The Skeletal System

1. The Skeletal System By: Alaa Alshaibani and Alexis Samuelson

2. System Structures and locationlink to video: http://www.youtube.com/watch?v=gp4SBFiP4-Y

3. The Skull • Made up of the cranium and the facial bones • It is located at the top of the body, the head of the body • Made up of roughly 22 bones:

4. Cranial Bones: • Frontal bones • Parietal bones • Occipital bone • Temporal bone • Sphenoid bone • Ethmoid bone

5. Facial bones: • Mandible • Maxillae • Palatine bones • Zygomatic bones • Lacrimal bones • Nasal bones • Vomer bone • Inferior nasal conchae

6. Vertebral Column • Begins at the base of the skull and ends at the pelvis. • Composed of vertebrae that are separated by intervebral discs • The column is divided into three parts • The final five is what creates the lumbar vertebrae • The sacrum forms the bottom of the lumbar vertebrae, the tip being the coccyx

7. Vertebral Column

8. Cervical Vertebrae • The first seven vertebrae • The first two are the atlas and axis and they help to rotate the head • The vertebrae are special in that they have transverse foramina and their spinous processes are bifid.

9. Thoracic Vertebrae • The next 12 bones of the vertebral column • Long pointed spinous process, the bodies increase in size as you go down • Connects to the ribs

10. Lumbar Vertebrae • The final five vertebrae • The sacrum forms the bottom of the lumbar vertebrae, the tip being the coccyx

11. Thoracic Cage • Made up of: • The ribs • Thoracic vertebrae • Sternum • Costal cartilages

12. 24 ribs total which attach to each of the thoracic vertebrae • The sternum is made up of the manubrium, body, and xiphone together are the breast bone

13. Pectoral Girdle • Located at the shoulder • Made up of the clavicles (collarbones) and scapulae (shoulder blades)

14. Upper Limb

15. Upper Limb • Bones form framework for arm, forearm, and hand • Provide attachments for muscles, function in levers • Bones include: humerus, radius, ulna, carpals, metacarpals, and phalanges

16. Upper Limb - Humerus • Extends from the scapula to the elbow • Greater and lesser tubercles provide attachments for muscles • Deltoid tuberosity provides attachment for deltoid muscle that raises the upper limb horizontally to the side • Coronoid fossa receives a process of the ulna when the elbow bends • Olecranon fossa receives ulnar process when upper limb straightens at elbow • The capitulum helps the humerus articulate with the radius

17. Upper Limb - Humerus

18. Upper Limb - Radius • Located on thumb side of forearm; extends from elbow to wrist and crosses over ulna when palm faces backward • Head at upper end of radius articulates with humerus and a notch of the ulna • Allows radius to rotate freely

19. Upper Limb - Ulna • Longer than radius; overlaps the end of the humerus posteriorly • Trochlear notch articulates with the humerus • Olecranon process and coronoid process provide attachments for muscles • Head articulates laterally with a notch of the radius

20. Upper Limb – Radius and Ulna

21. Upper Limb - Hand • Made up of the wrist, palm, and fingers • Eight small carpal bones that are bound in two rows of four bones • Five metacarpal bones form framework of the palm • Each finger has three phalanges (proximal, middle, and distal phalanx), except for thumb

22. Upper Limb - Hand

23. Pelvic Girdle • Consists of two coxae which articulate with each other anteriorly and with the sacrum posteriorly • Sacrum, coccyx, and pelvic girdle form pelvis • Girdle supports trunk of the body, provides attachments for lower limbs, protects the urinary bladder and reproductive organs • Each coxa develops from an ilium, an ischium, and a pubis

24. Pelvic Girdle

25. Pelvic Girdle

26. Lower Limb

27. Lower Limb • Bones form frameworks of the thigh, leg, and foot • Includes femur, tibia, fibula, tarsals, metatarsals, and phalanges

28. Lower Limb - Femur • Extends from hip to knee • Large, rounded head projects medially into acetabulum of the coxa • Patella (kneecap) articulates with femur • Lateral and medial condyles articulate with tibia

