The-Skeletal-System.pdf

ANATOMY AND PHYSIOLOGY OF FARM ANIMALS NOMENCLATURE FOR SYSTEMATIC ANATOMY System Name of Study Chief Structures 1.Skeletal Osteology Bones 2. Articular Arthrology Joints 3. Muscular Myology Muscles 4. Digestive Splanch...

ANATOMY AND PHYSIOLOGY OF FARM ANIMALS NOMENCLATURE FOR SYSTEMATIC ANATOMY System Name of Study Chief Structures 1.Skeletal Osteology Bones 2. Articular Arthrology Joints 3. Muscular Myology Muscles 4. Digestive Splanchnology Stomach, intestines 5. Respiratory Splanchnology Lungs, air passages 6. Urinary Splanchnology Kidneys, bladder 7.Reproductive Splanchnology Ovaries, testes 8. Endocrine Endocrinology Ductless glands 9. Nervous Neurology Brain,spinal cord, nerves 10.Circulatory Angiology Heart, vessels 11.Integumentary Dermatology Skin 12. Sensory Esthesiology Eye, ear INTERNAL ANATOMY OF FARM ANIMALS: THE SKELETAL SYSTEM OBJECTIVE:  Explain the factors affecting the growth & maturity of the bones, muscles & other parts of the animal body with consideration on the endocrinology & the genetics of the animal. SKELETAL SYSTEM 3.1. Gen. Composition of bones 3.2. Main skeletal divisions 3.3. Main classification of bones 3.4. Joints & Articulations 3.5. Fracture of the bones SKELETAL SYSTEM Functions:  Framework of the body (all endoskeleton)  Gives physical support (vertebral column)  Protection  Muscle attachment  Leverage for locomotion  Manufacture of RBC (bone marrow)  Storage of mineral OSTEOLOGY – study of bones. TERMS ROUTINELY USED IN REFERENCE TO BONES: spongy bone  Compact bone (dense or compact cortical) - refers to the hard Epiphysis bone layer of bone that covers most bones and forms almost the Endosteum entire shaft of long bones.  Cancellous (spongy) bone - Diaphysis composed of plates arranged to form a porous network. yellow marrow Sharpey’s fibers  Cortex - denotes the compact bone that forms the shaft of a long bone periosteum Epiphysis hyaline cartilage Microscopic Structure of Compact Bone STRUCTURE OF A LONG BONE: GROSS ANATOMY spongy bone A. Diaphysis or shaft - makes up most of the bone's length; compact bone composed of compact bone; Epiphysis Endosteum B. Periosteum - covers and protect the shaft; responsible for the increase in bone diameter; functions Diaphysis in the healing of fractures yellow marrow Sharpey’s fibers C. Sharpey 's fibers - connective tissue fibers that secure the periosteum to the periosteum underlying bone. Epiphysis hyaline cartilage D. Medullary cavity (marrow cavity) - space Articular cartilage Epiphysis surrounded by the cortex of Spongy bone Epiphyseal plate a long bone. In young animals - filled Compact bone  with red blood marrow w/c Medullary cavity gradually changes to fatty yellow marrow in old Diaphysis animals. E. Epiphysis - refers to either extremity of long bone. Epiphysis F. Epiphyseal Line - remnant of the Articular cartilage epiphyseal plate/ disc seen in a Epiphysis Spongy bone young; Epiphyseal plate Epiphyseal cartilage or disc (physis) - layer of hyaline cartilage separating diaphysis & Compact bone epiphysis w/in the metaphysis of an immature bone; Medullary cavity  cause the lengthwise growth of a long Diaphysis bone. End of puberty: a) hormones stop long bone growth, b) epiphyseal plates completely replaced by bone, leaving only the epiphyseal lines. Epiphysis G. Endosteum - fibrous membrane that lines the marrow cavity & Epiphysis Articular cartilage osteonal (Haversian) Spongy bone Epiphyseal plate canals of a bone. H. Articular cartilage - Compact bone thin layer of hyaline Medullary cavity cartilage that covers the articular surface of a bone. Diaphysis Epiphysis  1.0 CLASSIFICATION OF BONES A. According to gross appearance: a. Long Bones greater in one dimension than any other,  consists of a cylindrical shaft (diaphysis) & two extremities (epiphysis) w/ metaphysis b/w each epiphysis & diaphysis; Functions: levers; aid in support & locomotion e.g. humerus, radius, ulna, femur, tibia, fibula b. Short Bones cuboid or approximately equal in all dimensions;  no marrow cavity, interior composed of spongy substance filled