u/Automatic-County6151

Introduction

The hyoid is a horseshoe-shaped / U-shaped bone that sits near the base of the throat, just beneath the mandible. The horns of the hyoid are both externally palpable through soft pressure and especially during coordinated functions, such as swallowing, when it might feel as if it's "bobbing" slightly, depending on the individual anatomy. The reason why it performs these movements is because it's held up by several muscles and ligaments, which, when our muscles contract when swallowing, the hyoid might "bob".

Pattern of Ossification and Process of Development

The hyoid bone develops via endochondral ossification. Instead of cartilage, it first forms as a mesenchymal model very early in life, which gradually turns to bone (locally) in a very coordinated, unique sequence throughout childhood and adolescence, ultimately finishing development by early adulthood.

During embryonic development, the hyoid first enters into existence through the formation of pharyngeal / branchial arches, of which the hyoid is derived. These arches are bilateral arches composed of the inner and outer epithelium, a mesoderm core, and neural crest-derived mesenchyme. These tissue bands help develop the neck and face, helping to slowly form the adult craniofacial framework. In the neck, they also develop the hyoid.

"Groundbreaking" is the first occurrence - mesenchymal condensation. Akin to the clavicle, which forms from a lateral plate mesoderm and mesenchyme, the hyoid begins this early stage of development via the grouping of stem cells from the neural crest and mesoderm, and condensing. Here, we get the earliest template, with no cartilage just yet.

The next step is chondrification - the formation of a cartilaginous model. Here, we see mesenchyme differentiating into cartilage to form a cartilage precursor, which corresponds to the structures derived from the second and third pharyngeal arches.

Now, these arches are extremely crucial for the early development of the hyoid, and there are six of them in total. However, only some may be fully developed in humans - the rest almost rudimentary, but still functional. Each one contains a mesenchymal core from the neural crest and mesoderm + clefts (ectoderm) and pouches (endoderm), a cartilage template that later forms bone or ligament, a muscle component, a cranial nerve (useful for identification), and an aortic arch artery, which is essential for carrying the necessary nutrients do each arch during early development.

The first arch: otherwise called the mandibular arch, this one is a major derivative of several different structures, meaning it later forms these structures:

• The mandible

• The masticatory muscles (masseter, temporalis, pterygoids), the mylohyoid, anterior digastric, tensor tympani, and tensor veli palatini.

• Parts of the maxilla, and our middle ear bones - the malleus and incus.

Identity: CN V (trigeminal nerve), specifically V3 (mandibular division).

It first contains Meckels cartilage to serve as a basic template, which largely regresses to contribute toward building the bones of the ears and the ligaments.

Its patterning sequence involves the reception of a mass influx of neural crest cells, followed by patterning by Hox-negative identity to allow for jaw formation, further supported / driven by high FGF, Shh, and BMP signaling gradients. Through maturation, only parts of it persist - the malleus, incus, and certain ligaments like the sphenomandibular ligament, while surrounding mesenchyme undergoes intramembranous ossification to form the mandible around Meckels cartilage.

Key muscle developments include the migration of myogenic precursors that differentiate into branchial muscle groups, of which the first arch is innervated by the trigeminal motor nucleus (V3). Shh from the epithelium helps expand the arch, while the Dlx gene code influences dorsal/ventral patterning of the jaw, and Endothelin-1 is for ventral identity (basically the mandible vs the maxilla).

The second arch: otherwise called the hyoid arch, its major derivatives primarily included the stapes (the stirrup-shaped bone in our ear), the styloid process, and the lesser horns & upper body of the hyoid.

It contains Reichert's cartilage, which is the rudimentary precursor to the derivatives of this arch (ear bones, stylohyoid). Additionally, it contributes to the development of the muscles of facial expression, such as the orbicularis oculi, buccinator, and the platysma, as well as the stapedius - the smallest skeletal muscle in the human body, located in the ear. Unlike in the first arch, cartilage in the second arch is partially retained and minimally ossified.

