Safe Zones and Danger Zones
The impact map of the human body—where striking is safe, where it carries specific risks, and where it is absolutely prohibited
“First, do no harm.”
The Primary Safe Zone: The Buttocks
The fleshy lower buttocks is the safest impact zone in the human body for most implements and intensity levels.
The gluteal musculature provides substantial padding over the underlying structures, and the relatively limited density of superficial nerve and vascular structures in this zone means that well-placed impact engages muscle without easily reaching more vulnerable anatomy.
The boundaries of the safe zone within the buttocks are more specific than “the buttocks” suggests.
The safe zone is the fleshy area in the center and lower portion.
The upper boundary is the level of the iliac crest—the bony ridge of the pelvis felt along the top of the hip.
Striking above this level means striking toward the lumbar region where the kidneys are located.
The lower boundary is above the sit bones (ischial tuberosities)—the bony prominences felt when sitting.
Striking the sit bones directly produces pain from bone rather than muscle and carries bruising risk disproportionate to the surrounding tissue.
These boundaries are not approximate. They are anatomically determined, and knowing them requires that the Striker be able to identify them on the specific body in front of them before beginning any significant impact.
Bodies vary in how they are proportioned.
The iliac crest is in a different location relative to visible landmarks depending on the person’s build.
Take a moment at the beginning of any encounter to locate these landmarks on this specific Receiver.
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Secondary Safe Zones
The upper and middle back is a secondary safe zone for Strikers who have sufficient anatomical knowledge to use it safely.
The target is the muscle mass of the erector spinae and trapezius on either side of the spine.
The absolute exclusion zone within the back is the spine itself (center line from neck to sacrum) and the lower back where the kidneys project.
The outer and back surfaces of the upper thighs are appropriate for moderate impact with adequate technique.
The inner thighs are highly sensitive and are appropriate for light to moderate impact with experienced Receivers and explicit pre-scene agreement.
Behind the knee (the popliteal fossa) contains major neurovascular structures very close to the surface and is never an impact target.
The upper arm and shoulder area is appropriate for light to moderate impact, with the shoulder joint itself excluded. The calves are appropriate for very light impact, with the Achilles tendon excluded.
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Absolute Danger Zones: No Exceptions
The following areas must not receive direct impact from any implement at any intensity level. Experience does not create exceptions. Consent does not create exceptions. These prohibitions exist because the anatomy cannot tolerate direct impact safely regardless of other conditions.
·?The lower back (lumbar region): the kidneys are located here, protected only by the lumbar musculature and retroperitoneal fat. Direct impact can cause renal contusion, which presents with flank pain and blood in the urine. Renal contusion requires medical evaluation and can cause lasting damage.
·?The spine: the vertebral column from the neck through the sacrum contains the spinal cord and the nerve roots that supply the limbs and organs.
Direct spinal impact can cause vertebral injury.
Never target the spine, and never design or allow techniques that routinely produce near-spine impact that may drift onto it.
·?The tailbone (coccyx): the coccyx projects at the junction of the buttock cleft and is vulnerable to direct impact even from light implements. Coccyx injuries are painful, heal slowly, and interfere significantly with sitting and movement.
·?The back of the knee (popliteal fossa): the popliteal artery, popliteal vein, tibial nerve, and common peroneal nerve all pass through this area with minimal overlying tissue protection. Direct impact can cause vascular or nerve injury.
·?The head, neck, and face: no impact implements, under any circumstances.
·?Major joints directly: elbows, knees, ankles, wrists, and hip joints should not receive direct impact. The joint capsule, cartilage, and associated ligaments are not designed to absorb the kinds of forces that impact implements generate.