Postcranial Axial Skeleton Flashcards
Postcranial Axial Skeleton
Vertebral Column: 24 vertebrae: 7 cervical, 12 thoracic, 5 lumbar, 5 fused sacral and 3-5 fused coccygeal
Ribs
Sternum
Functions of Vertebral Column
Provides surface area for muscle attachment
Supports and protects spinal cord
Attaches to thoracic cage and pelvis
Weight-bearing
Positions the head
Supports upright positioning and allows movements such as extension, flexion, lateral flexion/extension and rotation of upper limbs
Curvatures of Vertebral Column
Primary (Thoracic + sacral), convex
Secondary (Cervical and lumbar), concave anteriorly
All begin concave anteriorly as this is foetal position
Exaggerations of spine curvature
Kyphosis/Hunch back (Thoracic)
Lordosis/Swayback (Lumbar)
Scoliosis
Individual Vertebrae Features
Body
Vertebral Arch - pedicle and lamina
Vertebral foramen to vertebral canal when stacked
Intervertebral foramina are formed through stacking
Processes - spinous, transverse, superior articular and inferior articular
Articular facets
Joints of the vertebral column
Intervertebral discs lie between vertebral bodies
Zygapophyseal joints between superior and inferior articular processes
1 and 3 cartilaginous symphysis, 2 is a gelatinous centre to give compression abilities
Structural: Synovial Plane
Functional: Non-axial Diarthrotic
Cervical Vertebrae
Small body as only skull above it
Large vertebral foramen
Bifid spinous process
Only vertebrae with transverse foramina to form passageway for an artery that carries oxygen to the brain
Zygapophyseal joints - articular surfaces aligned more horizontally than in thoracic or lumbar regions
Atypical Cervical Vertebrae - Atlas (C1)
Articulates with skull
No vertebral body, lateral masses with large facets instead
Large vertebral foramen
Condalar joints give movement of the head
Atypical Cervical Vertebrae - Axis (C2)
Dens/Odontoid process forms a pivot joint
Atypical Cervical Vertebrae - C7
Is the transition to the thoracic region
Bifid is lost and transverse foramina does not have the artery going through it
Thoracic Vertebrae Structure
Heart shaped body Smaller vertebral foramen Facets for articulation with ribs Spinous process projects inferiorly Large transverse process Zygapophyseal joints - articular surface alignment more vertical than cervical region
Lumbar vertebrae structure
Large oval body Triangular vertebral foramen Small transverse process Stumpy spinous process Zygapophyseal joints - articular surface more vertical than cervical region, sagittaly sitting and vertical not very good for lateral flexion or rotation movements
Sacrum and Coccyx
Sacrum - 5 fused vertebrae, articulates with pelvic girdle via the sacroiliac joint
Coccyx - 3-5 fused vertebrae that fuse late in adult
Thoracic cage Functions
12 thoracic vertebrae, 12 ribs and the sternum
The diaphragm forms the flor of the thoracic cavity, boundary between this and abdominal cavity
Provides surface area for muscle attachment
Supports and protects thoracic organs
Attaches to and supports pectoral girdle, scapula and clavicle
Respiratory movements
Ribs - General Structure
Head articulates with costal facets of vertebrae (body)
Neck
Tubercle articulates with transverse process (facet)
Body
Costal groove - inner surface, inferior side is the groove some vessels run through for protection
Ribs Connections
True ribs 1-7 connect to sternum via costal cartilages
- 1st costal cartilage connects with sternum via synarthrosis
- Costal cartilages 2-7 form synovial gliding joints with the sternum
False ribs 8-12 lack direct attachment
- 8-10 via cartilage of rib 7
Floating ribs 11 & 12 have no sternum connection
Sternum Parts
Manubrium articulates with clavicle and 1st costal cartilage, includes clavicular notch
Body articulates with costal cartilages 2-7
Xiphoid process has muscular attachments such as diaphragm
