4.4 the vertebral columnn Flashcards
The vertebral bodies of different segments possess different shapes and structures:
- Cervical (rounder)
- Thoracic (heart-shaped)
- Lumbar (oval/kidney-shaped)
• Most of the head rotation occurs at the levels of C1 – C2 (neck is the mobile portion of the spine which allows for flexion and extension, rotation and lateral flexion)
• Distinguished by the ______________ within the transverse processes
foramen transversarium
ATLAS (C1)
The C1 vertebra (atlas) is a ring-like bone holding up head:
• Atlas has no ____________ (instead possessing a posterior tubercle)
• Course of vertebral artery: passes through the __________ (within the transverse process) → runs in groove on ___________ (along with C1 spinal nerve)
Joints
- Atlantooccipital: Superior facet of the atlas articulates with the ____________
• Nodding head up and down (flexion and extension)
- Atlantoaxial: Inferior facet of the atlas rotates on the ______________
• Rotate head from side to side (lateral rotation)
*The craniovertebral joints are synovial joints (larger range of motion than other joints of vertebral column).
vertebral body or spinous process;
transverse foramen;
posterior arch;
occipital condyle;
articular facets of C2
AXIS (C2) The C2 vertebra (axis) is the strongest cervical vertebra which serves as the point of articulation where the head turns on the neck (axis of rotation):
• _____________ projects superiorly (atlantoaxial joint)
• Vertebral artery: via transverse foramen
Dens (odontoid process/peg)
What are the bones involved in the medial atlantoaxial joint (synovial pivot joint) ?
Anterior arch of atlas (C1) with dens of axis (C2) → allows for rotation of the head independent of the torso
what are the bones involved in the lateral atlantoaxial joints (synovial plane joints)?
Inferior articular facets of atlas (C1) with superior articular facets of axis (C2) → forms 2 lateral joints
what are the cruciate ligaments that Holds C1 onto C2 (prevents slippage of the head when it turns) → retains dens in contact with the atlas
- transverse ligament ( Across posterior aspect of dens (to small tubercles on lateral masses of the atlas))
- Superior longitudinal band (crus superius)
- Inferior longitudinal band (crus inferius)
what are the longitudinal ligaments that prevents hyperextension and hyperflexion?
- Anterior longitudinal
- Posterior longitudinal
what is the deep ligament that
- attaches to Lateral aspects of dens to tubercles on medial side of occipital condyle
- Prevents excessive rotation of head and holds skull to C2
Alar ligaments
where does apical ligament attaches to
Tip of dens to anterior margin (basion) of foramen magnum
tectorial membrane joins clivus to the body of C2. where does it attach to?
Basilar groove of occipital bone and dura mater to posterior surface of body of axis
The remaining cervical vertebrae (C3 to C7) have small vertebral bodies for flexion of neck:
• C7 is known as the ______________ (most superior vertebra that is palpated in the neck)
• Large triangular vertebral foramen (through which spinal cord passes)
• C3 to C5 possess short _____________ (splits into two distally), while C6 and C7 have long spinous processes
• Possess narrow intervertebral foramina (higher risk of nerve root compression)
vertebra prominens;
bifid spinous processes
what is the ligament that connects the spinous processes of adjacent vertebrae?
interspinous ligament
Supraspinous ligament: Attaches to the ___________(continues as the ligamentum nuchae from C1 – C7)
• Ligamentum nuchae is the proximal attachment for the rhomboids and trapezius muscles
tips of the spinous processes
Ligamentum flavum: Connects _____________ of adjacent vertebrae:
• Thickening of the ligamentum flavum can cause posterior compression of the spinal cord (anterior/lateral compression by intervertebral discs)
articular processes of laminae
The vertebral column possesses a natural curvature which consists of lordosis and kyphosis:
• Thoracic and sacral curvatures (kyphosis) are primary curvatures (inborn), while the cervical and lumbar curvatures (lordosis) are secondary curvatures
• Secondary curvatures are accentuated by learned behaviours (e.g. support of head, upright posture)
Lordosis*: Anterior curvature of the spine (normal in the ____________ regions)
Kyphosis*” Posterior curvature of the spine (normal in the _________ regions)
Scoliosis:Abnormal lateral/rotational spinal curvature
*Excessive kyphosis and lordosis are abnormal.
cervical and lumbar;
thoracic and sacral
which surface landmarks of the verebrae are important?
- C7: Prominent palpable spinous process in the neck (accentuated with anterior flexion of the head)
- T3: Level of the scapular spines
- T7: Inferior angles of the scapula
- L2: Midpoint of the vertical line drawn from the transpyloric plane (L1) and subcostal plane (L3)
- L4: Supracristal plane (horizontal plane across the highest points of the iliac crests)
The vertebral artery supplies the posterior brain, spinal cord and lateral medulla:
• Arises from the ________________ and passes superiorly through the ______________-then through the foramen magnum
• Gives off several important branches (e.g. spinal arteries, posterior spinal arteries, posterior inferior cerebellar arteries)
• Left and right vertebral arteries unite at the lower border of the pons to form the ____________ (runs in the pontine basilar sulcus)
• Splits into the ___________________ at the upper border of pons
1st part of the subclavian artery (medial to scalenus anterior);
foramen transversarium of C1 – C6 ;
basilar artery;
terminal posterior cerebral arteries (PCA)
The spinal cord develops from the lower part of the neural tube inferior to the medulla oblongata, and is surrounded by meninges and the vertebral column:
• Possesses an _______________ (deeper) and a posterior median sulcus
anterior median fissure
The spinal cord gives rise to 31 pairs of spinal nerves (8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal):
• Tapers off at the level of ____________
• Remaining spinal nerves (L2 – Co) continue downwards and exit below respective vertebrae (cauda equina)
• Lumbar punctures are performed below the level of the conus medullaris (usually done around ____________) → CSF should be a clear fluid (xanthochromia → red/orange CSF indicates _____________)
*All the spinal nerves are mixed nerves (motor and sensory) except for C1 (only motor to the _____________ → no C1 dermatome).
L1/L2 (conus medullaris);
L3 – L4;
subarachnoid haemorrhage;
geniohyoid muscle
SPINAL MENINGES The dura mater in the spinal cord only possesses one layer (instead of the endosteal and meningeal layers in the cranial dura):
• Dura is much thicker in the spinal cord and does not have any ____________
• __________ is larger (allowing for more drainage of CSF)
• Possesses ______________ (extensions of the pia mater into the dura) which separate the anterior and posterior components of spinal cord and provides stability to the top of the nerve roots
venous sinuses;
Epidural space ;
denticulate ligaments
