Understanding the Human Skeletal System: Structure and Function of Bones and Joints

1. The Skeletal System

2. The skeleton, composed of bones, cartilages, joints, and ligaments, accounts for about 20% of body mass. There are 206 bones in the human body. Introduction -The Basics

3. The axial skeleton forms the long axis of the body and includes the bones of the skull, vertebralcolumn, and rib cage. There are 80 bones in the axial skeleton.

4. The Appendicular skeleton consists of the bones of the upper and lower limbs, and the shoulder bones and hip bones. There are 126 bones in the Appendicular Skeleton.

5. The skull consists of two sets of bones – the cranium and the facial bones. There are eight cranial bones and fourteen facial bones.  The joints between bones of the skull are immovable and called sutures. The Axial Skeleton

8. Baby Skull Sutures

9. Sutures in Adult Skull

10. The SPHENOID BONE- acts like a bridge between the cranial & facial bones

12. Only the mandible is attached by a freely movable joint. The hyoid bone is the only bone in the body that does not articulate (match up with) another bone. The hyoid bone acts as an attachment point for several muscles that help with speech and swallowing. The hyoid bone is attached to the skull by ligaments. The Axial Skeleton

14. The vertebral column consists of vertebrae separated by disks of fibro-cartilage. 7 cervical vertebrae   12 thoracic vertebrae   5 lumbar vertebrae   The bony thorax forms a cage to protect major organs The Axial Skeleton

15. SPINAL (VERTEBRAL) COLUMN The spinal column (or vertebral column) extends from the skull to the pelvis and is made up of 33 individual bones termed vertebrae.

16. The bony thorax is made up of three parts: 1)Sternum 2)Ribs 3)Thoracic vertebrae The Axial Skeleton

17. You have three different types of ribs True ribs are the first seven pairs of ribs. True ribs attach directly to the sternum by costal cartilages. False ribs are the next five pairs. They either attach indirectly to the sternum or not at all. Floating ribs are the last two pairs of false ribs. They lack sternal attachments. The Axial Skeleton

18. The 3 parts of the appendicular skeleton are: 1)Limbs (appendages) 2)Pectoral girdle (shoulder) 3)Pelvic girdle (pelvis) The Appendicular Skeleton

19. The pectoral girdle (or shoulder) is composed of two bones 1)Clavicle – collarbone 2)Scapula – Shoulder blade The clavicle and the scapula allow the upper limbs to have free movement The Appendicular Skeleton

20. The arm is formed from a single bone, the humerus. The forearm has two bones: the ulna and radius The Appendicular Skeleton

21. The hand contains three types of bones: 1)Carpals – wrists 2)Metacarpals – palm 3)Phalanges - fingers The Appendicular Skeleton

22. The thigh has one bone – the femur. The lower leg has two bones – the tibia and fibula. The Appendicular Skeleton

23. The foot has three types of bones: 1)Tarsals – ankle 2)Metatarsals – sole 3)Phalanges - toes The Appendicular Skeleton

24. The pelvic girdle is made up of the hip bones. The “hip bones” are composed of three pair of fused bones – the ilium, ischium, and pubic bone. The Appendicular Skeleton

25. The total weight of the upper body rests on the pelvis. The pelvic girdle protects several organs – the reproductive organs, the urinary bladder, and part of the large intestine. The Appendicular Skeleton