HNS Anatomy 2 - Spinal Cord Flashcards
List the functions of the vertebral column
Support and protection
- Body weight
- Transmits forces
- Supports the head
- Supports the upper limbs (and aids movement)
- Spinal cord (protective role)
Movement
- Upper limbs and ribs (extrinsic muscles, which go outside of the vertebral column)
- Postural control and movement (intrinsic muscles which remain inside the vertebral column)
List the curvatures of the vertebral column present in a normal adult
- Cervical (secondary)
- Thoracic (primary)
- Lumbar (secondary)
- Sacral (primary)
What is the function of the vertebral body?
It is the major weight bearing part
List the functions of the vertebral arch
- Forms the roof of the vertebral canal
- Has projections for attachment of muscles and ligaments
- Has sites of articulation for adjacent vertebrae
What is the function of the pedicles?
Anchor the vertebral arch to the vertebral body
List the typical features of cervical vertebrae
- Vertebral body (bean shape) is short in height and square shaped when viewed from above, with a concave superior surface and convex inferior surface
- Each transverse process is trough shaped perforated by a round foramen transversarium
- Short and bifid spinous process with a triangular vertebral foramen
List the typical features of the axis and atlas
- No intervertebral disc between the two - as the vertebral body of C1 forms the dens of C2
- C1 lacks a vertebral body
- Atlas is ring shaped with two lateral masses interconnected by an anterior and posterior arch
List the typical features of the thoracic vertebrae
- Characterised by their articulation with ribs, typically 2 partial facets (superior and inferior) on each side of the vertebral body.
- Superior costal facet is much larger than inferior
- Transverse processes have facets for articulation with the tubercle of each rib
- Vertebral body is heart shaped
- Vertebral foramen is circular
List the characteristics of lumbar vertebrae
- Large size
- Lack facets for rib articulation
- Long and thin transverse processes (except L5 which are massive and cone shaped)
- Vertebral body is cylindrical (kidney shaped)
- Vertebral foramen is triangular, larger than thoracic
List the characteristics of the sacrum
- Triangluar shape, apex inferiorly projecting
- Curved with a concave anterior surface
- Articulates with L5 and the coccyx
- Two large L shaped facets for articulation with the pelvic bones
- 4 pairs of sacral foramina on the anterior surface and posterior surface
List the characteristics of the coccyx
- Small triangular bone, represents 3-4 fused coccygeal vertebrae
- Small size and absence of vertebral arches and therefore vertebral canal
Describe the structure of intervertebral discs
- Anulus fibrosis outside
- Nucleus pulposis inside
List the movements of the spine and the muscles involved
- Extension (lean back - erector spinae)
- Flexion (rectus abdominis/psoas major)
- Lateral flexion (leaning side to side - oblique muscles, rhomboid, serratus anterior)
- Rotation - oblique muscles, sternocleidomastoid, erector spinae
List the common spinal pathologies
- Low back pain
- Prolapsed intervertebral disc (sciatica)
- Spondolysis (degeneration)
- Spondylolysis (stress fracture of pars interarticularis)
- Spondylolisthesis (forward displacement of vertebra)
- Spondylitis (inflammation of vertebrae)
List the abnormal curvatures of the spine
- Excessive kyposis, often seen in older people - can be normal (cervical curve)
- Excessive lordosis - can be normal or exaggerated (lumbar curve)
- Scoliosis, more common in females during puberty (lateral curve)
Describe the development of the curvatures
- Primary curvatures have concave side facing anteriorly (these are the same as in a foetus)
- Secondary curvatures have a convex side facing posteriorly (develop through age)
When is the lumbar curvature enhanced?
- In obesity
- In pregnancy
- To move the centre of gravity backwards
Why are the intervertebral discs important?
- They help to bear weight
- They allow rotation of the spine
Where are the alar ligaments?
From the skull to the odontoid peg
Why is the atlantooccipital joint called the yes joint?
Because this joint allows us to nod our heads (flexion and extension)
Why is the atlantoaxial joint called the no joint?
This joint allows us to shake our head (rotation)
What is an important risk of the intervertebral discs reducing in height?
- The intervertebral foramen becoming smaller
- This crushes the nerves emerging from the foramen, and can result in pain
What is the cauda equina?
- The bundle of nerves making their way down from the spinal cord, which ends at L2, to the lower vertebrae.
- Here injections are placed for anaesthetic/epidural
What is a prolapsed intervertebral disc?
