They generally don't, other than the fact that some of the letters are named for body parts, such as:
The body parts that have the same number of letters as the word "elbow" are wrist and ankle.
kidneyspleencheekspelvisfingermuscletonguenervesglands
parts of a letter: * heading * greeting * body * closing
clavicle
Ulna, uterus
armeareyelegliptoe
elbow
The letters spell the word thorax. It is a body part.
The parts of your body = hachelakim shel haguf shelcha/shelach (החלקים של הגוף שלך)
Eye, toe, jaw, hip, arm and rib are body parts. Additional body parts include ear, leg, gum and lip.
Anus, iris, feet, gums and calf are body parts. Additional body parts include nail, neck, face, nose, foot, cell and chin.
The six standard parts included in all block letters are the date, recipient's address, salutation, body, closing, and sender's name.