Arms

7 structured phenotype dimensions · drawn from peer-reviewed scales

Elbows

General Description: Elbows are the joints connecting the upper and lower parts of the arms. They are pivotal for arm movement and dexterity.

Ethnic Variations: While elbow functionality is universal, the size and angular shape of elbows can vary subtly among different ethnic groups.

Cultural Significance: Elbows are often not culturally accentuated but are essential for many functional and expressive gestures.

AI Character Design Considerations: In AI character design, elbow joints should be articulated accurately to allow for natural and diverse arm movements.

Arms — taxonomy

7 dimensions · 7 photo-assessable · v1.0.0 · UBERON: UBERON:0001460

Upper-extremity morphology: arm length, upper arm and forearm circumference, biceps definition, brachioradialis visibility, cubital alignment. Splits the original 'Limb' atlas category into separate arms.json + legs.json files for finer-grained morphology. Dimensions are drawn from sports-medicine and anthropometry literature.

Dimensions

Arm length (proportional)
partly photo-observable
ordinal · arm_length_qualitative
Total arm length (acromion to fingertip) relative to torso length.
Aligned with anthropometry descriptors of upper-extremity proportional length relative to torso.
Valid values (3)
- shortShort— Arms appear short relative to torso.
- balancedBalanced— Standard proportional arm length.
- longLong— Arms appear long relative to torso.
Upper arm circumference (relative)
photo-observable
ordinal · upper_arm_girth_qualitative
Upper arm girth at mid-bicep, qualitative bucket.
Aligned with anthropometry descriptors of mid-bicep circumference relative to forearm.
Valid values (4)
- slenderSlender
- averageAverage
- muscularMuscular
- very_muscularVery muscular
Biceps definition
photo-observable
ordinal · biceps_definition_qualitative
Visible biceps definition (separation between biceps brachii and surrounding tissue).
Aligned with sports-medicine descriptors of brachial musculature visibility.
Valid values (4)
- minimalMinimal— Biceps not visible as a discrete landmark.
- moderateModerate— Biceps visible under tension only.
- definedDefined— Biceps clearly visible at rest with separation from triceps.
- highly_developedHighly developed— Pronounced biceps mass with peak definition.
Forearm circumference (relative)
photo-observable
ordinal · forearm_girth_qualitative
Forearm girth at maximum proximal circumference.
Aligned with anthropometry descriptors of forearm girth.
Valid values (4)
- slenderSlender
- averageAverage
- muscularMuscular
- very_muscularVery muscular
Brachioradialis visibility
partly photo-observable
ordinal · brachioradialis_qualitative
Visibility of the brachioradialis muscle as a distinct surface landmark on the lateral forearm.
Surface-anatomy descriptor aligned with sports-medicine and aesthetic-anatomy literature.
Valid values (3)
- not_visibleNot visible
- subtleSubtle— Visible under tension only.
- definedDefined— Clearly visible at rest.
Cubital (carrying) angle
partly photo-observable
categorical · carrying_angle_qualitative
Angle between the upper arm and forearm at the elbow when the arm is extended and supinated. Sex-dimorphic and individually variable.
Aligned with orthopedic descriptors of the elbow carrying angle. Reference: typical female ~10-15° valgus, male ~5-10° valgus.
Valid values (4)
- minimal_straightMinimal / straight— Arm extends nearly straight; carrying angle <5°.
- normal_male_rangeMale-typical range (~5-10°)
- normal_female_rangeFemale-typical range (~10-15°)
- pronouncedPronounced (>15°)— Substantial valgus; cubitus valgus when extreme.
Shoulder-to-arm proportion
photo-observable
categorical · shoulder_arm_proportion_qualitative
Relative dominance of shoulder breadth versus arm girth — captures the V-shape silhouette differently from torso.json's shoulder_breadth dimension.
Aligned with artistic-anatomy proportional descriptors.
Valid values (3)
- shoulder_dominantShoulder-dominant— Shoulders pronounced relative to arm girth.
- balancedBalanced
- arm_dominantArm-dominant— Arm girth pronounced relative to shoulder breadth.

References (2)

Standring S (ed.) (2020). Gray's Anatomy: The Anatomical Basis of Clinical Practice, 42nd Edition. Elsevier.
Paraskevas G, Papadopoulos A, Papaziogas B, Spanidou S, Argiriadou H, Gigis J (2004). Study of the carrying angle of the human elbow joint in full extension. Surgical and Radiologic Anatomy, 26(1).