The Vertebral Column Flashcards
What is a consequence of bleeds in the cranial cavity
Increased intracranial pressure
Summarise the support and protection functions of the vertebral column
Body weight Transmits forces Supports the head Supports the upper limbs (and aid movements) Spinal cord
Summarise the movement functions of the vertebral column
Upper limbs and ribs (extrinsic muscles)
Postural control and movement (intrinsic muscles
What is a key consequence of the ligaments in the vertebral column
Ligaments limit the space in the vertebral column- protrusions (of the intervertebral discs e.g) must pass through the intervertebral foramina (path of least resistance)- leading to impingement on the spinal nerves- which can lead to a lot of pain.
Why isn’t it difficult to damage the vertebral column
The bones that constitute the vertebral column can transmit forces- for example when landing with straight legs- forces may be transmitted up the femur- then to the pelvis and then to the vertebral column- leading to fractures in any of these structures.
Describe the intrinsic muscles of the vertebral column
Muscle attachments within the vertebral column (or between the vertebrae and the ribs)- stiffen the spine and ultimately allow you to stand upright, or maintain posture
Also give you stability whilst moving the limbs- huge interaction between limb movement and vertebral column- posture disturbed in pathology- with massive implications on activities of daily living
Describe the extrinsic muscles
originate in the vertebral column but then attach outside it- move the upper limbs and ribs
Summarise the roles of the intrinsic and extrinsic muscles
Extrinsic- move the upper limbs and ribs
Intrinsic- maintain posture and move the vertebral column: these movements include flexion (anterior bending), extension, lateral flexion, and rotation
What is key to remember about movement in the vertebral column
Although the degree of movement between any two vertebrae is limited, the effects between vertebrae are additive along the length of the vertebral column.
Also, freedom of movement and extension are limited in the thoracic region relative to the lumbar part of the vertebral column.
Muscles in more anterior regions flex the vertebral column.
Describe how the vertebral column protects the nervous system
The vertebral column and associated soft tissues of the back contain the spinal cord and proximal parts of the spinal nerves. The more distal parts of the spinal nerve pass into all other regions of the body, including certain regions of the head
Where is herniation in the vertebral column particularly common
Interface between lumbar and sacral vertebrae (because of the curvature)
Describe the classifications of the curvatures
Named according to whether they were present during foetal development or not
Primary- present during foetal development
Secondary- curvatures in the opposite direction- formed as we learned to stand upright
Describe the primary curvatures
Concave anteriorly (reflecting the original shape of the embryo), and is retained in the thoracic and sacral regions in adults
Describe the secondary curvatures
Concave posteriorly and found in the cervical and lumbar regions and bring the centre of gravity in a vertical line, which allows the body’s weight to be balanced on the vertebral column in a way tat expends the least amount of muscular energy to maintain an upright bipedial stance.
Why are lower back problems common
Because stresses on the back increase from the cervical to lumbar regions
What happens to these curvatures during pregnancy and in obese patients
To maintain the centre of gravity- they lean further back to counter the anterior growth of baby (or extra centripetal weight that they are carrying)
Most of body tends to hang anterior to the vertebral column- lots of muscles activated just to remain upright- and excessive curvatures can put stresses on the back and lead to back problems.
State 3 common deviations in spinal curvature
Scoliosis = abnormal lateral curvature of the spine Kyphosis = excessive outward curvature of the spine, causing hunching of the back (excessive thoracic curvature- often due to degenerative changes) Lordosis = excessive inward curvature of the spine (excessive lumbar curvature).
In which view should we not see any curvatures
Front view
Curvatures from the lateral view are normal- but can be exaggerated (as in lordosis and kyphosis)
Describe scoliosis
Common in females during puberty- and so may have a hormonal cause
organs in the chest and abdomen can be compressed by the severe angles of curvature- severe chronic pain too from any change in upright stance- same with exaggerated kyphosis
In severe cases- surgery may be required whereby screws and rods are screwed into the vertebral column- so that the vertebral column becomes upright- in less severe cases a brace is often inserted.