Its identity is unique to CN VII (facial nerve), and it is vascularized by the stapedial and hyoid arteries. For the creation of the facial expression musculature, muscles migrate into this arch and spread throughout the face, all controlled by the facial nerve motor nuclei. Oftentimes, a developmental shift occurs during development - cleft lifting. When the second arch overgrows the third and fourth arches, this can form the cervical sinus, which is later obliterated.

The third arch: this arch is more focused and specialized compared to the first two, but it plays a very critical role in stabilizing the developing neck and swallowing apparatus. Its primary skeletal contribution is toward the greater horns and lower body of the hyoid bone, making it a direct continuation of the hyoid’s structural framework.

Unlike the second arch, which produces a broader range of derivatives, the third arch is more functionally streamlined. Muscularly, it gives rise to a single, highly specific muscle: the stylopharyngeus, which elevates the pharynx during swallowing, marking the third arch as a key contributor to pharyngeal motion and coordination.

Its identity is unique to the glossopharyngeal nerve (CN IX), which is unique in that it exclusively innervates third arch derivatives. This tight 1:1 relationship makes the third arch particularly easy to track neurologically. Vascularly, it contributes to portions of the common carotid and internal carotid arteries, which are essential for supplying the head and neck.

From a developmental standpoint, the third arch represents a transition point - moving from the broader, more diverse derivatives of Arches 1 and 2 toward the more specialized airway and laryngeal structures of Arches 4 through 6.

The fourth arch: this arch marks a major shift toward the development of the airway and laryngeal framework. Its skeletal contributions are directed toward the laryngeal cartilages, particularly components of the thyroid cartilage and surrounding structures that help define the upper airway.

Muscular derivatives include the pharyngeal constrictors (critical for swallowing), the cricothyroid, and the levator veli palatini. These muscles collectively coordinate airway protection, bolus (lump) propulsion during swallowing, and tension and positioning within the vocal apparatus.

The fourth arch is innervated by the vagus nerve (CN X) via its superior laryngeal branch, which reflects its role in controlling upper laryngeal function. Its arterial contribution is rather asymmetrical: left side contributes to part of the aortic arch, while the right side contributes to the right subclavian artery.

Developmentally, this arch begins to integrate respiratory and digestive pathways, forming a structural and functional bridge between them.

The fifth arch: this arch is often described as rudimentary or absent, but its mention is still important here for understanding the full developmental sequence. In most cases, it either fails to form entirely or appears transiently and regresses rapidly. Even though it does not produce any consistent skeletal, muscular, or neural derivatives in humans, its presence in developmental descriptions reflects the evolutionary template of the pharyngeal system rather than a functionally significant structure in modern human anatomy.

The sixth arch: this arch completes the series and is heavily involved in forming the lower laryngeal structures and airway mechanics. Its skeletal derivatives include key components of the larynx, such as the cricoid cartilage, the arytenoid cartilages, and additional elements that support vocal fold function. These structures are essential for maintaining airway patency, regulating airflow, and enabling phonation (producing vocal sounds).

Muscularly, the sixth arch forms the intrinsic muscles of the larynx (with the exception of the cricothyroid, which belongs to the fourth arch). These muscles control vocal cord movement, opening and closing of the airway, and fine adjustments in voice production.

Innervation is again via the vagus nerve, but specifically through the recurrent laryngeal nerve, which has a unique developmental course. It loops around major arteries (subclavian on the right, aortic arch on the left), then ascends back toward the larynx. This pattern reflects embryologic vascular changes and is a classic example of how developmental pathways shape adult anatomy.

Vascularly, the sixth arch contributes to the pulmonary arteries, and (on the left side) the ductus arteriosus during fetal life.

So, Arches 1 through 3 are the major developmental contributors toward the structures of the jaw, face, and hyoid, while Arches 4 through 6 focus on developing the airway and larynx.

Developmental Staging and Visual Details on Medical Scans

The developmental pattern above can be tracked using medical imaging over the course of several years. It is sometimes partially visible on dental panoramics, where the scan can catch a glimpse of the upper portion of the hyoid body and its greater horns. It is best visible on x-rays, CT, and MRI.

