**Question:** A patient involved in a road traffic accident presents with quadriparesis, sphincter disturbance, sensory level up to the upper border of the sternum and a respiratory rate of 35/minute. The likely level of lesion is -

A. C5-C6
B. C6-C7
C. C7-T1
D. T1-T2

**Correct Answer:** A. C5-C6

**Core Concept:** The spinal cord is responsible for controlling motor, sensory, and autonomic functions in the body. Its levels are designated using the cervical (C) and thoracic (T) regions as well as their corresponding spinal segments. The cervical spinal cord is divided into 8 cervical segments (C1-C8), which correspond to certain areas of the body.

**Why the Correct Answer is Right:** The patient presents with quadriparesis (weakness of all four limbs), sphincter disturbance, and sensory level up to the upper border of the sternum. These symptoms suggest a lesion involving the spinal cord at a higher level than the lower limb motor and sensory segments, which are typically affected at the level of the lesion. The cervical spinal cord segments which include the upper limb motor and sensory segments are C5-C8.

**Why Each Wrong Option is Incorrect:**

**A. C6-C7:** This option is incorrect because it only covers the lower limb motor and sensory segments. The patient's symptoms are more consistent with a lesion involving the upper limb motor and sensory segments.

**B. C7-T1:** This option is also incorrect as it only covers the lower limb motor and sensory segments. The patient's symptoms are more consistent with a lesion involving the upper limb motor and sensory segments.

**C. C7-T1:** This option is incorrect as it only covers the lower limb motor and sensory segments. The patient's symptoms are more consistent with a lesion involving the upper limb motor and sensory segments.

**D. T1-T2:** This option is incorrect because it only covers the lower limb motor and sensory segments. The patient's symptoms are more consistent with a lesion involving the upper limb motor and sensory segments.

**Clinical Pearl:** The clinical scenario described represents a spinal cord lesion at the C5-C8 level, which corresponds to the upper limb motor and sensory segments. The symptoms and signs are consistent with a lesion affecting these segments. In this scenario, the spinal cord lesion is likely to be at the cervical level due to the involvement of upper limb motor and sensory segments.