VAN211-MODULE-2-SKELETAL-ANATOMY.pdf

VAN211 MODULE 2 - SKELETAL ANATOMY MODULE 2. SKELETAL ANATOMY OUTLINE Introduction Bone composition and structure Classification of bones The axial and appendicular skeleton Bone markings LEARNING OUTCOMES Ident...

VAN211 MODULE 2 - SKELETAL ANATOMY MODULE 2. SKELETAL ANATOMY OUTLINE Introduction Bone composition and structure Classification of bones The axial and appendicular skeleton Bone markings LEARNING OUTCOMES Identify the structure and anatomical features of a bone; Compare compact and spongy bones; Know the different classifications of bones; Classify the bones according to their shapes; and Define and name examples of bone markings. A. INTRODUCTION OSTEOLOGY  Derived from the Greek words osteon (bone) & logos (knowledge)  Defined as the study of the structure and function of bones BONE CHARACTERISTICS  Hardest structure in the body  Support and protect body tissues  Serve as framework of the body  Act as levers to which muscle or their tendons are attached FUNCTIONS OF BONES  Gives rigidity and shape to the body  Provide attachment for muscles thereby acting as levers for muscular action  Protect vital organs of the body (e.g. heart, lungs)  Reserve for minerals (e.g. calcium, phosphorus, magnesium)  Site of production of blood cells TYPES OF OSSEOUS TISSUE  Bone is a type of connective tissue.  Made up of protein, collagen matrix, and minerals like calcium, phosphorus, and magnesium.  The incorporated minerals make bone hard and strong while the collagen provides flexibility so that the bone can resist breaking.  Bones are composed of an exterior compact bone that surrounds the internal spongy bone.  Periosteum lines the outer surface of bone, and the endosteum lines the inner medullary cavity. RHD/CTU-CVM BARILI CAMPUS 11  VAN211 MODULE 2 - SKELETAL ANATOMY COMPACT / CORTICAL BONE  Heavy, tough and compact in nature.  Made up of osteons or haversian systems.  Fill the outer layer of most bones.  Form the shaft or diaphysis of long bones.  Provide support and protection to the inner cancellous/spongy layer. SPONGY BONE  Light, spongy and soft in nature.  Made up of trabeculae (small, needle-like pieces of bone arranged like a honeycomb).  Fill the inner layer of most bones.  Form the ends or epiphyses of long bones.  Help lessen the weight of a bone while still providing strength. BONE MARROW  Bone marrow fills the cylindrical cavities in the bodies of long bones and occupies the spaces inside spongy bone.  There are two types of bone marrow: the yellow marrow and red marrow.  Yellow marrow is found in the central cavities of long bones and consists mostly of fat.  Red marrow is found in the medullary cavities of flat and short bones, articular ends of long bones, bodies of vertebrae, spongy bone of the flat bones.  Red marrow consists mostly of hematopoietic tissue and little fat and is essential for red blood cell production. B. THE SKELETON CLASSES OF SKELETON  Exoskeleton  Endoskeleton EXOSKELETON  Found on body surface  Seen in invertebrates  Crab and tortoise: shell  Present in higher vertebrates as nails on digits, horns, hooves, etc. How many bones does a dog have in its skeletal system? Skull and hyoid bones – 50 Vertebral column – 50 Ribs and sternum – 34 Thoracic limb – 90 Pelvic limb – 96 Heterotopic skeleton (baculum) – 1 ENDOSKELETON  Embedded in soft tissues within the body  Consists of:  Axial skeleton  Appendicular skeleton  Axial skeleton  Consists of skull, vertebral column, and rib cage RHD/CTU-CVM BARILI CAMPUS 12  VAN211 MODULE 2 - SKELETAL ANATOMY  Appendicular skeleton  Pectoral pelvic girdle/limb (forelimb) and pelvic girdle/limb (hindlimb)  Splanchnic/Visceral skeleton  Only one in dogs: baculum or os penis (male dogs) C. BONE TYPES ACCORDING TO SHAPE TYPES OF BONES Flat Irregular Long Sessamoid Short FLAT BONES  Thin, flattened, slightly curved with two parallel layers of compact bone sandwiching a layer of spongy bone  Protect the internal organs (e.g. brain, heart, lungs, pelvic organs)  Provide large areas of attachments for muscles  Found in skull, thoracic