Humans have an amazing ability to use their hands and fingers to interact with and touch parts of their own bodies. However, there is one part of every person’s body that they can never physically touch with their own hands – the back of their head!
Why can’t we touch the back of our own head?
The main reason we can’t touch the back of our own head is due to the physical limitations of our arms. Our arms simply aren’t long enough to reach all the way behind our head. Even if we try to stretch our arms over our head, our elbows don’t bend far enough to allow our hands to touch the back of our head.
Here are some key facts about why we can’t touch the back of our own head:
- Our arms are only so long. The average arm length of an adult is around 2.5 feet (75 cm).
- Our elbows can only bend back so far. The range of motion of our elbow joint is around 145-160 degrees when fully extended.
- Our shoulders don’t rotate enough. Our shoulder joint can only rotate internally and externally around 90 degrees in each direction.
- The combined length and range of motion is not enough. Even using the full length of our arms and range of elbow/shoulder motion, our hands cannot reach the back of the head.
The back of the head is simply too far back and in the wrong position for our hands to be able to touch it! Our arm and joint range of motion causes a physical limitation that does not allow us to make contact with that part of our body.
Are there any exceptions?
For most people, it is physically impossible to touch the back of their own head with their hands. However, there are some rare exceptions:
- People with extra flexible shoulder joints or double-jointed elbows may be able to bend their arms far enough to barely touch the back of their head if they stretch to the extreme.
- People with unusually long arms relative to their body size may be able to just barely reach the back of their head with their fingertips.
- Using tools or devices may help extend a person’s reach. For example, using a grabber tool or having a very long handled brush may allow some people to indirectly touch the back of their head.
However, these exceptions are very uncommon. The vast majority of people have arms and joint flexibility within a typical range that does not allow their hands to physically touch the back of the head.
Are there any workarounds?
Since most people are unable to touch the back of their own head with their hands directly, here are some workarounds that can allow you to interact with or touch this area in other ways:
- Use a wall corner. By backing up into a corner, you can touch the back of your head to the wall to reach it.
- Use a head scratcher tool. These tools have a long handle and hand piece that let you scratch and touch the back of your head.
- Get someone else to touch your head. Having a friend or family member touch the back of your head is the easiest workaround.
- Use a remote camera. A camera device on a flexible mount could be worn to allow viewing or inspecting your own head remotely.
- Set up mirrors. With the proper mirror setup, you may be able to see and inspect the back of your head even if you can’t directly touch it.
Being unable to touch the back of our heads is one of the physical limitations we live with. But with some creativity, there are ways to be able to access and interact with this one unreachable part of our bodies.
How do we know what the back of our head feels like?
If we’re unable to touch the back of our own head, how do we know what that part of our body feels like? Here are some explanations for how we gain an understanding of the texture and shape of the back of our head:
- Feeling it as a baby. When we’re infants, parents and caregivers will often touch the backs of our heads during caregiving activities.
- Observing it touched. Seeing someone else, like a hairdresser or doctor, touch the back of our head gives us a sense of the feeling.
- Washing our hair. We wash and feel other parts of our head during hair washing, which provides an understanding of texture and shape.
- Seeing reflections. Viewing the back of our head in mirrors or photographs allows us to visually interpret what it looks and feels like.
- Logical deduction. We know what skin and hair feel like on other parts of our body, so we can deduce what the texture is like in an area we can’t reach.
Even without being able to touch it directly, we gain enough secondary information and experiences to form a mental impression of the physical qualities of the back of our head. The inability to reach and touch it does not mean we have no concept at all of what that part of our body is like.
Child development and the back of the head
The ability for a child to touch the back of their own head emerges over time as their bodies grow and develop. Here is an overview of children at different ages and whether they can reach the back of their head:
| Age | Can Touch Back of Head? |
|---|---|
| Newborn | No |
| 6 months | No |
| 1 year | No |
| 2 years | No |
| 4 years | Some may be able to |
| 6 years | Most can touch or almost touch |
| 8+ years | Yes |
Babies and toddlers lack the arm length, even when stretched overhead, to reach the back of their heads. As a child’s limbs grow and they gain greater motor control and flexibility, they eventually are able to touch the back of their heads, often by age 6 or older.
Being unable to reach and touch the back of their heads is normal for infants and young toddlers. But this ability emerges later in childhood development as their bodies grow and gain greater capacity for coordinated movement.
Evolutionary perspective on why we can’t touch our head back
From an evolutionary perspective, there are a few theories on why humans lost the ability to touch the back of their own heads with their hands:
- Tool use became more important. As early humans evolved to use tools, longer arms and greater manual dexterity took priority over self-touching ability.
- Brain size increased. As human brains expanded, the head shifted back on the spine, putting the back of the head out of reach.
- Visual focus increased. As eyes and vision developed, it became more important to look outward than inward, reducing need for self-touch.
- Social groups formed. As humans lived in groups, others could touch heads for grooming, reducing need for self-touch.
In evolutionary terms, the ability to touch our own heads was likely sacrificed in favor of other adaptations like tool use, vision, intelligence, and socialization. Losing this ability may simply have been the byproduct of natural selection for other traits that proved more essential for early human development and survival.
Psychological perspective on head touching
From a psychological perspective, here are some insights on why our inability to touch the back of our heads may not be that detrimental:
- The head has fewer touch receptors. Areas like the hands and face have many more touch receptors than the scalp, reducing need to touch the head.
- Other sensory inputs give us head awareness. Vision, hearing, balance, etc. provide sensory information about our head position without needing to touch.
- Frequent head touching has associations with distress. Frequency touching one’s own head is often associated with anxiety, trauma, or other difficulties.
- Indirect head touching satisfies most needs. Using tools or having others touch our head provides enough tactile input for most needs.
Overall, the inability to touch the back of our heads does not seem to cause significant psychological disturbance or deprivation. Our mental body maps can be formed without needing direct access to touch every part of our physical form.
Medical considerations related to the back of the head
From a medical perspective, there are some important considerations regarding the back of the head since we cannot visually inspect or physically touch this area ourselves:
- Monitoring for lumps and bumps. Cancers or cysts could go undetected if the back of the head is not visually monitored.
- Checking for injuries. Bumps from falls or other impacts can occur on the back of the head without one’s awareness.
- Watching for pain or numbness. Neurological conditions that cause sensations on the back of the head often require another person to notice.
- Observing hair appearance. Hair thinning or appearance changes on the back of the head needs external monitoring.
- Controlling parasites. Lice or fungal/bacterial infections of the scalp need help for monitoring and treatment on the back of the head.
Routine medical exams and observation of the back of the head by others are important to watch for any warning signs of potential health issues that the individual themselves cannot see or touch directly.
Conclusion
The back of our heads is seemingly just beyond the reach of our hands due to the physical limits of our upper limb length and range of motion. This inability to touch this part of ourselves is simply a quirk of our anatomical evolution and development. While we can never actually touch the back of our own heads, through observation, logical deduction, and indirect sensation we can still form an accurate mental impression of this unreachable part of our bodies.