Understanding the Role of the Neck in Sport: Part 1 Anatomy and Complexity

Introduction

The neck plays a critical yet often overlooked role in sports performance, injury prevention, and recovery. Unlike other regions of the musculoskeletal system, the neck must uphold the demands of flexibility, stability, and precision - keeping the head balanced and supported in space. As we will discuss, a uniquely challenging and underappreciated task! This edition of my Newsletter will be the first in a series to explore the multifaceted role of the neck in sports. Here, in part 1 we will examine its unique anatomy and range of motion. In future editions, we will explore its proprioceptive function and integration with balance, muscular anatomy and neuromuscular control of movement and its critical role in preventing injuries such as concussions and neck injuries. By understanding the interplay between the structural complexity of the neck and its functional demands in sport, athletes, coaches, and medical professionals can better optimize training, reduce injury risk, and enhance performance.

?Anatomy of the Neck: A Specialized Structure

?The neck's structural complexity is a defining feature, consisting of seven cervical vertebrae (C1-C7) and a network of muscles, ligaments, and nerves. The uppermost vertebrae and bottom of the skull—occiput (C0), atlas (C1), and axis (C2)—create a highly specialized system designed for mobility, allowing a wide range of head movements like nodding and rotation within a compact space. This region accounts for up to 75% of axial rotation (Zhou, 2020) and 50% of neck flexion and extension (Panjabi, 1988). It’s what enables the expression “having your head on a swivel.” However, this extensive range of motion comes at the expense of stability. Biomechanically, these joints have very little surface area—the two atlanto-occipital joints, where the skull rests on the neck, have less surface area than your thumb joints (Briggs 2008, Kovler 2004)! Yet, they must support and balance the 8-10 pound weight of the head all day long. Adding to the complexity, this area is also where the brain ‘leaks out’ of the protective confines of the skull and into the spinal cord, further highlighting this crucial and delicate region in the body.

In contrast, the lower cervical vertebrae (C3-C7) play a more stabilizing role, supporting the head’s weight and enabling controlled, complementary movements. The intervertebral discs, starting between C2 and C3, provide greater biomechanical support, particularly for compressive forces. These lower vertebrae allow for more subtle and controlled movements across three planes—flexion, extension, and lateral bending—necessary for full head mobility but with a trade-off: greater stability at the cost of some flexibility. Understanding these distinctions is key for designing effective training and rehabilitation strategies that address both the stability and mobility requirements of the neck.

A Primary Function of the Neck: Keeping the eyes level?

When examining the axial rotation range of motion of the cervical spine, there is something rather interesting that occurs known as coupled movements. What this means is that, due to the shape of the vertebrae, rotation cannot occur without concurrent anatomical side flexion. The interesting part is that the lower cervical spine (C3-C7) couple ipsilaterally (meaning to the same side, so right rotation occurs with right side flexion) while the upper cervical segments (C0-C2) couple contralaterally (meaning to the opposite side, so right rotation occurs with left side flexion) (Cook 2006).?

At first blush, this may seem like an odd anomaly of ‘that’s just the way it is’, like how turning the radio down makes it easier to look for directions. Still, examining the effect this has on the head, the reason becomes more evident (not turning the radio down, the coupled movements). As we know, two of the three main balance systems are in the head (the visual system and the vestibular system). We also know that walking or running on two feet is evolutionarily more challenging than on four. Therefore, to maintain our upright orientation with gravity it is crucial that we have an accurate representation of where our head is in space in relation to the rest of our body and with the earth i.e., we keep our heads in-line with the pull of gravity. To achieve this most effectively, our eyes must stay parallel with the horizon regardless of whether we are looking straight ahead or looking over our shoulder. The change in coupling from contralateral in the upper cervical vertebrae to ipsilateral in the lower cervical vertebrae cancel each other out allowing us to keep our eyes level and parallel to the ground as we look over our shoulders. This is one reason why some people seem to lose their balance if they try to ‘walk and talk’ with someone at the same time. If they have some cervical stiffness or dysfunction that throws off the relationship of movement between the upper and lower cervical vertebrae, then their eyes will tip ‘out of level’ when they rotate their head, causing a challenge to both the visual and vestibular systems of balance.

If you don't think keeping your eyes perfectly parallel in relationship to your body and your environment is that important, try tilting all of your paintings, pictures, or posters by 1 degree in the same direction and see how long it takes before friends and family start twitching, fixing them when you aren’t looking, or eventually staging an intervention. As an example, did you notice the tilt in the image above? You probably thought something wasn't right in the image but maybe couldn't put your finger on it! If you did notice right away, please mention it in the comments section.

To summarize, here are some takeaways from this newsletter:

The Neck's Critical Role in Sport: The neck supports head stability, balance, and precise movement, playing an often underappreciated role in performance and injury prevention.?

Complex Anatomy: The neck's unique anatomy includes specialized regions to balance the need for flexibility (upper cervical spine) and stability (lower cervical spine), each contributing different amounts of movement across all three planes to keep your head and eyes level with the earth.

Training Implications: Understanding these anatomical and functional intricacies can help optimize neck training, reduce injury risk, and improve sports performance.

?Stay tuned for future editions as we explore the muscular anatomy and neuromuscular control, proprioception, and injury prevention strategies!

?References

?Briggs L, Hart J, Navis M, Clayton S, Boone R. Surface area congruence of atlas superior articulating facets and occipital condyles. Journal of Chiropractic Medicine. 2008 Mar 1;7(1):9-16.

?Cook C, Hegedus E, Showalter C, Sizer Jr PS. Coupling behavior of the cervical spine: a systematic review of the literature. Journal of manipulative and physiological therapeutics. 2006 Sep 1;29(7):570-5.

?Kovler M, Lundon K, McKee N, Agur A. The human first carpometacarpal joint: osteoarthritic degeneration and 3-dimensional modeling. Journal of Hand Therapy. 2004 Oct 1;17(4):393-400.

?Zhou C, Wang H, Wang C, Tsai TY, Yu Y, Ostergaard P, Li G, Cha T. Intervertebral range of motion characteristics of normal cervical spinal segments (C0-T1) during in vivo neck motions. Journal of biomechanics. 2020 Jan 2;98:109418.????????

Panjabi M, Dvorak J, Duranceau J, Yamamoto I, Gerber M, Rauschning W, Bueff Hu. Three-dimensional movements of the upper cervical spine. Spine. 1988 Jul 1;13(7):726-30.