w/ marrow spaces; Function: absorb concussion e.g. tarsus and carpus c. Flat Bones thin & expanded in two dimensions; Functions: protect vital organs ;muscle attachment e.g. scapula and pelvic bone d. Sesamoid Bones  resemble a sesame seed;  are developed along the course of tendons; Function: reduce friction or change the course of tendons e.g. patella e. Irregular bones unpaired bones located on the median plane; Functions: protect, support & for muscle attachment e.g. vertebrae B. According to formation: a) Cartilage bone – starts first as a cartilage (chondrofication) and later hardens into a bone (ossification).  e.g. some bones of the skull b) Membrane bone – develop immediately into a hard bone.  e.g. bones of the forelimb C. According to Location: Divisions of the body skeleton A. Axial skeleton B. Appendicular skeleton C. Visceral skeleton A. Axial skeleton- found at the center of the body. a.Skull a.1. Cranial bones a.2. Facial bones  Single bones: occipital,  Single bones: vomer, sphenoid, ethmoid  Paired bones: maxilla, premaxilla,  Paired bones: inter-parietal, palatine, pterygoid, nasal, lacrimal, parietal, frontal, temporal malar, dorsal & ventral turbinates b. Vertebrae  Five Regions of the Vertebrae 1. Cervical region – neck 2. Thoracic region - thorax 3. Lumbar region - back 4. Sacral region - pelvic area 5. Caudal/coccygeal region- tail c. Ribs 1. True (sternal) - Join sternum by coastal cartilage 2. False (asternal) - not directly connected with sternum 3. Floating - last 1 or 2 pairs connected only with vertebrae d. Sternum - chest bone Types of Cattle and Sheep and Horse Pigs Chicken Vertebrae Buffalo goat Cervical 7 7 7 7 15-17 Thoracic 13 13 18 14-15 7 Lumbar 6 6 6 6-7 14 sacral 5 4 5 4 Coccyge 18-20 16-18 15-21 20-30 5-6 al  B. APPENDICULAR SKELETON BONES OF THE LIMBS b. Pelvic limb (hindlimb) a. Pectoral limb (forelimb) 1. Rump or hip – ilium, ischium, 1. Shoulder – scapula, clavicle, pubis coracoid 2. Thigh - femur 2. Arm - humerus 3. Kneecap - patella 3.Forearm – radius, ulna 4. Leg or shank – tibia. fibula 4. Wrist - carpals 5. Ankle (hock) - tarsal 5. Manus (forefoot) – metacarpals, 6. Pes (hindfoot) – metatarsals, phalanges phalanges C. Visceral skeleton - consists of bones that had developed in the soft tissue of the body 1) os rostri - found in the soft tissue of the external nares of swine. 2) os cordis - found around the origin of the aorta and pulmonary artery at the base of the heart in cattle and sheep. 3) os penis - found within the penis of dog, mink, some rodent species, seals, walruses and raccoons.  COMPOSITION AND PHYSIOLOGY OF BONE Three types of Bone Cells 1. Osteoblasts - bone forming cells; responsible for formation of osteoid tissue. Osteoblast 2. Osteocytes - mature bone cells. Osteocyte 3. Osteoclasts - bone destroying cells; digest cells Osteoclast  MICROSCOPIC STRUCTURE OF COMPACT BONE A. Osteocytes - mature bone cells;  found in tiny cavities within the matrix called: B. Lacunae  where osteocytes are located.  arranged in concentric circles called Lamellae around central (Haversian) canals; C. Osteon or Haversian System – consists of central (haversian) canal & matrix rings;  Central canals run lengthwise thru bony matrix, carrying blood vessels & nerves to all areas of the bone. D. Canaliculi - tiny canals radiate outward from central canals to all lacunae;  connects lacunae w/in the substance of bone;  transmits tissue fluid essential for maintaining life of osteocytes.  Lacunae & Canaliculi are formed because the osteoblasts (bone forming cells) are interconnected by cytoplasmic processes at the time the osteoid material is laid down. E. Perforating Volkmann’s canals - communication pathway from outside of the bone to its interior (and the central canals);  run into the compact bone at right angles to the shaft.  100 cm3 of bone contain 10,000 mg of calcium, thus, bone serves as mineral reservoir.  Calcium salts - deposited in the matrix; give bone its hardness;  Organic parts (especially the collagen fibers) provide for bone's flexibility & great tensile strength.  