Skeletal System Unit 7:4

SKELETAL SYSTEM The skeletal system is made up of organs called bones. In the adult there are 206 bones.

FUNCTIONS OF BONES Framework: supports the body ’ s muscles, fat, & skin. Protection: surround vital organs to protect them. E.g.: Skull surrounds & protects brain. Ribs protect your heart & lungs. Levers: attach to muscles to help provide movement. Produce Blood Cells: Produce red & white blood cells & platelets. Storage: Store most of the calcium supply of the body.

Parts of Long Bones Long bones are bones of the extremities (arms & legs) Diaphysis: long shaft Epiphysis: two extremities or ends Medullary Canal: Cavity in the diaphysis filled with yellow marrow Yellow Marrow: Located within the medullary canal composed of mainly fat cells Endosteum: membrane that lines the medullary canal, keeps the yellow marrow intact & provides some bone growth.

Periosteum: Tough membrane covering the outside of bones. It contains blood & lymph vessels. It also contains osteoblasts which are special cells that form new bone tissue. It is necessary for bone growth, repair, & nutrition. Articular Cartilage: Thin layer that covers epiphysis and acts as a shock absorber when two bones meet to form a joint.

Red Marrow: Found in certain bones such as vertebrae, ribs, sternum, cranium, & proximal ends of the humerus & femur. Produces red blood cells, platelets, & some white blood cells. Bone marrow is important in the manufacturing of blood & is involved with the body ’ s immune response. It is used in diagnosing blood diseases and given as transplants to people with defective immune systems.

Two Sections of Skeleton Axial Skeleton forms the main trunk of the body & is composed of the skull, spinal column, ribs, & sternum

Appendicular Skeleton forms the extremities & is composed of the shoulder girdle, arm bones, pelvic girdle, & leg bones.

SKULL Composed of the cranium and facial bones. Cranium is the round structure that surrounds & protects the brain. It is made up of 8 bones –Frontal –Two parietal –Two temporal –Occipital –Ethmoid –Sphenoid

At birth the cranium is not solid bone. There are spaces called fontanels or “ soft spots ” that allow for enlargement of the skull as brain growth occurs. The fontanels are made of membrane & cartilage that turns into solid bone by about 18 months of age.

Facial Bones There are 14 facial bones, but the main bones are: –Mandible: Lower jaw –Maxilla: 2 bones forming upper jaw –Zygomatic: 2 cheek bones –Nasal: 5 bones in the upper part of the nose –Lacrimal: 2 bones at inner aspect of eyes –Palantine- 2 bones of hard palate or roof of the mouth.

Sutures: areas where cranial bones have joined together. Sinuses: Air spaces in the bones of the skull that provide strength with less weight. They act as resonating chambers for the voice & are lined with mucous membranes. Foramina: Openings in bones that allow nerves & blood vessels to enter/exit bone.

Vertebrae The spinal column is made of 26 bones called vertebrae. They protect the spinal cord & provide support for the head & trunk. The main sections are: –Cervical- 7 neck vertebrae –Thoracic-12 vertebrae in back of chest, attach to ribs –Lumbar-5 vertebrae by waist –Sacrum-1 large vertebrae on back of pelvic girdle –Coccyx: 1 fused vertebrae called the tailbone

Ribs or Costae 12 pairs of long slender bones that attach to the thoracic vertebrae on the dorsal surface of the body True ribs: First 7 pairs of ribs that attach directly to the sternum on the front of the body False ribs: The next 5 pairs of ribs. The first three pairs attach to the cartilage of the rib above it. The last 2 pairs of ribs are the “ floating ribs ”. Floating ribs don ’ t attach to the front of the body.

Sternum Breastbone Consists of three parts: –Manubrium or upper region –Body or center area –Xiphoid process: small piece of cartilage at the bottom Two clavicles attach to the manubrium by ligaments. Ribs attach to sternum with costal cartilages to form a cage that protects the heart & lungs

Shoulder or Pectoral Girdle Two clavicles or collarbones Two scapulas (scapulae) or shoulder bones Scapula provides for attachment of upper arm bone.

Bones of the Arm Humerus: upper arm bone Radius: lower arm bone on thumb side Ulna: larger bone of lower arm that contains a projection called the olecrannon process at the upper end forming the elbow. Carpals: 8 wrist bones on each hand Metacarpals: 5 bones on each hand to form palms Phalanges: 14 bones on each hand to form thumb & fingers

Bones of Pelvic Girdle Made of two os coxae (coxal or hip bones) Join with the sacrum on dorsal part of body & join together at a joint called the symphysis pubis on ventral part of body Each os coxa made of three bones that are fused or joined: ilium, ischium, pubis

Contains two recessed areas or sockets called acetabulums that provide for attachments of bones of the leg. Obturator foramen: opening between the ischium & pubis that allows for passage of nerves & blood vessels to & from the legs.

