Question

Patient Information:

• Name: John Smith
• Age: 45
• Occupation: Office worker
• Medical History: No significant medical history
Presenting Complaint:
John Smith presented to the orthopedic clinic with complaints of severe lower back pain that radiated down his left leg. The pain started a week ago and has progressively worsened. He also experienced numbness and tingling sensations in the left leg.
Physical Examination Findings:
• Tenderness and muscle spasm in the lumbar region
• Positive straight leg raise test on the left side, reproducing leg pain
• Decreased sensation in the left leg along the L5 dermatome
• Weakness in the left ankle dorsiflexion and toe extension
Imaging Studies:
An MRI scan of the lumbar spine was performed, which revealed a disc prolapse at the L4-L5 level, causing compression of the left L5 nerve root.

What is the cause of john pain?
Why john had numbness and weakness?
What is the dermatome and myotome?
What is straight leg raise test?
Why there is a weakness in dorsiflexion and toe extension?

Answer 1

Based on the provided information, the cause of John's pain is a disc prolapse at the L4-L5 level of his lumbar spine. Disc prolapse refers to the displacement or herniation of the intervertebral disc, located between the L4 and L5 vertebrae. This herniation can result in compression or irritation of the adjacent nerve roots, leading to pain and other associated symptoms.

John experienced numbness and weakness due to left L5 nerve root compression. The compression of the nerve root can interfere with the normal functioning of the nerve, causing sensory disturbances such as numbness and tingling sensations. Additionally, it can affect the motor function of the nerve, resulting in weakness in specific muscle groups innervated by the affected nerve.

Dermatome refers to an area of skin supplied by a single spinal nerve. Each spinal nerve corresponds to a specific dermatome, and damage or irritation to a nerve can cause sensory abnormalities within that dermatome. In John's case, the decreased sensation along the L5 dermatome indicates that the L5 nerve root, which supplies sensation to that specific area, is affected.

Myotome refers to a group of muscles innervated by a single spinal nerve. Like dermatomes, each spinal nerve corresponds to a specific myotome. Weakness in dorsiflexion (lifting the foot upwards) and toe extension (extending the toes) indicates a deficit in the function of the muscles innervated by the L5 nerve root, which includes the muscles responsible for these movements.

The straight leg raise test is a physical examination maneuver used to assess irritation of the nerve roots in the lumbar spine, particularly the sciatic nerve. In this test, the patient lies on their back, and the healthcare provider lifts the patient's leg while keeping the knee flat. A positive test is indicated if the maneuver reproduces the patient's leg pain. In John's case, a positive straight leg raise test on the left side suggests irritation or compression of the left L5 nerve root. This is consistent with his symptoms.

The weakness in dorsiflexion and toe extension is due to compression of the left L5 nerve root. The muscles responsible for dorsiflexion and toe extension are innervated by this nerve root. When the nerve root is compressed or irritated, the signals from the brain to these muscles are disrupted, leading to weakness or difficulty in performing these movements.