Skeletal System PDF

SKELETAL SYSTEM c. Bone substance – EM and cells § It consists of the bone, cartilage, tendons and ligaments. Histology of Bone § Skeleton; dried (Greek)...

SKELETAL SYSTEM c. Bone substance – EM and cells § It consists of the bone, cartilage, tendons and ligaments. Histology of Bone § Skeleton; dried (Greek) Osteoblasts – bone-forming cells; repair and remodeling of bone Functions (S2PMB) 1. Support Osteocytes – bone cells located between the lamellae 2. Protection (thins sheets of EM) 3. Movement 4. Storage Lacunae – spaces within the lamellae 5. Blood cell production Canaliculi – tiny canals within the lamellae Extracellular Matrix § Composed of connective tissues Types of Bone Tissue a. Compact bone Collagen – tough ropelike protein § Forms most of the diaphysis of long bones § Central Canal / Haversian Canal – concentric Proteoglycans – large molecules consisting of rings that contains blood vessels; ‘bull’s eye’ polysaccharides attached to core proteins § Osteon / Haversian System – central canal + lamellae + osteocytes Tendons & Ligaments – large amounts of collagen fiber b. Spongy bone Cartilage – contains collagen & proteoglycans § Located mainly in the epiphyses of long bones § Forms the interior of all other bones Bone – contains collagen and minerals (Calcium & § Consists of trabeculae (interconnecting rods, Phosphate) plates of bone) without central canals Hydroxyapatite – calcium phosphate crystals Bone Ossification Ossification – formation of bone by osteoblasts General Features of Bone § Long bones; upper and lower limbs Types of Ossification § Short bones; wrist and ankle a. Intramembranous ossification – osteoblasts § begin to produce bone in connective tissue § Irregular bones; vertebrae and facial bones Ø Ossification centers – where intramembranous ossification begins Long Bones a) Diaphysis – central shaft b. Endochondral ossification – bone formation b) Epiphysis – ends occurs inside the cartilage; bones at the base of c) Epiphyseal plates – growth plate; where the the skull and remaining skeletal system are bone grows in length formed Ø Chondrocytes – cartilage cells; increase Articular cartilage – covers the ends of the epiphyses in no., enlarge, and die Epiphyseal line – bone growth stops and the epiphyseal Primary ossification center – where bone first begins to plate is replaced by bone appear Medullary Cavity – large cavity in the diaphysis; Osteoclasts – cells that remove calcified cartilage matrix contains the marrow Secondary ossification center – form in the epiphyses Marrow – soft tissue within the cavity Bone Growth Yellow Marrow – consists of adipose tissue (fat) § Deposition of new bone lamellae onto existing bone Red Marrow – consists of bone forming cells; site of § Bone elongation occurs at the epiphyseal plate; blood formation leads to increase in height (endochondral ossification) Layers of a Bone § Chondrocytes proliferate, enlarge, die, and are a. Periosteum – outermost layer; surround the replaced by bone diaphysis; contain blood vessels, nerves, osteoblasts Appositional growth – increase in bone width or diameter b. Endosteum – innermost layer; lines the medullary cavity (thinner connective tissue) M o r a n o , M. A. Bone Remodeling AXIAL SKELETON § Removal of existing bone by osteoclasts § Composed of the skull, vertebral column, and § Deposition of new bone by osteoblasts thoracic cage § Responsible for change in bone shape, bone § Form the longitudinal axis of the body adjustment, repair, and calcium ion regulation I. Skull Bone Repair § 22 bones § Clot is formed in the damaged area § Blood vessels and cells invade the clot and form Braincase a callus (network of fibers and islets of cartilage) § 8 bones § Osteoblasts enter the callus and from a spongy § Covers and protects the fragile brain tissue bone § Bone is slowly remodeled to compact bone 1. Frontal Bone – forehead, bony projections under the eyebrow, part of the eye’s orbit Bone and Calcium Homeostasis   § Osteoclasts remove calcium = blood calcium 2 - 3. Parietal Bone (paired) – the superior and levels