The hyoid bone is not always the easiest structure to visualize depending on the modality and age of the individual. Because it starts out largely cartilaginous, early-stage imaging (especially in younger children) may show it as faint, partially radiolucent, or even difficult to distinguish altogether.

As ossification progresses through childhood, the hyoid becomes increasingly visible. The body typically ossifies first, followed by the greater horns, while the lesser horns may remain subtle or partially separate for an extended period. On dental panoramic radiographs, the hyoid can sometimes be seen incidentally as curved radiopaque structures inferior to the mandible, though this view is often incomplete.

Lateral cephalometric x-rays provide a better sense of its vertical positioning, which is particularly useful when observing its gradual descent in the neck over time. In younger individuals, the hyoid tends to sit higher, closer to the mandible. With maturation, it shifts inferiorly, reflecting coordinated changes in the airway and surrounding structures.

For more precise detail, CT scans offer the clearest visualization of segmentation, the degree of ossification, and fusion between the body and horns overall three-dimensional morphology. MRI, while less optimal for bone detail, can still demonstrate its relationship to surrounding soft tissues, particularly the tongue and the larynx, both of which develop in close functional association with the hyoid.

One of the most consistent imaging findings across development is this gradual positional descent, which correlates with airway expansion, laryngeal repositioning, and changes in vocal tract configuration.

Does it have growth plates?

The hyoid bone does not have traditional growth plates like long bones do, and this is a key distinction in understanding its developmental behavior.

Instead of a structured epiphyseal growth plate with organized zones of chondrocytes, the hyoid develops through a segmented, multi-center process. It begins with cartilaginous precursors derived from the second and third pharyngeal arches, and these segments each undergo endochondral ossification independently. Growth, therefore, does not occur through linear elongation driven by a physis. Rather, it occurs through cartilage modeling and gradual replacement by bone, appositional growth at the surfaces, and progressive fusion between separate ossification centers. I will go over this in a little bit.

The body, greater horns, and lesser horns each follow their own timeline of ossification and eventual integration. In many individuals, this fusion is incomplete or asymmetrical, especially involving the lesser horns. Because of this, the hyoid’s development is better described as an assembly and consolidation process, rather than a simple lengthening mechanism, and that's because it's all for function. The hyoid is not a load-bearing bone, and its role is not to support weight or generate leverage in the same way as long bones. Instead, it serves as a dynamic anchor point, suspended by muscles and ligaments, adapting its shape and position in response to surrounding functional demands like swallowing and speech.

Fusion Sequences through Adolescence

One of the more nuanced and often overlooked aspects of the hyoids bone is how its separate components gradually come together over time.

Unlike long bones that follow a clear epiphyseal fusion pattern, the hyoid undergoes a segmented fusion sequence where each part matures and integrates on its own timeline.

Early in life, the body, greater horns, and lesser horns exist as distinct elements, connected more by cartilage and soft tissue than by solid bone.

As childhood progresses into adolescence, the body of the hyoid becomes increasingly ossified and structurally dominant, acting almost like a central anchor. The greater horns, which initially remain partially separate, begin to ossify more fully and move toward fusion with the body, typically in a posterior-to-anterior (back to front) and medial-to-lateral (center-outward) consolidation pattern. This process is gradual and not always symmetrical, meaning one side may appear more fused than the other at any given time.

The lesser horns follow an even more variable course. In some individuals, they begin to integrate with the body through fibrous or cartilaginous connections that may later ossify. In others, they remain partially or completely unfused well into adulthood, which is considered a normal anatomical variation rather than an anomaly. Because of their smaller size and more delicate structure, their ossification is often subtler and less consistently visible on imaging.

Through mid to late adolescence, what we tend to see is less of a “fusion event” and more of a progressive tightening and consolidation of the entire structure. The boundaries between the body and greater horns become less distinct, and the overall morphology shifts from a collection of parts into a more unified, horseshoe-shaped form. This is also the stage where the hyoid begins to exhibit more stable positioning in the neck, even though it still retains its characteristic mobility.

