osteology – anatomical orientations, planes,...

Osteology – Anatomical Orientations, Planes, Directions


• In order to be able to describe orientation of skeleton and dental structures and their component parts in 3 dimensions, uniformity of description is necessary


Reference Positions:

• 1. Standard Anatomical Position of

Skeleton – for skeleton as a whole

• 2. Frankfort Horizontal (FH) - for skulls

Osteology – Orientations:Standard Anatomical Position

• Standing

• Feet together pointing forward

• Palms forward (no bones crossed), arms at

sides

• Looking forward

• No matter what position a bone or skeleton is

found in, surfaces are referred to as if individual

is standing erect in standard anatomical position

Standard Anatomical Position

-standing-feet together-palms forward-looking forward

From Gosling et al

Standard Anatomical Position

Modified from Moore

Fetal Anatomic Position

Osteology – Orientations:Frankfort Horizontal for Skulls

• Named for city of 1884 convention

• Plane defined by 3 points: right and left porion (at top of auditory meatus), and left orbitale (bottom of left orbit)

• 6 standard viewing perspectives: all perpendicular or parallel to FH (norma occipitalis – from behind, frontalis – from in front, basalis – from base, lateralis – from right and left sides, verticalis –from above)

Frankfort Horizontal

Modified from Rhine

Skull and face –left lateral view

Frankfort Horizontal is defined by plane between right and left porion and left orbitale

Osteology – Planes of Reference

1. Sagittal (midsagittal, median, midline)

2. Coronal (frontal) plane

3. Transverse (horizontal) plane

4. Oblique plane

Planes of Reference - Sagittal

• Sagittal = midline = median = midsagittal

• Divides body into right and left halves

• Any planar slice paralleling this plane is parasagittal

• Is a vertical anteroposterior plane

• Parallel to sagittal suture of skull


Posterior

Anterior

Right Left

Schematic human –seen from above


Posterior

Anterior

Sagittal plane

Right Left



Posterior

Anterior

Sagittal plane

Parasagittal planes

Right Left


Planes of Reference – Sagittal

Right Left

Body is divided into left and right halves

Planes of Reference - Coronal

• Coronal = frontal

• Divides body into anterior and posterior halves

• At right angle to sagittal plane

• Vertical side-to-side plane

• Approximately parallel to coronal suture

Planes of Reference – Coronal (Frontal)

Posterior

Anterior

Coronalplane


Planes of Reference - Transverse

• Transverse = horizontal

• Slices through body at any height

• Perpendicular to sagittal and coronal planes

• In case of an organ or other structure, a transverse or cross section is at right angles to long axis of that organ or structure

Planes of Reference – Transverse (Horizontal)

Transverse plane slices through body at any height and is perpendicular to sagittal and coronal planes

Planes of Reference – Long Axis and Transverse Axis of Organ

Long axis

Transverse axes

Planes of Reference - Oblique

• May lie at any other angle

Planes of Reference – Oblique

Oblique plane may lie at any angle

Oblique plane

General Skeletal Terminology

• Cranial skeleton: skull (= cranium + mandible)

• Post-cranial skeleton: remainder of skeleton (axial and appendicular skeleton)

• Axial skeleton: bones of trunk, including ribs, vertebrae, sternum, pelvis

• Appendicular skeleton: bones of limbs, including shoulder girdle

General Skeletal Terminology –Cranial - Postcranial

Cranial skeleton

Post-cranial skeleton

General Skeletal Terminology –Axial - Appendicular

Axial skeleton = skeleton of the trunk

Appendicular skeleton = skeleton of the limbs

Terms of Relationship

• “Three pairs of relative terms can express relationship of any given structure to another” (Grant)

• Superior-Inferior (up-down)

• Anterior-Posterior (front-back)

• Medial-Lateral (to and away from midline)

Terms of Relationship:Superior - Inferior

• Superior: toward head end of body, hominid or quadruped; “cranial” and “cephalic” are synonymous for hominids and quadrupeds

• Inferior: opposite of superior; away from head in hominids; “caudal” refers to tail end of quadruped, but can be used to describe fetal orientation, e.g. craniocaudal length of fetus, craniocaudal growth of CNS

General Skeletal Terminology –Superior - Inferior

Superior – toward the head end

Inferior – away from the head end

Terms of relationship

Terms “cephalic” and “caudal” are more frequently used to describe fetal directions

Modified from Moore

Terms of Relationship:Superior - Inferior

• “Superior” and “inferior” are usually used to describe direction in bones of axial skeleton

• “Proximal” and “distal” are usually used to describe direction in bones of appendicularskeleton, i.e. proximal meaning nearer to the axis of the body and distal meaning further from the axis of the body

General Skeletal Terminology –Superior-Inferior, Proximal-Distal

Superior

Inferior

Proximal upper arm

Distal upper arm

Proximal forearm

Distal forearm

APPENDICULAR AXIAL

Terms of Relationship:Anterior - Posterior

• Anterior: toward front of body; “ventral” can be used homologously for hominids and quadrupeds; “palmar” or “volar” for palms of hands, “plantar” for soles of feet

• Posterior: toward back of body, opposite of anterior; “dorsal” can be used homologously for both hominids and quadrupeds; by convention “dorsum”is top of foot or back of hand

General Skeletal Terminology -Anterior

Superior

Inferior

AnteriorAnterior

General Skeletal Terminology –Posterior

Posterior Posterior

Superior

Inferior

Terms of Relationship:Medial - Lateral

• Medial: toward midline (median plane of body)

• Lateral: opposite of midline; away from midline

• May be used to describe axial and appendicular elements of skeleton

General Skeletal Terminology –Medial - Lateral

Medial –toward the midline

Lateral –away from the midline

Terms of Comparison

• Describe relationships of structures between species, as well as within species

