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Unit 2: Skeletal System Lab 2: Axial Skeleton. Jessica Radke -Snead, RD, MS Bio 241 Anatomy & Physiology. Review: Bones of the Adult Skeletal System. Appendicular skeleton (126) LAB 3 Pectoral girdle (4) Upper limb (60) Pelvic girdle (2) Lower limb (60). Axial skeleton (80) LAB 1
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Unit 2: Skeletal SystemLab 2: Axial Skeleton Jessica Radke-Snead, RD, MS Bio 241 Anatomy & Physiology
Review:Bones of the Adult Skeletal System • Appendicular skeleton (126) • LAB 3 • Pectoral girdle (4) • Upper limb (60) • Pelvic girdle (2) • Lower limb (60) • Axial skeleton (80) • LAB 1 • Skull (22) • Auditory ossicles (6) • Hyoid bone (1) • LAB 2 • Vertebral column (26) • Thoracic cage (25)
Cervical Vertebrae • Distinctive features • All have transverse foramen—protection for the vertebral arteries—that are NOT present in any other vertebrae • C1 (atlas) and C2 (axis) allow for head movement Axis is the only vertebrae with a dens; begins to form during the first year of life and fuses with the axis by the age of 3-6 years • C3-C6 have transverse foramina and bifid spinousprocesses • C7 is different—spinous process is not bifid, but especially long and forms the prominent bump on the lower back of the neck (vertebra prominens) • Atlanto-occipital joint: articulation between the atlas and the cranium • Atlanto-axial joint: articulation between the atlas and axis
Thoracic Vertebrae • Distinctive features • Lack transverse foramina and bifid processes • Spinous processes pointed and angle sharply downward • Include costal facets No other vertebrae have ribs articulating with them • T1-T10 have transverse costal facets at the end of each transverse process provides a second point of articulation for ribs 1-10 • T11 and T12 have NO transverse costal facets ribs 11 and 12 attach only to the bodies of vertebrae (“floating ribs”) • Inferior and superior costal facet: position on the vertebrae, not articulating rib • Superior and inferior articular facets: position on a vertebrae • T12 inferior articular facets face laterally instead of anteriorly positions them to articulate with the medially facing superior articular facets of the first lumbar vertebrae
Thoracic vertebrae: include: Rib facets: round fossa where ribs connect to the vertebrae or Demifacets:rib facet divided between 2 vertebraes
Lumbar Vertebrae • Distinctive features • Thick, stout body • Blunt, square-like spinous processes • Articular processes oriented differently: • Superior processes face medially • Inferior processes face laterally (toward the superior processes of the next vertebrae) resistant to twisting
Lumbar vertebrae lack: Rib facets and Transverse foramina
Sacrum • Consists of 5 vertebrae Fuses age 16-26 • Forms the posterior wall of the pelvic cavity
Coccyx • Consists of 4-5 small vertebrae Fuses age 20-30 • Serves as attachment points for muscles of the pelvic floor • Cornua: hornlike projections that serve at attachment points for ligaments that bind the coccyx to the sacrum
Thoracic Cage:Ribs • 12 pairs, no differences between genders • Attached at posterior (proximal) end to the vertebral column • Costal cartilage • Hyaline cartilage extends from the anterior (distal) ends of ribs 1-7 to the sternum “true ribs” • Ribs 8-10 attach to the costal cartilage of rib 7 – “false ribs” • Ribs 11-12 do not attach to anything at the distal end, but are embedded in muscle “false ribs”, “floating ribs”
Lab 2 Objectives • Identify and describe the bones and features of the vertebral column and thoracic bones designated in your lab • Observe these structures from multiple viewpoints to develop a 3D comprehension • Review the bones and features of the skull (adult and fetal) designated in lab 1 • Put together a comprehensive understanding of the axial skeleton Please be careful with the bones—ask for assistance if needed! Enjoy!