cage, pelvis  Skull (occipital, parietal, frontal, nasal, lacrimal, and vomer)  Thoracic (sternum and ribs)  Pelvis (ilium, ischium, and pubis) FLAT BONE LAYERS  Periosteum: thin, outer lining of compact bone; w/ blood vessels & nerves  Compact bone: hard, dense tissue  Spongy bone: innermost layer, lightweight, absorbs sudden stress LONG BONE  Characterized by a shaft that is much longer than it is wide  Has rounded head at each end of the shaft  Made of compact bone, with lesser amounts of spongy bone and marrow  Support weight of the body and facilitate movement  Located in appendicular skeleton  Forelimb bones (e.g. radius, ulna, digits)  Hindlimb bones (e.g. femur, tibia, digits) GROSS ANATOMY OF A LONG BONE  Periosteum: dense fibrous membrane covering bone surfaces  Cortical or compact bone  Cancellous or spongy bone  Bone marrow  contained in the medullary cavity  soft, spongy tissue w/ blood vessels PARTS OF A LONG BONE  Composed of diaphysis and epiphysis  Diaphysis  Tubular shaft that runs between the proximal and distal ends of the bone  Medullary cavity - hollow region in the diaphysis which is filled with yellow marrow  Walls of the diaphysis - composed of dense and hard compact bone  Epiphysis  Wider section at each end of the bone that si filled with spongy bone.  Red marrow fills the spaces in the spongy bone. RHD/CTU-CVM BARILI CAMPUS 13  VAN211 MODULE 2 - SKELETAL ANATOMY  Metaphysis  Area where epiphysis meets the diaphysis near the end of the bone.  A narrow area that contains the epiphyseal plate (growth plate).  Epiphyseal plate  Composed of a layer of hyaline cartilage in a growing bone.  In adulthood, replaced by osseous tissue and the epiphyseal plate becomes an epiphyseal line. GROSS ANATOMY OF A LONG BONE SHORT BONE  Short and roughly cube-shaped  Has a thin layer of cortical bone surrounding a spongy bone interior  No marrow activity  Absorb concussion (shocks)  Provide stability & some movement  Found in carpals and tarsals RHD/CTU-CVM BARILI CAMPUS 14  VAN211 MODULE 2 - SKELETAL ANATOMY IRREGULAR BONES  Vary in shape and structure  Complex shapes protect internal organs  Examples: vertebrae, sacrum, coccyx, temporal, sphenoid, ethmoid, zygomatic, maxilla, mandible, palatine, hyoid SESSAMOID BONES  Small, round bones embedded in tendons of hands, knees, and feet  Helps decrease friction  Increase leverage to muscles and tendons  E.g. patella (knee cap) ANATOMY OF A FLAT BONE FLAT BONE (pelvis) FLAT BONE (skull) LONG BONES SHORT BONES (carpals, tarsals) IRREGULAR BONES (lumbar vertebrae) SESSAMOID BONE RHD/CTU-CVM BARILI CAMPUS 15  VAN211 MODULE 2 - SKELETAL ANATOMY VISCERAL BONES  Small bones that occur in the tissues of an organ or other structures  NOT part of regular skeleton  Occur in particular sites and in particular species of animals  Aka splanchnic or heterotrophic bone  Examples  Os penis - penis of dogs, bats, rodents and some primates  Os cordis - heart of cattle  Os rostri - snout of pigs  Os phrenic / os diaphragmaticum - diaphragm of camels PNEUMATIC BONES  Bones containing air spaces  Cavities / spaces lined by mucous membrane (sinuses)  Communicate indirectly with the external air  Mammals: communicate w/ nasal cavity  Birds: communicate w/ the air sacs  Examples  Mammals: frontal, maxilla, premaxilla, palatine, sphenoid, ethmoid  Birds: vertebrae, sternum, humerus, femur OS PENIS / BACULUM PNEUMATIC BONE IN AVIAN SPECIES D. BONE MARKINGS ANATOMICAL TERMINOLOGY GENERAL CLASSES OF BONE MARKINGS  Articulations  Projections  Holes ARTICULATION  Where two bone surfaces come together.  Surfaces tend to conform to one another, e.g. one being rounded and the other cupped, to facilitate articulation. TERM DEFINITION/DESCRIPTION EXAMPLES Rounded surface that articulates Condyle occipital condyles of skull with another bone Facet Flat surface articular facets of vertebrae Head Prominent rounded surface femoral head, head of femur RHD/CTU-CVM BARILI CAMPUS 16  VAN211 MODULE 2 - SKELETAL ANATOMY EXAMPLES CONDYLE (skull) FACET (vertebra) HEAD (femur) PROJECTION  Area of a bone that projects above the surface of the bone.  