What is meant by a true scoliosis
Involves not only lateral curvature but also a rotational element of one vertebra upon another
Describe the different types of scoliosis
Idiopathic- never present at birth and tend to occur in either the infantile, juvenile or adolescent age groups. The vertebral bodies and posterior elements are normal in these patients- most common type
Congenital- present from birth- associated with other developmental abnormalities. In these patients, there is a strong association with other abnormalities in the chest wall, genitourinary tract, and heart disease. These patients need careful evaluation by many specialists.
Muscular dystrophy- where the muscle is abnormal- rare. The abnormal muscle does not retain the normal alignment of the vertebral column, and curvature develops as a result. A muscle biopsy is needed to make the diagnosis.
List some other disorders that can produce scoliosis
Bone tumours, spinal cord tumours, and localised disc protrusions.
What is kyphosis often secondary to
This condition occurs in certain disease states, the most dramatic of which is usually secondary to TB infection of a thoracic vertebral body, where the kyphosis becomes angulated at the site of the lesion. This produces the gibbus deformity, a deformity that was prevalent before the use of antituberculous medication
Besides curvatures, what else can put strain on the vertebral column
One leg longer than the other- can tilt the pelvis- spine will also tilt to counter this
Summarise the bones of the vertebral column
7 cervical 12 thoracic 5 lumbar 5 sacral (fused) 4 coccygeal (fused)
Regions based on morphology and location
What else contributes to the skeletal framework of the vertebral column besides the vertebrae and the intervertebral discs
Skull
Scapulae
Ribs
Provide attachment for muscles
What contributes to the lack of flexibility seen in each vertebrae
The ligaments
Although some people, naturally, have hypermobile joints (mainly due to loose ligaments and joint capsule)- can be very painful
Where are the palpable landmarks for the vertebral column NOT found
Anterior
Describe what is meant by a typical vertebra
A typical vertebra consists of a vertebral body and a posterior vertebral arch. Extending from the vertebral arch are a number of processes for muscle attachment and articulation with adjacent bone.
Describe the vertebral body of a typical vertebra
Weight-bearing part of the vertebra and is linked to adjacent vertebral bodies by inter vertebral discs and ligaments. The size of the inter vertebral discs increases inferior as the mount of weight supported increases.
Describe the vertebral arch
Surrounds the vertebral column like a roof
Forms the lateral and posterior parts of the vertebral column.
What is the vertebral canal formed by
The vertebral foramina of all the vertebrae together form the vertebral canal, which contains and protects the spinal cord. Superiorly, the vertebral canal is continuous , through the foramen magnum of the skull, with the cranial cavity of the head.
What does each vertebral arch consist of
Two pedicles- bony pillars that attach the vertebral arch to the vertebral body
Two laminae- flat sheets of bone that extend from each pedicle to meet in the midline and form the roof of the vertebral arch (Between the spinous process and the transverse process)
Describe the spinous process
A spinous process projects posteriorly and inferiorly from the junction of the two laminae and is a site for muscle and ligament attachment.
Describe the transverse process
A transverse process extends posterolaterally from the junction of the pedicle and lamina on each side and is a site for articulation with ribs in the thoracic region.
Describe the superior and inferior articular processes
Also projecting from the region where the pedicles join the laminae are superior and inferior articular processes (Fig. 2.19), which articulate with the inferior and superior articular processes, respectively, of adjacent vertebrae.
Between the vertebral body and the origin of the articular processes, each pedicle is notched on its superior and inferior surfaces. These superior and inferior vertebral notches participate in forming intervertebral foramina.
Summarise the key features of cervical vertebrae
▪
The vertebral body is short in height and square shaped when viewed from above and has a concave superior surface and a convex inferior surface.
▪
Each transverse process is trough shaped and perforated by a round foramen transversarium. Transverse processes have anterior and posterior tubercles.
▪
The spinous process is short and bifid.(except C1 and C7)
▪
The vertebral foramen is triangular.
