Bones, Joints, and Connective Tissue Bones - Functions Our skeleton forms a strong, solid internal framework of bones for our body, and it makes up about 14% of our total body weight. The bones of the skeleton support our skin, give our body shape, protect our organs and make it possible for us to move by acting as single and double levers. Bones do not move on their own; muscles move our bones by pulling on them. Muscles cannot push against the bone, so muscles come in pairs, one muscle pulls the bone one way and the paired muscle opposite Many bones also contain marrow, which is used in the production of red blood cells. Bones are also used to store minerals. The skeleton is divided into the axial (upper) and appendicular (lower and extremities) Axial Skeleton This section is comprised of the 80 bones in our upper body. Our arms hang from the axial section. ● ○ ○ ○ ● ● ○ ○ ○ ○ ○ ● ● Skull (facial and cranial bones) Mandible (Jaw bone) Nasal Bones Maxilla (Upper jaw bone) Hyoid Vertebrae in the spine (backbones) Cervical (7) Thoracic (12) Lumbar (5) Sacral (5) Coccygeal (4) Ribs Sternum (breastbone) The Appendicular Skeleton: Bones of the Upper Appendage (Arm) ■ ■ ■ ■ ■ ■ ■ Shoulder girdle—scapula (shoulder blade), clavicle (collar bone) Humerus—long bone of the upper arm Radius—long bone of the forearm; connects with the humerus to form the elbow Ulna—long bone of the forearm; connects with the humerus to form the elbow Carpals—8 small bones of the wrist Metacarpals—small bones of the hand Phalanges—14 bones of the fingers (3 in each finger) and thumb (2 in the thumb) The Appendicular Skeleton: Bones of the Lower Appendage (Leg) ■ ■ ■ ■ ■ ■ ■ ■ ■ Pelvic Girdle—made up of the right and left hip bones which are joined in the back with the sacrum and in the front at the symphysis pubis Hipbone—made of the ilium, pubis and ischium Femur—long bone of the thigh and longest bone in the body; connects with pelvis to form and hip joint and the tibia and fibula to form the knee joint Tibia—long bone of the lower leg (shin bone); connects with the femur to form the knee Fibula—thinner, long bone of the lower leg Patella—kneecap Tarsals—small bones of the ankle Metatarsals—foot Phalanges—bones of the toes (3 in each toe and 2 in the big toe) Joints Joints(articulations) are formed where the surfaces of two or more bones meet and articulate with each other. There are about 400 joints in the human body. Joints allow both movement and flexibility. Joints are classified by how much movement they allow, function, or what they are made of, structure. Joints are usually classified structurally by the tissue that connects them. The tissue could be cartilage, fibrous tissue, synovial fluid, or some combination of the three. Functionally, joints can be classified by the degree of movement possible, the number of bones involved, and the complexity of the joint. Most body joints allow us to move, and some only allow movement in certain ways. Fixed or immovable joints allow no movement. A dislocated joint happens when the bones of the joint are forced out-of-place, usually while playing sports but can also happen with accidents. There are 3 major functional joints and 3 major types of structural joints. Functional Joints ■ Immovable (synarthrotic) joints—the bones are held together by fibrous tissue so they don’t move at all; example is the skull bones ■ Slightly movable (amphiarthrotic) joints—the bones are held together by cartilage that allows only a little movement; examples are the joints in the spine ■ Freely movable (diarthrotic) joints—also called synovial joints, allow the most movement; examples are hip and knee joints Structural Joints ■ ■ ■ Fibrous: the articular surfaces (point on the bone’s surface where the two bones meet) are held together by fibrous connective tissue. Very little movement is possible. For example, the joint between fibula and tibia Cartilaginous: the bones in cartilaginous joints are held together by cartilage which allows slight movement. For example the symphysis pubis. Synovial: the bony surfaces on the ends of the bones are covered with articular cartilage and separated by a slippery, lubricating fluid called synovia. They bones are held together in the joint by ligaments lined with synovial membranes which produce the synovial fluid. These freely moving joints are mostly found in our arms and legs. Synovial joints also include: ■ A joint cavity or joint space: space between the articulating surfaces; articulating surfaces are the bone surfaces that move against each other when the