Anatomical Position and Directional Terms

Anatomical Position (AP)

AP is the reference position used to describe the location of anatomical parts and to describe and explain human movement.

The subject is:• standing upright with feet flat on the floor• arms at the side of the body• facing the observer• palms are facing forward (supinated)

Anatomical Position

Directional TermsNote: the midline is an imaginary vertical line that divides

the body into equal left and right sidesAbduction• occurs when a body part is moved away from the

midline of the body• e.g. shoulder, hip, fingersAdduction• occurs when a body part is moved toward the midline

of the body• e.g. shoulder, hip, fingers• remember “add to your midline”• e.g. shoulder, hip, fingers

Directional Terms

Anterior (ventral): nearer to or in front of the body• e.g. the sternum is anterior to the heart• Bilateral• Refers to both sides of the body• e.g. The victim in the car crash suffered bilateral tibia

fractures.

• Contralateral• Refers to the opposite side of the body• e.g. He has hurt his left knee before, but no history of

contralateral injury.

Skeletal System

• Appendicular• The section of the skeleton referring to the arms

and legs.

• Axial• The section of the skeleton referring to the head

and trunk.

Skeletal System

• Bone• The hard connective tissue that forms the

skeleton of vertebrates.

• Bursa• A fluid filled sac that reduces friction.

• Cartilage• Connective tissue that covers the ends of bones

Coronal plane• vertical plane that cuts the body into anterior

(front) and posterior (back) partsDeep: farther away from the surface of the body• e.g. the ribs are deep to the skin of the chestDistal: farther from the attachment of an

extremity (limb) to themtrunk; farther away from the point of origin

Dorsiflexion: Flexion of the foot in an upward direction.

• eg. Pulling your toes towards your noseEversion• turning the sole of the foot outward at the

ankle (so the sole of the foot faces away from the midline)

Extension• extension at a joint results in an increase of

the angle between the two segments that meet at that joint

• if the movement occurs beyond the extended position, the action is called hyperextension

• eg- To straightenExternal Rotation: Rotation away from the

midline

Fascia: Connective tissue that covers muscleFlexion• flexion at a joint results in a decrease of the

angle between the two segments that meet at that joint

• eg- to bendInferior: farther away from the head. Situated

below• e.g. the stomach is inferior to the lungs

Pronation• rotation of the forearm and hand to the palms

down positionProne• Lying face downProximal: nearer to the attachment of an

extremity (limb) to the trunk; nearer to the point of origin

• e.g. the humerus is proximal to the radius

Rotation• the movement of a bone around its own axis; this

is also known as a pivot• e.g. the head, neck, and trunk can pivot around

the longitudinal axisSagittal plane• a vertical plane that cuts the body into right and

left sidesSuperficial: on or near the surface of the body• e.g. the skin is the most superficial organ of the

body

Superior: nearer the head• Situated above• e.g. the heart is superior to the liverSupination• rotation of the forearm and hand to the palms up

position (remember holding a cup of “soup”)Supine• Lying face up• “Supine your on your spine”

Tendons• Connect muscle to boneTransverse plane• horizontal plane that cuts the body into

superior and inferior partsPosterior (dorsal): nearer to or at the back of

the body• e.g. the esophagus is posterior to the trachea

Planes of the Body

Directional Terms

Anterior (ventral): nearer to or in front of the body

• e.g. the sternum is anterior to the heartPosterior (dorsal): nearer to or at the back of

the body• e.g. the esophagus is posterior to the trachea

Directional Terms

Note: the midline is an imaginary vertical line that divides the body into equal left and right sides

Superior: nearer the head• e.g. the heart is superior to the liverInferior: farther away from the head• e.g. the stomach is inferior to the lungs

Directional Terms

Medial: closer to the midline of the body• e.g. the ulna is on the medial side of the

forearmLateral: farther away from the midline of the

body• e.g. the ear is lateral to the nose in all

individuals

Directional Terms

Proximal: nearer to the attachment of an extremity (limb) to

• the trunk; nearer to the point of origin• e.g. the humerus is proximal to the radiusDistal: farther from the attachment of an extremity

(limb) to themtrunk; farther away from the point of origin

• e.g. the phalanges are distal to the carpals (wrist bones)

Directional Terms

Superficial: on or near the surface of the body• e.g. the skin is the most superficial organ of

the bodyDeep: farther away from the surface of the body• e.g. the ribs are deep to the skin of the chest

Planes of Motion and Axes

• Biomechanics is the study of human movements through the use of physics. As such, biomechanics has its own language and terminology. The language of biomechanics establishes a common reference system of standard terms. Planes and axes of motion are an important part of this language.

