Week 5- Skeletal System (Lecture) PDF

SKELETAL SYSTEM HAPP111 Class Cyruz H. Estacio, RMT, ASCPi  SKELETAL SYSTEM OBJECTIVES: ❑ Differentiate completely the bones and the functions they play in the maintenance of the proper body structure and the production of movements with the aid of joints. ❑ Distinguish prec...

SKELETAL SYSTEM HAPP111 Class Cyruz H. Estacio, RMT, ASCPi  SKELETAL SYSTEM OBJECTIVES: ❑ Differentiate completely the bones and the functions they play in the maintenance of the proper body structure and the production of movements with the aid of joints. ❑ Distinguish precisely the different bones of the skeletal system  SKELETAL Support SYSTEM Protection Allow movement FUNCTIONS Storage Blood cell Formation  Functions of bones… Bones are composed of about 50% water and 50% a solid, calcified, rigid substance known as osseous tissue. 1. Bones provide shape, support, and the framework of the body. 2. Bones protect internal organs. 3. Bones serve as a storage place for minerals such as salts, calcium, and phosphorus. Functions of bones… 4. Bones play an important role in hematopoiesis- the formation of blood cells that takes place in bone marrow. 5. Bones provide a place to attach muscles. 6. Bones make movement possible through articulation (manner in which the parts come together at a joint).  SKELETAL SYSTEM ❑ Axial Skeleton- bones that form longitudinal axis of the body. ❑ Appendicular Skeleton- bones of the limbs and girdles that attach them to axial skeleton.  SKELETAL SYSTEM ❑ Axial Skeleton- bones that form longitudinal axis of the body. The axial skeleton consists of 80 bones. The primary bones of the axial skeleton are the skull, spine, ribs and sternum (thorax). Anterior means front; posterior means back. This is an anterior view of the skeleton.  SKELETAL SYSTEM ❑ Appendicular Skeleton- bones of the limbs and girdles that attach them to axial skeleton. The appendicular skeleton consists of 126 bones. The primary bones of this skeleton are the shoulder or pectoral girdle, arms, hands, pelvic girdle, legs, and feet. CLASSIFICATION OF BONES Compact bone- dense and looks smooth and homogenous. Spongy bone- spiky, open appearance like sponge. CLASSIFICATION OF BONES ACCORDING TO SHAPE Long bones- longer than they are wide. Flat bones- thin flattened and usually curved. Short bones- are generally cube- shaped and contain mostly spongy bone. Irregular bones- bones that do not fit one of the preceding categories. Classifications of bones by shape… ❑ SHORT bones include the carpals of the wrist and tarsals of the ankle. Classifications of bones by shape… ❑ FLAT bones include the skull, sternum (breastbone), and scapula (shoulder bone). Classifications of bones by shape… ❑ IRREGULAR bones include the vertebrae (spine), and pelvic. GROSS ANATOMY OF A LONG BONE ❑Epiphysis- ends of long bones ❑Epiphyseal plate – flat plate of hyaline cartilage. ❑Diaphysis- shaft; makes up the most of the bone’s length and is composed of compact bone, covered by a fibrous connective tissue membrane called the periosteum. ❑Periosteum- outside covering ❑Medullary- inner space containing bone marrow ❑Endosteum- lining of medullary cavity ❑ Red marrow and Yellow marrow ❑ Bone markings – reveal where muscles, tendons, and ligaments attach and where blood vessels and nerves pass. ▪ Projections or processes – grow out of the bone surface. ▪ Depression or cavities – indentations in the bone. BONE MARKINGS MICROSCOPIC ANATOMY Osteocytes – mature bone cells found in tiny cavities called lacunae. The lacunae are arranged in concentric circles called lamellae around central/haversian canals. Each unit is called osteon, or haversian system. Canaliculi – tiny canals that radiate outward from central canals to all lacunae. Perforating canals a.k.a Volkmann’s Canals. ANATOMY OF COMPACT BONE WITH A DETAILED VIEW OF AN OSTEON  BONE FORMATION, GROWTH AND REMODELLING Skeleton CARTILAGE- (young children) BONE OSSIFICATION- “process of bone formation”. OSTEOBLAST- “bone-building