Spinal Cord Injury Level with Shoulder and Upper Chest Sensation Preserved
If a patient retains sensation in the shoulders and upper chest, the spinal cord lesion is most likely at the C5-C6 level or below, as the C4 dermatome innervates the shoulders and upper chest region, and preservation of these areas indicates that the injury is caudal to this level.
Anatomical Localization Based on Dermatomes
The key to determining the level of spinal cord injury lies in understanding dermatomal distribution:
- C4 dermatome: Covers the shoulders and upper chest (clavicular region)
- C5 dermatome: Extends to the lateral arms
- C6 dermatome: Includes the lateral forearm and thumb
- T1-T6 dermatomes: Cover the periscapular region and upper thoracic area
Since the patient can feel their shoulders and upper chest, the C4 nerve root and spinal segments above it remain intact. This means the lesion must be at C5 or lower 1.
Clinical Context and Implications
Cervical vs. Thoracic Injury Patterns
The distinction between cervical and thoracic injuries has significant implications:
- Cervical injuries (C2-C5) produce respiratory failure and loss of cardiovascular sympathetic innervation, leading to profound hypotension 2
- Upper thoracic injuries (T1-T6) may present with preserved shoulder sensation but can still cause autonomic dysreflexia and respiratory compromise 3
- Patients with complete cervical lesions and upper thoracic lesions (C4-T6) typically respond to intra-abdominal pathology with early nonlocalized abdominal pain and autonomic dysreflexia 4
Sympathetic Level Assessment
Important caveat: The sympathetic level of injury may not correspond exactly to the somatic sensory level. In 34% of complete ASIA A patients, a sympathetic zone of partial preservation extends below the lesion on sensory denervated dermatomes 5. This means that even with preserved shoulder sensation, sympathetic dysfunction may extend further caudally than expected.
Prognostic Considerations
The level of injury directly impacts recovery potential and lesion characteristics:
- Lesion length is approximately two times longer in thoracolumbar compared to cervical SCI (p < 0.0001), likely related to differences in spinal anatomy, biomechanics, and perfusion 6
- Preserved tissue bridges on MRI are more predictive of AIS grade conversion than lesion length, regardless of injury level 6
- High-level thoracic injuries (above T6) have higher prevalence of rotator cuff disorders due to decreased trunk control compared to lower thoracic injuries 7
Clinical Assessment Priority
According to current guidelines, neurological monitoring should be performed using the International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI) to precisely determine the neurological level 1. This standardized examination will definitively establish whether the injury is at C5, C6, or a thoracic level based on motor and sensory testing of key dermatomes and myotomes.