1. The Musculoskeltal System

2. Objectives Name the structures that make up the musculoskeletal system
State the functions of the musculoskeletal system
Identify types of joints and where they are found in the body

3. Introduction Consists of bones, muscles, tendons, and ligaments
Skeleton makes up the bony structure of the animal, providing support and protection for vital organs
Muscular system allows animal to move
Skeleton is adaptable to bend and grow

4. Bones
Hard, active tissue that consists mostly of calcium and forms the skeleton of the animal
Serve as a mineral reserve to the body, storing calcium and phosphorous for use when necessary and providing nutrients to aid in red blood cell formation
Number varies with the age and species of animal

5. Structure and Classification
Structure described as long, short, flat or irregular
Structure is classified as compact or cancellous
Compact bone is thick tissue that forms the outer layer of bone
Can be repaired and it gives elasticity and rigidity to a bone
Cancellous bone is sponge-like and softer and located inside the end of the bones

6. Formation Formed through the process of ossification
Hollow center within the bone is a medullary cavity
Produces blood cells within a fluid known as bone marrow

7. Other Structures of Bone
Osteoblast
Particles that begin ossification in young, developing bones
Osteocyte
Bone cells that begin to develop mature bone
Osteocast
Mature bone particles that form minerals and compact bone
Periosteum
Thin connective tissue covering outer bone
Endosteum
Thin connective tissue covering inner bone

8. Joints Area where two bones meet forms a joint
Allow animals to bend in areas with level-like movement
Three main types:
Fibrous joint
Cartilage joint
Synovial joint

9. Types of Joints Fibrous joint- fixed joint with little to no movement
Area where two bones of a fibrous joint meet is called a suture
Cartilage joint- connects at the end of joint where cartilage forms to protect and cushion the area where two bones meet
When animal is young and growing this is called the growth plate
Synovial joint- movable and may be a
hinge joint that opens and closes in a one-way movement
Pivot joint rotates around a fixed point
Ball and socket joint that rotates in numerous directions

10. Joint Movements Flexion- bend closing to cause joint to shorten
Extension- opening to cause joint to lengthen
Abduction- movement away from the body
Adduction- movement toward the body

11. Muscles and Connective Tissues
Muscles located throughout animals body and allow movement
Attach to different locations of the body and serve as protection and provide the animal strength
Ligaments are fibrous strands of tissue that connect one bone to another bone and serve as support to all areas of the body
Also allow bending and movement of the limbs
Tendons are fibrous strands of tissue that connect a bone to a muscle
Aid in movement of the limbs

12. Skeleton Skeleton divided into two parts: Axial Skeleton
Appendicular Skeleton

13. Axial Skeleton
Contains the bones of the body that lie perpendicular or lengthwise
Includes: skull, spinal column, ribs and sternum

14. Skull Holds and protects the brain and is made up of many bones
Maxilla (upper jaw), mandible (lower jaw)
Small open spaces located within the skull and nasal canal are called sinuses
Spinal column contains the vertebrae which are individual bones that surround and protect the spinal cord

15. Spinal Column
First section calls cervical vertebrae and extends over the head and neck area
First vertebra located at base of skull is the atlas and is the first cervical vertebra that allows the up and down nodding motion of the head to occur
Second cervical vertebra is the axis and allows for the rotation and shaking motion of the head

16. Spinal Column Continued
Second section of vertebrae is thoracic vertebrae
Lies over the shoulders and chest area
Each rib attaches to an individual thoracic vertebra and protects the heart and lungs
The sternum, or breastbone, helps to protect the organs of the chest

17. Spinal Column Continued
Third section of vertebrae is lumbar vertebrae
Lies over the lower back or loin area
Sacral vertebrae form over pelvis and rump area
Last section of the spinal cord is the coccygeal vertebrae
Forms the tail area

18. Appendicular Skeleton
The part of the body that contains the appendages or limbs
Foreleg or forelimb is the front leg of an animal
Includes the scapula (shoulder blade), olecranon (elbow), humerus (large upper bone of the forelimb), radius and ulna
Lower leg forms the carpal bones (similar to wrist bones)
Several small carpal bones that are arranged in two rows called the carpus joint

19. Appendicular Skeleton
Metacarpal bones form the long bones of the front feet
Hoofed animals: cannon bone
Horses have two small bones that form at back of cannon bone called splint bones
Phalanges form the toes or digits
Short inside bone that forms the first digit and acts as an opposable thumb is a dewclaw

20. Appendicular Skeleton
Hind limb or pelvic limb forms the rear leg of the animal
Pelvic is formed by three sections:
Ilium
Ischium
Pubis
Pelvis holds rear limb in place by the acetabulum or ball and socket joint of the hip
Femur or thigh bone forms the large bone of the upper rear leg

21. Appendicular Skeleton
Patella forms joint between upper and lower bones of the rear leg (kneecap)
Bones in lower leg called tibia or fibula
Point where tibia and fibula meets is called the hock
Forms several bones to ankle bone called tarsal bones
Metatarsal bones form the long bones of the rear feet and the digits of both the front and rear limbs are all called phalanges