Lecture 3 Flashcards
Costal Facets
Rib head articulates ENTIRELY with surface T11-T12
Typical Thoracic Vertebra: Vertebral Body
- Heart Shaped
- Convex anterior surface, concave posterior
- Have costal facets or demifacets for rib articulation
Demifacets
Half of rib head articulated with facet of vertebra above and half with facet of vertebra below T1-T10
Typical Thoracic Vertebra: Pedicles
- Space posteriorly
- Small vertebral canal
- Short with inferior vertebral notch
Typical Thoracic Vertebra: Laminae
Short, broad & thick
Typical Thoracic Vertebra: Spinous Process
- Long, slender with triangular shape in cross-section
- Point obliquely downward overlapping the vertebrae below
Typical Thoracic Vertebra: Transverse Process
- Large, thick, strong & long
- Thickened ends, point laterally, posteriorly and superiorly
- T1-T10 have large costal facets on anterior aspect
Typical Thoracic Vertebra: Intervertebral foramen
- Circular and relatively smaller compared to lumbar and cervical
Typical Thoracic Vertebra: Articular Facet
- Form angle 60 degree to sagittal plane
- Superior facet orientated superolateral & posterior
- Inferior facet orientated inferomedial & anterior
Typical Thoracic Vertebra: Intervertebral Disc
- Slightly wedge shaped
- Anterior height less then posterior making a kyphotic curve
Thoracic: Intervertebral Joints
- Connects body of vertebrae
- Secondary cartilaginous joints composed of fibrocartilage
- Amphiarthroses (allow only slight movements)
Thoracic: Zygapophyseal Joints
- Joints of vertebral arches
- Between superior and inferior articular processes
- Enclosed by a thin & loose fibrous capsule
Atypical Thoracic Vertebrae
T1:
- Resembles C7 and has 1 facet on the first rib
T9-T12:
- Rib articulations vary
T11 & T12:
- Resembles Lumbar vertebrae
Thoracic Curve
- 20-50 degress, average 45
- Present from birth (primary curve)
- Curve is partially due to posterior vertebral body 2mm higher
Thoracic Ligaments
- Anterior longitudinal ligament
- Posterior longitudinal ligament
- Ligamentum flavum
- Interspinous ligament
- Supraspinous ligament
- Joint capsule
Superior Costotransverse Ligament
- Neck of rib to TP of vertebra above it
Radiate Ligaments
- Fan-shaped ligament
- Arises from the anterior aspect of the head of rib
- Extends to the bodies of two adjacent thoracic vertebrae
Biomechanics of Thoracic Spine
Shape and orientation of zygapophyseal/facet joint:
- Allows for large rotational and lateral flexion movements
- Limit flexion & Extension
Limitation of flexion & extension due to:
- Thin intervertebral discs relative to vertebral body height
- Inferiorly projecting SP
- Projection of ribs anteriorly
Functions of rib cage
- Protect organs
- Increase stability of thoracic spine
- Ventilation
Borders of Rib Cage
Anterior: Sternum
Posterior: Thoracic Spine
Lateral: Ribs
Superior: Jugular notch of the sternum first costocartilage and first ribs
Inferior: Xiphoid process, costocartilage of Rib 7 & 10, inferior portions of Rib 11-12 and T12
Parts of sternum
- Manubrium
- Body
- Xiphoid Process
Manubrium
Articulates with clavicles and the costal cartilage of first pair of ribs
Sternum Body
- Individual costal cartilages from rib pairs 2-7 are also attached to body
- Rib pairs 8-10 are also attached to body, but by a single pair of cartilages shared with rib pair 7.
Xiphoid Process
- Angles dorsally from sternum
- Muscular diaphragm & rectus abdominis muscle sttach at xiphoid process