- The nucleus pulposis herniates into the vertebral canal, which results in nerve impingement, pain and sciatica (pain radiating down the leg)
- More likely further down the spine as there is more weight being transmitted
Describe the range of motion of the cervical spine
- Rotation (L/R 80 degrees)
- Extension and flexion (45 degrees)
- Right and left lateral flexion (45 degrees)
Describe the range of motion of the thoracolumbar spine
- Extension (30 degrees)
- Flexion (90 degrees)
- Lateral flexion (30 degrees)
- Rotation (L/R 30 degrees)
Where do the different layers of the meninges end in the spinal cord?
- Pia mater ends with the spinal cord (L2) at the filum terminale, which extends down from the base of the spinal cord alongside the cauda equina
- Arachnoid and dura mater extend down to the level of S2 vertebra, so there is a large epidural space
When are needles inserted to the epidural space via the sacral hiatus?
- In patients with severe sciatica, anaesthetics and analgesics are administered.
- This can reduce inflammation and reduce need for disc surgery.
Compare the location of epidural and spinal anaesthetics
- Epidural in the epidural space (used for the duration of labour, over many hours)
- Spinal in the subarachnoid space (used for a procedure of known length, such as C-section/ hip replacement, if someone is not fit for general anaesthetic)
What is the conus medullaris?
The tapered lower end of the spinal cord
Where is the nuchal ligament?
At the back of the neck, continuous with the supraspinous ligament
Which ligament is most likely to be damaged in whiplash?
Anterior longitudinal ligament
List the functions of the trapezius muscle
- Elevates and depresses the scapula
- Rotates the arm
- Retracts the scapula
List the functions of the rhomboid major and minor muscles
- Depress the scapula
- Retracts the scapula
Where does prostate cancer commonly metastasise to?
The vertebral body, which can result in compressed spinal cord
List the muscles making up the erector spinae
- Illiocostalis
- Longissimus
- Spinalis
(I like standing) - lateral to medial
Compare the dura in the brain and in the spinal cord
- In the brain, there are two layers - meningeal and periosteal
- In the spinal cord there is only the meningeal layer
Describe what is looked at initially in a spinal examination
- Look at curvatures
- Wide stance suggests stenosis
- Look for asymmetry (shoulder blades and pelvis)
Describe the assessment of the cervical spine
- Split into two (upper and lower)
- Look for musclar atrophy (or increased tone) or asymmetry in the shoulders and upper limbs
- Look at movements - flexion (head moved forwards), extension (head moved backwards), lateral flexion, and rotation of the head
- Protraction and retraction of the head can also be looked at
- C7 is the first vertebra you can see and feel
- C1 and 2 rotation is used and the transverse processes are held
- Look for associated movement in the thoracic spine
Describe the process of a thoracic spine examination
- Patient sits down, places their hands on the opposite shoulder and moves forwards (flexion)
- Extension - patients puts their hands on neck and leans backwards
- Patient puts hands on the same shoulder and rotates either side
- To look at pain, do a percussion test (palpate the spinous process and tap, see if the patient feels pain to detect a vertebral compression fracture)
Describe the assessment of the lumbar spine
- Look for lordosis
- Flexion (run hands down thighs as far as you can), Extension (run hands down back of legs)
- Look at where movement takes place
- Latriflex their hand down the side of each leg
- Palpation is used to identify pain (use iliac crest for L4 level) use a thumb and gentle compression
Describe the assessment of the sacro-iliac joint
- Compression test (hold and compress the iliac crest)
- To compress the sacro-iliac joint push the iliac crests outwards
- Gaenslen test - drop one leg off the table and then push the other knee towards the chest
- Thigh thrust test - press down on the knee through the thigh
- Roll onto their tummy and push the sacrum down
- 3/5 tests increases likelihood of pain arising from sacro-iliac joint by 50%
Describe the process of assessing spinal posture
Ask them to lift their chest and bring into a neutral posture
Describe the neural assessment of the spine in the upper limbs
- Reflexes (brachial, pectoralradialis, triceps, c7 (thumb flexion is hoffmans reflex)
- Look at myotomes - pressure into your hand, shrug shouler, adduct the arm and maintain pressure, flex arm, bring their thumb up, extend the wrist, grip the hand
- Sensation - light touch along the arm and pinprick
When is neural assessment of the spine undertaken?
- Spinal fracture
- Cervical myelopathy
- Assess the neural integrity - reflexes, myotomes and dermotomes
Describe the neural assessment of the spinal cord in the legs
- Reflexes - hyporeflexia/hyper (knee, ankle)
- Push foot upwards, flex toes against opposing pressure
- Up and down 3 times when standing on one foot
- Sensation (sweep a hand along the dermatomes) and then pinprick
- Look for fanning of the toes and big toe extension as well as beating on the foot
- Straight leg raise and dorsiflex the foot.
- Crossed over straight leg raise (when disc prolapse occurs)
- Thrust test (flex head and straighten leg)
