TNCC Spinal Cord and Vertebral Trauma 2 — Questions and Answers
Question 1: A patient with a C5 spinal cord injury would be expected to retain which motor function?
- Wrist extension
- Finger flexion and intrinsic hand muscles
- Biceps function and shoulder movement (Correct answer)
- Triceps function and elbow extension
Correct answer: Biceps function and shoulder movement
C5 innervates the deltoid and biceps muscles, allowing shoulder abduction/flexion and elbow flexion. Wrist extension (C6), triceps (C7), and hand intrinsics (T1) are lost.
Understanding spinal cord injury levels requires knowledge of myotomes (motor) and dermatomes (sensory). Key motor levels: C4 — diaphragm (spontaneous breathing preserved), shoulder shrug (trapezius). C5 — deltoid (shoulder abduction), biceps (elbow flexion). C6 — wrist extensors (extensor carpi radialis). C7 — triceps (elbow extension), wrist flexors. C8 — finger flexors. T1 — hand intrinsics (finger abduction/adduction). A complete C5 injury preserves C5 and above: the patient can shrug shoulders, abduct shoulders, flex elbows (biceps), but cannot extend wrists (C6), extend elbows (C7), grasp (C8), or use hand intrinsics (T1). This determines functional capacity: C5 injuries allow some self-feeding with adaptive equipment but require assistance for most ADLs. The ASIA (American Spinal Injury Association) Impairment Scale classifies injury completeness from A (complete) to E (normal), which significantly affects prognosis and rehabilitation goals.
Question 2: Spinal shock is characterized by:
- Permanent loss of all neurological function below the injury
- Temporary loss of reflexes, motor function, and sensation below the injury level (Correct answer)
- Cardiovascular collapse from spinal cord transection
- Chronic pain syndrome following spinal cord injury
Correct answer: Temporary loss of reflexes, motor function, and sensation below the injury level
Spinal shock is the temporary, physiological suppression of all spinal cord function (reflexes, motor, sensory, autonomic) below the injury level, which may last hours to weeks.
Spinal shock is distinct from neurogenic shock (cardiovascular manifestation) — it is a neurophysiological phenomenon where all spinal cord function below the injury level is temporarily suppressed. During spinal shock: (1) All reflexes are absent below the injury (areflexia) — including deep tendon reflexes, bulbocavernosus reflex, and cremasteric reflex. (2) Flaccid paralysis replaces any spasticity. (3) Sensation is absent. (4) Autonomic function is disrupted (bladder areflexia, bowel ileus, loss of temperature regulation). The resolution of spinal shock is marked by the return of the bulbocavernosus reflex (S2-S4 mediated reflex arc — anal sphincter contraction in response to squeezing the glans penis or tugging the Foley catheter). Once spinal shock resolves (hours to 6 weeks), the true extent of neurological injury can be assessed. Prognosis cannot be accurately determined during spinal shock. Any neurological function that returns after spinal shock resolution represents incomplete injury, which has a better prognosis.
Question 3: Which mechanism of injury is most associated with a Jefferson fracture (C1 burst fracture)?
- Hyperflexion of the cervical spine
- Axial loading (compression) force to the top of the head (Correct answer)
- Hyperextension with rotation
- Lateral bending of the neck
Correct answer: Axial loading (compression) force to the top of the head
A Jefferson fracture results from axial loading transmitted through the occipital condyles to the C1 lateral masses, causing the ring of C1 to burst outward. Common mechanisms include diving into shallow water or objects falling onto the head.
The Jefferson fracture is a burst fracture of the C1 (atlas) ring caused by axial compression — force transmitted vertically through the skull to the lateral masses of C1. The occipital condyles act as wedges, driving the C1 lateral masses apart and fracturing the anterior and posterior arches. Classic mechanisms: diving into shallow water (vertex impact), falling objects striking the crown of the head, or axial loading in MVCs. On open-mouth (odontoid) X-ray, the hallmark finding is bilateral lateral mass overhang — the C1 lateral masses extend beyond the borders of C2. CT with reconstructions confirms the fracture pattern. Jefferson fractures are inherently unstable if the transverse ligament is disrupted (total lateral mass overhang >7 mm suggests ligament rupture). Despite the dramatic mechanism, Jefferson fractures may have a relatively good prognosis because the spinal canal at C1 is the widest in the spine, and the burst pattern tends to expand the canal rather than compress the cord. However, associated C2 fractures and vertebral artery injuries must be evaluated.
Question 4: A patient with a T10 complete spinal cord injury is most likely to experience which bladder dysfunction?