Osteoblasts function in bone growth and in fracture repair.  Ossification - formation of true bone by the deposition of calcium salts in a matrix of osteoid tissue.  Calcification - deposition of calcium salts in any tissue.  Bone decreases or increases in size, repair itself, can reshape itself according to good engineering principles so as to sustain a max. of stress w/ a min. of bone tissue. Bone Atrophy occurs when: 1. pressure is constant & excessive, 2. when periods of pressure exceed periods of release 3. when there is little or no stress.  Proliferation of bone occurs in response to concussion or intermittent pressure.  B. THE ARTICULAR SYSTEM Arthrology – study of joints.  Joints are formed when two or more bones come together & are united by fibrous, elastic or cartilagenous tissue.  Classification of joints: a. Synarthroses – an immovable joint. b. Diarthroses – movable joint c. Amphiarthroses - partially movable joints a. Synarthroses  Joints united by fibrous tissue and/or cartilage.  no joint cavity  Many become firmly united to each other by bony growth. Include: 1. Sutures 2. Syndesmoses 3. Synchondroses 4. symphysis 5. gomphoses 1) sutures – bones united by fibrous connective tissue (ligaments) along lines w/c can be extremely irregular, e.g. joints in the skull. 2) syndesmoses - white fibrous &/or yellow elastic tissues unite the bones. e.g. union of the shafts of metacarpals in horse. 3) synchondroses – bones are united by cartilage. e.g. union of diaphysis & epiphysis of an immature bone. 4) symphysis - bones are united by flattened discs of flbrocartilage. e.g. b/w bodies of adjacent vertebrae 5) gomphosis - joints b/w a tooth & its socket.  DIARTHROSIS- FREELY MOVABLE (SYNOVIAL JOINTS)  Joints which possess a cavity, capsule & mobility;  movement have the following articular surfaces: articular cartilage, joint capsule and joint cavity TYPES OF DIARTHRODIAL JOINTS: 1. Ginglymus (hinge) joint - move only in the sagittal plane, e.g. fetlock joint 2) Arthrodial joint - have only a slight gliding movement between relatively flat opened surfaces. These surfaces are called facets. e.g. joints between adjacent carpal bones 3) Trochoid (pivot) Joints - rotary movement occurs around one axis e.g. atlanto-axial joint 4) Enarthrodial or ball and socket Joint - permit movement in nearly any direction e.g. coxo-femoral or hip joint  C. AMPHIARTHROSES  Slightly Movable Joint  share some characteristics of both synarthrodial and diarthrodial joints  these joints unite the bodies of the vertebrae  TYPES OF GAIT ( MANNER OF WALKING) 1. Plantigrade – entire sole of the foot touches the ground. e.g. man, apes, racoons and bears 2. Digitigrade – digits touch the ground, rest of the foot is elevated ( digits provided with special sole pads) e.g. cats, dogs, any member of the feline family 3. Unguligrade- tips of the digits (specialized into hoofs) touch the ground. e.g. hoofed mammals like carabaos, cows, pigs, goats and sheep.  COMMON TYPES OF BONE FRACTURES Fracture Illustration Description Comment Type Comminuted Bone breaks Common in into many the aged (w/ fragments brittle bones) Compression Bone is Common in crushed porous (osteoporotic) bones Depressed Broken bone Typical of skull is pressed fracture inward Fracture Illustration Description Comment Type Impacted Broken bone Commonly occurs ends are when one attempts forced into to break a fall w/ each other outstretched arms Spiral Ragged break Common sports occurs when fracture excessive twisting forces are applied to a bone Greenstick Bone breaks Common in young incompletely animals (bone more flexible)  INTERESTING FACTS  In human body: Three bones in the inner ear, malleus, incus & stapes, are the smallest bones. The thigh bone, or femur, is the longest bone.  The hyoid bone situated behind the lower jaw is also called a ‘floating’ bone (not part of any joint nor directly attached to any other bone); resistant to fractures. Broken hyoid bone indicate death from strangulation.  Newborn babies have about 300 bones. Many of these bones fuse together to form the 206 bones of adult. THE END