Body Parts

For reference, all the Japanese vocabulary concerning body parts that you'll ever need.

Let's start with the word for "body" in Japanese: karada 体. It's often read tai 体 when it's part of another word, e.g. tainai 体内, "inside of the body.

Head
- Face
- Eye
- Nose
- Mouth
  - Teeth
Arm
- Hand
  - Finger Names
Torso
- Back
Leg
Organs
Bones
Word Patterns
Idioms

Head

The body parts of the head in Japanese:

atama 頭
Head. (general.)
- Can mean the "head" of an organization, etc.
- Has idioms.
toubu 頭部
Head. (anatomical.)
odeko お凸
Forehead. (casual.) ^{(polite prefix.)}
hitai 額
Forehead.
kami 髪
Hair.
- kamigata 髪型
  Hairstyle.
- kami 神
  God.
- kami 紙
  Paper.
mimi 耳
Ear.
- mimikazari 耳飾り
  Earring. "Ear decoration."
- nekomimi 猫耳
  Cat-ears.
mimitabu 耳たぶ
Earlobe.
kubi 首
Neck.
- It also refers to a "decapitated head."
- kubi ni naru 首になる
  To become a "decapitated head."
  To be decapitated.
  To be fired from your job. ^(idiom.)

Face

kao 顔
Face. (general.)
- Also means "expression."
- As a suffix, sometimes pronounced gao 顔 because of rendaku.
- okao お顔
  Face. ^{(polite prefix.)}
men 面
Face. (a face as in a side of a thing, an aspect, etc.)
- Often used to talk about honor, "to save face," etc.
- kamen 仮面
  "Temporary face."
  Mask. (like in kamen rider.)
ganmen 顔面
Face. (body part only.)
- Fun fact: the "gunmen" of Gurren Lagann are actually called ganmen in Japanese because they have faces.
egao 笑顔
Smiling expression.
- warau 笑う
  To laugh.
- hohoemi 微笑み
  Smile.
negao 寝顔
Sleeping expression.
- neru 寝る
  To sleep.

Eye

me 目 (or 眼)
Eye.
- 眼 is often read kan 眼 instead.
- 目 can mean many other things, see: dame 駄目.
- ome お目
  Eye. ^{(polite prefix.)}
- omeme お目目
  Eyes. ^{(reduplicated plural, children language.)}
- ome ni kakaru お目にかかる
  To meet [someone]. ^(idiom.)
- hidari-me 左目
  Left eye. ^(side.)
- migi-me 右目
  Right eye. ^(side.)
medama 目玉
Eyeball.
hitomi 瞳
Pupil.
kousai 虹彩
Iris.
kakumaku 角膜
Cornea.
mabuta 瞼 (or 目蓋)
kangen 眼瞼
Eyelid.
- uwa-mabuta, shita-mabuta 上瞼, 下瞼
  Upper eyelid. Lower eyelid. ^(sides.)
- naigankakuzeihi 内眼角贅皮
  mouko-hida 蒙古襞
  Epicanthic fold. "Mongolian" fold.
  Skin fold of the upper eyelid found in Asians.
  People around "Mongolia," mouko 蒙古 had this "fold," hida 襞, so, in the past, in a certain racial theory that's now considered inaccurate, the term "Mongoloid" was used to refer to the Asian "race." Afterwards, the term was also used to refer to people with Down syndrome, because they also had the fold. This is why "Mongoloid" is a pejorative today.
mayu 眉
Eyebrow. (area.)
mayuge 眉毛
Eyebrow. (hair.)
- ke 毛
  Hair. Fur.

Nose

hana 鼻
Nose.
- ohana お鼻
  Nose. ^{(polite prefix.)}
- hana 花
  Flower. (homonym.)
- hanadi 鼻血
  Nosebleed. (extremely important word in anime.)
- hanamizu 鼻水
  "Nose water." Snot. Dripping nose.
bikou 鼻孔
Nostril.
- hana no ana 鼻の穴
  Nose hole. Nostril.
hanage 鼻毛
Nose hair. Nostril hairs.
hanasuji 鼻筋
Bridge of the nose.
hanasaki 鼻先
Tip of the nose. Nose tip. ^(side.)