joint moves. ■ Articular capsule: a sac-like structure that surrounds the joint and has an outer layer lined with a synovial membrane (synovium) that makes the synovial fluid. Seal ■ Reinforcing ligaments: tough, fibrous connective tissues that connect the bones and reinforce the joint capsule. On the outside of the joint capsule are thick strap-like bands, called collateral ligaments. These ligaments direct the force that travels through the joint and keep the joint on track. Synovial Joints ■ ■ ■ ■ ■ ■ Gliding (plane) joint: have flat or slightly curved articular surfaces and allow gliding movements. The way they are bound together by the ligaments may not allow movement in all directions. Examples of a gliding joint are the intertarsal and intercarpal joints. Hinge joint: have a convex (curved outward) part of bone that fits into the concave (curved inward) part of another bone. The joint is like a door hinge and motion is limited to bending and straightening. Our elbows and knees are examples. Pivot (swivel) joint: have a bone with a rounded end fitting into a groove in another bone. Pivot joints allow one bone to pivot on the other bone. An example is the radius rotating within the groove of the ulna. Condylar (ellipsoidal) joint: these joints have a bony surface that is oval-shaped fitting into a concave surface of another bone. These joints allow bending and straightening. An example is in the hands. Saddle joint: these joints are similar to condylar joints but allow more movement. The only saddle joints are in the thumb. Ball-and-socket joint: these bones fit together like it sounds: the round end of one bone fits into the concave socket of the other bone. The only ball-and-socket joints are the shoulders and hips. Connective Tissue ● ● ● ● ● Loose/dense connective tissue - is found everywhere in the body as filling between apposed body parts. It is also called areolar tissue. It consists of both fibrous extracellular molecules and a number of different cell types. Adipose tissue - fat tissue acting as padding for the body Blood and blood forming tissues Cartilage - a firm tissue that is softer and much more flexible than bone. Found in joints between bones for example the elbows, knees and ankles; as well as at the ends of the ribs, between the vertebrae in the spine, in the ears and nose, and in the bronchial tubes. Bones are also considered connective tissue. Compound Fracture ❏ ❏ ❏ ❏ The bone breaks in such a way that the bone protrudes through the skin This type of fracture increases the risk of serious bleeding and infection It takes a great amount of force to break a bone so MOI must be significant When assessing fractures us the 6 P’s ❏ ❏ Pain, Pallor, paralysis, Paresthesia, Pressure, and Pulses There is only one chance to reset the bone so the field may not be the best environment https://www.youtube.com/watch?v=cM7Prs9j03U Other types of Fractures Dislocation ❏ ❏ ❏ ❏ Dislocation is the displacement of a bone from its normal position in the joint Can cause damage to blood vessels and nerves through compression or tearing Dislocation often occurs from the joint going beyond its max range of motion To treat dislocation immobilize the injury and bring the patient to the hospital to pop it back into place. Medical Conditions ● Osteoporosis - a disease that weakens the bone and leads to more damaged or broken bones. It is caused when either new bone cells do not form or old bone cells are not transported away properly and end up being reabsorbed. As of right now there is no cure for osteoporosis, only supplements and a healthy lifestyle. Consuming calcium on a regular basis is a proven way to prevent it from developing. ● ● https://www.youtube.com/watch?v=_iZWFEFwgBw Osteosarcoma is a type of cancer that produces immature bone. It is the most common type of cancer that arises in bones, and it is usually found at the end of long bones, often around the knee. Most people diagnosed with osteosarcoma are under the age of 25. Osteosarcomas range from low grade tumors that only require surgery to high grade tumors that require an aggressive treatment regimen. Fun Facts ● ● ● Humans are born with around 270 bones at birth, but due to fusion by adulthood we have 206 left. Peak bone density occurs around age 21. It takes 4000 Newtons to break a femur. https://www.youtube.com/watch?v=nPP6tc8HI9Q Sources https://www.healthpages.org/anatomy-function/musculoskeletal-system-bones-joints-cartilage-ligaments/ http://lifesci.dls.rutgers.edu/~babiarz/lct.htm http://sarcomahelp.org/osteosarcoma.html
