Chapter 4 – Bony landmarks and surface checkpoints

Chapter 4: Bony Landmarks & Surface Checkpoints

Created by Sarah Choi (prompt writer using ChatGPT)

Bony Landmarks & Surface Checkpoints

Why Bony Landmarks Matter for Creature Artists

You can think of bony landmarks as anchor points on a creature’s body—places where the skeleton comes close enough to the surface that it creates a reliable shape change, ridge, bump, or sharp plane. These landmarks are crucial for creature concept artists because they:

Give you consistent measuring points for proportion and perspective.
Help you keep anatomy solid even when you stylize muscles, fat, fur, armor, or scale.
Make poses, weight, and motion reads more believable, even in quick sketches.

Whether you’re on the concepting side (exploratory, loose, cinematic) or the production side (turnarounds, callouts, rig‑aware designs), knowing where the skeleton shows through is one of the fastest ways to improve structure.

This article focuses on Comparative Anatomy & Construction—how bony landmarks work across common vertebrate body plans and how to turn them into surface checkpoints you can quickly hit in your drawings.

1. What Are Bony Landmarks and Surface Checkpoints?

1.1 Bony Landmarks

Bony landmarks are points on the skeleton that are:

Close to the skin.
Not heavily covered by thick muscle or fat.
Often visible as edges, corners, ridges, or firm round bumps.

Examples in familiar anatomy:

The edge of the eye socket and brow ridge.
The angle of the jaw.
The bumps of the spine along the back.
The protrusion of shoulder blades, elbows, knees, and ankles.

These points don’t change much in volume—even when the creature gains weight or flexes—so they act as stable markers.

1.2 Surface Checkpoints

“Surface checkpoints” are practical drawing targets made from those landmarks. They are spots you deliberately place early in construction to:

Verify proportions (e.g., distance from skull base to shoulder joint).
Confirm angle and tilt (e.g., pelvis vs ribcage orientation).
Align limbs and joints in perspective.

In your process, checkpoints might be little crosses, circles, or plane changes. They keep your creatures from drifting into mushy, undefined forms.

2. Global Landmarks: The Big Structural Bones

Before zooming into regions, it helps to understand the big bones that underpin most vertebrate‑inspired creatures: skull, spine, ribcage, pelvis, scapulae, and major limb joints.

2.1 Skull

The skull provides:

Volume for the head and housing for the brain.
Anchor points for jaw muscles, facial structures, horns, and crests.

Key landmarks:

Brow/eye rim: plane break around the eyes.
Zygomatic arch (cheekbone): defines the side plane of the face.
Nasal bridge and snout ridge.
Jaw angle and jawline.
Occipital bump at the back of the skull.

These landmarks define head planes and give you consistent alignment for eyes, ears, horns, and beaks.

2.2 Spine

The spine runs from the base of the skull to the tail and is the main axis of the body.

Landmarks:

In many creatures, individual spinous processes (spine tips) create a ridge or line down the back.
The neck vertebrae create rhythm in the throat and back of neck.
Tail vertebrae create a segmented flow toward the tail tip.

Even under fur or armor, a subtle spine line helps you organize motion and gesture.

2.3 Ribcage

The ribcage forms the main barrel of the torso, protecting heart and lungs.

Landmarks:

The front top of the ribcage (where the neck meets the chest) often forms a notch or small plateau.
The side arcs of the ribs define the widest part of the chest.
The bottom edge of the ribcage creates a subtle plane break before the soft belly.

The ribcage gives you a reliable mass to attach shoulders, wings, and front limbs.

2.4 Pelvis

The pelvis is the foundation of the hindquarters.

Landmarks:

Iliac crests (hip bones) can show as high points or bumps at the rear of the torso.
The sacrum bridges pelvis and spine, creating a shape change at the base of the back.
Seat bones and acetabulum (hip sockets) inform the thigh’s origin.

The orientation of the pelvis relative to the ribcage is a major gesture tool: tilt it to show sitting, crouching, rearing, or striding.

2.5 Scapulae (Shoulder Blades)

Scapulae are highly visible in many animals.