Serve as attachment points for tendons and ligaments.  Generally, their size and shape indicate the forces exerted through the attachment to the bone. TERM DEFINITION/DESCRIPTION EXAMPLES a raised or prominent part of the Crest Iliac crest edge of a bone a projection superior to a lateral & medial epicondyle Epicondyle condyle of the femur Eminence a small projection or bump intercondylar eminence of the tibia Linea or line a slightly raised, elongated ridge temporal line of the skull transverse process Process any bony prominence (vertebra) Protruberance bony outgrowth or protruding external occipital part protruberance Spine sharp, slender, narrow process spine of the scapula literally a pencil shaped pointed styloid process (radius, Styloid process ulna) a rough prominence at the upper Trochanter greater & lesser trochanter part of the femur Tubercle a small, rounded process greater & lesser tubercle Tuberosity a rough elevated surface radial & ulnar tuberosity EXAMPLES CREST (pelvis) EPICONDYLE (humerus) RHD/CTU-CVM BARILI CAMPUS 17  VAN211 MODULE 2 - SKELETAL ANATOMY EMINENCE (prox. tibia) LINEA OR LINE (skull) PROCESS (lumbar vertebra 5) PROTRUBERANCE (skull) SPINE (scapula) STYLOID (radius, ulna) TROCHANTER (femur) TUBEROSITY (radius, ulna) TUBERCLE (humerus) RHD/CTU-CVM BARILI CAMPUS 18  VAN211 MODULE 2 - SKELETAL ANATOMY HOLE OR DEPRESSION OR OPENING  Sites allowing passage of soft tissue (nerves, blood vessels, ligaments, tendons) or formation of joints TERM DEFINITION/DESCRIPTION EXAMPLES a tubular passage or tunnel in a Canal optic canal in the skull bone Cotyloid Deep cup like articular depression acetabulum cavity Fissure a slit through a bone palatine fissure of the skull a shallow depression in a bone Fossa fossa for lacrimal sac surface a hole in a bone through which Foramen obturator foramen (hip bone) nerves and blood vessels pass shallow pit that allow the Fovea fovea capitis of the femur attachment of a ligament Glenoid a shallow cup-like articular glenoid cavity of scapula cavity depression an elongated concavity between groove for external carpi Groove parallel ridges radialis Notch an indentation, esp. on the edge of alar notch of atlas vertebra a bone or organ Sinus an air-filled cavity or space within a frontal sinus of the forehead bone a groove for a tendon, nerve, or Sulcus gingival sulcus blood vessel Meatus an opening into a canal ext. acoustic meatus (ear) EXAMPLES CANAL/FISSURE/FOSSA/FORAMEN (skull) CANAL (vertebra) GROOVE (radius, ulna) NOTCH (atlas vertebra) RHD/CTU-CVM BARILI CAMPUS 19  VAN211 MODULE 2 - SKELETAL ANATOMY REVIEW QUESTIONS 1. Describe osseous tissue. 2. Why are bones hard but not brittle? 3. Compare and contrast the two main types of osseous tissue. 4. Compare and contrast yellow and red bone marrow. 5. Give an example of a flat bone. 6. What type of bone is embedded in tendons? 7. What is a notch in anatomy? 8. Define a fossa and give an example 9. Where can you find the glenoid cavity? 10. Explain the different classifications of bone and provide at least two examples of each type. REFERENCES IMAGES 1. https://training.seer.cancer.gov/anatomy/skeletal/tissue.html 2. https://biologydictionary.net/spongy-bone/ 3. https://www.histology.leeds.ac.uk/bone/bone_types.php 4. https://en.wikivet.net 5. https://orthodog.com 6. https://anatomylearner.com 7. https://veteriankey.com INTERNET 1. Anatomy and Physiology: Bone Structure. 2. Osteon-Wikipedia 3. Bandovic, I., Holme, M. R., & Futterman, B. (2022). Anatomy, bone markings. In StatPearls [Internet]. StatPearls Publishing. BOOKS 1. Budras, K. D., Horowitz, A., & Berg, R. (2007). Anatomy of the dog, 5th revised ed. Hannover, Germany. 2. Goody, P. C. (1997). Dog anatomy: a pictorial approach to canine structure. JA Allen & Co. Ltd.. 3. Reece, W.O. (2009). Functional anatomy and physiology of domestic animals, 4th ed. Wiley-Blackwell, Ames, Iowa. 4. Miller, B. F., & Keane, C. B. (2003). Encyclopedia and dictionary of medicine, nursing, and allied health. Saunders, Elsevier, Inc. RHD/CTU-CVM BARILI CAMPUS 20