An instructor at the Romsey karate club was emphasising that it was important to know not only where to hit but also why it had effects.

I will cover strikes to the head first.

If unsure where some of these strikes are, then refer to my earlier Under Pressure blog posts. Striking nerve targets produces considerable pain in the hope that it causes the attacker to back off. This blog looks at more serious effects from striking the head.

These effects are listed in order of acute medical risks.

Epidural hematoma

A strike to the temple is at the thinnest point of the skull, measuring approximately 2–3 mm. This point is situated above the middle meningeal artery. Even moderate impact can fracture here and lacerate this artery, causing what is known as an epidural hematoma. This is a collection of blood that forms between the skull and the dura mater, the outer protective layer of the brain. It can be a life-threatening condition that requires immediate medical attention and often surgery to relieve pressure on the brain.

Knockout (KO) or loss of consciousness.

A KO is essentially a transient traumatic loss of consciousness caused by:

1. Rapid spinning movement damages the reticular activating system (RAS) in the brainstem/upper midbrain. The brain, floating in cerebrospinal fluid, lags behind skull movement, causing shear stress on axons. This is typically caused by a strike to the jaw, causing head rotation. The brainstem also controls motor output, which explains the characteristic stiffening, dropping, and involuntary movements seen in knockouts (KOs).
   A fighter who is “out before they hit the ground” has sustained brainstem-level disruption. This is never trivial, even if recovery appears rapid.
2. Vascular changes to blood pressure by striking baroreceptors in the carotid arteries to cause a vasovagal faint. [this is covered in a previous blog.]
3. Back-of-the-head strike – see below.

Occiput impact

This is where the back of the skull is struck, causing a cerebellar/brainstem contusion. Some describe these strikes as ‘hitting the brain’s fuse box’, as they can cause a knockout. The occipital lobe is essential for reading and spatial awareness (amongst many functions). Damage to it can cause vision problems, object recognition issues, or difficulties perceiving depth. Severe damage can cause an occipital haematoma, bleeding on the brain.

Eye & Orbital Injuries

1. An orbital blowout fracture happens when pressure from an impact pushes through the eye to the thin bone at the bottom or side of the eye socket, causing a break and trapping the muscle that helps move the eye, which can lead to blurry vision.
2. Retinal detachment: Sudden eye compression or acceleration can shear the retina.
3. Hyphema: Bleeding into the eye; this can lead to secondary glaucoma.
4. Commotio retinae: Traumatic retinal oedema (swelling of the retina due to fluid accumulation) from blunt force can cause permanent vision loss even without detachment.

Repeated subconcussive impacts

This isn’t really ‘a strike’ but the culmination of repeated strikes.

Chronic Traumatic Encephalopathy (CTE)
CTE is the defining long-term risk of repeated head trauma. Pathologically:
• Abnormal tau protein accumulation in neurons and astrocytes.
• Progressive neurodegeneration.
Often years to decades post-exposure:
• Behavioural/mood changes first — impulsivity, aggression, depression, and suicidality.
• Later: cognitive decline, memory loss, executive dysfunction.
• Motor symptoms in advanced cases (parkinsonism, dysarthria)
CTE can currently only be diagnosed post-mortem. Research increasingly supports the relationship between cumulative subconcussive impacts (not just diagnosed concussions) and CTE— meaning sparring volume matters enormously, not just competition KOs.

Neck Damage

A whiplash-type injury from a snapping head movement can result in cervical facet joint damage and disc herniation (injury to the intervertebral disc between two vertebrae).

Ear trauma

• Cauliflower ear (auricular haematoma): This occurs from blunt trauma, typically in boxing and wrestling. It occurs when blood collects between the cartilage and skin, leading to a lumpy appearance if not treated promptly.
• Tympanic membrane (eardrum) rupture: Caused by slap-type strikes over the ears causing pressure waves (as seen in old Tango TV adverts). It usually heals spontaneously but risks conductive hearing loss.
• Labyrinthine concussion is a disruption of the inner ear, which can lead to symptoms such as vertigo (a sensation of spinning), tinnitus (ringing in the ears), and sensorineural hearing loss (hearing loss caused by damage to the inner ear or the auditory nerve).

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I’m adding this section for awareness if you are involved in martial arts instruction or if you witness or are subject to assault.

Clinical Red Flags After Head Strike
These warrant immediate emergency evaluation:
• Loss of consciousness (any duration)
• Seizure activity
• Deteriorating consciousness
• Severe or worsening headache (“worst of my life”)
• Repeated vomiting
• Focal neurological deficit (weakness, speech disturbance, vision loss)
• Unequal pupils
• Clear fluid from nose or ears (Cerebrospinal fluid leak → basal skull fracture)
• Neck pain with neurological symptoms

Return-to-Sport Considerations
Medically sound return-to-sport protocols require:
1. Symptom-free at rest.
2. The individual remains symptom-free when following a graded exertion protocol.
3. Neuropsychological baseline testing comparison.
4. Medical clearance is more important than just symptom resolution.

The metabolic recovery of the brain significantly lags behind symptomatic recovery, which is why premature return is so dangerous.