mei:dimensions 

Information about the physical size of a bibliographic source; usually
includes numerical data.

Element Information

Model

(mei:address) | (mei:annot) | (mei:bibl) | (mei:date) | mei:abbr | mei:expan | (mei:identifier) | (mei:lb) | (mei:num) | mei:name | mei:corpName | mei:persName | (mei:repository) | (mei:geogName) | mei:rend | mei:stack | (mei:title) | (mei:fig) | mei:bloc | mei:country | mei:district | mei:geogFeat | mei:region | mei:settlement | mei:postBox | mei:postCode | mei:street | mei:periodName | mei:styleName | mei:ptr | mei:ref | mei:symbol | mei:mei_model.dimLike
Children: mei:abbr, mei:address, mei:annot, mei:bibl, mei:bloc, mei:corpName, mei:country, mei:date, mei:district, mei:expan, mei:fig, mei:geogFeat, mei:geogName, mei:identifier, mei:lb, mei:mei_model.dimLike, mei:name, mei:num, mei:periodName, mei:persName, mei:postBox, mei:postCode, mei:ptr, mei:ref, mei:region, mei:rend, mei:repository, mei:settlement, mei:stack, mei:street, mei:styleName, mei:symbol, mei:title

Attributes

QName Type Fixed Default Use Inheritable Annotation
analog xs:string optional 
Contains a reference to a field or element in another descriptive encoding
system to which this MEI element is comparable.
label xs:string optional 
Provides a name or label for an element. The value may be any
string.
n optional 
Provides a number-like designation for an element.
translit xs:NMTOKEN optional 
Specifies the transliteration technique used.
unit union of(xs:NMTOKEN, restriction of xs:token, restriction of xs:token, restriction of xs:token, restriction of xs:token, restriction of xs:token, restriction of xs:token, restriction of xs:token, restriction of xs:token, restriction of xs:token, restriction of xs:token, restriction of xs:token, restriction of xs:token, restriction of xs:token) optional 
Indicates the unit of measurement. Suggested values include: 1] byte; 2]
char; 3] cm; 4] in; 5] issue; 6] mm; 7] page; 8] pc; 9] pt; 10] px; 11] record; 12] vol;
13] vu
xml:base mei:mei_data.URI optional 
Provides a base URI reference with which applications can resolve relative
URI references into absolute URI references.
xml:id xs:ID optional 
Regularizes the naming of an element and thus facilitates building links
between it and other resources. Each id attribute within a document must have a unique
value.
xml:lang xs:language optional 
Identifies the language of the element's content. The values for this
attribute are language 'tags' as defined in BCP 47. All language tags that make use of
private use sub-tags must be documented in a corresponding language element in the MEI
header whose id attribute is the same as the language tag's value.

Source 

<xs:element name="dimensions" substitutionGroup="mei:mei_model.physDescPart">
  <xs:annotation>
    <xs:documentation>Information about the physical size of a bibliographic source; usually includes numerical data.</xs:documentation>
  </xs:annotation>
  <xs:complexType mixed="true">
    <xs:choice minOccurs="0" maxOccurs="unbounded">
      <xs:group ref="mei:mei_model.textphraseLike.limited"/>
      <xs:element ref="mei:mei_model.dimLike"/>
    </xs:choice>
    <xs:attributeGroup ref="mei:mei_att.common.attributes"/>
    <xs:attributeGroup ref="mei:mei_att.bibl.attributes"/>
    <xs:attributeGroup ref="mei:mei_att.lang.attributes"/>
    <xs:attributeGroup ref="mei:mei_att.measurement.attributes"/>
  </xs:complexType>
</xs:element>

Sample