increases lateral walls of the cranium; coronal suture § Osteoblasts deposit calcium = blood calcium levels decrease 4 - 5. Temporal Bone (paired) – lies inferior to the parietal bone; squamous suture Hormones that maintain Calcium Homeostasis Ø External Auditory Meatus (EAM) – a 1. Parathyroid hormone (PTH) canal that leads to the eardrum and the § Parathyroid gland; middle ear § Increase bone breakdown & increase blood Ø Styloid process – a sharp, needlelike calcium levels; structure located inferior to the EAM § Stimulates the kidneys to from active vitamin D Ø Zygomatic process – a bridge of bone that joins with the cheekbone anteriorly 2. Calcitonin Ø Mastoid Process – a rough projection § Thyroid gland posterior and inferior to the EAM § Decrease bone breakdown and decrease blood calcium levels 6. Occipital Bone – inferior and posterior bone of the cranium; lambdoid suture General Considerations of Bone Anatomy Ø Foramen magnum – where the spinal § 206 bones = adult cord joins the brain § 276 bones = newborn baby Ø Occipital condyles –rests on the first vertebra of the vertebral column Foramen – hole in a bone Ø Foramen ovale – allows the fiber of cranial nerve 5 to pass Canal / Meatus – elongated hole in a tunnel like body 7. Sphenoid Bone – butterfly-shaped bone that Fossa – depression in a bone spans the width of the skull Ø Sella Turtica – saddle-shaped structure Tubercle / Tuberosity – lump on a bone at the central region; contains the pituitary gand Process – projection from a bone 8. Ethmoid Bone –   irregularly shaped bone that Condyle – end of a bine that forms a joint with another lies anterior to the sphenoid bone bone Facial bones Facet – small flattened articular surface § 14 bones; 13 solidly connected, 1 movable (mandible) Crest – prominent ridge § Holds the facial muscles in place § Joined together by sutures (interlocking, Trochanter – tuberosity found only on proximal femur immovable) Fissure – cleft 1-2. Maxillae – main bones of the face; carries the upper teeth Sinus – cavity 3-4. Palatine Bones – lies posterior to the Suture – a joint uniting the bones of the skull palatine processes of the maxilla 5-6. Zygomatic Bones – cheekbones M o r a n o , M. A.  7-8. Lacrimal Bones – bones forming part of the Ø Vertebral canal – where the spinal cord is medial wall of each orbit located; protects the spinal cord from injury 9-10. Nasal Bones – bones forming the bridge Ø Intervertebral foramina – where spnal nerves of the bone exit the spinal cord 11-12. Inferior Nasal Conchae – thin curved Ø Articular process – where the vertebra articulate bones projecting from the lateral wall of the with each other nasal cavity Ø Articular facet – smooth ‘little face’ 13. Vomer Bone – single bone in the median of the nasal cavity Regional Differences in Vertebrae 1. Cervical Vertebrae – very small bodies, 14. Mandible – lower jaw; only freely movable dislocation and fractures are common int his joint of the face area Ø Atlas – 1st CV; holds up the head; ‘yes’ shaking Hyoid Bone – U-shaped bone; provides attachment to Ø Axis – 2nd CV; considerable amount of rotation; tongue muscles; elevates the larynx during speech and ‘no’ shaking swallowing v Dens – where the rotation occurs II. Vertebral Column 2. Thoracic vertebrae – long, thin spinous § Central axis of the skeleton processes; articulate the ribs § 26 individual bones; Ø 7 cervical vertebrae 3. Lumbar vertebrae – large, thick bodies; heavy, Ø 12 thoracic vertebrae rectangular transverse + spinous processes; Ø 5 lumbar vertebrae carry large amount of weight; ruptured Ø 1 sacral bone intervertebral disks are common Ø 1 coccyx bone Functions 4. Sacrum – five sacral vertebrae fused in one 1. Supports the weight of the head and the trunk. Ø Median Sacral Crest – spinous process of the 1st 2. Protects the spinal cord. four SV 3. Allows the spinal nerves to exit the spinal cord. Ø Sacral Hiatus – inferior end of the sacrum; the 4. Site for muscle attachment. 