Vertebrae
| Property | Cervical | Thoracic | Lumbar |
| Vertebral body | Small, oval. | Heart shaped, Medium | Big, kidney shaped |
| Spinous process | Bifid and obliquely angled down | Long and slope down | Short and horizontal |
| Facet joints | 45 degrees angles inferiorly anteriorly | Angled coronally | Angled sagitally |
| Movement | Flexion, extension, lateral flexion, rotation | Rotation | Flexion, extension, lateral flexion |
| Special | Transverse foramina | Costal articulation on transverse process and body | Short thick, hatchet like |
| Vertebral foramen | Large, triangular | Circular and smaller | Triangular, medium size |
Vertebral column:
- Cervical 7
- Thoracic 12
- Lumbar 5
- sacral 5
- coccyx
Atypical vertebrae:
- C1(atlas)
- C2(axis, odontoid process)
- C7(long spinous process, not bifid)
General characteristics of vertebrae.
- Vertebral body
- Transverse process
- Spinous process
- Pedicle
- Lamina
- Facet joint/zygoapophysial joint
- Vertebral canal
- Inferior and superior vertebral notch.
Spinal cord:
Conscious tracts – Comprised of the dorsal column-medial lemniscal pathway, and the anterolateral system.
- Dorsal column – vibration, proprioception, fine touch. Dorsal column–> medial leminiscus(brain stem). UL travel in fasciculus cuneatus. LL travel in fasciculus gracillis. Decuss in medulla as second order neuron which goes to thalamus(ventral posterolateral nucleus). Third order neuron: Thalamus–> internal capsule–> sensory cortex.
- Anterolateral spinothalamic tract – crude touch, pressure.
- Lateral spinothalamic tract – pain, temperature
Both enter and ascend 1-2levels then terminate in dorsal horn(substantia gelatinosa). 2nd order decusses, separate into the two tracts and rises to thalamus(ventral posterolateral nucleus) Then third neuron–> internal capsule to sensory cortex.
Unconscious tracts – Comprises of the spinocerebellar tracts. – balance
Descending tracts
- Cortex –> internal capsule(between thalamus and basal ganglia)–> crus of cerebri–> midbrain/pons/medulla–> divides into lateral and anterior corticospinal tracts–> terminate in ventral horn at synapse with lower motor neuron.
- Lateral tract decuss at medulla while anterior spinal tract descends to cervical/thoracic level then decuss.
Blood supply / venous drainage of spine.
- 1 anterior spinous artery and 2 posterior spinous artery
- At each level the dorsal rami gives segmental(posterior intercostal) artery which is important
- Epidural plexus with 2 anterior and posterior longitudinal sinuses. Anterior external venous plexus. Lumbar Vein.
- 3 anterior and posterior spinal veins.
C1 & C2 plus ligaments and movements
- 3 atlanto axial joints – 2 lateral and odontoid in middle
- Joint capsules and tectorial membrane.
- Rotation.
Occiput+C2
- Cruciate ligament on odontoid – superior/inferior longitudinal band, transverse ligament of atlas(on C1)
- Alar ligament
- Tectorial membrane(continuation of posterior longitudinal ligament)
Patterns of spinal injury (popular question)
- Complete transection. (Wikipedia)
- Cervical
- Cervical (neck) injuries usually result in full or partial tetraplegia (Quadriplegia).
- Injuries at the C-1/C-2 levels will often result in loss of breathing, necessitating mechanical ventilators or phrenic nerve pacing.
- Injuries at C3 and above typically result in loss of diaphragm function, necessitating the use of a ventilator for breathing.
- C4 results in significant loss of function at the biceps and shoulders.
- C5 results in potential loss of function at the biceps and shoulders, and complete loss of function at the wrists and hands.
- C6 results in limited wrist control, and complete loss of hand function.
- C7 and T1 results in lack of dexterity in the hands and fingers, but allows for limited use of arms.
- Patients with complete injuries above C7 typically cannot handle activities of daily living making functioning independently difficult and not often possible.
- Additional signs and symptoms of cervical injuries include:
- Inability or reduced ability to regulate heart rate, blood pressure, sweating and hence body temperature.
- Autonomic dysreflexia or abnormal increases in blood pressure, sweating, and other autonomic responses to pain or sensory disturbances.
- Thoracic
- Complete injuries at or below the thoracic spinal levels result in paraplegia. Functions of the hands, arms, neck, and breathing are usually not affected.
- T1 to T8 : Results in the inability to control the abdominal muscles. Accordingly, trunk stability is affected. The lower the level of injury, the less severe the effects.
- T9 to T12 : Results in partial loss of trunk and abdominal muscle control.
- Typically lesions above the T6 spinal cord level can result in autonomic dysreflexia.
- Lumbosacral
- The effects of injuries to the lumbar or sacral regions of the spinal cord are decreased control of the legs and hips, urinary system, and anus.
- Cervical
- Hemisection (Brown-Séquard’s syndrome)
- Interruption of the lateral corticospinal tracts:
- Ipsilateral spastic paralysis below the level of the lesion
- Babinski sign ipsilateral to lesion
- Interruption of posterior white column:
- Ipsilateral loss of tactile discrimination, vibratory, and position sensation below the level of the lesion
- Interruption of lateral spinothalamic tracts:
- Contralateral loss of pain and temperature sensation.
- This usually occurs 2-3 segments below the level of the lesion.
- Interruption of the lateral corticospinal tracts:
- Central cord syndrome.
- UL motor affected more than lower limb, variable sensory loss below and bladder symptoms such as urinary retention.
- Anterior spinal artery syndrome.
- Motor weakness bilaterally
- Loss of pain and temp sensation bilaterally
- Maintain proprioception, vibration and fine touch.
Intervertebral discs / ligaments.
- Supraspinous ligament
- Interspinous ligament
- Ligamentum flavum(between lamina)
- Posterior longitudinal ligament(back of v body)
- Ant longitudinal ligament (ant to vertebral body)
- Nuchal ligament – between occiput and C7 supraspinous ligament.