29. Lower Limb - Femur

30. Lower Limb - Tibia • Larger of the two leg bones, located on medial side • Medial and lateral condyles articulate with condyles of the femur • Tibial tuberosity provides an attachment for patellar ligament • Inferior surface of tibia’s distal end articulates with the talus of the ankle

31. Lower Limb - Fibula • Long, slender bone on lateral side of the tibia • Head articulates with tibia just below the lateral condyle, but does not enter into the knee joint

32. Lower Limb – Tibia and Fibula

33. Lower Limb - Foot • Made up of the ankle, the instep, and the toes • Ankle is composed of seven tarsal bones (largest is calcaneus) • Instep is made up of five elongated metatarsal bones that articulate with the tarsus • Phalanges align and articulate with the metatarsals; each toe has three phalanges except for the great toe (no middle phalanx)

34. Lower Limb - Foot

35. Skeletal System Information

36. Function of Skeleton • The skeleton serves to: • Protect vital organs • Support the body • Create blood cells • Help to stabilize and shape the body

37. Bones, Tendons, Ligaments • Bones: the organs of the skeletal system made up of cartilage, bone tissue, dense connective tissue, and nervous tissue • Tendons: white fibrous connective tissue that attaches muscle to bone • Ligaments: connective tissue that ties together two or more bones at a joint

38. Structures of a long bone • Epiphysial plates, articular cartilage, compact bone, medullary cavity, yellow marrow, periosteum, proximal epiphyses, diaphysis, distal epiphysis, endosteum

39. Bone growth • Endochondral bonesbegin as a cartilaginous model. As it grows the diaphysis in the middle, with the help of osteoblasts replace the cartilage with spongy bone—the primary ossification center, and form a thin layer of compact bone around it. • Secondary ossification centers form in the epiphyses, an epiphyseal plate separates the two ossification centers, which expands, causing the bone to lengthen. • The extracellular matrix calcifies, osteoclasts break it down, osteoblasts release new bone tissue to replace it. • The bone continues to lengthen, only stopping once the diaphysis and epiphysis ossification centers meet.

40. Joints

41. Joints • Bind parts of skeletal system, allow bones to grow, permit the skeleton to change shape during childbirth, and let the body respond to skeletal muscle contractions • Can be immovable, slightly movable, or freely movable • Vary in structure and function

42. Classification of Joints by Tissue

43. Classification - Fibrous • Lie between bones that closely contact one another • Formed by thin layer of dense connective tissue • Doesn’t allow much movement • Examples: • Sutures between pairs of flat bones of the skull • Articulations of teeth in jaw bones (gomphosis)

44. Classification - Cartilaginous • Hyaline cartilage (fibrocartilage), makes for slight flexibility • Helps to absorb shock and equalize pressure • Examples: • Intervertebral discs are composed of a band of fibrocartilage surrounding gelatinous core • Symphysis pubis

45. Classification - Synovial • Allow free movement, make up a majority of joints within skeletal system • Articular ends of bones in synovial joints are covered with hyaline cartilage and a surrounding capsule of dense connective tissue • This + an outer layer of ligaments + inner lining of synovial membrane = joint capsule

46. Classification - Synovial • Menisci – flattened, shock-absorbing pads of fibrocartilage between articulating surfaces of bones • Bursae – fluid-filled sacs lined with synovial membrane • Commonly located between tendons and bony prominences (patella, elbow, etc.)

47. 6 Types of Synovial Joints

48. Ball-and-Socket Joint • Consists of a bone with a ball-shaped head that articulates with the cup-shaped cavity of another bone • Allows widest range of motion and movements in all planes, in addition to rotational movement • Example: • Shoulder and hip joints

49. Condyloid Joint • Oval-shaped condyle of one bone fits into elliptical cavity of another • Permits a variety of movement in different planes, but not rotational movement • Example: • Joints between metacarpals and phalanges

50. Gliding Joints • Articulating surfaces are nearly flat or slightly curved • Allow sliding and twisting movements • Examples: • Most joints within the wrist and ankles • Sacroiliac joints and joints formed between ribs 2-7 that connect with the sternum