Planes of MotionA plane of motion can be defined as the two dimensional space

cut by a moving body or the plane along which movements occur. There are generally three planes used to describe segmental and body movements in physical activity. These are:

Sagittal plane• a vertical plane that cuts the body into right and left sidesFrontal plane• vertical plane that cuts the body into anterior (front) and

posterior (back) partsTransverse plane• horizontal plane that cuts the body into superior and inferior

parts

Anatomical Planes

Anatomical Axes

An axis is the point about which rotation of a body or of a body segment occurs. There are three axes of rotation. Each axis is associated with a plane of motion and the axis is perpendicular to that plane.

Horizontal axis (…think East and West)• passes through the body from side to side• perpendicular to the sagittal planeAntereoposterior axis (axis)• passes through the body from front to back• perpendicular to the frontal planeLongitudinal axis (…think North and South pole)• passes through the body from top to bottom• perpendicular to the transverse plane

Planes & MovementsMovements in the sagittal plane around a horizontal

axis• (e.g. front roll, back roll, cycling, running)Flexion• flexion at a joint results in a decrease of the angle

between the two segments that meet at that jointExtension• extension at a joint results in an increase of the angle

between the two segments that meet at that joint• if the movement occurs beyond the extended

position, the action is called hyperextension

Examples of flexion and extension• shoulder flexion and extension• elbow flexion and extension• wrist flexion and extension• fingers flexion and extension• hip flexion and extension• knee flexion and extension• ankle dorsi flexion and plantar flexion• tilt of pelvis under• Dorsi flexion: bringing the toes toward the shin• Plantar flexion: pointing the toes away from the shin (toward

the floor)

Planes & Movements Movements in the frontal plane around a antereoposterior axis • (e.g. cartwheel, jumping jacks, galloping)Abduction• occurs when a body part is moved away from the midline of

the body• e.g. shoulder, hip, fingersAdduction• occurs when a body part is moved toward the midline of the

body• e.g. shoulder, hip, fingers• remember “add to your midline”• e.g. shoulder, hip, fingers

Movements & PlanesInversion• Turning the sole of the foot inward at the ankle (so the sole of the foot

faces toward the midline)Eversion• turning the sole of the foot outward at the ankle (so the sole of the foot

faces away from the midline)Elevation• raising a part to a superior position• e.g. raising your shoulders toward your ears; closing your jaw Depression• lowering a part to an inferior position• e.g. lowering your shoulders to normal or lower than normal position;

lowering your jaw to an open position

More…

Protraction• Sticking jaw out (pouting)Retraction• Bringing jaw back to anatomical position• Lateral bending• bending of the spinal column in the frontal plane to

the left or right• e.g. bending side to side at the waist

And More…Movements in the transverse plane around a longitudinal axis• (e.g. twist, pirouette)Rotation• the movement of a bone around its own axis; this is also

known as a pivot• e.g. the head, neck, and trunk can pivot around the

longitudinal axisInternal (medial) rotation• Rotation towards the midline• E.g. turning forearn in towards bodyExternal (lateral) rotation• Rotation away from midline• E.g. turning forearm away from body

More…

Pronation• rotation of the forearm and hand to the palms down positionSupination• rotation of the forearm and hand to the palms up position

(remember holding a cup of “soup”)Protraction• Shoulder rounding (hunching shoulders)Retraction• Bringing shoulders back to anatomical position, or squeezing

shoulder blades together at back

Special movementsCircumduction• a combination of abduction, adduction, flexion and extension• this action describes a circle• e.g. moving the shoulder in a circle (swimming, windmill

throw in baseball); can also be done at the hip jointOpposition• Bringing thumb towards fingersReposition• Returning thumb back to anatomical position