What’s particularly interesting is the fact that this fusion process is not purely structural, but it is also functionally influenced. The constant pull of the suprahyoid and infrahyoid muscles, along with repeated actions like swallowing and speaking, likely contribute to subtle remodeling and reinforcement at the junctions between components. Rather than being driven by a growth plate, the hyoid is shaped through a combination of ossification, mechanical forces, and integration with surrounding tissues.

By early adulthood, most individuals will show a partially to fully consolidated hyoid, particularly between the body and greater horns. However, complete fusion is not universal, and some degree of segmentation can persist without any impact on function. This variability is part of what makes the hyoid unique - it does not follow a rigid developmental script, but instead exhibits a range of normal outcomes within a shared structural framework.

Positional Descent and Spatial Reorientation

A key understanding of the hyoid bone through development is not just how it forms, but how it changes position within the neck over time. Early in life, the hyoid sits in a relatively high and anterior position, closer to the base of the mandible and the developing oral cavity. This elevated position reflects its close developmental and functional integration with early swallowing patterns and airway protection mechanisms.

As growth progresses, the hyoid undergoes a gradual inferior migration, effectively descending within the cervical region. This is not a sudden shift, but rather a slow and continuous adjustment that parallels overall craniofacial and cervical growth. The descent is closely tied to the vertical development of the face, elongation of the neck, and the expansion of the airway.

As the larynx descends during puberty, the hyoid follows a coordinated trajectory, maintaining its functional relationships with surrounding structures. Ossification rates also advance due to T influence, particularly in boys, which drives this descension of the larynx and the hyoid with it.

What makes this particularly important is that the hyoid is not simply relocating in space, it is maintaining a dynamic equilibrium. Its muscular attachments effectively “pull” it into functional positions depending on activity, posture, and development. This means that even as it descends, it remains functionally responsive, adjusting its position slightly with every swallow, breath, and vocalization.

Functional Biomechanics and Dynamic Anchoring

Biomechanically, the hyoid bone functions less like a rigid structural bone and more like a suspended biomechanical node. It does not articulate with any other bone which is unique in the human skeleton. Instead, it is held in place by a complex network of muscles and ligaments that create a balance of forces in multiple directions.

The suprahyoid muscles, such as the digastric, mylohyoid, and geniohyoid, tend to elevate and stabilize the hyoid, often pulling it upward during swallowing. In contrast, the infrahyoid muscles (including the sternohyoid, omohyoid, and sternothyroid) generally act to depress and reposition it. The interplay between these two groups creates a system where the hyoid is constantly being fine-tuned in real time.

This balance is especially evident during swallowing, where the hyoid undergoes a coordinated sequence of movements: anterior displacement, superior elevation, and temporary stabilization. This movement helps open the upper esophageal sphincter and protect the airway by elevating the larynx. In this way, the hyoid acts as a functional bridges between the respiratory and digestive systems, ensuring that these pathways remain coordinated and separated during critical moments.

Because of its suspended nature, the hyoid also distributes mechanical forces across multiple muscle groups. Instead of bearing load in a traditional sense, it serves as a tension-regulating structure, absorbing and redirecting muscular forces in a way that supports both movement and stability simultaneously.

Craniofacial Growth Relationships and Structural Integration in Biological Adulthood

The development and final positioning of the hyoid bone are deeply intertwined with broader craniofacial growth patterns. As the mandible lengthens and remodels during growth, the hyoid adapts in both position and orientation to maintain functional alignment with the airway and tongue.

One of the key relationships is with the vertical dimension of the face. Individuals with greater lower facial height often exhibit a more inferior hyoid position, while those with a shorter vertical pattern tend to have a relatively higher hyoid. This is not merely coincidental as it it reflects coordinated growth between skeletal structures and soft tissue function.

