HK 302 U3 L2

Largest vertebrae in the body

Lumbar vertebrae

Primary motion of the lumbar spine

Flexion and extension

What is spondylolysis?

Unilateral stress fracture of the pars interarticularis

Spondylolysis fracture range

Can range from hairline to complete

Classic x-ray appearance of spondylolysis

“Scottie-dog” fracture appearance

What is spondylolisthesis?

Bilateral stress fracture of the pars interarticularis

What can spondylolisthesis cause?

Vertebral body instability and anterior translation

Most common site for spondylolysis/spondylolisthesis

L5-S1

Second most common site for spondylolysis/spondylolisthesis

L4-L5

Pain pattern in spondylolysis/spondylolisthesis

General diffuse pain increased by activity and extension

Management of spondylolysis/spondylolisthesis

Referral, bone scan vs MRI, bracing, rest from activity, therapeutic exercises

Exercise focus for spondylolysis/spondylolisthesis

Flexion and stabilization

Causes of transverse or spinous process fractures

Direct blow to the back or extreme forced motion

Where are vertebral body compression fractures commonly seen?

Thoracic-lumbar junction

Why are vertebral body compression fractures dangerous?

Possibility of impingement on the spinal canal

Thoracic discs compared with other regions

Shorter discs with decreased disc/body ratio, so less motion

Special articular features of thoracic vertebrae

Costal pits where ribs articulate

Primary motion of thoracic spine

Rotation

Thoracic spinous processes

Long with a steep angle

How many ribs are in the thoracic rib cage?

24

Ribs 1-7

True ribs

Ribs 8-10

False ribs

Ribs 11-12

Floating ribs

Thoracic rib cage also includes

Sternum with xiphoid process, costal cartilages, and 12 thoracic vertebrae

Cause of wedge fractures in thoracic spine

Axial compression through the thoracic spine

Who is more likely to sustain thoracic wedge fractures?

Females with osteopenia

How do rib fractures occur?

Compression of the rib cage or direct blow

What is Scheuermann’s disease?

Degeneration of the epiphyseal end plates of the vertebral bodies in at least 3 adjacent segments

Main presentation of Scheuermann’s disease

Greatly increased thoracic kyphosis

Typical onset age of Scheuermann’s disease

About 8 to 12 years old

Scheuermann’s disease sex distribution

Twice as common in girls as boys

Approximate breathing rate per minute

17 breaths per minute

Approximate breaths per day

23,000 per day

How much tidal volume does the diaphragm contribute when sitting or standing?

About 2/3

How much tidal volume does the diaphragm contribute when lying down?

About 3/4

Function of external intercostals

Elevate ribs

Expiration at rest

Passive process

Accessory inhalation muscles

Sternocleidomastoid, scalenes, serratus anterior, pectoralis major, serratus posterior superior

Accessory exhalation muscles

Internal intercostals and serratus posterior inferior

Upper cervical spine levels

C1-C2

Mid-cervical spine levels

C3-C6

Cervical-thoracic junction

Where the cervical and thoracic vertebrae meet

Common tendency of the cervical-thoracic junction

Tends to become hypermobile

Atlas name and level

Atlas = C1

Atlas vertebral body

No vertebral body

Atlas spinous process

No spinous process

Atlas transverse processes

Big transverse processes with a foramen

Atlas facet joints

Two facet joints to hold the occiput

Axis name and level

Axis = C2

What projects upward on the axis?

Odontoid process (dens)

Why are the superior facet joints of C2 flat?

To allow rotation above it

Typical cervical vertebrae

C3-C6

Spinous processes of typical cervical vertebrae

Bifid

What passes through the transverse process foramina of typical cervical vertebrae?

Cervical vertebral artery

What is the occipito-atlantal joint?

Joint between the occiput and C1

Primary motion at the occipito-atlantal joint

Flexion and extension

Approximate flexion-extension range at O/A

15-20 degrees

Approximate sidebending at O/A

About 5 degrees

Rotation at O/A

Little to none

What is the atlantoaxial joint?

Joint between C1 and C2

Primary motion at the atlantoaxial joint

Rotation

How much of all cervical rotation occurs at A/A?

About 50%

Flexion-extension allowed at A/A

Small amount, about 5 degrees

Sidebending at A/A

Very little to none

What ligament holds the atlantoaxial joint together?

Transverse ligament

Atlantoaxial instability in Down syndrome

Occurs in 10% to 30% of children with Down syndrome

Primary motion in the mid-cervical spine

Mostly flexion and extension

Second most allowed motion in the mid-cervical spine

Sidebending

Rotation in the mid-cervical spine

Relatively little

What is the ligamentum nuchae?

Proliferation of the supraspinous ligament

What motion does the ligamentum nuchae resist?

Cervical flexion

Anterior longitudinal ligament in the cervical spine

Runs over anterior vertebral bodies and resists extension

What is the tectorial membrane?

Widened continuation of the posterior longitudinal ligament

Tectorial membrane position

Most superficial of the internal cervical ligaments from posterior to anterior

What is the cruciform ligament?

Cross-shaped ligament

Function of vertical part of cruciform ligament

Limits flexion

Function of horizontal part of cruciform ligament

Holds the dens and C1 together

Another name for the horizontal part of the cruciform ligament

Transverse ligament

What is the alar ligament?

Ligament from the occiput down to the dens

Deepest internal cervical ligament

Alar ligament

When does the alar ligament tighten?

Flexion, contralateral sidebending, and contralateral rotation

General severity of cervical fractures

Can range from minor to potentially life-threatening depending on type and location

What is a hangman’s fracture?

Bilateral pars interarticularis fracture of C2 that leaves the dens unstable

Common causes of cervical fractures

Axial loading or extreme cervical flexion

Most common fracture sites in the cervical spine

C4, C5, and C6

Palpation sign of cervical fracture

Painful palpation over spinous processes

Neurologic signs of cervical fracture

Radiating pain, weakness, numbness into the dermatome/myotome

Severe signs of cervical fracture

Paralysis and/or loss of bowel or bladder control

Phrenic nerve levels

C3-C5

Function of phrenic nerve

Innervation of the diaphragm

Frontal bone forms

Anterior roof of cranium, forehead, roof of nasal cavity, superior arch of orbits

Parietal bone forms

Superior and lateral side of skull

Temporal bone forms

Inferior lateral side of skull and posterior portion of zygomatic arch

Structures contained in the temporal bone

Mandibular fossa, external auditory meatus, mastoid process

Occipital bone forms

Posterior portion of skull

Structures contained in the occipital bone

Foramen magnum and occipital condyles

Maxillary bone forms

Upper jaw, hard palate, inferior arch of orbits, lateral and inferior nasal canal

Zygomatic bone forms

Lateral margin of orbit and anterior portion of zygomatic arch

Nasal bone forms

Superior and anterior portion of nasal canal

Mandible forms

Lower jaw