The Musculoskeletal System BONES & JOINTS

Link with the Nervous System The nervous system controls and coordinates movements within our bodies. It collects sensory information that is relayed to the brain, causing our bodies to react. The musculoskeletal system is what makes those movements possible. Without our muscles and our bones, we would not be able to stand, write, or even open our eyes.

Basic Information The human skeleton is made up of 206 bones. Around 80% of these bones are found in our hands and feet. At birth, humans have 270 bones. As we grow, our bones fuse together until adulthood. The bones of the body can be divided into three anatomical regions: The head – cranium, mandible, maxilla, etc. The trunk – sternum, clavicle, scapula, ribs, etc. The limbs – humerus, femur, tibia, carpals, etc.

The Head 1. The head Skull (cranium) Face Houses the brain Cranial bones are flat and are immovable Face All bones are immovable, except the jaw (mandible)

The Trunk Thorax or rib cage Spinal column 2. Trunk (2 main groups of bones) Spinal column 33 vertebrae (short bones joined by cartilage which allow only limited movements) It is flexible, mobile and resists shocks 5 parts Cervical (neck) Thoracic (chest) Lumbar Sacral (sacrum) Coccygeal (coccyx) Thorax or rib cage Ribs, sternum, thoracic vertebrae Make a bony cage that protects organs and can change in volume for gas exchange 3 main types of ribs True False Floating

Limbs Occur in pairs Each has 3 parts (i.e. arm, forearm, hand) They are jointed held together by ligaments

Bone Anatomy Bones are made up of bone cells. These cells are constantly renewing, (mitosis), and make up the hardest material in the human body.

Diaphysis middle section of the bone (yellow marrow) 2 Epiphyses ends of the bone (red marrow) = red blood cells Periosteum Responsible for growth in width thin membrane that encloses the bone role in growth of the thickness of the bone, in healing fractures. Continually active, but decreases with age

Compact bone is dense and hard, giving bones their durability. Within each bone is a variable proportion of spongy bone and compact bone. Spongy bone contains small cavities. Marrow, (yellow and red), is found here. Yellow marrow produces fat and bone. Red marrow produces red and white blood cells and platelets. Compact bone is dense and hard, giving bones their durability.

Bone Classification Bones come in a variety of shapes and sizes. The longest bone in the body is the femur, at around 60 cm long. The smallest bones are the ossicles in the ear, which are around the size of a pea. Bones are classified into four types: Long bones Short bones Irregular bones Flat bones

Type of bone Example in body Main Function in body Long Bones Femur, humerus. work with muscles to move body parts, storage, support, blood production. Short bones Tarsals, carpals, clavicle work with muscles to move body parts, storage Flat bones Sternum, cranium, scapula   Protect organs, blood production Irregular Bones The vertebrae, mandible, Iliac. Support, blood production, movement

Bone Shape Humerus 2.Radius 3.Ulna 4.Femur 5.Fibula 6.Tibia 7.Cranium long 2.Radius Long 3.Ulna 4.Femur 5.Fibula 6.Tibia 7.Cranium Flat 8. Mandible Irregular 9. Clavicle Short 10.Scapula 11.Sternum 12. Rib cage 13. Vertebrae 14. Iliac / os coxa 15.Carpals 16.Phalanges 17.Patella 18.Tarsals 19.Phalanges of the foot

Joints Any place where two bones meet. Because of their rigidity, bones are held together by cartilage. Cartilage is more elastic and flexible, allowing movement between bones. It also acts as a shock absorber. Ligaments are tissues that hold bones in their place.

Types of Joints Immovable Moveable Pelvis Skull Ball and socket Hinge Gliding Pivot

… Ball and Socket When a rounded end of one bone fits into a cup-like cavity in another bone. Ex – Humerus in the scapula, femur in the pelvis.

… Pivot When one bone rotates within another. Ex – Neck, radius and ulna

… Hinge When two bones move back and forth in relation to one another, like the hinges of a door. Ex – Elbow joint, (humerus to radius), knee joint, (femur to tibia).

… Gliding When one bone slides past another. Ex – carpals and metacarpals, tarsals and metatarsals.