The hyoid is also closely linked to the development of the tongue, which plays a major role in shaping the oral cavity and influencing jaw position. As the tongue grows and changes position, it exerts subtle but continuous influence on the hyoid through muscular and connective tissue attachments. These relationships are often evaluated in cephalometric analysis, where the hyoid serves as a reference point for airway and skeletal relationships. Its position can provide insight into airway space, tongue posture, mandibular positioning, and overall facial growth direction.

Rather than being in isolation, the hyoid functions as part of a larger integrated system, where bone, muscle, and airway all influence one another in a continuous feedback loop.

Variability and Individual Structural Differences

Although the hyoid bone follows a general developmental pathway, its final form exhibits a significant degree of variability between individuals. This variability can be seen in its size, shape, degree of ossification, and even its symmetry.

In some individuals, the hyoid appears more broad and robust, with fully fused connections between the body and greater horns. In others, it may appear narrower or more segmented, with visible separation between components. These differences are not necessarily pathological, rather they often reflect normal variation in developmental timing and mechanical influences.

Asymmetry is also relatively common. One side of the hyoid might show more advanced ossification or fusion compared to the other, particularly during adolescence, which is normal. This reflects the fact that the forces acting on the hyoid are not always perfectly symmetrical, as muscle usage and growth patterns can differ subtly between sides of the body.

Even in adulthood, variation persists. Some individuals retain a degree of separation between the body and lesser horns, while others exhibit near-complete fusion. This spectrum highlights the hyoid’s identity as a functionally adaptive structure rather than a rigidly standardized one.

Sexual Dimorphism and Pubertal Influence

During puberty, the hyoid bone undergoes changes that are influenced by broader hormonal and structural shifts. In general, males tend to develop a larger and more inferiorly positioned hyoid, while females often retain a slightly higher position relative to the mandible.

This difference is closely tied to the development of the larynx, which enlarges more significantly in males, contributing to the deepening of the voice. As the larynx grows and descends, the hyoid follows this trajectory to maintain its functional relationship with the airway.

Hormonal influences, particularly androgens, play a role in these changes by affecting both skeletal growth and muscle mass. The result is a system where the hyoid becomes part of a broader transformation of the neck region, reflecting changes in both structure and function.

Despite these general trends, there is still overlap between individuals, and the hyoid should not be viewed as a strict indicator of sex. Instead, it represents one component within a continuum of anatomical variation influenced by multiple factors.

Clinical and Functional Relevance

The hyoid bone holds important clinical significance due to its central role in airway protection and swallowing mechanics. Because it is suspended and relatively mobile, it can be vulnerable to injury under specific circumstances, particularly those involving direct compression.

In forensic contexts, fractures of the hyoid are often associated with significant neck trauma, although the likelihood of fracture depends on factors such as age, ossification, and bone density. In younger individuals, the hyoid is more flexible and less likely to fracture, whereas in older individuals it becomes more rigid and susceptible to injury.

Clinically, the hyoid is also a key landmark in procedures involving the airway, neck anatomy, and surgical approaches. Its position can influence airway patency and is sometimes evaluated in sleep-related breathing disorders, where positional relationships between the hyoid, tongue, and airway structures become especially relevant.

Ultimately, the hyoid’s importance lies not merely in its size, but in its central role within a tightly coordinated system that governs essential life functions like breathing, swallowing, and speech.

Conclusion

In its greater whole, the hyoid represents a structure that resists simple categorization within skeletal development, forming not through a single linear growth plate-driven process but through a coordinated sequence of pharyngeal arch contributions, segmented ossification, and gradual structural consolidation.

Across childhood and adolescence, it transitions from a loosely organized cartilaginous framework into a partially or fully fused yet inherently mobile structure whose final form reflects both its embryologic origins and the mechanical forces acting upon it, while its positional descent mirrors broader craniofacial and airway development and its variability highlights the range of normal anatomical outcomes. Functionally, it operates as a central anchoring point connecting the tongue, airway, and laryngeal system, enabling coordinated swallowing, speech, and breathing through a finely tuned balance of muscular forces, and ultimately stands as a dynamic, responsive interface between structure and function rather than a static skeletal element. It really is a beautiful structure.