Bones of the Legs Femur: thigh bone Patella: kneecap Tibia: long supporting bone of lower leg, medial surface Fibula: smaller bone of lower leg, lateral surface Tarsals: 7 bones of ankles, calcaneous is heel bone Metatarsals: 5 bones forming instep of foot Phalanges: 14 bones on each foot, form toes

Joints Areas where two or more bones join together Ligaments: connective tissue bands that hold long bones together Three main types of joints: –Diarthrosis: freely movable. E.g. ball & socket joints of the shoulder & hip; and hinge joints of the elbow & knee –Amphiarthrosis: slightly movable. E.g. vertebrae –Syntharthrosis :immovable. E.g. cranium

Skeletal System Day 2 Diseases of the skeletal system

Diseases of Skeletal System Arthritis: group of diseases involving an inflammation of the joints. There are two main types: Osteoarthritis & rheumatoid arthritis

Osteoarthritis Chronic disease that occurs with aging. Symptoms: joint pain, stiffness, aching, limited range of motion Treatment: rest, heat/cold applications, aspirin, anti- inflammatory meds, steroid injections, special exercises

Rheumatoid Arthritis Chronic inflammatory disease of connective tissues joints. Three times more common in women, often begins between age Progressive attacks cause scar tissue formation & atrophy of bone & muscle tissue, which results in permanent deformity & immobility. Treatment: rest & prescribed exercise, anti- inflammatory meds, aspirin & steroids, surgery, or arthroplasty, to replace damaged joints such as hips or knees.

Bursitis Inflammation of bursae, small fluid-filled sacs surrounding joints. Frequently affects shoulders, elbows, hips, or knees. Symptoms: severe pain, limited movement, accumulation of fluid in joint. Treatment: Pain medications & rest, injections of steroids & anesthetics into joint, aspiration (withdrawal of fluid with a needle) of joint; physical therapy to preserve joint motion.

Fractures Types of fractures: –Simple: complete break with no damage to skin –Compound: break in bone that ruptures through skin; increased chance of infection –Greenstick: bone is bent & splits causing a crack or incomplete break; common in children –Comminuted: bone fragments or splinters into more than two pieces –Impacted: broken bone ends jam into each other Involve a crack or break in a bone

–Spiral: severe twisting of a bone causes one or more breaks; common in skiing & skating accidents –Depressed: broken piece of skull bone moves inward: common with severe head injuries –Colles: breaking & dislocation of the distal radius that causes a characteristic bulge at the wrist; caused by falling on an outstretched hand

Reduction: process by which bone is put back into proper alignment. Closed reduction: position bone in alignment, usually with traction, and apply cast or splint to maintain position. Open reduction: surgical repair of bone, & at times, insertion of pins, plates, & other devices.

Fun with Fractures Can you identify the type of fracture in the following x-rays?

Dislocation Bone is forcibly displaced from a joint. Frequently occurs in shoulders, fingers, knees, & hips. Reduced & immobilized with splint, cast, or traction.

Sprain Twisting action tears ligaments at a joint. Common sites are wrists & ankles. Symptoms: pain, swelling, discoloration, limited movement. Treatment: rest & elevation, immobilization with elastic bandage or splint, cold applications.

Osteomyelitis Inflammation of bone usually caused by pathogenic organism. The pathogen causes formation of abscess within bone & accumulation of pus in medullary canal. Symptoms: pain at site, swelling, chills & fever. Treatment: antibiotics for infection

Osteoporosis Metabolic disorder with increased porosity or softening of bones. Etiology: Deficiency of hormones, especially estrogen in females, prolonged lack of calcium in the diet, sedentary lifestyle. Loss of calcium & phosphate causes bones to become porous, brittle, & prone to fracture. Bone density tests lead to early detection & preventative treatment. Treatment: Increased intake of calcium & vit. D, exercise, meds to increase bone mass, estrogen replacement.

Ruptured Disk Also called a herniated or slipped disk Intervertebral disk ruptures or protrudes out of place & causes pressure on the spinal nerve. Most common site is lumbar-sacral area; can occur anywhere on the spinal column. Symptoms: Severe pain, muscle spasm, impaired movement, &/Or numbness. Treatment: pain, anti- inflammatory & muscle relaxant meds, rest & traction, PT & massage, Chiropractic treatment, heat or cold applications, Laminectomy=surgical removal of the protruding disk for severe cases.

Abnormal Curvature of the Spine Kyphosis: “ hunchback ” or rounded bowing of the back at the thoracic area Scoliosis: side to side or lateral curvature of spine Lordosis: “ Swayback ” or abnormal inward curvature of lumbar vertebrae Causes: poor posture, structural defects of vertebrae, degeneration of vertebrae. Treatment: Therapeutic exercises, firm mattresses, & braces. Surgical repair for severe deformities.