What is special about C1 and C2
The first and second cervical vertebrae—the atlas and axis—are specialized to accommodate movement of the head.
What passes through the foramen transversarium
The vertebral arteries
Describe the articular facets of the cervical vertbra
Oblique, relatively horizontal articular facets directed primarily and inferiorly
Describe the uncinate processes of cervical vertebrae
An Uncinate Process of a vertebra is a hook-shaped process on the posterolateral borders of the superior surface of the vertebral bodies of the third to the seventh cervical vertebrae and first thoracic vertebra. Luschka’s joints involve the vertebral uncinate processes.
Function
prevents posterior linear translation movements of the vertebral bodies
reinforces the disc posterolaterally
limits lateral flexion (side-bending)
Describe the features of typical thoracic vertebra
The twelve thoracic vertebrae are all characterized by their articulation with ribs. A typical thoracic vertebra has two partial facets (superior and inferior costal facets) on each side of the vertebral body for articulation with the head of its own rib and the head of the rib below (Fig. 2.20C). The superior costal facet is much larger than the inferior costal facet.
Each transverse process also has a facet (transverse costal facet) for articulation with the tubercle of its own rib. The vertebral body of the vertebra is somewhat heart shaped when viewed from above, and the vertebral foramen is circular.
In the thoracic vertebra, how does the size of the vertebral column compare to the size of the vertbral body
Much smaller
Describe the articular facets in the thoracic vertebra
Nearly vertical articular facets directed primarily posteriorly and anteriorly
Describe the spinous process and transverse process of each thoracic vertebra
Spinous- long and sloping- overlaps each inferior vertebra
Transverse- long, strong, extend posterolaterally
Describe the characteristics of the lumbar vertebra
The five lumbar vertebrae are distinguished from vertebrae in other regions by their large size (Fig. 2.20D). Also, they lack facets for articulation with ribs. The transverse processes are generally thin and long, with the exception of those on vertebra LV, which are massive and somewhat cone shaped for the attachment of iliolumbar ligaments to connect the transverse processes to the pelvic bones.
The vertebral body of a typical lumbar vertebra is cylindrical and the vertebral foramen is triangular in shape and larger than in the thoracic vertebrae.
Describe the spinous and transverse processes of the lumbar vertebra
spinous- short, broad and blunt
transverse- long, slender and directed laterally
Describe the size of the vertebral foramen in lumbar vertebra
Intermediate in size
Describe the articular facets in lumbar vertebrae
Nearly vertical articular facets, directed primarily medially and laterally
Summarise the sacrum
The sacrum is a single bone that represents the five fused sacral vertebrae (Fig. 2.20E). It is triangular in shape with the apex pointed inferiorly, and is curved so that it has a concave anterior surface and a correspondingly convex posterior surface. It articulates above with vertebra LV and below with the coccyx. It has two large L-shaped facets, one on each lateral surface, for articulation with the pelvic bones.
Describe the posterior surface of the sacrum
The posterior surface of the sacrum has four pairs of posterior sacral foramina, and the anterior surface has four pairs of anterior sacral foramina for the passage of the posterior and anterior rami, respectively, of S1 to S4 spinal nerves.
What can happen to the posterior wall of the vertebral canal
The posterior wall of the vertebral canal may be incomplete near the inferior end of the sacrum.
Describe the mamillary processes of lumbar vertebrae
The mammillary process is a superior process on costal process connected in the lumbar region with the back part of the superior articular process.
Summarise the features of the coccyx
The coccyx is a small triangular bone that articulates with the inferior end of the sacrum and represents three to four fused coccygeal vertebrae (Fig. 2.20F). It is characterized by its small size and by the absence of vertebral arches and therefore a vertebral canal.
Where are the superior and inferior articular facets located in each vertebra
Cervical:
Superior- Posterosuperior.
Inferior- anteroinferior
Thoracic:
Superior- Posterolateral
Inferior- anteromedial
Lumbar:
Superior-Medial.
Inferior- Lateral