- Normal voluntary bladder control
- Upper motor neuron (spastic/reflex) bladder (Correct answer)
- Lower motor neuron (flaccid/areflexic) bladder
- No bladder dysfunction at this level
Correct answer: Upper motor neuron (spastic/reflex) bladder
Injuries above the conus medullaris (L1-L2) produce an upper motor neuron bladder — the sacral micturition reflex arc (S2-S4) is intact but disconnected from voluntary control, resulting in a spastic, reflex bladder.
Bladder function after SCI depends on the relationship between injury level and the sacral micturition center (S2-S4): (1) Upper motor neuron (UMN/spastic) bladder — injury ABOVE the conus (above L1-L2): the sacral reflex arc is intact but disconnected from voluntary cortical control. The detrusor muscle contracts reflexively when the bladder fills to a threshold, causing involuntary voiding with high intravesical pressures. Detrusor-sphincter dyssynergia (simultaneous contraction of detrusor and external sphincter) is common, causing incomplete emptying, high pressures, and risk of autonomic dysreflexia, vesicoureteral reflux, and upper tract damage. (2) Lower motor neuron (LMN/flaccid) bladder — injury AT or BELOW the conus (L1-L2 or cauda equina): the sacral reflex arc is destroyed. The bladder becomes atonic, distends without contracting, and overflows. T10 is above the conus, so this patient has a UMN bladder. Management includes intermittent catheterization, anticholinergic medications, and urodynamic monitoring to prevent renal damage.
Question 5: When logrolling a patient with a suspected spinal injury, the minimum number of personnel required is:
- Two — one at the head and one at the torso
- Three — one at the head directing, plus two supporting the body
- Four — one at the head plus three supporting the body (Correct answer)
- One experienced nurse can safely logroll a patient alone
Correct answer: Four — one at the head plus three supporting the body
A minimum of four persons is recommended for logrolling: one maintains manual in-line stabilization of the head/neck and directs the maneuver, while three support the torso, pelvis, and legs to maintain spinal alignment.
Proper logrolling technique for suspected spinal injury requires a minimum of four team members: (1) Person 1 — positioned at the head, maintains manual in-line stabilization (MILS) of the cervical spine and DIRECTS the roll by calling commands. This person does not move the head independently — the head moves with the body as a unit. (2) Person 2 — supports the shoulders and upper torso. (3) Person 3 — supports the hips and pelvis. (4) Person 4 — supports the legs. Some protocols call for five people (additional support at the mid-torso). The technique: on the leader's command, the team rolls the patient as a single unit ('like a log'), maintaining strict spinal alignment. Arms are positioned at the patient's sides or across the chest. Once on the side, the posterior is quickly examined and palpated, then the patient is rolled back. A fifth person may examine the posterior and/or place a backboard. Logrolling is performed for posterior examination, backboard placement/removal, and turning for care. Inadequate personnel leads to spinal malalignment and potential secondary cord injury.
Question 6: Which clinical finding differentiates Brown-Sequard syndrome from other incomplete spinal cord injury patterns?
- Loss of all motor and sensory function below the injury
- Ipsilateral motor loss and proprioception loss with contralateral pain and temperature loss (Correct answer)
- Bilateral loss of pain and temperature with preserved motor function
- Loss of motor function in upper extremities only with preserved lower extremity function
Correct answer: Ipsilateral motor loss and proprioception loss with contralateral pain and temperature loss
Brown-Sequard syndrome results from hemisection of the spinal cord, producing ipsilateral motor paralysis and proprioception loss (posterior columns) with contralateral pain and temperature loss (spinothalamic tract) below the injury.
Brown-Sequard syndrome is caused by lateral hemisection of the spinal cord, most commonly from penetrating trauma (stab wounds). The asymmetric presentation is explained by neuroanatomy: (1) Ipsilateral motor loss (corticospinal tract) — this tract crosses at the medulla (above any cervical/thoracic injury), so damage produces same-side paralysis. (2) Ipsilateral proprioception and vibration loss (dorsal columns) — these fibers ascend ipsilaterally and cross at the medulla. (3) Contralateral pain and temperature loss (spinothalamic tract) — these fibers cross within 1-2 levels of entry, so damage affects opposite-side sensation. Other incomplete SCI patterns: Central cord syndrome (upper > lower extremity weakness, often in elderly with hyperextension), Anterior cord syndrome (motor and pain/temperature loss with preserved proprioception — worst prognosis of incomplete injuries), and Posterior cord syndrome (rare, loss of proprioception with preserved motor and pain). Brown-Sequard has the BEST prognosis of incomplete SCI patterns, with over 90% of patients regaining functional ambulation.
TNCC Spinal Cord and Vertebral Trauma 2
A patient with a C5 spinal cord injury would be expected to retain which motor function?