Lecture 2 - Anatomy of the Vertebral Column PDF

Anatomy of the Vertebral column  Learning Outcomes Identify the vertebral regions, and describe the distinctive structural and functional characteristics of vertebrae in each region. Explain the significance of the articulations between the vertebrae, the thoracic vertebrae...

Anatomy of the Vertebral column  Learning Outcomes Identify the vertebral regions, and describe the distinctive structural and functional characteristics of vertebrae in each region. Explain the significance of the articulations between the vertebrae, the thoracic vertebrae and the ribs. Describe the key structural differences among the vertebral column of infants, children, and adults. Identify and describe the curvatures of the spinal column and indicate the function of each.  The Vertebral Column Transmits weight of trunk to the lower limbs Surrounds and protects the spinal cord Serves as attachment sites for muscles of the neck and back In the adult is formed from 26 bones in has five major regions – Seven cervical vertebrae of the neck region (C1–C7) – Twelve thoracic vertebrae (T1–T12) – Five lumbar vertebrae (L1–L 5) – Sacrum—five fused bones – Coccyx—four fused bones Regions and Normal Curvatures Curvatures increase resilience of spine Primary curvatures are present at birth – Convex posteriorly (kyphosis) – Thoracic and sacral curvatures Secondary curvatures develop when baby begins to walk – Concave posteriorly (lordosis) – Cervical and lumbar curvatures Lateral curvatures are not normal, any lateral curve is considered pathological conditions known as scoliosis. Disorders of the Vertebrae Abnormal spinal curvatures – Scoliosis—an abnormal lateral curvature – Kyphosis—an exaggerated thoracic curvature; “humpback” – Lordosis—an accentuated lumbar curvature; “swayback”  General Structure of a Vertebrae Common structures to all regions – Body – Vertebral arch – Vertebral foramen – Spinous process – Transverse process – Vertebral foramina – Intervertebral foramina General Structure of a Vertebrae Superior articular Pedicle process Transverse process Vertebral body Spinous process Inferior articular facet Arrow passing Inferior articular through vertebral process foramen b A lateral and slightly inferior view of a vertebra Superior articular facets Intervertebral Discs Are pads of fibrocartilage Lamina of vertebral arch Between the Intervertebral vertebral foramen bodies Intervertebral disc Spinous process Transverse process Vertebral body Inferior articular facet Arrow passing through vertebral canal e A lateral and sectional view of three articulated vertebrae  Superior articular facets Superior articular process Lamina of vertebral arch Spinous process Intervertebral disc Transverse process Vertebral body Inferior articular d A posterior view of process three articulated vertebrae Ligaments of the Spine 3 Major supporting ligaments – Anterior longitudinal ligament Attaches to bony vertebrae and intervertebral discs Prevents hyperextension – Posterior longitudinal ligament Narrow and relatively weak Attaches to intervertebral discs – Ligamentum flavum Attaches between the lamina of each vertebra Ligaments and Intervertebral Discs of the Spine Ligaments and Intervertebral Discs of the Spine The supraspinous ligament surrounds the spinal column The interspinous ligament is between each spinous process. Cervical Vertebrae Seven cervical vertebrae (C1–C7) – Are the smallest and lightest vertebrae – C3–C7 are typical cervical vertebrae – Body is wider laterally – Vertebral foramen are large and triangular – Transverse processes contain transverse foramina – Superior articular facets face superoposteriorly – Spinous processes are short and bifid Except C7 Regional Characteristics of Cervical, Thoracic, and Lumbar Vertebrae The Atlas C1 is the atlas C1 lacks a body and spinous process Supports the skull – Superior articular facets receive the occipital condyles Allows flexion and extension of neck – Nodding the head “yes” The First and Second Cervical Vertebrae The First and Second Cervical Vertebrae The Axis Has a body and spinous process Dens (odontoid process) projects superiorly – Is formed from fusion of the body of the atlas with the axis – Acts as a pivot for rotation of the atlas and skull – Rotating the head side to side to indicate “No” The First and Second Cervical Vertebrae Posterolateral Views of Articulated Vertebrae Thoracic Vertebrae (T1–T12) All articulate with ribs Have heart-shaped bodies from the superior view Spinous processes are long and point inferiorly Transverse processes articulate with tubercles of ribs Each side of the body of T1–T10 bears demifacets for articulation with ribs – T1 has a full facet for the first rib – T10–T12 have only a single facet Regional Characteristics of Cervical, Thoracic, and Lumbar Vertebrae Ribs Lumbar Vertebrae (L1–L5) Bodies are thick and robust Transverse processes are thin and tapered Spinous processes are short, flat, hatchet-shaped, and they point posteriorly Vertebral foramina are triangular Superior and inferior articular facets directly medially Allows flexion and extension—rotation prevented Regional Characteristics of Cervical, Thoracic, and Lumbar Vertebrae Posterolateral Views of Articulated Vertebrae Sacrum (S1–S5) Shapes the posterior wall of pelvis Sacral promontory – Where the first sacral vertebrae bulges into pelvic cavity Ala—develops from fused rib elements – Anterior sacral foramina Passage for ventral rami of sacral spinal nerves – Posterior sacral foramina Passage for dorsal rami of sacral spinal nerves Median sacral crest—Fused spinous processes Lateral sacral crest —Fused transverse processes Auricular surface—Thick, flattened area articulates with pelvic girdle (forming sacroiliac joint) Coccyx Is the “tailbone” offers only slight support to pelvic organs Formed from 3–5 fused vertebrae Attaches ligaments and a constricting muscle of the anus First two coccygeal vertebrae have transverse processes Coccygeal cornua (horns) – Formed by laminae of first coccygeal vertebra The Sacrum and Coccyx