Axial Skeletal System Study Guide PDF

# **STUDY GUIDE CHAPTER 7: THE AXIAL SKELETON SYSTEM** 1. The axial skeletal system is composed of 80 bones. 2. Long bones have greater length than width and consist of a shaft and a variable number of extremities. 3. Short bones are somewhat cube-shaped because they are nearly equal in length and...

# **STUDY GUIDE CHAPTER 7: THE AXIAL SKELETON SYSTEM** 1. The axial skeletal system is composed of 80 bones. 2. Long bones have greater length than width and consist of a shaft and a variable number of extremities. 3. Short bones are somewhat cube-shaped because they are nearly equal in length and width. 4. Flat bones are generally thin and composed of two nearly parallel plates of compact bones tissue enclosing a layer of spongy bone tissue. 5. Irregular bones have complex shapes and cannot be grouped into any of the previous categories. 6. Sesamoid bones develop in certain tendons where there is considerable friction, tension and physical stress and are shaped similarly to a sesame seed. 7. Sutural bones are small, flat, irregular shaped bones between the sutures of some cranial bones. 8. The vertebrae, calcaneus, and hip bones are classified as irregular bones 9. Carpal bones and tarsal bones are classified as short bones 10. Cranial bones, sternum, ribs, and scapula are flat bones. 11. Bones that belong the axial skeletal system include * Cranial bones * Facial bones * Hyoid bone * Thoracic cage * Vertebral column 12. Functions of the axial skeletal system includes * Protects the brain and spinal cord * Provides an attachment for muscles that move the head, neck, and trunk, and muscles for respiration (not for the limbs) 13. Condyle is a smooth, rounded articular process 14. Tuberosity is a small, rough projection. 15. Tubercle is a small, round projection 16. Trochanter is a large, rough projection of the femur. 17. Foramen is a rounded passageway for blood vessels and nerves. 18. Meatus is a passageway through a bone (tube-like opening). 19. Fissure is an elongated cleft. 20. Sulcus is narrow groove. 21. Fossa is a shallow depression. 22. Crest is a prominent ridge. 23. The major landmarks of the occipital bone include: * Foramen magnum * Occipital condyles * External occipital protuberance * Hypoglossal canal * Jugular foramen 24. The major landmarks of the sphenoid bone include: * Sella turcica * Superior orbital fissure * Greater wings * Lesser wings * Pterygoid processes * Foramen ovale * Foramen rotundum * Foramen spinosum * Foramen lacerum * sinuses 25. Sphenoid bone serves as a bridge uniting the cranial and facial bone 26. Sphenoid bone is also called the “keystone” of the cranial floor because it articulates with every other cranial bone. 27. The hypophyseal fossa is a depression of the sella turcica that contains the pituitary gland. 28. The major landmarks of the ethmoid bone include * Perpendicular plate (superior portion of the nasal septum) * Cribiform plate * Olfactory foramina * Crista gali * Olfactory foramina * Superior and middle nasal conchae * Sinuses 29. Sagittal suture: a joint (articulation) between two parietal bones. 30. Lambdoid suture: a joint between the parietal bones and occipital bone 31. Coronal suture: a joint between the frontal and parietal bones 32. Squamous sutures: a joint between the temporal and parietal bones 33. The occipital bone articulates with the first cervical vertebra (C1) at the occipital condyles to form atlanto-occipital joint. 34. Atlanto-occipital joint allows flexion of the head. 35. The mastoid process of the temporal bone serves as a point of attachment for muscles that rotate or extend the head. 36. Seven bones that form the orbit include sphenoid, ethmoid, frontal, maxillae, palatine, zygomatic and lacrimal bones. 37. Zygomatic arch is formed by the union of temporal process of the zygomatic bone and zygomatic process of the temporal bone. 38. The external auditory meatus of the ear is found in the temporal bone. 39. The nasal septum is formed by the perpendicular plate of the ethmoid (superior portion) and vomer bone (inferior portion). 40. A bent nasal septum that slows or prevents sinus drainage is known clinically as a deviated septum. 41. Damage the nasal septum would cause nose bleeding. 42. The mandible articulates with the temporal bone at the mandibular fossa. 43. The superior and middle conchae belong to the ethmoid bone. Their function is to make air to swirl (turbulence & eddies) within the nasal cavity. 44. Hard palate is the bony roof of the mouth. Hard palate is formed by the palatine and the maxilla. 45. Mandible or lower jawbone is the largest, strongest facial bone. 46. The only movable bone in the skull is the mandible. 47. Mental foramina of the mandible are for the passageways of the nerves carrying sensory information from the lips and the chin. 48. Mandibular foramina of the mandible are for the passageways of the nerves carrying sensory information from the teeth and gums of the lower jaw. 49. The facial nerve (nerve VII) passes through stylomastoid foramen of the temporal bone. 50. The paired maxillae unite to form the upper jawbone. 51. Infraorbital foramen is an opening in the maxilla inferior to the orbit, allows a passageway of the blood vessels and nerves. 52. Inferior orbital fissure is located between the greater wing of the sphenoid and the maxilla. 53. The maxillae contain the largest sinus. 54. Lacrimal bones are the smallest facial bones. 55. Vomer bone is a triangular bone on the floor of the nasal cavity. 56. Vomer bone forms the inferior portion of the nasal septum 57. Zygomatic bones are cheekbones that form the prominences of the cheek and part of the lateral wall and floor of each orbit. 