Vertebral column and spinal cord Flashcards
What makes up the vertebral column?
Consists of 7 cervical vertebrae, 12 thoracic vertebrae, 5 lumbar and the sacrum which consists of 5 fused vertebrae and the coccyx (4 or more rudimentary vertebrae).
What are the distinguishing features of the cervical vertebrae?
Bifid spinous process – the spinous process bifurcates at its distal end.
Exceptions to this are C1 (no spinous process) and C7 (spinous process is longer than that of C2-C6 and may not bifurcate).
Transverse foramina – an opening in each transverse process, through which the vertebral arteries travel to the brain.
Triangular vertebral foramen
What are the distinguishing features of the thoracic vertebrae?
Two demi-facets: superiorly and inferiorly placed on either side of its vertebral body. The demi facets articulate with the heads of two different ribs.
Costal facet: for articulation with the shaft of a single rib.
The spinous processes of thoracic vertebrae are oriented obliquely inferiorly and posteriorly.
The vertebral foramen of thoracic vertebrae is circular.
What are the distinguishing features of the lumbar vertebrae?
Large vertebral bodies, which are kidney-shaped. They lack the characteristic features of other vertebrae, with no transverse foramina, costal facets, or bifid spinous processes.
Triangular-shaped vertebral foramen.
Their spinous processes are shorter than those of thoracic vertebrae and do not extend inferiorly below the level of the vertebral body.
What is the vertebra prominens?
‘Vertebral prominent’: 7th cervical vertebra is palpable as it has a long and non-bifid spine.
At what vertebral level is the iliac crest?
The highest point of the iliac crest (palpable) is in line with the interval between L3-L4 spines.
What are the features of the altas?
The atlas articulates with the occiput of the head and the axis. It differs from the other cervical vertebrae in that it has no vertebral body and no spinous process.
Instead, the atlas has lateral masses which are connected by an anterior and posterior arch. Each lateral mass contains a superior articular facet and an inferior articular facet.
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.
What are the features of the axis?
Has an odontoid process which extends superiorly from the anterior portion of the vertebra.
It articulates with the anterior arch of the atlas creating the medial atlanto-axial joint. This allows for rotation of the head independently of the torso.
The axis also contains superior articular facets, which articulate with the inferior articular facets of the atlas to form the two lateral atlanto-axial joints.
How does the shape of the spine develop?
The sinusoidal shape of the vertebral column is developed after birth. In the foetus the vertebral column is C shaped with the concavity facing anteriorly. After birth secondary curvatures with convexity develop in the cervical region when the child holds up its head and in the lumbar region when the legs start weight bearing.
What movements can the spine perform?
Movements of the vertebral column are forward flexion, extension, lateral flexion and rotation. Rotation is maximum at the thoracic region where as it is very limited in the lumbar spine. Flexion and extension on the other hand is limited in the thoracic region due to the presence of the rib cage.
What are intervertebral discs?
Intervertebral discs are strong fibrocartilaginous structures that can withstand compression forces but are flexible enough to allow movements between the vertebrae.
What are the different parts of the intervertebral disc?
Each disc has two parts, a Nucleus Pulposus surrounded by an Annulus Fibrosus. The former is a well hydrated gel with proteoglycan, collagen and cartilage cells. The Annulus fibrosus is made of 10-12 concentric layers of collagen whose oblique arrangement alters in successive layers.
What can narrow the intervertebral foramen?
Herniation of the intervertebral disc, arthritis of the facet joints and bony irregularities in the pedicle or vertebral body of the vertebrae can narrow the intervertebral foramen and cause compression of the nerve root.
What happens in herniation of the intervertebral disc?
In herniation, the annulus fibrosus of the intervertebral disc no longer contains the nucleus pulposus and it bulges into the spinal canal or intervertebral foramina. A straight herniation is often prevented by the firm attachment of the disc to the posterior longitudinal ligament.
A herniation into the intervertebral foramina is more common. Herniation occurs more commonly in the lumbar region.
Where does radiculopathy common occur?
AKA a pinched nerve
Nerve root pathology, most commonly compression due to prolapsed intervertebral disc. Most commonly at L5/S1 in the lumbar region or C6/7 in the neck.