5th process of the SV that does not form; 5. Permits movement of the head and trunk. common side of caudal anesthetic injections Ø Sacral Promontory – anterior edge of the 1sy SV Kyphosis – posterior curvature; hunchback that bulges; landmark felt during vaginal examination; reference point in vaginal delivery Lordosis – anterior curvature; swayback condition of a baby Scoliosis – lateral curvature 5. Coccyx – tailbone; fusion of 4 or more/less fused vertebrae; easily broken General Plan of the Vertebral Column Body – weight-bearing portion III. Rib Cage Ø Intervertebral disks body – separates the § Also called the thoracic cage vertebral bodies § Protects the vital organs § Prevents thorax collapse during respiration Ø Vertebral arch – surrounds the vertebral foramen 1. Rib Cage v 2 Pedicles – extends from the body to § 12 pair of ribs the transverse process Ø 1 – 7 true ribs (attached directly to the sternum) v 2 Laminae – extends from the transverse Ø 8 – 12 false ribs (do not attach directly to the to the spinous process sternum) v Provides attachment sites for the muscles v 11 – 12 floating ribs (do not attach to that move the vertebral column; the sternum) Transverse process – extends laterally bet. the lamina and 2. Sternum pedicle § Also called the breastbone Spinous process – projects Ø Jugular notch – a depression bet. the ends of the dorsally where the two laminae clavicles where they articulate with the sternum meet Ø Sternal angle – a slight elevation felt at the junction of the manubrium and the sternum; Ø Vertebral foramen – a large opening important landmark bcos it identifies the 2nd rib M o r a n o , M. A.  Ø Xiphoid process – important landmark of the 4. Hand – 5 metacarpal bones are attached to the sternum during CPR carpal bones Ø Phalanges – 3 small bones on each finger APPENDICULAR SKELETON § 126 bones III. Pelvic Girdle § Consists of the bones of the upper and lower § Where lower limbs attach to the body limbs, as well as the girdles Coxal bones – hip bones; join each other anteriorly and I. Pectoral Girdle the sacrum posteriorly to form a ring of bone called the § Also called the shoulder girdle pelvic girdle § Consists of 4 bones; 2 scapulae + 2 clavicles Ø Ilium – most superior Ø Ischium – inferior and posterior; sit down bone 1. Scapula – shoulder blade; where muscles Ø Pubis – inferior and anterior extending to the arm are attached Iliac crest – seen along the superior margin of each ilim 2. Glenoid cavity – 4th fossa; where the head of the Ø Anterior Superior Iliac Spine – important hip humerus connects to the scapula landmark; anterior end of the iliac crest Ø Spine – a ridge that runs across the posterior surface fo the scapula Pubic symphysis – where coxal bones join anteriorly Ø Sacroiliac joints – joins the sacrum posteriorly 3. Acromion process – extends from the scapular spine to form the point of the shoulder Acetabulum – socket of the hip joint 4. Clavicle – collarbone; articulates with the Obturator foramen – large hole in each coxal bone scapula art the acromion process Pelvic inlet – formed by the pelvic brim and the sacral 5. Coracoid process – provides for the attachment promontory of arm and chest muscles Pelvic outlet – bounded by the ischial spines, pubic II. Upper Limb symphysis, and coccyx 1. Arm – region bet, the shoulder and the elbow; contains the humerus; has two tubercles: greater Male pelvis: larger and massive; Female pelvis; broader tubercle and lesser tubercle Ø Deltoid Tuberosity – where the deltoid muscle IV. Lower Limbs attaches 1. Thigh – region bet. the hip and the knee; Ø Epicondyles – provide attachment sites for contains the femur forearm muscles Ø Head of the femur – articulates with the acetabulum of the coxal bone 2. Forearm Ø Condyles – articulates with the tibia Ø Radius – lateral to the thumb Ø Epidondyles – points of ligaments attachments v Radial tuberosity – where the arm Ø Trochanters – lateral to the head after the neck muscles (biceps brachii) attaches Ø Patella – knee cap; enables the tendon to bend Ø Ulna – medial to the little finger over the knee v Trochlear notch – forms most of the elbow joint 2. Leg – region bet. the knee and the ankle v Coronoid process – helps complete the Ø