WEEK1: SPINAL COLUMN AND SKULL Flashcards
How many bones make up the skull?
Made of 29 bones
The 29 bones can be subdivided into 9 divisions:
Calvaria (dome-like roof)
Face
Floor of cranial cavity
Orbit
Nasal cavity
Oral cavity
Infratemporal fossa
Pterygopalatine fossa
Bones in middle ear cavity
Describe the skull.
*Generally constructed differently c.f. rest of body
Non-weight-bearing
Mostly no attachments for strong muscles
*Most of bones irregular & delicate
Some paper thin
Exception: mandible & bones encasing brain – flat & strong
State the 2 main parts of the skull.
Has 2 main parts
1.Neurocranium
Encases brain and cranial meninges.
*Has calvaria (roof) and basicranium (base)
-Frontal, parietal, occipital bones, sphenoidal, temporal, + a bit of ethmoidal bone
Several foramina (openings) into the skull via the base
2.Viscerocranium (facial)
Bones surrounding mouth, nasal cavity, and most of orbit
15 irregular bones
3.Pneumatized (air-filled) bones – air spaces or sinuses
Frontal, temporal, sphenoidal, & ethmoidal
May serve to decrease their weight.
What is Spinal (Vertebral) Column?
Vertical stack of vertebrae articulating.
What is located proximally and distally to the spinal column. (attachments)?
With occipital bone proximally
Pelvic ilia (pl.) distally
State the 4 primary curves in lateral view.
State whether they are concave or convex.
Posterior concavity – cervical spine
Posterior convexity – thoracic spine
Posterior concavity – lumbar spine
Posterior convexity – sacral spine
State the typical structures that make up the vertebral column.
1.Body (size increases top to bottom, esp from T4)
2.Vertebral (neural) arch – lamina (2) & pedicles (2)
3.Spinous process
4.Transverse processes (2)
5.Superior and inferior articular processes (2+2)
State the function of the vertebral column.
*Encases and protects the spinal cord
*Supports head, limbs, ribs
What are C1 and C2 called?
C1= Atlas
C2= Axis
Describe the C1 and C2 vertebrae.
C1
*It has no vertebral body and no spinous process.
*Has lateral masses which are connected by an anterior and posterior arch.
Each lateral mass contains a superior articular facet (for articulation with occipital condyles), and an inferior articular facet (for articulation with C2).
*The anterior arch contains a facet for articulation with the dens of the axis.
*This is secured by the transverse ligament of the atlas – which attaches to the lateral masses.
*The posterior arch has a groove for the vertebral artery and C1 spinal nerve.
C2
*Has a den (odontoid process) which extends superiorly from the anterior portion of the vertebra.
How does C1-C2 allow for head movement?
They form the Atlanto-axial joint.
*The transverse binds the dens of C2 to the atlas and, as such, acts as a “seat belt,” allowing the C1 to rotate safely on C2, as seen above.
The alar ligament binds the dens to the skull. As such, it’s in a prime location to prevent lateral motion of C1 on C2 when the patient bends the head to the side.
Describe the cervical column.
*7 vertebrae
*Smallest bodies
*Triangular vertebral foramen.
*Bifid spinous process – this is where the spinous process splits into two distally.
*Transverse process perforated by transverse foramina
Passage for vertebral arteries and veins
Potential for injury to the vascular structure
*C7 (vertebra prominens) has most prominent spinous process
*Most flexible
Several muscle attachments to scapula, clavicle, head,
spine
Susceptible to injuries (e.g. whiplash, arthritic changes)
Describe the thoracic column.
*12 vertebrae
*Bodies articulate with ribs
*Each transverse process articulates with only 1 rib
*Both lamina & spinous process overlap next level
*Long inferiorly oriented spinous process
*Rib cage and overlap of articular processes restrict mobility
Describe the lumbar column.
*5 large vertebrae
*Reflects physical demands
*Bodies quite large & strong
*Large intervertebral foramen – large nerve roots
*Significant mobility at L5-S1 junction
*The fifth lumbar vertebrae, L5, has some distinctive characteristics of its own. It has a notably large vertebral body and transverse processes as it carries the weight of the entire upper body.
*Susceptible to pathology
*Lumbar sprain/strain & low back pain
*DJD & OA at lumbar spine
*Spondylolisthesis (L5 slides anteriorly on S1)
*May encroach onto neural structures
Describe the sacral column.
*Sacrum – 5 fused vertebrae
*Proximal aspects articulate with ilia
*Sacroiliac joints
*Susceptible to instability: post-delivery, etc
*Vertebral canal ends at sacral hiatus
