# Clinical Cases: Back - Vertebral Column

## Case 1: Lumbar Disc Herniation with Radiculopathy

### Clinical Image
![Lumbar Disc Herniation MRI](case_01_image.jpg)
*Source: [Wikimedia Commons - Lumbar Disc Herniation MRI](https://commons.wikimedia.org/wiki/File:Lumbar_Disc_Herniation_MRI.jpg) - CC BY-SA 3.0*

### Case Presentation
A 42-year-old warehouse worker presents with 3 weeks of severe lower back pain radiating down his right leg to the foot. The pain started suddenly while lifting a heavy box and has progressively worsened. He describes the leg pain as sharp and burning, traveling along the back of his thigh, lateral calf, and into the top of his foot and great toe. Pain is exacerbated by sitting, coughing, and bending forward. He reports numbness along the same distribution and weakness when trying to lift his big toe. Physical examination reveals antalgic gait with listing to the left. Straight leg raise is positive at 30 degrees on the right with reproduction of radicular symptoms. Neurological examination demonstrates weakness of right great toe dorsiflexion (EHL - 4/5), decreased sensation over the dorsum of the foot, and diminished Achilles reflex. MRI of the lumbar spine reveals a large posterolateral disc herniation at L4-L5 compressing the traversing L5 nerve root. After failing 6 weeks of conservative management with physical therapy, NSAIDs, and epidural steroid injection, he undergoes L4-L5 microdiscectomy with complete resolution of radicular symptoms.

### Key Learning Points
- Intervertebral discs consist of a central nucleus pulposus (type II collagen, proteoglycans) and outer annulus fibrosus (type I collagen)
- Disc herniation typically occurs posterolaterally where the annulus is weakest (posterior longitudinal ligament is narrow)
- At L4-L5, a posterolateral herniation compresses the traversing L5 root (not the exiting L4 root)
- L5 radiculopathy causes weakness of ankle/toe dorsiflexion (tibialis anterior, EHL) and sensory loss over dorsal foot
- The straight leg raise test stretches the sciatic nerve and L4-S1 nerve roots

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## Case 2: Spondylolisthesis

### Clinical Image
![Spondylolisthesis X-ray](case_02_image.jpg)
*Source: [Wikimedia Commons - Spondylolisthesis](https://commons.wikimedia.org/wiki/File:Spondylolisthesis.jpg) - Public Domain*

### Case Presentation
A 16-year-old competitive gymnast presents with chronic low back pain that has worsened over the past 6 months. She describes the pain as a dull ache in her lower back, worse with extension-based activities such as backbends and dismounts. The pain occasionally radiates into her buttocks but not below the knees. She denies lower extremity weakness, numbness, or bowel/bladder dysfunction. Physical examination reveals hyperlordosis of the lumbar spine. Pain is reproduced with lumbar extension and single-leg hyperextension (stork test) bilaterally. There is palpable step-off at the L5 spinous process. Neurological examination is normal. Lateral standing radiographs reveal Grade II (26-50% slip) anterolisthesis of L5 on S1 with bilateral pars interarticularis defects visible on oblique views (spondylolysis). The "Scottie dog" appearance shows the collar representing the pars defect. She is placed in a thoracolumbosacral orthosis (TLSO) brace, restricted from gymnastics, and begins physical therapy focusing on core stabilization and hip flexor stretching.

### Key Learning Points
- Spondylolysis is a defect in the pars interarticularis, often a stress fracture from repetitive hyperextension
- Spondylolisthesis is anterior slippage of one vertebra on another, commonly occurring when bilateral pars defects are present
- L5-S1 is the most common level (90%) due to the lumbosacral angle and mechanical stress
- The Meyerding classification grades slip severity: I (0-25%), II (25-50%), III (50-75%), IV (75-100%), V (spondyloptosis)
- Young athletes in extension sports (gymnastics, diving, football linemen) are at highest risk

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## Case 3: Cervical Spine Fracture

### Clinical Image
![Cervical Spine Fracture](case_03_image.jpg)
*Source: [Wikimedia Commons - Jefferson Fracture](https://commons.wikimedia.org/wiki/File:Jefferson_fracture.jpg) - CC BY-SA 3.0*

### Case Presentation
A 24-year-old man is brought to the trauma center by EMS after diving into a shallow pool and striking his head on the bottom. He was found floating face-down and pulled from the water by bystanders. He is awake and alert but immobilized on a backboard with cervical collar in place. He reports severe neck pain but denies extremity weakness or numbness. Physical examination, maintaining cervical immobilization, reveals midline cervical tenderness at the upper cervical region. He has full strength in all extremities, intact sensation, and normal reflexes. CT cervical spine reveals a burst fracture of C1 (Jefferson fracture) with lateral mass displacement, as well as an associated C2 (axis) fracture through the base of the odontoid (type II dens fracture). MRI shows no spinal cord injury or ligamentous disruption. The patient is placed in a halo vest for immobilization. After 3 months, follow-up imaging shows adequate healing, and the halo is removed. This case demonstrates the vulnerability of the upper cervical spine to axial loading injuries.

### Key Learning Points
- The atlas (C1) and axis (C2) are atypical vertebrae with unique articulations allowing rotation and nodding
- Jefferson fracture is a burst fracture of the C1 ring from axial loading (diving, falls on head)
- Odontoid (dens) fractures are classified by location: Type I (tip), Type II (base, most common), Type III (into C2 body)
- Type II dens fractures have highest nonunion rates due to limited blood supply at the base
- The atlantoaxial joint is stabilized primarily by the transverse ligament of the atlas, which holds the dens against the anterior arch