It's a new model, and it's got quite a few strengths. Only weaknesses are it's a rough estimate and not a prediction (notice how I left out PAH for predicted adult height), accuracy is dependent on BA quality, and results may vary depending on what reference group is selected. It's a neat little tool.

https://bonexpert.com/ahp/

Growth isn't linear, nor is it ever perfectly steady. From a distance, everything seems to be an upward curve, but once you get up close, you tend to see numerous upticks, downticks, peaks at two separate intervals - maybe seemingly more than one. It's essentially a weird curve that can be more "predictable" in the sense that you can keep track of it and know where your trajectory is potentially headed. But, knowing for sure is difficult.

I made a post going over the PHV vs the sustained high, and how both of them tend to overlap. But, I realized maybe this would help - understanding the rolling average velocity. This simple calculation could help save you months of confusion: when was my PHV? When did I start to taper? How long did I sustain my rapid growth? Let this bother you no longer.

The four easy steps: all you need to do is remain consistent with your daytime measurements, keep track of postural differences, have someone measure you using either a stick ruler or a stadiometer, and include a small error margin (±0.1-0.3 cm) for each measurement.

Step 1) Pick the time of day. You can do morning, afternoon, or evening measurements as long as you don't deviate wildly from your sleep schedule. Ideally, maintaining an 8-10 hour sleep schedule on average is best for tracking long-term height increases. For best results, record your wake up and sleep times for every measurement to maintain high accuracy, and note any lifestyle changes that happened within the last few months (dietary, physical, etc).

Step 2) Postural differences matter. Consistently sedentary individuals tend to lose less height throughout the day than consistently physically active people. As long as you're moving and standing at varying periods throughout the day, you're going to lose a little more height than you would have just sitting all day. Understand your own fluctuations, and keep this consistent.

Step 3) Instead of measuring yourself, have someone else do it for you, and ideally someone who is your height or taller. Measuring yourself can create subtle yet meaningful inaccuracies because of a few reasons:

• Reaching your arm up to mark a point where your head touches the wall can alter your posture temporarily.

• What I call "standing at attention": this military-appearning stance can alter your posture slightly. Relax, and don't spread your shoulders. Don't lock your knees or strain your back. Look straight ahead and keep your chin parallel with the floor plane / not leaning up or tilting down. Keep your arms pinned comfortably at your sides, and of course, take your shoes off and press your heels against the wall, back pressed gently on the surface.

Avoid the floppy plastic rulers. They bend under slight pressure. Instead, use a hard stick ruler and have a friend or family member (or a stranger) carefully mark the spot on the wall where the top of your head best aligns, then plant the ruler and hold it firmly against the wall, adjacent to this spot. Stadiometers are by far the most accurate tool to use when used under the right conditions.

Step 4) After each measurement is taken, give a random error margin for safety. This isn't of utmost importance, but it's still useful to secure the accuracy.

Why is the rolling average important?

Well, to keep it short, it reduces the frequency of catching false "mini peaks" or dips, and using it prevents the graph from looking jagged. With the method, your graph becomes a lot smoother, the true PHV is more discernible as well as the tapering sequence, and short-term fluctuations are minimized. I know none of you want to see these random, weak inflections followed by oddball dips and the occasional "mini peak" that most likely never existed during the taper in the first place. Most of you would want something clean and something sharply clear.

Window timing + tips

Keep your measurements spread out over several months, not just days.

In early puberty, it becomes more useful for measurement frequency to be increased from once or twice a year to three or four times a year. This helps catch the "early-pubertal rise" in action, tracking any upticks and the lead-up into PHV itself. Since GH production inherently fluctuates (especially in puberty), you will probably see some downticks here and there, but it's mostly blended with the overall rise toward the peak. What you want to track is that slope - a steady rise, or sharper depending on your growth tempo. It's a good idea to keep measurements relatively timely and every 3-6 months.