They sit on the upper sides of the ribcage.
They slide and rotate with front limb motion.

In surface terms, scapulae look like moving planes or wedges that pop and disappear during strides.

2.6 Major Limb Joints

Key limb joint landmarks:

Shoulder/hip joints: where limbs plug into torso.
Elbows/knees: angular protrusions along limb mid‑segments.
Wrists/ankles: smaller but sharp changes in form.

These joints give you hinges in space—critical checkpoints for drawing limbs accurately in perspective.

3. Regional Landmarks: Head & Neck

3.1 Skull Planes and Facial Structure

Across mammals, reptiles, birds, and stylized creatures, you can rely on:

A hard brow ridge above the eyes.
A cheekbone arc defining the side plane.
A jawline running from chin to jaw angle.
A cranial dome (top of skull) with a clear curvature.

These create a boxy or wedge‑like head volume with clear corners. Even in stylized or armored skulls (dragon heads, helmets, etc.), echoing those corner points maintains believability.

3.2 Neck Vertebrae and Landmarks

The neck connects skull to torso and allows orientation of the head.

Landmarks:

The back of the neck often shows a subtle spine line.
The side of the neck may show built‑up muscles over transverse processes.
The front of the neck can be smoother or show laryngeal and tracheal structures in lean creatures.

Creatures with flexible necks (birds, serpentine monsters) still follow a segmented underlying structure—your surface checkpoints follow that S‑curve.

4. Regional Landmarks: Shoulders, Forelimbs & Wings

4.1 Shoulder Girdle and Scapula

In most quadrupeds and winged creatures, the shoulder zone includes:

Scapula sliding over the ribcage.
Humerus head buried deeper in the mass.

Surface checkpoints:

A plane change or plateau on the upper side of the ribcage where the scapula sits.
A moving ridge when the limb lifts or extends.

When drawing a run or pounce, placing scapular landmarks first helps align forelimbs correctly with the torso.

4.2 Elbows, Wrists, and Forepaws/Hands

Forelimbs usually follow a pattern: shoulder → upper limb → elbow → lower limb → wrist → hand/paw.

Bony landmarks:

Elbow: sharp point that often defines limb silhouette.
Wrist (carpal region): smaller bony cluster that forms a visible angle.
Knuckles / metacarpals: form the base of fingers or claws.

Checkpoints:

The relative distance from shoulder to elbow, elbow to wrist—great for proportion checks.
The angle of the elbow in relation to the ground and torso for weight support.

4.3 Wings and Their Skeletal Landmarks

Wings obey a modified limb pattern: shoulder → upper wing bone (humerus) → forearm → fused hand/digits.

Landmarks:

Shoulder joint where wing attaches.
Elbow of the wing: often visible both in birds and fantasy dragons.
Wrist/hand joint that defines the bend in the wing’s leading edge.

In surface drawing, you can use a simplified three‑point structure: shoulder, elbow, wrist; connect them to build convincing wing poses.

5. Regional Landmarks: Ribcage, Spine & Torso

5.1 Ribcage Outline

From the side, the ribcage forms a curved polygon:

Top: spine line.
Front: slanted plane toward the neck.
Bottom: arc where ribs end.

Surface checkpoints:

Highest point of the ribcage (often just behind the shoulders).
Lowest visible rib edge before the soft belly.

These help you maintain consistent torso thickness around limbs and armor.

5.2 Spine and Back Landmarks

The spine creates one of the most important gesture guides.

Checkpoints:

Mark the spine path from skull base → between scapulae → over ribcage → over pelvis → into tail.
Identify high and low points along the back for arches and dips.

In stylized creatures, you might exaggerate spines into ridges, plates, or fins, but they should still follow the underlying vertebral arc.

5.3 Chest and Sternum

On front chests (especially mammals and birds):

Sternum (breastbone) can create a central ridge or plateau.
Large pectoral muscles anchor to the sternum but the sternum itself defines a hard midline.

For winged creatures, a keel‑like sternum suggests powerful flight muscles; for quadrupeds, a subtler sternum gives you a central axis for front view construction.

