The document provides an overview of the human skeletal system, including its main components and functions. It is divided into two main sections: the axial skeleton and appendicular skeleton. The axial skeleton comprises the skull, vertebral column, sternum, and ribs. It forms the central framework and protects the brain, spinal cord, and internal organs. The appendicular skeleton includes the bones of the upper and lower limbs, as well as the pectoral and pelvic girdles that attach the limbs to the axial skeleton.

1. WELCOME TO HUMAN SKELETAL SYSTEM

2. PRESENTED BY MR.ATUL MANKAR P.G.T. (BIOLOGY) Kendriya Vidyalaya DIPHU

3. OBJECTIVES To impart knowledge about human skeletal system To make the viewers realize their body framework

4. CONTENTS INTRODUCTION DIVISIONS OF SKELETON FUNCTIONS

5. The human skeletal system consists of frame work of Cartilages Bones (206) (few) INTRODUCTION

6. Bones & Cartilages are specialized connective tissues BONES CARTILAGE Has hard matrix Has slightly pliable matrix Presence of Ca salts Presence of chondroitin salts

8. Human Skeleton Grouped into 2 main divisions Axial skeleton Appendicular skeleton HUMAN SKELETON

9. AXIAL SKELETON Comprises of 80 bones distributed along the main axis of the body Comprises of – Skull Vertebral column Sternum Ribs

11. SKULL Cranial bones (8) Skull Facial (14) Cranial bones form the hard protective outer covering of the brain Facial bones form front part of the skull

12. Hyoid It is a single U shaped bone present at the base of buccal cavity Also included in the skull

13. Our each middle ear contain 3 tiny bones- Mallaeus ,Incus & Stapes Called ear ossicles

14. Human skull is dicondylic as it articulates with the superior region of vertebral column with the help of 2 occipital condyles.

15. VERTEBRAL COLUMN Formed of 26 serially arranged units called vertebrae It is dorsally placed Extends from base of the skull Constitutes main framework of the trunk The spinal cord passes through the central hollow neural canal of the vertebrae

18. 1 st vertebra - Atlas It articulates with the occipital condyles 7 cervical vertebrae - make up the neck part 12 thoracic vertebrae 5 lumbar vertebrae 1 fused sacral vertebrae 1 fused coccygeal vertebrae

19. Function of Vertebral Column Protects the spinal cord Supports the head Serves as point of attachment for the ribs & musculature of the back

20. STERNUM It is a flat bone on the ventral midline of the thorax

22. RIBS 12 pairs of ribs Each rib is a thin flat bone connected dorsally to the vertebral column & ventrally to the sternum Has 2 articulation surface on it’s dorsal end (dicephalic) 1 st 7pairs of ribs -true ribs. attached dorsally to the vertebral column & ventrally to the sternum with the help of hyaline cartilage 8 th ,9 th & 10 th pairs of ribs called false ribs. Do not articulate directly with the sternum but join the 7 th rib with the help of hyaline cartilage (vertebrochondral rib) 11 th & 12 th pairs of ribs called floating ribs. They are not connected ventrally RIB CAGE --- THORACIC VERTEBRAE + RIBS+ STERNUM

24. APPENDICULAR SKELETON Limb bones + Girdles LIMB - Each limb made of 30 bones Forelimb - Bones are humerus , radius + ulna carpals (wrist- 8) metacarpals (palm -8), phalanges (fingers- 14) Hind limb - Bones are femur (thigh bone - longest) tibia + fibula tarsals (ankle-7), metatarsals (sole -5), phalanges(toes - 14) Knee - covered by a cup shaped bone called patella

27. Pectoral GIRDLES Pelvic Girdle bones helps in the articulation of the upper & lower limbs with the axial skeleton

28. Each half of pectoral girdle consists of a CLAVICLE & a SCAPULA Scapula-large triangular flat bone Situated in the dorsal part of the thorax between the 2 nd & 7 th ribs Dorsal side has a slightly elevated ridge called spine which extends as a flat expanded acromian process It articulates with the clavicle Below acromian a depression called glenoid cavity which atriculates with head of humerus to form shoulder joint (ball & socket joint) Clavicle - called collar bone - Long slender bone with 2 curvatures

29. Pelvic girdle consists of 2 coxal bones: = Each coxal bone formed by fusion of 3 bones = Ilium ,Ischium & Pubis = At the point of fusion of the 3 bones is a cavity , acetabulum to which femur articulates (ball& socket joint) = The 2 halves of the pelvic girdle meet ventrally to form pubic symphysis containing fibrous cartilage