SKELETAL SYSTEM

Functions of the Skeletal System Bones are made of OSSEOUS TISSUE Support and Protection Body movement Blood cell formation (bone marrow) - hematopoeisis Storage of inorganic materials                     (salt, calcium, potassium….)

About 206 bones 2 Main Divisions – Axial & Appendicular ORGANIZATION About 206 bones 2 Main Divisions – Axial & Appendicular

Axial Skeleton Head, neck, trunk Skull Hyoid Bone Vertebral Column Thoracic Cage (ribs, 12 pairs) Sternum

Appendicular Skeleton Limbs & Bones that connect to the Pectoral Girdle (shoulders) Pelvic Girdle (hips)

Compact (wall of the diaphysis) Types of Bone Tissue Compact (wall of the diaphysis) Spongy (cancellous, epiphysis) - red marrow

Bone Details Matrix: Where bone cells live Osteocytes: Mature bone cells All bones start as dense membranes Primary Ossifications: shafts ( diaphysis) Secondary Ossifications: ends (epiphesis)

Medullary Cavity – hollow chamber filled with bone marrow Inside the Long Bone Medullary Cavity – hollow chamber filled with bone marrow Red Marrow (blood) Yellow Marrow (fat) Endosteum – lining of the medullary

BONE STRUCTURE - Long Bone Epiphysis: end part of long bone Diaphysis :Shaft of long bone Articular Cartilage: covers the articular surfaces of the bones participating in a synovial joint. Periosteum: dense layer of vascular connective tissue enveloping the bones except at the surfaces of the joints Endosteum layer of vascular tissue lining the inside of some bones ( also called medullary membrane)

Bone Development & Growth EPIPHYSEAL DISK  (growth plate) is a band of cartilage between the epiphysis (the end part of a long bone and the diaphysis (the shaft or central part of a long bone)   These areas increase bone length as the cells ossify Cartilage becomes OSTEOBLASTS make new bone Osteoclasts: breaks down bones in reabsorption

Types of Joints (articulations) Synarthrotic (not moveable, aka sutures) Amphiarthrotic (slightly moveable, vertebrae) Diarthrotic (moveable joint, aka synovial joints)

Synovial fluid - fluid within the joints that helps to lubricate Types of Joints 1.  Ball and Socket 2.  Hinge 3.  Pivot 4.  Saddle

BONES OF THE SKULL Frontal: Anterior portion of eye 2. Parietal – one on each side of skull 3. Occipital –forms back of skull 4. Temporal – forms sides and base of cranium 5. Sphenoid – wedged between several bones 6. Maxilla – forms upper jaw 7. Mandible – forms lower jaw ( only moveable bone

Suture - refers to any connection between large bones (in fetal skulls, these are called fontanels) Fissure - any wide gap between bones

Sutures 1. Coronal - between frontal and parietal bones 2. Lambdoidal - between occipital and parietal bones 3. Squamosal - between temporal and parietal bones 4. Sagittal - between parietal bones

Figure 6.10

Fontanels Cranium not solid at birth Spaces called fontanels or “soft spots Fibrous Tissue: allows for cranial expansion during birth Foranum Magnum Large opening where Spinal cord enters skull

Thoracic Cage Thoracic Cage: 12 pairs of ribs True ribs: first seven pairs attach directly to the sternum by vertebral sternal ( costal cartilage) False ribs: last five pairs. Indirectly attached Floating ribs : last two pairs within false ribs

Vertebrae Neck = cervical   Middle Back = thoracic Lower Back = lumbar

Pectoral girdle Shoulders Two clavicles ( collar bones) Two Scapulas ( shoulder blades) Arms: humerus, radius and ulna Wrist: 8 small bones called carpals Fingers: phlanges

Bones of the Arm Ulna goes to pinky  (P-U) Radius goes to thumb

Wrist Bones For test Carpels Metacarpals Phalanges *extra credit opportunity

Pelvic Girdle Hips : Two large bones called coxal bones Legs: Femur ( thigh bone), tibia & fibula ( lower leg Ankle & upper foot :7 bones called tarsals Largest is heel bone called the calcaneus, metatarsals and phlanges

Pelvic Girdle

Bones of the Leg

Bones of the Ankle

Broken Bones

Open fracture Bone sticking through skin

Types of bone Long Bones : Femur, Humerus and Tibia but are also some of the smallest includin the Metacarpals, Metatarsals and Phalanges. Classification of a long bone includes having a body which is longer than it is wide, with growth plates (epiphysis) at either end.

Flat bones Flat bones are as they sound, strong, flat plates of bone with the main function of providing protection to the bodies vital organs and being a base for muscular attachment. The classic example of a flat bone is the Scapula (shoulder blade). The Sternum (breast bone), Cranium (skull), os coxae (hip bone) Pelvis and Ribs are also classified as flat bones. Flat bones are as they sound, strong, flat plates of bone with the main function of providing protection to the bodies vital organs and being a base for muscular attachment. The classic example of a flat bone is the Scapula (shoulder blade). The Sternum (breast bone), Cranium (skull), os coxae (hip bone) Pelvis and Ribs are also classified as flat bones. Flat bones are as they sound, strong, flat plates of bone with the main function of providing protection to the bodies vital organs and being a base for muscular attachment. The classic example of a flat bone is the Scapula (shoulder blade). The Sternum (breast bone), Cranium (skull), os coxae (hip bone) Pelvis and Ribs are also classified as flat bones.

Irregular Bones These are bones in the body which do not fall into any other category, due to their non-uniform shape. Good examples of these are the Vertebrae, Sacrum and Mandible (lower jaw). They primarily consist of cancellous bone, with a thin outer layer of compact bone.

Sesamoid Bones Sesamoid bones are usually short or irregular bones, imbedded in a tendon. The most obvious example of this is the Patella (knee cap) which sits within the Patella or Quadriceps tendon.

Abnormal Bone Conditions BONE SPURS: abnormal growth. Can occur on any bone (e.g. heel). OSTEOPOROSIS: Increased activity of osteoclasts cause a break down bone, and the subsequent fewer minerals in the extracellular matrix make it fragile. The spongy bone especially becomes more porous. Men get it as well as women. What’s the best way to prevent osteoporosis? Exercise! What does exercise do? Makes bones bigger. The most common bone used for a bone graft is the iliac bone of the hip.

Osteoporosis Figure 6.15

Rheumatoid arthritis is an autoimmune disease which causes joint stiffness and bone deformity Source: http://www.thetimes.co.uk/tto/public/article3233439.ece 

ABNORMALITIES OF THE SPINE SCOLIOSIS is a lateral curve in the spine KYPHOSIS is a hunchback curve LORDOSIS is a swayback in the lower region. ANKYLOSIS is severe arthritis in the spine and the vertebrae fuse.

SCOLIOSIS

LORDOSIS

ANKYLOSIS

FUN FACTS ABOUT BONES Bone is made of the same type of minerals as limestone. Babies are born with 300 bones, but by adulthood we have only 206 in our bodies. The giraffe has the same number of bones in its neck as a human: seven in total. The long horned ram can take a head butt at 25 mph. The human skull will fracture at 5mph.