See also: [[Neuro - upper limb#Dermatomes|upper limb dermatomes]] and [[Neuro - lower limb#Dermatomes of lower limb|lower limb dermatomes]], [[Neck and spine trauma#Exam|Neck and spine trauma clinical exam]], [[Neurovascular assessment]], [[Cervical spine trauma radiology#Spinal cord syndromes|spinal cord syndromes]], [[Trauma - C-spine exam]] > localisation of T1 - T12 injuries best done with sensory level on dermatomes chart or per table below ![[Pasted image 20250411002626.png]] |Level of lesion|Resulting level of loss of sensation| |---|---| |C2|Occiput| |C3|thyroid cartilage| |C4|suprasternal notch| |C5|below clavicle| |C6|thumb| |C7|index / middle finger| |C8|small finger| |T4|nipple line| |T10|umbilicus| |L1|femoral ulse| |L2 - L3|medial aspect of thigh| |L4|knee| |L5|lateral aspect of calf| |S1|latearl aspect of foot| |S2 - S4|perianal region| ## Spinal exam 1. Document the presence or absence of mid-line neck or back tenderness. 2. Test motor function for muscle groups. 3. Determine the level of sensory loss, and investigate proprioception or vibratory function to examine posterior column function. 4. Test for “saddle anesthesia,” which is a sensory deficit in the region of the buttocks, perineum, and inner aspect of the thighs. 5. Test deep tendon reflexes along with anogenital reflexes because “sacral sparing” with preservation of anogenital reflexes denotes an incomplete spinal cord level, even if the patient has complete sensory and motor loss. 1. To test the bulbocavernosus reflex, squeeze the penis to determine whether the anal sphincter simultaneously contracts. 2. Document anal sphincter tone and sensation around the anus. An “anal wink reflex” (contraction of the anal musculature when the perianal region is stimulated with a pin) indicates some sacral sparing. 3. Test the cremasteric reflex by stroking the medial thigh with a blunt instrument. If the scrotum rises, some spinal cord integrity exists. 4. Conversely, **priapism implies a complete spinal cord injury** ### Motor | Grade | Movement | | ----- | ------------------------------------------ | | 5 | Normal power | | 4 | Movement against gravity + some resistance | | 3 | Movement against gravity | | 2 | Movement with gravity eliminated | | 1 | Trace visible or palpable contraction | | 0 | No active contraction | - Because a single motion is often governed by muscles innervated by multiple spinal segments, localizing a spinal lesion based **solely on motor function** is **extremely difficult**. - Testing the presence and strength of those motions outlined in [[Neck and spine trauma#Spinal Motor Examination|spinal motor exam]] table provides a rapid baseline assessment. - When a deficit is noted, the motor and neurologic examination should be repeated because progression of dysfunction may occur. Even the most minimal of motor response should be elicited and documented, because any response improves prognosis. A slight toe flicker in an otherwise paralyzed individual indicates that the patient may again eventually walk unassisted. ### Reflexes See also [[Trauma - C-spine exam#important motor and reflex changes]] - The presence of **cord-mediated deep tendon reflexes** can be helpful as a localizing diagnostic aid. - C6 - biceps - C7 - triceps - L4 - patellae - S1 - Achilles - Typically, muscle paralysis associated with *intact* deep tendon reflexes indicates an **upper motor neuron** (spinal cord) lesion, whereas paralysis associated with *absent* deep tendon reflexes indicates a **lower motor neuron** (nerve root or cauda equina) lesion. This differentiation is important because the latter condition may be caused by a surgically correctable lesion. - After the initial period of areflexia, reflexes gradually return after 1 to 3 days and, after 1 to 4 weeks, patients with SCI will manifest characteristic hyperreflexia and spasticity. Reflexes are typically absent during the initial phase of spinal shock in the emergency department (ED). ### Sensory - Sensory function can be quickly evaluated through the use of a structured approach or dermatome chart (see above table and pic). - After locating an area of **hypesthesia**, one should move the sensory stimulus from areas of decreased sensation upward, rather than the reverse, because patients are more sensitive to the appearance of sensation than to its disappearance. - A cotton swab may be used to assess sensitivity to light touch, a **posterior column function**. - A pin should be used to assess pain, which is an **anterior spinothalamic** tract function. Even in the presence of complete motor paralysis, the presence of islands of preserved sensation within an affected dermatome or below the level of dysfunction indicates potential for functional recovery. An accurate baseline sensory examination is imperative because **cephalad progression of hypesthesia is the most sensitive indicator of deterioration**. When this is observed in the cervical region, one should anticipate **impending respiratory failure** and preemptively secure the airway.