Mouth

kuchi 口
Mouth.
- okuchi お口
  Mouth. ^{(polite prefix.)}
- kuchi ni au 口に合う
  okuchi ni au お口に合う
  To suit your palate. ^(idiom.)
kuchibiru 唇
Lips.
- joushin 上唇
  uwa-kuchibiru 上唇
  Upper lip. ^(side.)
- shita-kuchibiru 下唇
  kashin 下唇
  Lower lip. ^(side.)
kougai 口蓋
Palate. Roof of the mouth.
shita 舌
Tongue.
- shita piasu 舌ピアス
  shita-pi 舌ピ
  Tongue piercing.
shitasaki 舌先
Tip of the tongue. ^(side.)
hoo 頬
Cheeks.
ago 顎
Chin.
- uwa-ago 上顎
  jougaku 上顎
  Upper jaw. Maxilla. ^(side.)
- kagaku 下顎
  shita-ago 下顎
  Lower jaw. ^(side.)

Teeth

ha 歯
Tooth. Teeth.
- mushiba 虫歯
  Cavity. "Bugged teeth."
- yaeba 八重歯
  Overlapped, protruding tooth. Anime fang.
- haguruma 歯車
  "Tooth-car." Gear. Cog. Cogwheel. (because it's a disc with "teeth.")
shiniku 歯肉
Gums. "Tooth flesh.
kiba 牙
Animal fangs.

nyuushi 乳歯
Baby tooth. "Milk tooth."
eikyuu-ha 永久歯
Permanent tooth. "Eternal tooth."

To form the teeth names in Japanese, you need to combine the following words:

jougaku-ha 上顎歯
Maxillary teeth. Upper jaw tooth.
kagaku-ha 下顎歯
Mandibular teeth. Lower jaw tooth.

sesshi 切歯
Incisor teeth.
- kiru 切る
  To cut.
kenshi 犬歯
Canine teeth.
- inu 犬
  Dog.
shoukyuushi 小臼歯
Premolar teeth.
- shou 小
  Small.
daikyuushi 大臼歯
Molar teeth.
- dai 大
  Big.

jougaku-chuu-sesshi 上顎中切歯
"Upper jaw middle cutting teeth."
Maxillary central incisor.
kagaku-soku-sesshi 下顎側切歯
"Lower jaw side cutting teeth."
Mandibular lateral incisor.
jougaku dai-ni daikyuushi 上顎第二大臼歯
"Upper jaw number 2 molar."
Maxillary second molar.

Arm

ude 腕
Arm.
- jouwan 上腕
  Upper arm. ^(side.)
- mae-ude 前腕
  zenwan 前腕
  Forearm. ^(side.)
kata 肩
Shoulder.
waki 脇
Armpit.
hiji 肘
Elbow.

Hand

te 手
Hand.
- ote お手
  Hand. ^{(polite prefix.)}
- otete お手手
  Hands. ^{(reduplicated plural, children language.)}
tekubi 手首
Wrist.
te no hira 掌
te no hira 手のひら
te no uchi 手の内
Palm.
te no kou 手の甲
Back of the hand.
yubi 指
Finger.
- oyubi お指
  Finger. ^{(polite prefix.)}
yubisaki 指先
Fingertip. ^(side.)
tsume 爪
Nail. Fingernail. Toenail.

Finger Names

The names for the finger in Japanese are:

oya-yubi 親指
Thumb. "Parent finger."
hito-sashi-yubi 人差し指
Index finger. "Person-pointing finger."
naka-yubi 中指
"Middle finger."
kusuri-yubi 薬指
Ring finger. "Medicine finger." (Latin name is digitus medicinalis, because of a vein that runs from the heart to it.^{[DIGITUS MEDICINALIS – THE ETYMOLOGY OF THE NAME - semmelweis.tripod.com on web.archive.org, accessed 2019-04-13]})
ko-yubi 小指
Pinky finger. "Little finger."

