How many times have you heard a yoga teacher cue a student to lift their head in a pose—or drop it?

This adjustment is as critical as any other modification in yoga asanas, yet one that is often misunderstood and undervalued.

The human head weighs between 10 and 12 pounds, the equivalent of a bowling ball. While it’s hard to imagine balancing a bowling ball on top of our bodies, this is actually what we humans do from that first moment we try to lift our heads up as infants.

Luckily, the human spine is engineered to balance the head on top of the vulnerable components of the critical axis (the spine). When we stand and sit with good posture—creating that plum line along the ears, shoulders, hips, knees and ankles—our head is perfectly balanced against the force of gravity on our bodies.

Here’s the problem: Modern humans tend to spend their lives slouching over computers, driving in cars and slouching in comfy couches. Add to that the demands of modern life, which has many of us ‘living in our heads,’ and we spend more time anticipating and worrying, rather than being grounded in the present (in the plum line!).

Over time, the weight of a forward-leaning head leads to rounded shoulders, collapsed chests and a litany of future woes. Physiotherapists warn that chronic slouching and head slumping can so compromise our breathing apparatus that with time this misalignment can lead to death!

A medical abstract by Kenneth Hansraj, M.D., Chief of Spine Surgery at New York Spine Surgery & Rehabilitation Medicine, explains the detrimental effect poor head posture has on our well being. Hansraj states that repetitive stress on the cervical spine from the head tilting forward—from hours spent on cell phones, tablets and laptops—leads to early wear, tear, degeneration and the possible need for surgery.

Hansraj explains that the weight borne by the spine dramatically increases when we flex the cervical spine—or tilt the head forward. The further we tilt forward, the greater the degree of stress on the spine. For example at 15 degrees, the head exerts a force of 27 pounds; at 30 degrees that force increases to 30 pounds. Chronic slouchers and those who spend hours a day texting or reading email on their phones, can, at a tilt of 30 degrees and higher, exert the force of up to 60 pounds on the cervical spine.

Let’s apply those principles to yoga. Cervical alignment—or the proper engagement of cervical and shoulder muscles to support the head—plays a critical role in the correct execution of a pose. Proper head alignment also allows us to achieve one of the ultimate goals of a yoga pose—sthira and sukha (or, steadiness and ease)—by encouraging balance.

Muscles like the sternocleidomastoid, scalenes, rectus capitis posterior and obliquus capitis inferior are a few of the dozen small structures in the neck region that play key roles in proper head alignment in poses like Virabhadrasana II (Warrior II), Matsyasana (Fish Pose) and Vrschikasana (Scorpion Pose). Anyone who practices Supported Headstand is likely aware of the subtle powers of deep neck muscles such as the longus colli, rectus capitis posteriors and anteriors. Bigger players, such as the rhomboid muscles in the back, help provide stability to the cervical region in poses like Parivrtta Parsvakonasana (Revolved Side Angle Pose) and Salamba Sarvangasana (Supported Shoulder Stand).

Yoga offers a powerful opportunity to become mindful of the muscles needed for proper head and neck alignment on and off the mat. Begin now to become firmly aware of what muscles you engage to align and support your head above your body. See if you can integrate this alignment—whether you are texting on the cell phone or standing in Tadasana (Mountain pose)—into more postures during your daily routines. Can you do this in a way that brings integrity into more of your regular movements?