6. Regional Landmarks: Pelvis, Hips & Hindlimbs

6.1 Pelvis Shape and Hip Points

The pelvis is often less obvious than the ribcage but equally important.

Landmarks:

Iliac crests can appear as bumps or ridges on the sides of the hips.
The top of the pelvis sits where the lower back transitions to the hindquarters.

Using these points:

Align hindlimbs correctly.
Show tilt or twist in the hips (for locomotion, turning, crouching).

6.2 Thigh, Knee, and Lower Leg

Hindlimb pattern: hip → thigh → knee → shank → ankle → foot.

Bony landmarks:

Greater trochanter (upper thigh bump near hip) sometimes shows as a subtle bulge.
Knee joint: a prominent angle in most quadrupeds.
Ankle joint (often mistaken for the knee in digitigrade creatures).

Checkpoints:

Clear placement of the knee relative to torso and ground plane.
Correct length relationships: thigh vs shank vs foot.

Identifying the true knee and ankle prevents classic mistakes in creature leg construction.

6.3 Hock and Heel in Digitigrade Limbs

In many fantasy creatures (and real predators), the hindlimb is digitigrade—the creature walks on its toes.

Landmarks:

Hock (ankle area) forms a backward‑bending angle.
Heel bone (calcaneus) may be visible as a bump at the back of the hock.

Marking these checkpoints early keeps poses structurally believable and helps animators understand where joints bend.

7. Regional Landmarks: Hands, Feet, Claws & Tails

7.1 Hands and Forepaws

Even with claws, paws, or hybrid appendages, the underlying structure often includes:

Metacarpals (palm bones) forming a block.
Phalanges (finger bones) extending out.

Surface landmarks:

Knuckle bumps for each digit.
Back‑of‑hand planes defined by extensor tendons.

These checkpoints help you pose grasping hands, splayed claws, and weight‑bearing paws in perspective.

7.2 Feet and Hindpaws

Hind feet mirror hands structurally but are often more robust.

Landmarks:

Ball of the foot/paw.
Toe knuckles.
Heel area (plantigrade) or raised heel (digitigrade, seen as hock region).

In contact poses, place these anchors firmly on the ground plane to sell weight and balance.

7.3 Tails and Caudal Vertebrae

Tail structure depends on length and function:

Long, flexible tails: many small vertebrae.
Short, stiff tails: fewer, thicker vertebrae.

Checkpoints:

Tail base alignment with pelvis/spine.
Key bends where major vertebra clusters might be.

Even with fins, feathers, or spikes, keeping a believable tail vertebral arc makes motion more convincing.

8. Comparative Landmarks Across Vertebrate Types

8.1 Mammal‑Based Creatures

Clear scapula, ribcage, pelvis separation.
Prominent elbows, knees, and hocks.
Often visible spine line and skull planes even under fur.

8.2 Reptile‑Based Creatures

Strong jaw and skull ridges.
Flatter, broader ribcage plates.
Ridges over spine and tail vertebrae.
Less obvious scapula surface, but clear limb joint angles.

8.3 Bird‑Based Creatures

Keel sternum (big chest) for fliers.
Thin but distinct leg bones (tibiotarsus, tarsometatarsus) forming visible landmarks.
Wing joints: shoulder, elbow, wrist visible as bends in wing silhouette.

8.4 Amphibian‑Based Creatures

Softer, rounder bony landmarks.
Still, subtle knee, elbow, and skull landmarks exist and help ground the design.

8.5 Fish‑Based Creatures

Skull landmarks around eyes and jaw.
Spine and fin base origins as structural guides.
Rib hints and vertebral flow along the body.

Knowing these differences helps you shift the visual language of “boniness” depending on the creature’s base.

9. Using Landmarks in Construction, Gesture & Perspective

9.1 Landmarks as Measurement Tools

When constructing a creature:

Place key bony checkpoints early: skull base, shoulder joints, ribcage widest point, pelvis top, hip joints, knee/elbow positions.
Use them to measure:
- Head height vs body length.
- Torso depth vs limb length.
- Joint spacing along limbs.

