RT 211 | LECTURE 4

• General Terms:

  • Os = a bone; pl. ossa; adj. osseous
  • Ossicle = a little bone, e.g. ossicles of ear
  • Ossify = to form bone
  • Calcification = a deposit of calcium, not the formation of bone
• • Facet: A smooth articular surface, an older term for smooth articular surface of vertebrae, ribs, etc
• • Spine or spinous process: A sharp slender process; the spine of ischium; spinous process of vertebrae
  • Styloid process: A sharp slender process; styloid process of temporal bone; styloid process of radius and ulna
  • Trochanter: A very large rounded process; lesser and greater trochanter of femur
  • Tubercle: A small rounded process; greater and lesser tubercle of the humerus
  • Tuberosity: A large rounded process, tuberosity of radius and ulna
  • Fovea: A small pit or depression; fovea capitis femoris; fovea costalis
• Bony Prominences, Projections, Depression:

  • Ala: A wing; ala of sacrum, or ilium
  • Condyle: A rounded knoblike projection of knuckle; condyles of femur and tibia
  • Cornu: A horn; cornu of hyoid bone; pl. cornua
  • Crest: A narrow ridge of bone the crest of the ilium; pl. crista
  • Epicondyle: A bony projection on or above a condyle; epicondyles of femur
  • Malleolus: A small hammer, a rounded bony prominence; lateral malleolus of fibula, medial malleolus of tibia; pl. Malleoli
  • Process: Any definite or marked bony prominence; mastoid process of temporal bone
• Functions of Bones:

  • Protection
  • Support and Framework
  • Levers
• Classification of Bones:

  • Long Bones: Humerus, radius, ulna, femur, tibia, fibula
  • Short bones: Carpal and tarsal bones
  • Flat bones: Skull, scapula, ribs, sternum
  • Irregular bones: Vertebrae, bones at the base of the skull
  • Sesamoid bones
• Part of Bones:

  • Long Bones:
  • Proximal or upper extremity (end)
  • Body or shaft
  • Distal or lower extremity (end)
  • Short bones: Body, sometimes processes
  • Flat bones: Body, other parts
  • Irregular bones: Bones, processes
• Structure of Bones:

  • Periosteum: A membrane that covers all bones with the exception of the articular surfaces
  • Compact bone: Cortical bone; dense closely knit bone resembling ivory, made up of compact Haversian system
  • Spongy or cancellous bone: Porous loosely-knit bone similar in appearance to a sponge, or honeycomb, or latticework
  • The medullary cavity: Or marrow cavity is a central cavity extending longitudinally in the shafts of long bones. It contains bone marrow
  • The endosteum: Membrane that lines the medullary cavities of a long bone
• Bone marrow:

  • Tissue occupying the medullary cavities of long bones and the spaces in spongy bone
  • Red bone marrow
  • Yellow bone marrow
• Ossification:

  • Intracartilaginous
  • Intramembranous
• Intracartilaginous Ossification:

  • The cartilage in the shafts of long bones and in the bodies of some other bones is replaced by bone while in the fetus is still within the uterus
  • Primary center of ossification: Group of bone cells that make their appearance in the center of the bodies of long and other bones
  • Diaphysis: Part of bone formed from a primary center of ossification and includes the body or shaft
  • Secondary center of ossification: Group of bones that makes its appearance in the end of a bone, or in a bony prominence
  • Epiphyseal cartilage:
• • The part formed from one or more secondary centers of ossification
  • Is a layer of cartilage between a diaphysis and epiphysis of bone, that persists during the growing period
  • Metaphysis: The end of diaphysis adjacent to an epiphyseal cartilage
• Intramembranous Ossification:

  • Occurs in the bones of the vault of the skull that form first as membranes
  • By the division of these bone cells the membrane is replaced by bone except for the suture
• Joints:

  • General Terms:
  • Articulation = a joint; adj. articular; (L) articulation
  • Arthron = a joint (G)
  • Arthrosis = a joint; adj. arthrodial; pl. arthroses
  • Junctura = a joint
• Movements at Joints:

  • Abduction: Movement away or across the median line of the body
  • Adduction: Movement towards or across the median line of the body
  • Flexion: The movement of bending
  • Extension: The movement of straightening or stretching out
  • Inversion: The movement of turning a part to face towards the median line
  • Eversion: The movement of turning a part away from the median line
  • Rotation: The movement of turning a part in one axis
  • Circumduction: Movement in a circular direction about a cone-shaped axis
  • Dorsiflexion: Bending backwards
• • Hyperextension: Extension beyond the normal limit
  • Hyperflexion: Flexion beyond the normal
  • Circumflexion: Bending around
  • Forced inversion: Forcibly inverting beyond normal
  • Internal rotation: Turning inwards in 1 axis
  • External rotation: Turning outwards in 1 axis
• Classification of Joints:

  • Fibrous joints/ Immovable joints/ Synarthrosis or Synarthrodial joints
  • Cartilaginous joints/ Slightly Movable joints/ Amphiarthroses or Amphiarthrodial joints
  • Synovial joints/ Freely Movable joints/ Diarthroses or Diarthrodial joints
• Varieties of Synovial Joints:

  • Gliding joints
  • Hinge joints
  • Condylar joints
  • Saddle joints
  • Pivot joints
  • Ball and socket joints
• Congenital Anomalies of the Developing Bones:

  • A secondary center of ossification may not unite with the body of a bone but may remain as a separate entity throughout life
  • A bone may have more secondary centers of ossifications than usual
  • A secondary center may not unite with the body of the bone to which it belongs but to an adjacent bone