ANATOMY BASICS TERMS

Anatomical Position

• Always the reference pose for description, no matter how a person is actually standing.

  • Upright stance, eyes looking forward.

  • Arms hanging at sides, palms facing forward, thumbs pointing away from trunk.

  • Feet slightly apart, parallel, toes pointing forward.

Core Directional Terminology

Anterior ↔ Posterior

• Anterior (ventral/front): Structure is in front of another.

  • Ex: Toes are anterior to heels.

• Posterior (dorsal/back): Structure is behind another.

  • Ex: Heel is posterior to toes.

Ventral ↔ Dorsal

• Ventral: Toward the belly (Latin venter).

• Dorsal: Toward the back (Latin dorsum).

  • Ex: Kneecap sits on ventral side of knee; popliteal fossa on dorsal side.

Left ↔ Right

• Determined relative to the person in anatomical position—never the observer.

  • Ex: Right lower limb vs. left lower limb.

Proximal ↔ Distal

• Proximal: Closer to trunk or point of origin.

• Distal: Farther away from trunk or point of origin.

  • Ex: Elbow joint is proximal to wrist; fingers are distal to elbow.

Medial ↔ Lateral

• Defined relative to the body’s midline (median).

  • Median (mid-sagittal) plane is the hypothetical line splitting body into equal left & right halves.

• Medial: Toward midline.

• Lateral: Away from midline.

  • Ex: Nose is medial to eyes; ears are lateral to eyes.

Superior ↔ Inferior (Cranial ↔ Caudal)

• Superior (cranial/supra-): Above.

• Inferior (caudal/infra-, hypo-, sub-): Below.

  • Ex: Nose is superior to mouth; mouth is inferior to nose.

  • Prefix usage examples:

  • Supraclavicular lymph nodes $\text{(supra = superior)}$ lie above clavicle.

  • Infraorbital artery $\text{(infra = below)}$ lies inferior to orbit.

  • Hypoglossal nerve is inferior (under) tongue; submandibular nodes are under mandible.

Superficial ↔ Deep

• Superficial: Near surface (usually skin).

• Deep: Further from surface.

  • Ex: Superficial vs. deep gluteal muscles.

External ↔ Internal (Outer ↔ Inner)

• External: Outside of a structure.

• Internal: Inside of a structure.

  • Ex: Stomach

Anatomical Position

• Always the reference pose for description, no matter how a person is actually standing.

• Upright stance, eyes looking forward.

• Arms hanging at sides, palms facing forward, thumbs pointing away from trunk.

• Feet slightly apart, parallel, toes pointing forward.

Core Directional Terminology

Anterior

Posterior

• Anterior (ventral/front): Structure is in front of another.

• Ex: Toes are anterior to heels.

• Posterior (dorsal/back): Structure is behind another.

• Ex: Heel is posterior to toes.

Ventral

Dorsal

• Ventral: Toward the belly (Latin venter).

• Dorsal: Toward the back (Latin dorsum).

• Ex: Kneecap sits on ventral side of knee; popliteal fossa on dorsal side.

Left

Right

• Determined relative to the person in anatomical position—never the observer.

• Ex: Right lower limb vs. left lower limb.

Proximal

Distal

• Proximal: Closer to trunk or point of origin.

• Distal: Farther away from trunk or point of origin.

• Ex: Elbow joint is proximal to wrist; fingers are distal to elbow.

Medial

Lateral

• Defined relative to the body’s midline or sagittal planes.

• Medial: Toward midline.

• Lateral: Away from midline.

• Ex: Nose is medial to eyes; ears are lateral to eyes.

Superior

Inferior (Cranial

Caudal)

• Superior (cranial/supra-): Above.

• Inferior (caudal/infra-, hypo-, sub-): Below.

• Ex: Nose is superior to mouth; mouth is inferior to nose.

• Prefix usage examples:

  • Supraclavicular lymph nodes $\text{(supra = superior)}$ lie above clavicle.

  • Infraorbital artery $\text{(infra = below)}$ lies inferior to orbit.

  • Hypoglossal nerve is inferior (under) tongue; submandibular nodes are under mandible.

Superficial

Deep

• Superficial: Near surface (usually skin).

• Deep: Further from surface.

• Ex: Superficial vs. deep gluteal muscles.

External

Internal (Outer

Inner)

• External: Outside of a structure.

• Internal: Inside of a structure.

• Ex: Stomach

Planes of the Body

• Sagittal Plane: A vertical plane that divides the body or an organ into left and right parts.

  • Median (Midsagittal) Plane: A specific sagittal plane that lies exactly in the midline, dividing the body into equal left and right halves.

  • Parasagittal Plane: Any sagittal plane parallel to the median plane but offset from the midline, dividing the body into unequal left and right parts.

• Coronal (Frontal) Plane: A vertical plane that divides the body or an organ into anterior (front) and posterior (back) parts.

• Transverse (Horizontal) Plane: A horizontal plane that divides the body or an organ into superior (upper) and inferior (lower) parts; often called a cross-sectional plane.