Anatomically, the fingers can be referred to by numbers:

dai isshi 第一指
First finger. Thumb.
dai ni-shi 第二指
Second finger. Index.
dai san-shi 第三指
Third finger. Middle.
dai yon-shi 第四指
Fourth finger. Ring.
dai go-shi 第五指
Fifth finger. Pinky.

Torso

Words for the upper body parts:

doutai 胴体
dou 胴
Torso. (the body minus the head, neck, limbs, and tail.)
taikan 体幹
Trunk.
mune 胸
Chest.
- chibusa 乳房
  Breasts.
- chikubi 乳首
  Nipple.
- nyuurin 乳輪
  Areola.
- nyuutou 乳頭
  Teat.
- See oppai おっぱい for breast-related terms and slangs.
hara 腹
ohara お腹
onaka お腹
Stomach. Abdomen.
heso 臍
Bellybutton.
mata 股
Crotch.
- The area where the torso becomes two legs.
- The word mata can also refer to the spot in which other things bifurcate similarly.
- michi no mata 道の股
  A street's "crotch." The spot where one street divides into two streets, each going to a different direction.
kokan 股間
Crotch. Groin.

Back

se 背
senaka 背中
Back. (body part.)
- mae 前
  Back. (in time.)
- ushiro 後ろ
  Behind. (something.)
- ato 後
  After. (in time.)
  Behind. (someone, following them, going "after" them.)
koshi 腰
Lower back.
Hips.
- koshibone 腰骨
  Hip bone.
shiri 尻
Butt. Buttocks.
- oshiri お尻
  Butt. ^{(polite prefix.)}

kenkoubu 肩甲部
Scapular region.
- kenkoujoubu 肩甲上部
  Suprascapular region. Region above the scapula, between neck and shoulders.
- kenkoukanbu 肩甲間部
  Interscapular region. Region between the scapulae.
- kenkoukabu 肩甲下部
  Infrascapular region. Region below the scapula.
sekichuubu 脊柱部
Vertebral region.
youbu 腰部
Lumbar region. Waist.
kankotsubu 寛骨部
Coxal region. Around the hip bone.
senkotsubu 仙骨
Sacral region. Between buttocks, at the end of the spine.
denbu 臀部
Gluteal region.

Not part of the torso, but:

shippo 尻尾
Animal tail.

Leg

The word for "leg" in Japanese is ashi 脚, but note it's homonymous with ashi 足. The difference between 足 and 脚 is that 脚 is the leg, while 足 is the foot.

ashi 脚
Leg.
- oashi お脚
  Leg. ^{(polite prefix.)}
momo 股
futomomo 太もも
Thighs.
hiza 膝
Knee.
- Can also mean "lap."
- hizamakura 膝枕
  Lap pillow.
sune 脛
Shank.
mukouzune 向こう脛
Shin.
fukurabagi 脹脛
Calf. Calves.
ashikubi 足首
Ankle. (area around leg, right before the foot)
kurubushi 踝
Ankle (referring to the joint.)
ashi 足
Feet.
- oashi お足
  Feet. ^{(polite prefix.)}
yubi 指
ashiyubi 足指
ashi no yubi 足の指
Toes.
tsumasaki 爪先
Tips of the toes. ^(side.)
ashi no kou 足の甲
Top of the foot. ^(side.)
ashi no ura 足の裏
Sole. ^(side.)
- ura 裏
  Reverse side. (often refers to something hidden from view, like when you have a figurehead in an organization and the real boss is controlling everything from the unseen shadows, from the ura.)

Organs

Words for organs, and things on the insides of the body:

naizou 内蔵
Internal organs
hifu 皮膚
Skin. (technical term.)
- hada 肌
  Skin. (general term, often used in idioms.)

shinkei 神経
Nerves.

nou 脳
nouzui 脳髄
Brains.
nou-miso 脳味噌
Innards of the brain.
- Often used by characters to say "get this inside your brain!" When calling other characters dumb.
- miso 味噌
  Fermented soybeans, and innards of things that resemble it.
- miso-shiro 味噌汁
  Soup of miso.