In mid puberty, pay attention to how early or late the peak comes. This will give you an idea of your pattern. Ideally, it's good to start measuring a little more frequently - maybe every 2-3 months at the minimum with a sharper eye being kept on the four steps above - to catch when you entered your PHV. Most boys enter this PHV about 18-30 months after puberty onset and most girls enter it about 12-18 months after puberty onset, but some can start a few months earlier or later. Here is where you can find your highest sustained velocity and your highest velocity overall - the PHV. These often overlap, and the sustained velocity tends to present itself shortly before, during, and shortly after the PHV. The PHV tends to last only a couple to a few months, while the sustained tends to last several more months to around a year or so longer than the PHV.

In late puberty, it's often reasonable to start tracking a bit less often. Every 6-12 months or so, sometimes longer if there are no noticeable gains occurring. This can help you track your taper and find roughly when you flattlined. Wait another 1-2 years to know whether you have truly attained your FAH or not, assuming no increases were recorded whatsoever. It is important to make measurements even less frequent, often about once or twice a year. Too frequent sessions can create "pseudo gains" that were actually never there from residual skeletal growth at all. This growth is best tracked as occurring over a ~6-12+ month window to be considered "true tail-end growth".

The formula

Keeping it simple and easy to maintain, take your height right now, subtract that from your height a few months ago, then divide that by the time between the two.

V = 🔺️h / 🔺️t

Velocity equals the height change over the time change.

For example: 74.8 inches (current), minus 69.6". The answer is 5.2 inches. Now, let's say you grew that much in 9 months, which is 0.75 years. Divide 5.2 by 0.75 to get ~6.93 in/yr. That's your sustained velocity. To convert months to years, just do 9 months divided by 12 and you get the fractional component.

Doing this consistently helps you find the average overall. So, assuming measurements get done every 3 months, let's bake up another random chart:

Age 14Y 0M - 61.4 inches

Age 14Y 3M - 62.1 inches

Age 14Y 6M - 63.5 inches

Age 14Y 9M - 64.2 inches

Age 15Y 0M - 65 inches

Gains:

14.0-14.25 - ~0.7 inches (lead-up)

0.7 / 0.25 = ~2.8 in/yr

14.25-14.5 - ~1.4 inches (PHV)

1.4 / 0.25 = ~5.6 in/yr

14.5-14.75 - ~0.7 inches (immediate taper)

~2.8 in/yr

14.75-15.0 - ~0.8 inches (mild uptick)

0.8 / 0.25 = ~3.2 in/yr

You can see exactly where the PHV happened - ages 14Y 3M to 14Y 6M. Followed by this is continued high-velocity growth for multiple months, showing mild tapering despite being well below peak levels. The early post-peak growth period tends to have consistent moderately strong gains with no significant deviation from a certain average (say 2-3 in/yr), but the nature is clearly no longer peak standard.

You don't want an erratic growth chart. Most of you want solid answers and solid estimates. This will help keep your growth on point tremendously. If your measurements are noisy or inconsistent, a rolling window helps separate real growth trends from measurement error.

BONUS (to help even further) - different types of growth curves and what they look like on a graph (in adolescence):

Monophasic pattern - from a distance, this curve is largely non-descript. It's often S-shaped, has a notable rise, a discernible singular peak, and a gradual decline to the flattline a small number of years later. The tapering pattern most often follows a gradual decline throughout, with potentially stronger dips depending on the frequency of each measurement.

Good idea to use a 3 to 6-month rolling window to identify the magnitudes and durations of the peak and the sustained high, and specific tapering start points. The rolling average basically reveals one clear PHV by smoothing out minor dips that would otherwise look like multiple peaks.

Biphasic pattern - from a distance, it looks like two distinct peaks. However, once you look even closer, you might see that one of those peaks is not a true peak after all. The difference in the two velocities is often small, and may be separated by a mild taper before the next notable rise, reaching velocities very close to the true PHV before tapering off for good.

Good idea to use both a short 3-month rolling window to catch sharper local peaks and a longer 6-month window to identify the true PHV. Yes, using both works and catches both simultaneously. Rolling averages help distinguish whether the second peak is a true PHV or just a temporary fluctuation.