cells”. Bones are remodeled continually in response to changes in two factors: (1) the calcium ion level in the blood and (2) the pull of gravity and muscles on the skeleton OSTEOCLAST: giant bone-destroying cells. Bone remodeling is essential if bones are to retain normal proportions and strength during long-bone growth as the body increases in size and weight. IMAGE ILLUSTRATES THE PROCESS OF BONE REMODELLING. BONE FRACTURES STAGES IN THE HEALING OF A BONE FRACTURE  SKELETON The skeleton is divided into two parts: the axial skeleton, the bones that form the longitudinal axis of the body, and appendicular skeleton, the bones of the limbs and girdles.  AXIAL SKELETON AXIAL SKELETON ❑Skull ❑Vertebral Column ❑Thoracic Cage  SKULL ❑Cranium- encloses and protects the fragile brain tissue. ❑Facial bones- form a cradle for the eyes that is open to the anterior and allow the facial muscles to show our feelings through smiles or frowns.  SKULL: CRANIUM ❑Frontal bone- forms forehead ❑Parietal bone- forms most of the superior and lateral walls of the cranium. ❑Occipital Bone- the most posterior bone of the cranium ❑Temporal bones- lie inferior to the parietal bones External acoustic meatus- canal that leads to the eardrum and the middle ear. Styloid Process- a sharp, needle like projection, is just inferior to the external auditory meatus. Zygomatic process- is a thin bridge of bone that joins with the cheekbone anteriorly. Mastoid Process- full of air cavities; rough projection posterior and inferior to the external acoustic meatus. Jugular Foramen- junction of the occipital and temporal bones.  SKULL: FACIAL BONES ❑Maxillary bone/Maxilla – bones that form the upper jaw. ❑Palatine bones – lie posterior to the palatine process of the maxilla. ❑Zygomatic bones – cheekbones. ❑Lacrimal bone – forms part of the medial walls of the orbit, serves as a passageway for tears. ❑Nasal bones – rectangular bones forming the bridge of the nose. ❑Mandible – lower jaw, the largest and strongest bone of the face. HYOID BONE ❑The hyoid bone is unique in that it is the only bone of the body that does not articulate (form a joint) with any other bone. ❑serves as a movable base for the tongue and as an attachment point for neck muscles that raise and lower the larynx when we swallow and speak.  The vertebral column… The vertebral column is composed of separate bones called vertebrae, connected to form four spinal curves. A curve has more strength than a straight line, so can support the weight of the body and provide balance needed to walk.  VERTEBRAL COLUMN Also called the spine, extends from the skull to the pelvis where it transmits the weight of the body to the lower limbs. Formed from 26 irregular bones connected by ligaments. Intervertebral discs – cushion the vertebrae and absorb shocks while allowing spine flexibility. Running through the central cavity is the spinal cord. The vertebral column… The cervical curve contains the first 7 vertebrae; the thoracic curve contains the next 12; the lumbar curve contains 5. The sacral curve does not contain vertebrae. It contains the sacrum and coccyx (KOCK siks) or tailbone.  CERVICAL VERTEBRAE C₁-C₇ Form the neck region of the spine. C ₁ – Atlas; receive the occipital condyles of the skull. C₂ – Axis; acts as a pivot for the rotation of the atlas and skull above. THORACIC VERTEBRAE T ₁ - T ₁₂ Larger than the cervical vertebrae and are distinguished by the fact that they are the only vertebrae to articulate with the ribs.  LUMBAR VERTEBRAE L₁ - L₅ Somewhat kidney bean shape. Sturdiest of the vertebrae. SACRUM AND COCCYX Sacrum is formed by the fusion of five vertebrae; Forms the posterior wall of the pelvis. Coccyx is formed from the fusion of three to five tiny, irregularly shaped vertebrae; the human “tailbone”.  