Muscle

kin'niku 筋肉
kin 筋
Muscle.
- kin'niku toreeningu 筋肉トレーニング
  kin-tore 筋トレ
  Muscle training.

fukkin 腹筋
Abs. "Stomach muscle."
daikyoukin 大胸筋
Pectoral muscles. Pecs. Pectoralis major.
soubou-kin 僧帽筋
Trapezius muscle.
sankaku-kin 三角筋
Deltoid.
nitou-kin 二頭筋
Biceps.
santou-kin 三頭筋
Triceps.
daitai shitoukin 大腿四頭筋
Quadriceps femoris.
hifuku-kin 腓腹筋
Gastrocnemius muscle.
kouhai-kin 広背筋
Latissimus dorsi muscle.
katsuyaku-kin 括約筋
Sphincter muscle.
- koumon katsuyaku-kin 肛門括約筋
  Anal sphincter.

Heart & Blood

shinzou 心臓
Heart. (real)
- kodou 鼓動
  Palpitation.
kokoro 心
Heart (of love, etc.)
- dokidoki ドキドキ
  *thump thump*
- shinpaku 心拍
  Heartbeat.
- shinpakusuu 心拍数
  Heart rate. Pulse rate. "Heartbeat number."

chi 血
Blood. (general.)
- chi no tsunagari 血の繋がり
  Link of blood. Connection of blood. Related by blood. Consanguinity.
ketsueki 血液
Blood. (anatomical.)
ketsuatsu 血圧
Blood pressure.
kekkan 血管
Blood vessel.

Blood Types

The terms for blood types in Japanese work just like in English, but using katakanized letters.

ketsueki-gata 血液型
Blood type.

ei-gata Ａ型
[Blood] type A.
bii-gata Ｂ型
[Blood] type B.
eibii-gata ＡＢ型
[Blood] type AB.
oo-gata Ｏ型
[Blood] type O.

Note that, in Japan, there's a lot of superstition about how your blood type reflects your personality.

aaru eichi アールエイチ
Rh. Rhesus.
aru eichi inshi Ｒｈ因子
Rh factor. Rhesus factor.
aru eichi purasu Ｒｈ＋
Rh+.
- purasu プラス
  Plus.
aru eichi mainasu Ｒｈ－
Rh-.
- mainasu マイナス
  Minus.

Respiratory Organs

kokyuuki 呼吸器
Respiratory organs.
- kokyuu suru 呼吸する
  To breathe.
bikou 鼻腔
Nasal cavity.
intou 咽頭
Pharynx.
koutou 喉頭
Larynx.
kikan 気管
Trachea. Windpipe.
- Written with ki 気, "air," "atmosphere," "feeling," and kan 管, "can," "pipe."
hai 肺
Lung.
kyoukaku 胸郭
Thorax.

Digestive Organs

shoukaki 消化器
Digestive organ.
- shouka suru 消化する
  To digest.
nodo 喉
Throat.
intou 咽頭
Pharynx.
shokudou 食道
Esophagus.
i 胃
Stomach.
- Yes, that's just a single i.
ibukuro 胃袋
"Stomach bag." Stomach.
- In reference to the bag-shape of the organ, in which goes the food.
suizou 膵臓
Pancreas.
- Kimi no Suizou wo Tabetai
  君の膵臓をたべたい
  I Want to Eat Your Pancreas. (actual name of an anime movie.)
tan'nou 胆嚢
Gallbladder.
boukou 膀胱
Urinary bladder.
nyoudou 尿道
Urethra.
nyoudoukou 尿道口
Urethral opening.
kanzou 肝臓
Liver.
chou 腸
Intestines.
shouchou 小腸
Small intestine.
- jyuunishichou 十二指腸
  Duodenum.
- kuuchou 空腸
  Jejunum.
  kaichou 回腸
  Ileum.
daichou 大腸
Large intestine.
- mouchou 盲腸
  Cecum.
- chousui 虫垂
  Appendix.
  (it's written with mushi 虫, "bug," "worm," because the appendix is vermiform: it's shaped like a worm.)
- kecchou 結腸
  Colon.
- esu-jou kecchou Ｓ状結腸
  esu-ji kecchou Ｓ字結腸
  Sigmoid colon. "S-shaped" colon. "S-letter" colon.
chokuchou 直腸
Rectum.
koumon 肛門
Anus. (does this count as inside of the body? Eh, whatever.)

