Download Week 1: Anatomical Terminology and Bones

Week 1: Anatomical Terminology and Bones
Week 1, Part 1: Anatomical Terminology
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We need to learn the international anatomical terminology that enables precise communication among
healthcare professionals and scientists worldwide
Many terms provide information about a structure’s shape, size, location or function or about the
resemblance of one structure to another (e.g. deltoid muscle covering the shoulders is triangular like the
symbol ‘delta’ and suffix ‘oid’ means ‘like’)
Anatomical Position
o The anatomical position refers to the body position as if the person were
standing upright with the:
 Head, eyes (gaze), and toes directed anteriorly (forward),
 Arms adjacent to the sides with the palms facing anteriorly,
 Lower limbs close together with the feet parallel
o All anatomical descriptions are expressed in relation to this consistent,
anatomical position, ensuring that descriptions are not ambiguous
Anatomical Planes
o Anatomical descriptions are based on 3 imaginary planes (sagittal, frontal and
transverse) that intersect the body in the anatomical position:
o Sagittal planes: is perpendicular to the ground/vertical plane and divides the body into left and right
 Median Plane (also, median sagittal plane): divides the body into left and right halves
 This plane defines the mid-line of the head, neck and trunk where it intersects the surface of
the body
o Frontal (Coronal) Planes: divides the body into front and back halves
 vertical planes passing through the body at right angles to the median plane, dividing the
body into anterior (front) and posterior (back)
o Transverse planes: divides the body into top and bottom halves
 horizontal planes passing through the body at right angles to the median and frontal
planes, dividing the body into superior (upper) and inferior (lower) parts.
 Often referred to as transaxial or axial planes
o Since the number of sagittal, frontal and transverse planes is unlimited, a reference point (usually a
visible landmark or vertebral level) is necessary to identify the location or level of the plane e.g.
‘transverse plane through the umbilicus (i.e. naval)’.
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There are also 3 cardinal axes (since 3D): Longitudinal (up, down),
sagittal axis (front, back) and Frontal/transverse axis (left and
right):
o Sagittal axis: passes horizontally from posterior to
anterior and is formed by the intersection of the sagittal
and the transverse planes
o Frontal/transverse Axis: passes horizontally from left to
right and is formed by the intersection of the frontal and
transverse planes
o Vertical Axis/Longitudinal: passes vertically from inferior
to superior and is formed by the intersection of the
sagittal and frontal planes
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The main use of anatomical planes is to describe sections:
o Longitudinal sections: run lengthwise or parallel to the long axis of the body or any of its parts and
the term applies regardless of the position of the body
 Note that although median, sagittal and frontal planes are the standard longitudinal
sections, there is a 180 degrees range of possible longitudinal sections
o Transverse sections (or Cross Sections): are slices of the body or its parts that are cut at right angles
to the longitudinal axis of the body or of any of its parts.
 Because the long axis of the foot runs horizontally, a transverse section of the foot lies in the
frontal plane
o Oblique sections: are slices of the body or any of its parts that are not cut along the previously listed
anatomical planes.
 In practice, many radiographic images and anatomical sections do not lie precisely in
sagittal, frontal or transverse planes – often they are slightly oblique
Terms of relationship and comparison of positions
o Various adjectives are used to compare the position of two structures relative to each other
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Some of these terms are specific for comparison made in the anatomical position or with reference
to the anatomical planes:
 Superior/Cranial and Inferior/Caudal:
 Superior refers to a structure that is nearer the vertex, the topmost point of the
cranium
 Cranial relates to the cranium (skull) and means towards the head/cranium
 Inferior refers to a structure that is situated nearer the role of the foot
 Causal means towards the feet or tail region
 Posterior/Doral and Anterior/Ventral/Rostral:
 Posterior (dorsal): denotes the back surface of the body or nearer to the back
 Anterior (ventral): denotes the front surface of the body
o Rostral: is often used instead of anterior when describing parts of the brain
(it means towards the rostrum i.e. beak and in humans it means nearer the
anterior part of the head e.g. frontal lobe of the brain is rostral to the
cerebellum)
 Medial and Lateral
 Medial indicates a structure nearer to the median plane of the body e.g. the 5th digit
of the hand (little finger) is medial to the other digits
 Lateral stipulates that a structure is farther away from the median plane e.g. the 1st
digit of the hand (thumb) is lateral to the other digits
 Dorsum and Palmer (surfaces):
 Dorsum usually refers to the superior aspect of any part that protrudes anteriorly
from the body e.g. dorsum of the tongue, nose or foot
o It is also used to describe the posterior surface of the hand, opposite the
palm
o This term is easier understood in quadripedal animal that walks on its palms
and soles e.g. a bear.
o Sole: is the inferior aspect or bottom of the foot, opposite the dorsum
o The surface of the hands, the feet and the digits of
both corresponding to the dorsum is the dorsal
surface
 Palmar surface: the surface of the hand and singers
corresponding to the palm and the surface of the foot and
toes corresponding to the sole is called the planter surface
o While all these terms above are relative to the anatomical position or planes,
the following terms are independent of them and relate primarily to the
body’s surface or its central core:
 Proximal and distal: apply when contrasting positions nearer
(proximal) or father (distal) from the attachment of a limb.
Remember ‘close proximity’ or ‘distal is distance’
 Superficial, intermediate and deep: describe the position of
structures relative to the surface of the body or the
relationship of one structure to another underlying or
overlying the structure
 External means outside of or father from the centre of an
organ or cavity while internal means inside or closer to the
centre, independent of direction
Terms of Movement
o Flexion and Extension: movements generally occur in sagittal planes
(the plane cuts left-right but goes from back to front hence is cut by
flexion and extension) around a transverse axis (the joints rotate around the transverse/frontal axis
which is horizontal generally)
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Flexion: indicates bending or decreasing the angle between the bones or parts of the body
 usually anterior movement but not always (e.g. flexion of knee)
Extension: indicates straightening or increasing the angle between the bones or parts of the
body  usually posterior movement but not always (e.g. knee extension)
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Dorsiflexion and Plantarflexion:
 Dorsiflexion describes flexion at the ankle joint e.g.
when walking uphill
 Plantarflexion: bends the foot and toes towards the
ground as when standing on your toes (basically
‘extension’ of ankle)
Abduction and Adduction: generally occur in the frontal plane (cuts
body front, back but plane goes left to right and around the sagittal axis
(back to front) hence imagine the joint almost attached to it and swinging left to right)
 Abduction: means moving away from the median plane
 E.g. when moving upper limb laterally away from the side of
the body
 Remember: Abducted by aliens
 Abduction of digits (fingers or toes): spreading them apart or
other digits moving away from the 3rd digit for fingers and
2nd digit for toes that are neutrally positioned 
o The 3rd finger (neutral) and 2nd toe (neutral) can do
lateral abduction and medial abduction away from
their neutral position 
 Adduction: means movement towards the median plane
 Remember: adding to the body
Thumb: Since the thumb is rotated 90 degrees relative to
other structures/fingers i.e. the thumbnail is positioned
laterally rather than posteriorly, flexion and extension of
the thumb occurs on the frontal plane while
adduction/abduction