THORACIC CAGE/BONY THORAX Forms a protective cage of slender bones and cartilages around the organs of the thoracic cavity. Sternum- Breastbone; is a typical flat bone and the result of the fusion of three bones— the manubrium, body, and xiphoid process. Ribs- Form the walls of the bony thorax. Has 12 pairs of ribs; True ribs (first seven pairs), False ribs (next five pairs), Floating ribs (last two pairs of false ribs) intercostal spaces – the spaces between the ribs APPENDICULAR SKELETON  SHOULDER GIRDLE/ PECTORAL GIRDLE ❑Consist of 2 bones: Clavicle and Scapula ❑Clavicle/collarbone – slender, double curved bone that helps prevent shoulder dislocation. ❑Scapula/shoulder blades – triangular and are commonly called “wings”. BONES OF THE UPPER LIMBS Arm Humerus Forearm Radius Ulna Hand Carpals Metacarpals Phalanges BONES OF THE PELVIC GIRDLE ❑Pelvic girdle- Formed by two coxal bones (hip bones). ▪ Bearing weight is its most important function. ▪ It also protects the reproductive organs, urinary bladder, and a part of the large intestine.  Each hip bone is formed by the fusion of three bones: ilium, ischium and pubis Ilium – forms most of the hip bone. Ischium – “sit down bone”, forms the most inferior part of the coxal bone Pubis – the most anterior part of the coxal bone The pubic bones fuse anteriorly to form a cartilaginous joint called pubic symphysis Acetabulum – receives the head of the thigh bone BONES OF THE LOWER LIMBS Thigh Femur/Thigh Bone Leg Tibia/ Shinbone Fibula Foot Tarsals Metatarsals Phalanges  JOINTS/ ARTICULATIONS Every bone in the body forms a joint with at least one other bone (except hyoid bone). the sites where two or more bones meet. They have two functions: They hold the bones together securely but also give the rigid skeleton mobility.  Synarthroses – immovable joints FUNCTIONAL CLASSIFICATION Amphiarthroses – slightly moveable joints OF JOINTS Diarthroses – freely moveable joints Joints… A joint is a place where two or more bones connect. The manner in which they connect determines the type of movement allowed at that joint. SYNARTHROSIS is a joint that allows no movement. An example would be a cranial suture.  AMPIARTHROSIS is a joint Joints… that allows slight movement. An example would be a vertebra. DIARTHROSIS is a joint that allows free movement in a variety of directions, such as knee, hip, elbow, wrist, and foot. STRUCTURAL CLASSIFICATION Fibrous joints – bones are united by fibrous tissue, such as those seen in sutures of the brain Cartilaginous joints – the bone Pubic symphysis and vertebral joints ends are connected by Joints between the ribs and the cartilage sternum Synovial joints – bone ends are separated by a joint cavity containing synovial fluid Types of body movements at diarthrotic joints… Flexion: Abduction: moving a body bending a limb part away from the middle. Extension: Adduction: moving a body straightening a part toward the middle. flexed limb Types of body movements at diarthrotic joints… Supination: lying supine or face upward; or turning the Circumduction: palm or foot upward. moving a body Pronation: lying prone or part in a circular face downward; or turning motion the palm downward. Types of body movements at diarthrotic joints… Dorsiflexion: Protraction: moving a body bending a body forward. part backwards. Retraction: moving a body part backward. Types of body movements at diarthrotic joints… Rotation: Inversion: turning inward. moving a body Eversion: turning outward. part around a central axis  Types of body movements at diarthrotic joints… Trendelenburg Lateral recumbent: lying on your left or Fowler’s position: sitting right side straight up or reclining slightly; legs straight or bent. Trendelenburg position: lying supine with head lower than feet. SKELETAL DISORDERS Arthritis- JOINT INFLAMMATION: ❖Osteoarthritis- the most common form of arthritis; a chronic degenerative condition that typically affects the aged.  Rheumatoid Arthritis- a chronic inflammatory disorder, also an autoimmune disease. ❖Gouty arthritis- is a disease in which uric acid (a normal waste product of purine catabolism) accumulates in the blood and may be deposited as needle-shaped crystals in the soft tissues of joints.