Bones

The human body has from 200 to 208 bones. ^{[人間の骨の一覧 - ja.wikipedia.org, accessed 2019-04-09]}

hone 骨
Bone.
- kossetsu 骨折
  Bone fracture.
- oru 折る (transitive.)
  oreru 折れる (intransitive.)
  To fracture. To break.
kokkaku 骨格
Skeleton. (anatomy.)
- gaikokkaku 外骨格
  Exoskeleton. "External skeleton."
- naikokkaku 内骨格
  Endoskeleton. "Internal skeleton."
gaikotsu 骸骨
Skeleton. (corpse, evil Halloween monster thing, etc.)
kansetsu 関節
Joint.
- dakkyuu 脱臼
  Dislocation.

The counter for bones is hon 本, since it counts long, cylindrical objects and bones are long, cylindrical objects.

hone ippon 骨一本
One bone.
ni-hon 骨二本
Two.
sanbon 骨三本
Three.
yon-hon 四本
Four.
ni-hyaku roku-hon ２０６本
Two hundred six.

Cranium Bones

zugaikotsu 頭蓋骨
Cranium. "Head lid bone."
koutoukotsu 後頭骨
Occipital bone. "Behind head bone."
zentoukotsu 前頭骨
Frontal bone. "Front head bone."
sokutoukotsu 側頭骨
Temporal bone. "Side head bone."
touchoukotsu 頭頂骨
Parietal bone. "Head top bone."
choukeikotsu 蝶形骨
Sphenoid bone. "Butterfly shape bone."
shikotsu 篩骨
Ethmoid bone.
jishoukotsu 耳小骨
Ossicles. "Ear small bone."
- tsuchikotsu 槌骨
  Malleus. "Hammer bone."
- kinutakotsu 砧骨
  Incus.
- abumikotsu 鐙骨
  Stapes.

Facial Bones

ganmenkotsu 顔面骨
Facial bone.
kabikoukai 下鼻甲介
Inferior nasal concha.
ruikotsu 涙骨
Lacrimal bone. "Tear bone."
bikotsu 鼻骨
Nasal bone. "Nose bone."
jokotsu 鋤骨
Vomer.
jougakukotsu 上顎骨
Maxilla. "Upper jawbone."
kougaikotsu 口蓋骨
Palatine bone. "Mouth lid bone."
kyoukotsu 頬骨
"Cheekbone." Zygomatic bone.
kagakukotsu 下顎骨
Mandible. "Lower jawbone."
zekkotsu 舌骨
"Tongue bone." Lingual bone. Hyoid bone.
shijou-hougou 矢状縫合
Sagittal suture.
kanjou-hougou 冠状縫合
Coronal suture.

Spine & Vertebrae

sebone 背骨
"Backbone." Spine.
sekitsui 脊椎
Spine. Backbone. Vertebral column.
- keitsui-doubutsu 脊椎動物
  Vertebrate animal.
- sekizui 脊髄
  Spinal cord.
sekichuu 脊柱
Spinal column. Spine.
tsuikotsu 椎骨
sekitsuikotsu 脊椎骨
Vertebra. (singular.)
Vertebrae. (plural.)
keitsui 頸椎
Cervical vertebrae. "Neck vertebra."
kyoutsui 胸椎
Thoracic vertebrae. "Chest vertebra."
youtsui 腰椎
Lumbar vertebrae. "Lower-back vertebra."
sentsui 仙椎
Sacral vertebrae.
bitsui 尾椎
"Tail vertebra."
Caudal vertebrae. (animals.)
Coccygeal vertebrae. (people.)

