity: is a large usually rounded roughened and non articular projection e.g.
Greater and Lesser tuberosities of Humerus.
Tubercle: A small rounded projection. e.g. supra and infra-glenoid tubercle in
Scapula.
Trochanter: A large blunt projection on the Femur bone.
Spine: A sharp thin elongated process e.g. spine of Scapula.
Crest: Prominent or well developed linear sharp ridge on the bone e.g. iliac crest
in ilium of os-coxae.

15. Marking on the Bones
Line: Less prominent or faint ridge. Inter-trochanteric line in Femur.
Foramen: An opening in the bone (for blood vessel and nerve) e.g. nutrient
foramen in Humerus.
Canal: is a tunnel through one or more bones. E.g. vertebral canal in
Vertebral Column.
Sinus: A large air cavity within a bone. E.g. Frontal sinus in Skull.
Fissure: a narrow cleft like opening between the adjacent bones e.g. Inferior
orbital fissure in Skull.
Meatus: a tube like canal through a bone e.g. external auditory meatus of Ear.

16. Marking on the Bones
Head: is a rounded, smooth, strongly convex articular projection, situated at the
end of the bone. E.g. head of humerus and femur.
Neck: is a constricted attachment between head and shaft of bone. E.g. neck of
humerus and femur.
Condyles: A large cylindrical shaped articular prominence, usually smooth and
convex at the end of the long bones e.g. condyles of Humerus and Femur.
Epicondyle: A roughened prominence just proximal to condyles e.g. Epicondyles of
Humerus and Femur.
Trochlea: Pulley shaped articular projection/structure e.g. Trochlea of Humerus
Cochlea: is an articular surface reciprocal to that of trochlea. Cochlea of Tibia.

17. Marking on the Bones
Fovea: is a small non-articular depression. E.g. fovea of femur.
Notch: Depression/cut on the edge of bone. E.g. semilunar or trochlear notch in
Ulna.
Groove: Small narrow furrow accommodating vessels, nerve or tendon e.g.
intertubercle groove (sulcus) of humerus.
Facet: Is a small articular surface, which may be flat, concave or convex. e.g.
costal facet in Thoracic vertebrae and Ribs. Mostly covered by hyaline cartilage.
Fossa: is a large non-articular depression. E.g. supraspinous fossa of scapula
Glenoid Cavity: is a smooth and shallow articular depression. E.g. glenoid cavity
of scapula.
Cotyloid Cavity/Acetabular Cavity: a deep articular depression e.g. acetabulum
of os-coxae.

18. Marking on the Bones

19. Marking on the Bones

20. Marking on the Bones

21. Marking on the Bones

22. Marking on the Bones

23. Marking on the Bones

24. Marking on the Bones

25. Marking on the Bones

26. Marking on the Bones

27. Marking on the Bones

28. Marking on the Bones

29. Marking on the Bones

30. Bone Surface Description
Long Bones: a bone longer than wider, consisting of a diaphysis (body) and two
epiphyses (extremities) with their articular cartilage (e.g. humerus, radius,
femur, tibia, metacarpals, metatarsals).
1. Diaphysis: the long shaft (body)of a long bone.
2. Epiphysis: the two enlarged ends (proximal and distal extremities) of long
bone.
3. Metaphysis: the joining point of diaphysis and epiphysis.
4. Periosteum: the fibrous covering around the bone that is not covered by
articular cartilage. This layer is necessary for bone growth, repair, nutrition
and attachment of ligament and tendon.
5. Articular Surface: the smooth layer of hyaline cartilage covering the
epiphysis where one bone forms a joint with other bone.
6. Medullary Cavity: the space in diaphysis consisting the marrow.
7. Endosteum: the fibrous tissue lining the medullary cavity of bone.

31. Bone Surface Description
8.Apophysis: any outgrowth of a bone---- a process.
9. Cortex: compact bone surrounding the medullary cavity.
10. Epiphyseal Cartilage, growth plate: the place of cartilage between the
diaphysis and epiphysis of immature long bones. This is where lengthening of
long bones takes place. Synonyms are-epiphyseal plate, physis, metaphyseal
plate, growth plate and growth cartilage.
11. Physis: term commonly used by radiologist for the epiphyseal growth plate.
12. Endochondral Ossification: the formation of long bones in the fetus by
transforming a cartilaginous model into bone. Bone replacement takes place in
three primary ossification centers---the diaphysis and two epiphysis. Lengthening
stops when growth plates are completely replaced by bone.
13. Intramembranous Ossification: the formation of flat bones (of head) in which
mesenchymal cells are changed into bones and does not use a cartilaginous
model.

32. Bone Surface Description
14. Compact Bone: the part of bone that looks solid.
15.Cancellous Bone/Spongy Bone: the part of bone consisting of
visible spaces/trabaculae.

33. Bone Surface Description

34. Bone Surface Description

35. Ossification Centers

36. Intramembranous Ossification: Intramembranous ossification follows four steps. (a) Mesenchymal
cells group into clusters, differentiate into osteoblasts, and ossification centers form. (b) Secreted
osteoid traps osteoblasts, which then become osteocytes. (c) Trabecular matrix and periosteum form.
(d) Compact bone develops superficial to the trabecular bone, and crowded blood vessels condense
into red bone marrow.