This keeps proportions under control even when you push stylization.

9.2 Landmarks as Gesture Anchors

Gesture doesn’t fight structure; it rides on it.

Use spine, pelvis, and ribcage landmarks to define the primary line of action.
Place joints (shoulders, hips, knees, elbows) along that line to express weight and direction.

Even with loose sketching, dropping a few accurate bony checkpoints can correct drift in your gesture.

9.3 Landmarks in Foreshortening

In foreshortened poses, landmarks help you keep forms coherent:

The distance between shoulder and elbow may visually shrink, but you still track those points in 3D.
Use circles, boxes, or ellipses for each landmark in perspective before wrapping muscles and skin.

This makes dynamic angles (creatures lunging at camera, diving, twisting) more controllable and production‑friendly.

10. Concepting vs. Production: Different Levels of Precision

10.1 On the Concepting Side

Concepting is fast and impressionistic, but landmarks still matter:

Hit a few key checkpoints per sketch: skull planes, spine line, scapula/hip clusters, major joints.
Let muscles and details stay loose; structure keeps the design believable.
Use landmarks to quickly prototype variant proportions (longer legs, deeper chest, higher hips) without losing coherence.

You don’t need to show bones explicitly, but your brushstrokes should be informed by their presence.

10.2 On the Production Side

Production requires clarity and consistency:

In orthos and turnarounds, lightly indicate bony landmarks under the surface.
Show how armor, fur, or scales relate to those checkpoints (where they flex, where they’re anchored).
Ensure joint placement and limb lengths match across front, side, and back views.

Include labeled callouts when necessary (e.g., “scapula here,” “hip rotation center here”) to guide rigging and modeling.

11. Practical Exercises: Training Your Eye for Landmarks

11.1 Landmark Tracing from Reference

Take photos of animals or creature sculpts.
On a layer above, trace key bony landmarks: skull corners, spine, scapulae, ribcage, pelvis, major joints.
Then hide the photo and attempt to reconstruct the creature using only your landmarks.

This trains you to see structure underneath surface detail.

11.2 Landmark‑Only Gesture Pages

Fill a page with quick gesture poses.
Instead of full shading, focus only on:
- Spine path.
- Ribcage and pelvis blocks.
- Shoulder/hip markers.
- Elbow, knee, wrist, ankle dots.

See how readable the pose is even with minimal information. If it reads well, your structural sense is strong.

11.3 Comparative Landmark Studies

Choose three different base animals (e.g., wolf, eagle, lizard).
Map their bony landmarks.
Design one hybrid creature that combines landmark rhythms from all three.

You’ll start to build an intuitive library of how different skeleton types show up on the surface.

11.4 Armor & Landmark Overlays

For an armored creature:

Sketch the underlying skeletal landmarks first.
Then design armor plates that respect those landmarks (hinges over joints, rigid plates over broad bones, flexible sections over soft tissue).

This results in armor that moves believably with the body.

12. Bringing It All Together

Bony landmarks and surface checkpoints give you a structural backbone for your creature drawings—literally and figuratively. They’re the reference points that:

Keep proportions and perspective consistent.
Ground your stylization in believable anatomy.
Communicate motion, weight, and joint behavior to downstream teams.

For both concepting and production creature artists, the workflow can be summarized as:

Identify the base body plan (mammal, reptile, bird, etc.).
Place key landmarks (skull corners, spine, ribcage, pelvis, major joints) as checkpoints.
Build gesture and volume around those checkpoints.
Layer muscles, skin, fur, scales, and armor on top, always referencing the underlying structure.

Whenever a creature feels wobbly, off‑balance, or “made of jelly,” pause and ask:

Did I anchor the head, spine, ribcage, and pelvis with clear landmarks?
Are my joints located and oriented in ways that support the pose?
Does the surface respect those structural points, or is it sliding around arbitrarily?

If you keep returning to these questions, bony landmarks will become natural waypoints in your drawing process—and your creatures will feel more solid, expressive, and ready for the demands of a real production pipeline.