Some specific vertebrae:

dai ichi keitsui 第一頸椎
First cervical vertebra. C1.
- Also known as:
- kantsui 環椎
  Atlas.
dai ni keitsui 第二頸椎
Second cervical vertebra. C2.
- jikutsui 軸椎
  Axis. Epistropheus.
dai nana keitsui 第七頸椎
Seventh cervical vertebra. C7.
- ryuutsui 隆椎
  (no English alias.)

Some other aliases:

senkotsu 仙骨
Sacrum.
- Formed when the sacral vertebrae S1 to S5 fuse together in adulthood, a process starting at 18 years of age and ending at 30 years old. ^{[SACRUM ANATOMY - scientificspine.com, accessed 2019-04-09.]}
- Wait, what.
- This happens?!
bikou 尾骨
Coccyx. "Tailbone."

Rib Cage Bones

kyoukotsu 胸骨
Sternum. "Chest bone."
rokkotsu 肋骨
abarabone あばら骨 (or 肋骨)
abara あばら (or 肋)
Rib bone.

There are 12 rib bones in total.

dai ichi rokkotsu 第一肋骨
First rib bone.
dai ni rokkotsu 第二肋骨
Second rib bone.
(etc.)
dai juu-ni rokkotsu 第十二肋骨
Twelfth rib bone.

Shoulder & Arm Bones

kenkoukotsu 肩甲骨 (or 肩胛骨)
Shoulder blade. Scapula.
sakotsu 鎖骨
Clavicle. Collar bone. "Chain bone."
jouwankotsu 上腕骨
Humerus. "Upper arm bone."
zenwankotsu 前腕骨
Forearm bones. (ossa antebrachii.)
- toukotsu 橈骨
  Radius. Radial bone.
- shakkotsu 尺骨
  Ulna.

Hand Bones

shukonkotsu 手根骨
Carpal bones. Carpus. "Hand-root bones."
Wrist bones. (colloquial.)
kin'i shukonkotsu 近位手根骨
Proximal carpal bones.
- shuujoukotsu 舟状骨
  Scaphoid bone. "Boat-shape bone."
- ketsujoukotsu 月状骨
  Lunate bone. Semilunar bone. "Moon-shape bone."
- sankakukotsu 三角骨
  Triquetral bone. Triquetrum. Pyramidal. "Triangle bone."
- toujoukotsu 豆状骨
  Pisiform bone. "Bean-shape bone." (pisiforme means "pea-shaped" in Latin.)
en'i shukonkotsu 遠位手根骨
Distal carpal bones.
- dairyoukeikotsu 大菱形骨
  Trapezium bone. Greater multangular bone. "Big diamond-shape bone."
- shouryoukeikotsu 小菱形骨
  Trapezoid bone. Lesser multangular bone. "Small diamond-shape bone."
- yuutoukotsu 有頭骨
  Capitate bone. "Having-head bone." (Latin: capitate, "having a head.")
- yuukoukotsu 有鈎骨
  Hamate bone. Unciform bone "Having-hook bone." (Latin: hamus, uncus, "hook.")
chuushukotsu 中手骨
Metacarpal bones. Metacarpus.
Palm bones. "Middle-hand bones."
- dai ichi chuushukotsu 第一中手骨
  First metacarpal bone. Metacarpal bone of the thumb.
- Etc.
shikotsu 指骨
"Finger bones."
Phalanx bone.
Phalanges. (plural.)
- Feet phalanges are shikotsu 趾骨.
- kisetsukotsu 基節骨
  Proximal phalanges. "Base joint bone."
- chuusetskotsu 中節骨
  Middle phalanges. Intermediate phalanges. "Middle joint bone."
- matsusetsukotsu 末節骨
  Distal phalanges. "End joint bone."
- daisshi 第一指 (hand.)
  daisshi 第一趾 (foot.)
  First phalanx.