Tibia – shinbone; larger; major weight-bearing grip of the ulna bone of the leg; medial malleolus v Olecranon process – extension of the Ø Fibula – thin and sticklike that forms the lateral ulna side of the leg; lateral malleolus v Styloid process – articulates with the bones of the wrist 3. Ankle – 7 tarsla bones Ø Talus – ankle bone 3. Wrist – short region bet. the forearm and the Ø Calcaneus – heel bone hand; 8 carpal bones (SLTPHCTT) Ø Cuboid Ø Scaphiod Ø Navicular Ø Lunate Ø Cuneiforms; medial, intermediate, lateral Ø Triquetrum Ø Pisiform 4. Foot Ø Hamate Ø Metatarsal bones and phalanges – arranged Ø Capitate and numbered in a similar manner to the hand Ø Trapezoi Ø Has 3 primary arches Ø Trapezium M o r a n o , M. A. JOINTS Types § Also called an articulation 1. Plane/Gliding Joints – two opposed flat § Where two bones come together surfaces that glide over each other a. Synarthrosis joints – non-movable 2. Saddle Joints – two saddle shaped articulating surfaces oriented at right angles; joint bet. the b. Amphiarthrosis joints – slight movable metacarpal bone and the carpal bone of the thumb c. Diarthrosis – freely movable 3. Hinge Joints – permit movement in one plane I. Fibrous Joints only; elbow and knee joints § 2 bones that are united by fibrous tissue Ø Menisci – shock-absorbing fibrocartilage pads § Exhibit little or no movement 4. Pivot Joints – restrict movement to rotation 1. Sutures – bet. the bones of the skull; squamous, around a single axis; rotation that occurs bet. the lambdoid, coronal axis and atlas; articulation bet. the ulna and Ø Fontanels – sutures that are quite wide in a radius newborn 5. Ball and socket Joints – consist of a ball (head) 2. Syndesmoses – bones are separated by some and a socket; shoulder and hip joints distance and held together by ligaments; FB connecting the radius and ulna 6. Ellipsoid/Condyloid Joints – elongated ball and socket joints; joint bet. the occipital condyles 3. Gomphoses – consists of pegs fitted into sockets (skull) and the atlas (vertebral column); joints and held in place by ligaments; joint bet. a tooth bet. the metacarpals and phalanges and its socket Types of Movement II. Cartilaginous Joints 1. Flexion – movement that takes place in a § Unites two bones by means of cartilage frontal/coronal plane § Slight movement can occur Ø Plantar flexion – when standing on the toes § Epiphyseal plates of growing long bones Ø Dorsiflexion – movement of the foot toward the § Cartilage bet. the ribs and the sternum shin (walking on heels) 2. Extension – movement that takes place in a § Fibrocartilage forms joints such as the posterior direction intervertebral disks 3. Lateral Flexion – movement of the trunk in the coronal plane III. Synovial Joints 4. Abduction – movement away from the median § Freely movable joints plane § Contains fluid in a cavity surrounding the ends 5. Adduction – movement toward the median of articulating bones plane 6. Pronation – rotation of the forearm so that the Articulating cartilage – thin layer that covers the palm is down articular surfaces of bones w/in the synovial joints 7. Supination – rotation of the forearm so that the palm faces up Joint cavity – filled with fluid 8. Eversion – opposite movement of the foot so that the sole faces in a lateral direction Joint capsule – encloses the cavity that helps hold the 9. Inversion – movement of the foot so that the bones together and allows for movement sole faces medially 10. Rotation – movement of a part of the body Synovial membrane – lines the joint cavity everywhere around its long axis 11. Circumduction – combination in sequence of Synovial fluid – produced by the SM; covers the the flexion, extension, abduction, adduction surfaces of the joint 12. Protraction – to move forward 13. Retraction – to move backward Bursa – a pocket or sac; located bet. Structures that rub 14. Hyperextension – abnormal, forced extension of together a joint beyond its normal range of motion Bursitis – inflammation of the bursa; often results to abrasion Tendon Sheath – extension of SM along some tendons M o r a n o , M. A.