58. The temporal process of zygomatic bone articulates with the zygomatic process of the temporal bone. 59. The hyoid bone: * Does not articulate with any other bone * Serves as a base of attachment for muscles that move the tongue * Is supported by the stylohyoid ligaments that are attached to the styloid process * Functions to support the larynx 60. Bones contain sinuses include * frontal * ethmoid * sphenoid * maxillae 61. Functions of the parasinuses include: * providing an extensive area of mucus epithelium * making the bone lighter * responding with temperature or humidity change * warming the incoming air that will increases mucus production in response to changes in temperature and humidity, viral (cold) or bacterial infection (sinusitis) 62. Parts of the frontal and sphenoid bones comprise the roof of the orbit. 63. Parts of the zygomatic and sphenoid bones form the lateral wall of the orbit. 64. Parts of the maxilla, zygomatic and palatine bones make up the floor of the orbit. 65. Parts of the maxilla, lacrimal, ethmoid, and sphenoid bones form the medial wall of the orbit. 66. Tear glands are found in the lacrimal fossa of the lacrimal bone. 67. Fontanels are areas where unossified mesenchyme develops into the dense irregular connective tissue. 68. The anterior fontanel or “soft spot” is the largest fontanel. 69. The roles of the fontanels are in allowing flexibility during childbirth and in permitting brain growth after birth. 70. CRANIOSTENOSIS is premature closure of the sagittal suture would result in a long and narrow head. 71. MICROCEPHALY refers to undersized head occurring in infancy. 72. Alveolar process of the maxilla is margin of the upper teeth to bone. 73. Damage or fracture of the alveolar process may result in losing some teeth. 74. Damage condylar process of the mandible may result in dislocated jaw. 75. Damage to the temporal bone would affect the sense of hearing. 76. Damage the nasal septum may cause nose bleeding (damage blood vessels). 77. The three basic parts of each vertebra are: * Vertebral body * Vertebral arch * Articular process 78. The vertebral column contains 7 cervical, 12 thoracic, 5 lumbar vertebrae, sacrum, and coccyx. 79. The vertebra prominens is another name for the seventh cervical vertebra (C 7) 80. Ligament nuchae is an elastic ligament between the C 7 and the occipital bone. 81. The odontoid process (dens) is found on C2 (axis). 82. Thoracic vertebrae can be distinguished from other vertebrae by facets for the articulation of ribs. 83. Cervical vertebrae can be distinguished from other vertebrae by presence of transverse foramina. 84. The sacrum is composed of 5 fused vertebrae. 85. The sacrum * Provide protection for reproductive and digestive organs * Provides a point of muscle attachment for the leg muscles * Articulates with the pelvic bone and the coccyx 86. Sacral promontory is the anterior projecting border of the base of sacrum. 87. Sacral promontory is one of the points used for measurement of the pelvis. 88. The coccyx is composed of 3-5 vertebrae. 89. Female shows the coccyx pointed inferiorly. 90. The portion of the sternum that articulates with the clavicles is the manubrium. 91. Ribs articulate with the vertebrae at transverse processes. 92. LORDOSIS: an exaggerated lumbar curve 93. KYPHOSIS: an exaggerated thoracic curve 94. SCOLIOSIS: deviation laterally of the spinal curve 95. Scoliosis is the most common abnormal curves 96. Kyphosis is common in individuals with advance osteoporosis. 97. PRIMARY CURVES: Thoracic and Sacral curves (occur late in fetal development): accommodate the thoracic and abdominopelvic viscera. (BEFORE BIRTH) 98. SECONDARY CURVES: Cervical and Lumbar curves : develop several months (AFTER BIRTH): compensation curves 99. The vertebral body transfers weight along the axis of the spine. 100. Intervertebral discs are found the bodies of adjacent vertebrae from C 2 to the sacrum. 101. Intervertebral disc is avascular. 102. Annulus fibrosus is an outer fibrous ring of the intervertebral disc, consisting of fibrocartilage, 103. Nucleus pulposus is an inner soft, elastic substance of the intervertebral disc. 104. The functions of intervertebral disc include: * Shock absorption * Permitting various movement of the vertebral column * Contributing of 25% of the height of the spine. 105. The lumbar vertebrae: * Do not have costal facets * Transverse process is slender and projects dorso-laterally * The vertebral foramen is triangular * Have the thickest intervertebral disk * Have the largest vertebral body * Bear body weight 106. Movements of the ribs cage assist in respiration. 107. Performing CPR incorrectly may damage ribs and fracture of the xiphoid process of the sternum that may damage the liver. 108. True ribs (the first seven pair of ribs) attach directly to the sternum by separate costal cartilage e. 109. False ribs (rib 8-10) attach indirectly to the sternum. They merge with the cartilages of rib pair #7 before they reach the sternum. 110. Floating ribs (rib 11 &12) have no connection with the sternum. 111. Major characteristics of the ribs: * ribs have articulations at the vertebrae on the transverse process * ribs have a flexible connection with the sternum * ribs affect the width and depth of the thoracic cage 112. The tubercle found on the neck of a rib articulates with a facet found on the transverse process of a thoracic vertebra. 113. The sternum contains * The manubrium * The body * The jugular notch (suprasternal notch) * Clavicular notch * The xiphoid process 114. Ossification of the sternum has not completed until at least 25 YO.