Leg Bones

kotsuban 骨盤
Bony pelvis.
koshibone 腰骨
"Hip bone." (common term.)
kankotsu 寛骨
Hip bone. (anatomical.)
- zakotsu 坐骨
  Ischium. "Sit bone."
- choukotsu 腸骨
  Ilium. "Intestine bone."
- chikotsu 恥骨
  Pubic bone. "Shame bone."
daitaikotsu 大腿骨
Femur. Thigh bone.
shitsugaikotsu 膝蓋骨
hiza no sara 膝の皿
Knee cap. Patella.
kataikotsu 下腿骨
Lower leg bone. (ossa cruris.)
- keikotsu 脛骨
  Tibia. Shinbone. Shankbone.
- hikotsu 腓骨
  Fibula. Calf bone.
sokkonkotsu 足根骨
Tarsus.
- kin'i sokkonkotsu 近位足根骨
  Proximal tarsals.
- kyokotsu 距骨
  Talus bone. Astragalus. Ankle bone.
- shoukotsu 踵骨
  Calcaneus. Heel bone.
- shuujoukotsu 舟状骨
  Os naviculare. (same name as the counterpart on the hand.)
- en'i sokkonkotsu 遠位足根骨
  Distal tarsals.
- naisoku ketsujoukotsu 内側楔状骨
  Os cuneiforme mediale.
- chuukan ketsujoukotsu 中間楔状骨
  Os cuneiforme intermedium.
- gaisoku ketsujoukotsu 外側楔状骨
  Os cuneiforme laterale.
- rippoukotsu 立方骨
  Cuboid bone.
chuusokukotsu 中足骨
Metatarsal bones. Metarsus.
shikotsu 趾骨
Phalanges. (feet.)

Word Patterns

There are some word patterns involving terms for the body parts that should be noted.

Body Sides

A number of words for body parts include a morpheme that refers to a side or location. For example:

uchi, nai 内
Inside. Inner. Internal. Endo-.
soto, gai 外
Outside. Outer. External. Exo-.
saki 先
Tip.
ura 裏
Under-side.
kou 甲
Carapace. (top side, e.g. hands, feet.)
ue, uwa, jou 上
Up. Upper. Above.
shita, ka 下
Down. Lower. Below.
hidari 左
Left.
migi 右
Right.
ryou 両
Both.
kata 片
One of two.

A vertical example:

kuchibiru 唇
Lip.
- uwa-kuchibiru 上唇
  Upper lip.
- kashin 下唇
  Lower lip.

Note above the uwa and kuchibiru are both kun'yomi readings, while ka and shin are both on'yomi readings.

A horizontal example:

te 手
Hand.
hidari te 左手
Left hand.
migi te 右手
Right hand.

An example with ryou and kata:

ryou te 両手
Both hands.
kata te 片手
One hand. (of the two hands you have.)

Some words that refer to general body sides:

tainai 体内
Inside of the body.
taigai 体外
Outside of the body.
jouhanshin 上半身
Upper-half of the body.
kahanshin 下半身
Lower-half of the body.
joutai 上体
Upper body.
katai 下体
Lower body.

Some morphemes that are used in more technical, anatomical words:

chuu 中
Center. Central.
soku 側
Side. Lateral.
kin'i 近位
Proximal. "Near position."
en'i 遠位
Distal. "Distant position."
zen 前
Front. Frontal.
kou 後
Behind. Posterior.

o- お～ Prefix

A number of words for body parts routinely get an o- お～ prefix attached to them. This is called bikago 美化語, "beautified language." Grammatically, it serves no purpose whatsoever, and doesn't change the meaning of the word. (although there are some exceptions.)

It merely gives a more respectful treatment to the word (for the body part) so it sounds more refined than normal, more polite.

te 手
Hand.
ote お手
Hand. (also.)
- But it sounds more refined.

In some words, the prefix go- ご～ is used instead with the same effect. They're both spelled with kanji as 御, but normally they're spelled without kanji.

Not all words get the prefix. More common words, such as hand, tend to get the prefix more often. Another word that normally gets the prefix is "stomach," onaka お腹.

