Skip to main content

Cytogenetics

Ergonomics

Cytogenetics is a discipline characterized by high-precision, repetitive tasks performed in static postures for extended periods. Whether analyzing chromosomes at a microscope, setting up cultures in a safety cabinet, or performing digital karyotyping at a computer, the cytogenetic laboratory scientist is at high risk for Work-Related Musculoskeletal Disorders (MSDs). These injuries - such as carpal tunnel syndrome, tendonitis, and chronic neck/back pain - are cumulative, meaning they develop slowly over time due to micro-traumas. An effective ergonomics plan focuses on fitting the workspace to the worker, rather than forcing the worker to fit the workspace

The Neutral Body Position

The goal of all ergonomic adjustments is to achieve a “Neutral Body Position.” This is the posture where the body is strongest and the least amount of stress is placed on joints and muscles. Deviating from neutral (e.g., twisting, hunching, reaching) increases the risk of injury

  • Neck: Balanced upright, ears directly above the shoulders (not craning forward)
  • Shoulders: Relaxed and low, not “shrugged” up toward the ears
  • Elbows: Close to the body, bent at a 90–100 degree angle
  • Wrists: Straight and in line with the forearm, not bent up (extension) or down (flexion)
  • Back: The natural “S” curve of the spine is supported

Microscope Ergonomics

The microscope is the primary tool in cytogenetics, and improper use is the leading cause of neck and upper back strain. Because microscopes are often shared instruments, they must be re-adjusted at the start of every shift

  • Chair Adjustment
    • Start by adjusting the chair height so that your feet are flat on the floor or on a footring
    • Ensure the backrest supports the lumbar curve
    • There should be a 2–3 finger gap between the back of your knee and the edge of the seat pan to prevent cutting off circulation
  • Table and Microscope Height
    • Adjust the table height (or microscope platform) so that you can look into the oculars while keeping your back straight and shoulders relaxed
    • Sign of poor adjustment: If you have to shrug your shoulders to reach the focus knobs, the table is too high. If you have to hunch over to reach the eyepieces, the table is too low (or the scope needs a riser)
  • Oculars and Head Position
    • Tilting Heads: Use an ergonomic head that tilts (0–35 degrees). Adjust the angle so your neck remains vertical
    • Interpupillary Distance: Adjust the width of the eyepieces to match your eyes perfectly. If incorrect, the brain works harder to fuse the images, leading to headaches
    • Eye Cups: Use them to block ambient light, but ensure they don’t force you to press your eyes too hard against the optics
  • Arm Placement
    • Forearms should rest comfortably on the benchtop or padded armrests to isolate the wrist movement for the focus knobs/stage control. Never “hover” your arms; the weight of the arms causes rapid shoulder fatigue

Biological Safety Cabinet (BSC) Ergonomics

Working in a hood presents unique challenges because the glass sash limits movement and the airflow grill can create contact stress

  • Reach Zones
    • Keep supplies (pipettes, media bottles) within the “Primary Reach Zone” (about 14–16 inches from the body)
    • Avoid “Over-reaching” (extending the arm fully), which puts stress on the shoulder capsule
  • Armrests and Contact Stress
    • The sharp metal edge of the sash or grill can compress the nerves in the forearm. Use foam armrests: or elbow pads designated for cleanroom use
    • Never block the airflow grill, but bridge over it with elevated armrests if possible
  • Visual Line
    • Position the work in the center of the hood so you do not have to twist your torso to see the flask. Lower the chair or raise the stool so you are looking through the glass, not straining to look under the sash or over the rim

Computer Workstation (Digital Karyotyping)

Modern cytogenetics involves hours of on-screen analysis (e.g., CytoVision, GenASIs). The principles of office ergonomics apply here

  • Monitor Placement
    • Height: The top of the monitor screen should be at or slightly below eye level. This forces the eyes to cast slightly downward, which is less fatiguing and allows the eyelids to cover more of the eye (reducing dryness)
    • Distance: The screen should be approximately an arm’s length away
  • Input Devices
    • Mouse: Keep the mouse close to the keyboard to prevent reaching. Cytotechs often suffer from “Mouse Shoulder.”
    • Wrist Rests: Use a gel pad to keep the wrist neutral, but rest the palm of the hand on the pad, not the soft tissue of the wrist (where the nerves are)

Manual Tasks (Harvesting & Pipetting)

The harvesting process involves repetitive plunging of pipettes and unscrewing of tubes

  • Pipetting
    • Use electronic pipettes whenever possible to eliminate thumb force
    • If using manual pipettes, choose models with low plunger force and finger hooks that allow you to relax your grip between steps
    • Avoid “Death Grip”: Hold the pipette only as tightly as necessary to control it
  • Standing Tasks
    • For tasks done while standing (e.g., using the fixative aspirator), use anti-fatigue floor mats
    • Wear supportive shoes
    • Work at elbow height. If the bench is too low, widen your stance to lower your center of gravity rather than bending your back

Micro-Breaks & Recovery

No matter how perfect the equipment, the human body is designed for movement. Static loading (holding still) restricts blood flow

  • The 20-20-20 Rule (Eye Strain): Every 20 minutes, look at something 20 feet away for 20 seconds. This relaxes the ciliary muscles in the eye that are locked in “close focus.”
  • Micro-Breaks: Every 30–60 minutes, take a 2-minute break to stand up and stretch
  • Reverse Stretching: If your work involves hunching forward, stretch backward (open the chest). If your work involves gripping, stretch the fingers wide open