Terms of Comparison:Proximal - Distal

• Proximal: end of a bone nearest the axial skeleton; used mainly to describe direction in limb bones, i.e. to describe direction in bones of appendicular skeleton

• Distal: opposite of proximal; farthest from axial skeleton

General Skeletal Terminology –Proximal - Distal

Superior

Inferior

Proximal upper arm

Distal upper arm

Proximal forearm

Distal forearm

APPENDICULAR AXIAL

Terms of Comparison:Ulnar - Radial

• Ulnar: near the little finger side; used for forearm, hand; corresponds to medial

• Radial: near the thumb side; used for forearm, hand; corresponds to lateral

General Skeletal Terminology –Radial - Ulnar

Radial –near the thumb side

Ulnar -near the little finger side

Terms of Comparison:Tibial - Fibular

• Tibial: near the tibial or shinbone side; used for lower leg, foot; corresponds to medial

• Fibular: near the fibular side; used for lower leg, foot; corresponds to lateral

General Skeletal Terminology –Tibial - Fibular

Fibular –near the fibular side

Tibial –near the shinbone side

Terms of Comparison:External - Internal

• External: outer

• Internal: inner

Terms of Comparison –Internal - External

From Grant From Grant

Terms of Comparison:Endocranial - Ectocranial

• Endocranial: inner surface of cranial vault

• Ectocranial: outer surface of cranial vault

Terms of Comparison –Endocranial - Ectocranial

Ectocranial – outer surface

Endocranial – inner surface

From Grant

Terms of Comparison:Superficial - Deep

• Superficial: close to surface

• Deep: opposite of superficial; far from surface

From Grant

Terms of Comparison –Superficial - Deep

From Grant

Terms of Comparison:Subcutaneous

• Just below skin

Terms of Comparison:Ipsilateral - Contralateral

• Ipsilateral: same side of body

• Contralateral: opposite side of body

Terms of Comparison –Ipsilateral - Contralateral

Ipsilateral – same side of body (e.g. right arm and right leg are on ipsilateral side of body

Contralateral –opposite side of body (e.g. right arm and left arm are on contralateral sides of body)

Attachment of Muscles

• Proximal end: origin

• Distal end: insertion

Dental Terminology

Teeth - Surfaces

• Each tooth has 5 surfaces

1. Mesial

2. Distal

3. Lingual

4. Labial or buccal

5. Occlusal

Dental Terminology:Mesial – Distal

• Mesial: toward point on midline where central incisors contact each other (medial surfaces of front teeth and anterior surfaces of side teeth are mesial (proximal))

• Distal: opposite of mesial

Dental Terminology – Mesial - Distal

Mesial: toward the midline

Distal: opposite of mesial

Dental Terminology:Lingual – Labial - Buccal

• Lingual: toward the tongue; opposite of labial or buccal

• Labial (toward the lip): opposite of lingual; used for incisors and canines (i.e. anterior surfaces of front teeth)

• Buccal (toward the cheek): opposite of lingual; used for premolars, molars (i.e. lateral surfaces of side teeth)

Dental Terminology – Lingual-Labial-Buccal

Labial (toward lip): anterior surfaces of incisors and canines

Buccal (toward cheek): lateral surfaces of premolars and molars

Lingual: toward the tongue (opposite of lingual or buccal); sameterm for all teeth

labial labial

buccal buccal

lingual

incisorsand canines

premolars and molars

Dental Terminology – Occlusal Surfaces

• Occlusal surfaces are biting surfaces, i.e. where teeth of upper (maxillary) and lower (mandibular) jaws meet are all “occlusal” surfaces (an occlusal surfaces faces the opposite dental arch)

• Occlusal = masticatory• Occlusal or biting surfaces of incisors =

incisal surfaces

Dental Terminology – Occlusal Surfaces

Occlusal surface: biting surface, masticatory surface; where maxillary and mandibular surfaces meet

Modified from Rhine

Dental Terminology –Occlusal Surfaces

Occlusal surface: biting surface, masticatory surface; where maxillary and mandibular surfaces meet

Dental Terminology -Contact Surfaces

• Proximal (mesial) and distal surfaces of adjacent teeth are contact surfaces

• Exceptions: distal surfaces of last molars

• Proximal (mesial) and distal surfaces of adjacent teeth rub against one another with chewing motion, producing areas of wear – these areas may match on adjacent teeth – may be useful in helping to establish dental identification

Dental Terminology:Interproximal

• In contact with adjacent teeth in the samejaw

Modified from Grant

Dental Terminology –Interproximal Regions and Contact Surfaces

Interproximal regions areindicated by arrows

Dental Terminology – Interproximal Contact Surfaces

Modified from Brothwell

Wear facets on mesial and distal surfaces are indicative of an interproximal articulation with adjacent teeth

Dental Terminology:Tooth Axes

• Mesiodistal: axis from mesial to distal surface

• Buccolingual or labiolingual: axis from buccal or labial to lingual surface

Teeth – Measurements -Mesiodistal Diameter

• Maximum diameter between mesial and distal contact points

Teeth – measurements – schematic – crown view

labial or buccal

lingual

Mesiodistal diameter –maximum diameter between mesial and distal contact points

Teeth – Measurements –Buccolingual Diameter

• Maximum diameter at right angles to mesiodistal diameter


labial or buccal

lingual

Buccolingual diameter –maximum diameter at right angles to mesiodistal diameter

Teeth – Measurements – Crown Module

• A measurement of “relative crown mass”

• Average of mesiodistal and buccolingual diameters


labial or buccal

lingual

Crown module –a measurement of relative crown mass

Crown module = (mesiodistal diameter + buccolingual diameter) /2

osteology – anatomical orientations, planes,...

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