Recovery pattern - from a distance, things look typical. Just numerous "bumps" - looks like normal fluctuations. But, when you look at it a bit more, you will see that these "upticks" might be fairly significant, especially if they occurred during the peak growth period. Depending on how intense these upticks are, the graph might seem messy - sometimes separate from the peak as a true dip, followed by a sharp rebound. As the taper continues, though, the frequency and magnitude of these upticks often declines gradually as growth comes to a stop, especially later on in the taper.

Good idea to use a slightly longer 4 to 6-month rolling window to smooth out noise and for comparison over time. For irregular growth, rolling averages help separate real growth trends from short-term spikes that can look like peaks but aren’t sustained.

Compressed PHV - from afar, everything from the lead-up to the PHV itself is visually dramatic and dynamic - almost completely vertical. The obvious, sharp rise, the explosive peak, and the energetic decline, potentially calming down at some point depending on the person.

Good idea to use a much shorter 2 to 3-month rolling window. During peak growth, this window can easily catch a whirlwind. Expect it to rise sharply, peak briefly, and potentially decline early before continuing a gradual decline (varies by individual tempo). It will essentially look like a narrow mountain on the chart. Be careful, though, because 2, 3, and 4 month windows can easily shake the interpretation, potentially missing the peak or trying to catch it too early. It's often very fast, so just remain patient, and follow this rolling window of 2-3 months.

Blunted / low-magnitude PHV - looking from afar, the graph looks standard and maybe a bit smoother than what you'd see on the "textbook curve". Often, it appears to taper quickly, especially in girls and faster maturers. Your suspicions might be confirmed once you take a closer look and notice that this peak wasn't so strong after all. Usually, peaks like these involve a gradual, "steady" rise into the peak, followed by a gradual taper.

Good idea to use a longer 6 to 9-month rolling window to reduce noise and focus on the relative maximum, since the curve tends to extend farther down than usual. Even if PHV isn’t very pronounced, a rolling average can still highlight the subtle peak that defines the growth spurt. Very important for not missing the PHV.

Prolonged PHV - from afar, the curve appears to go on for a long time. It's smooth, often low to the ground, and continues to drag on so far along the chart that the taper almost whispers along unnoticed. You might double back and wonder where this slowdown even started. This is also what I like to call the "incremental pattern"; structurally similar to the blunted pattern, but different in tapering style.

Good idea to implement multiple rolling windows: 3 months to show local peaks, 6 months to show a sustained high, and 9-12 months to show the overall plateau. In prolonged PHV patterns, rolling averages show that the "peak" is actually a plateau of sustained high velocity rather than a sharp spike.

The early-tapering phase is often the most gradual part of the taper - still mildly or moderately fast post-PHV growth. Dips later on in the taper (as major growth plates are closing) might change the apparent angle of the curve along the X-axis.

Subpatterns of PHV timing rather than an identifiable growth pattern:

Early peak - an early, distinguishable peak on the otherwise monophasic curve. For most people, more growth remains from the end of PHV to cessation- about 2-4 years worth (sometimes slightly more) and ~3-5 inches or so of post-PHV growth in total (sometimes a bit more; typically not more than 6 inches).

Late peak - a late, distinguishable peak on the monophasic curve. Slightly less post-peak growth remains on average, usually about 2-3 inches, but this varies significantly.

• A delayed rise will simply appear "smoother" before rising.

• An early rise will often approach the climax slightly earlier and have less time to appear "smooth" early on.

● The angle of the curve (visual interpretations ONLY; varies by the units along each axis, the scaling, and the window being looked at): shallow, flat, or low-sloping for mildly strong ramp-ups into PHV (less extreme diagonally), noticeably inclining or consistently sloping for moderately strong ramp-ups (more elevated diagonally), and "skyrocketing" for very strong ramp-ups (very steep and nearly vertical), which fits faster or more compressed peak growth patterns.

Once you have your growth chart largely established, it's good to go through and test each rolling window on your data to see what pattern you may have had. And that's what's so sweet about this. It helps a ton!