In anime, caring, refined characters tend to use the refined words more. Specially caring mothers talking to their children, or the maiden-like girls.

Some words pretty much always get the prefix. For example, odeko お凸, "forehead," is the normal way of saying the word, rather than just deko 凸.

Reduplicated Plurals

There are some very specific body parts that can get the o prefix and get reduplicated (said twice) to refer to their plural. For example:

otete お手手 (or お手々)
Hands.
omeme お目目 (or お目々)
Eyes.

One way it's used:

otete wo arau お手手を洗う
To wash hands.
- Very important so you don't get sick!

Such words aren't used formally. They're mostly used toward babies, small children, pet animals, etc. It's also unnecessary due to how plurals work in Japanese. But you may end up seeing them in anime eventually.

In particular, since it's used toward children, the words can sound patronizing depending on context: like if you tell someone to show their hands using otete you're treating them like a small child.

Idioms

A number of body parts are involved into idiomatic expressions. For reference:

hara ga tatsu 腹が立つ
"The stomach stands up."
- To get angry at something or someone. To become irritated, annoyed about something.
te wo dasu 手を出す
"To let out one's hand." (in the same sense as unsheathing a sword or pulling out a gun.)
- To put your hand on someone. To do something to someone.
- In anime, generally used as: "don't you dare put your hands on her!"
te wo utsu 手を打つ
"To shoot a hand."
- Or "to deal a hand." In the sense of making a move in a game, a strategical move.
- uteru te wa uta 打てる手は打った
  The hands [that] [I] can shoot [I've] shot.
  I've done everything I could do.
  I've exhausted my strategic moves, now I can only pray the plan works out.
mimi wo kasu 耳を貸す
"To lend a ear."
- To listen to what someone has to say.
kata wo kasu 肩を貸す
"To lend a shoulder."
- To come to someone's aid.
kuchi ni au 口に合う
"To match one's mouth."
- To suit one's taste. If someone will like eating, drinking it.
- okuchi ni au ka wakarimasen ga
  お口に合うか分かりませんが
  [I] don't know if it will suit your palate, however. (expression used when offering someone food they might not like.)
atama wo furu 頭を振る
kubi wo furu 首を振る
"To shake one's head."
- Eh, this isn't an idiom but whatever. It means "to say no," but your head. You know, the gesture.
koshi wo ireru 腰を入れる
"To insert one's back."
- To put strength in it.
kubi ni naru 首になる
"To become a neck."
- kubi can mean "decapitated head," so:
- To become a decapitated head.
- But this is normally used in the sense of:
- To be fired from your job.

Phrases that compliment or criticize a body part are usually actually referring to an ability intrinsic of that body part. For example:

atama ga ii 頭がいい
"[Your] head is good."
[You're] smart.
atama ga warui 頭が悪い
"[Your] head is bad."
[You're] stupid.
me ga ii 目がいい
"[Your] eyes are good."
You have a good sense for this. You can tell a product of good quality when you see one.
me ga nai 目がない
"[You] don't have eyes."
To you, quality doesn't matter.
- A more specific example:
- amai mono ni me ga nai 甘いものに目がない
  Toward sweet things, [he] doesn't have eyes.
  He will eat anything that's a sweet. It doesn't matter what it is, he won't be picky, he won't be choosy, he has no eyes for them.
me ni kurui wa nai 目に狂いはない
"[You] have no insanity in the eyes."
- Your judgement isn't wrong.
- You judged something correctly.
- For example, when a character A recruits character B to become a super-hero and save the world and then B ends up being exactly the sort of good guy that A expected him to be. In that case, A's judgement of B wasn't wrong. There was no "insanity" in A's eyes.
ashi ga hayai 足が速い
"[Your] legs are fast."
[You're] fast.

The following is a set phrase that's considered humble language, so it normally comes with the o prefix:

ome ni kakaru お目にかかる
"To pour [me] onto [your] eyes."
To meet [you].
- Often used when you meet someone important for the first time, e.g. the boss of another company, a king of some country, the tic-tac-toe world champion, etc.