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The Alimentary System
山东大学医学院 解剖教研室
李振华
The abdominal regions 腹部分区
——Nine regions
R. hypochondriac
region 右季肋区
R. lateral regions
右外区
R. inguinal region
右腹股沟区
Pubic region 耻区
Epigastric region 腹上区
L. hypochondriac region
左季肋区
L. lateral regions
左外侧区
Umbilical region 脐区
L. inguinal region
左腹股沟区
The abdominal regions 腹部分区
——Four quadrants


Left and right upper
quadrants
Left and right lower
quadrants
Composition
Alimentary canal消化管
Mouth 口腔
 Pharynx 咽
 Esophagus 食管
 Stomach 胃


Small intestine小肠
Duodenum 十二指肠
Jejunum 空肠
Ileum 回肠

Superior alimentary canal
上消化道
Large intestine 大肠
Inferior alimentary canal
下消化道
Alimentary glands 消化腺



Major salivary glands 大唾液腺
Liver 肝
Pancreas 胰
Function: ingestion, digestion, absorption, egesting
Major salivary glands
Mouth
Pharynx
Esophagus
Liver
Duodenum
Ileum
Stomach
Pancreas
Large intestine
Jejunum
Alimentary canal 消化管
The Oral Cavity 口腔
The Oral Cavity 口腔

Consists of two parts

Oral vestibule 口腔前庭: between
cheeks and lip and teeth

Oral cavity proper 固有口腔: within
arch of teeth

Boundaries





Anterior and lateral: gum and teeth
Posterior: isthmus of fauces 咽峡
Roof: palate
Floor: tongue, muscles and mucous
membrane
Oral vestibule leads, by the space
behind the molar teeth, into the oral
cavity proper
Palate 腭

Two parts

Hard palate 硬腭: anterior 2/3，
formed by the maxilla and
palatine bone Soft palate 软腭:
posterior 1/3





Velum palatinum 腭帆
Uvula 腭垂
Palatoglossal arch 腭舌弓
Palatopharyngeal arch 腭咽弓
Isthmus of fauces 咽峡 formed
by uvula, free border of velum
palatinum, both side of palatoglossal
arches, and root of tongue.
Teeth 牙
Teeth 牙
General features


Two sets:
 Deciduous 乳牙
 Permanent 恒牙
Classification:
 Incisors 切牙
 Canine 尖牙
 Premolars 前磨牙
 Molars 磨牙
Deciduous teeth 乳牙


20 in number, ten teeth in each mandibular and maxillary arch
Deciduous central incisor 乳中切牙, deciduous lateral incisor 乳侧切牙,
deciduous canine 乳尖牙, first deciduous molar 第一乳磨牙，second
deciduous molar 第二乳磨牙 in each quadrant
Upper jaw
Lower jaw


Ⅰ
in.
Ⅱ
Ⅲ
Ⅳ
Ⅴ
total 20
in. can. mol. mol.
Eruption: stars at about 6 mouth of age and continues to beginning
of 3rd year
Shedding: occurs between 6th and 12th years with replacement by
permanent teeth
Ⅱ
Ⅳ
Deciduous teeth 乳牙
Deciduous central incisor 乳中切牙
Deciduous lateral incisor 乳侧切牙
Deciduous canine 乳尖牙
First deciduous molar 第一乳磨牙
Second deciduous molar 第二乳磨牙
Permanent teeth (adult)恒牙


32 in number，sixteen in each mandibular and maxillary arch
Two incisors, one canine, two premolars, and three molars in
each quadrant
Upper jaw
1 2 3 4 5 6 7 8 total 32
Lower jaw


First permanent molar－ appears at about 6 years
Third molars (wisdom teeth)－many erupt at any time after 12
years of age or not at all (impaction).
3
7
Permanent teeth 恒牙
3rd molar 第三磨牙
2nd molar 第二磨牙
1st molar 第一磨牙
2nd premolar 第二前磨牙
1st premolar 第一前磨牙
Canine 尖牙
Lateral incisor 侧切牙
Central incisor 中切牙
Teeth 牙
Part and structure of the teeth

Each tooth consists of 3 parts:




Crown 牙冠
Neck 牙颈
Root 牙根
Dental cavity 牙腔


Pulp chamber 牙冠腔
Root canal 牙根管 transmits the
nerves and vessels to and from the
dental cavity through the apical
foramen 根尖孔
Teeth 牙

Calcified tissues 牙组织




Dentine 牙质－ is a yellowish white
tissue, that forms the bulk of tooth.
Enamel 釉质－is a hard, brittle white
tissue that covers the crown of the
tooth
Cement 牙骨质－is an unusual form
of bone that covers the root of the
tooth
Dental pulp 牙髓 formed connective
tissue, blood vessels and nerves.
Teeth 牙

Periodontal tissue 牙周组织

Periodontal membrane 牙周膜

Alveolar bone 牙槽骨

Gum 牙龈
Teeth 牙
Tongue 舌
Two parts: divided two parts by v-shaped
terminal sulcus 界沟

Body of tongue 舌体－anterior 2/3



Apex of tongue 舌尖－free rounded tip
At the apex of terminal sulcus is a
small median pit, the foramen cecum
of tongue 舌盲孔
Root of tongue 舌根－ posterior 1/3
Tongue 舌
Lingual mucous membrane


Papillae of tongue 舌乳头

Filiform papillae 丝状乳头

Fungiform papillae 菌状乳头

Foliate papillae
叶状乳头

Vallate papillae
轮廓乳头
Lingual tonsil 舌扁桃体
－masses of submucosal
lymphoid tissue on the root of
tongue
contain taste
buds 味蕾
Inferior surface of tongue
Frenulum of tongue 舌系带
－a midline fold of mucous
membrane connecting tongue to
floor of mouth
Sublingual caruncle 舌下阜
－small elevation
Sublingual fold 舌下襞
Muscles of tongue 舌肌
Intrinsic muscles of tongue


Involved in changing shape of
tongue
Include longitudinal, transverse
and vertical muscles of tongue
Tongue 舌

Extrinsic muscles of tongue




Genioglossus 颏舌肌
 Arises from mental spine of
mandible and inserts into either
side of midline of tongue
 Action: acting together draw
tongue forward and downward
(depresses and protrudes
tongue ); acting along making
apex of tongue to opposite side
Hyoglossus 舌骨舌肌
Tyloglossus 茎突舌肌
Involved in determining shape
and position of tongue
Major salivary glands 大唾液腺
Parotid gland 腮腺



Superficial part: triangular in shape,
lies below and in front of the external
acoustic meatus, and partially covers
the masseter.
Deep part: lies deep to medial
pterygoid .
Parotid duct: arises front anterior
border of gland, runs over the
masseter a finger’s breadth below
the zygomatic arch to pierce the
buccinator and opens into the mouth
cavity, opposite the upper second
molar tooth
Major salivary glands 大唾液腺
Submandibular gland
下颌下腺
 Position: lies in submandibular
triangle, between anterior and
posterior bellies of digastric
 Duct opens on to sublingual
caruncle
Major salivary glands 大唾液腺
Sublingual gland 舌下腺

Position: situated beneath the
mucous membrane of the floor of
mouth

Ducts


Major sublingual duct－opens
onto the sublingual caruncle
Minor sublingual ducts－open
onto the sublingual fold
The Pharynx 咽
General features


A –fibromuscular tube, part of
digestive and respiratory systems
Extends from base of skull to the
inferior border of cricoid cartilage
(lower border of C6 level)
Three segments



Nasopharynx 鼻咽
Oropharynx 口咽
Laryngopharynx 喉咽
The Pharynx 咽
Nasopharynx 鼻咽—posterior to nasal
cavities

Extends from the base of skull to
level of soft palate, below

Features

Pharyngeal opening of auditory tube
咽鼓管咽口

Tubal torus 咽鼓管圆枕

Pharyngeal recess 咽隐窝

Tubal tonsil 咽鼓管扁桃体

Pharyngeal tonsil 咽扁桃体
The Pharynx 咽
Oropharynx 口咽－posterior to oral
cavity


Lies below soft palate, extends
to upper border of epiglottis
Features

Median glossoepiglottic fold
舌会厌正中襞


Epiglottic vallecula 会厌谷
Palatine tonsil 腭扁桃体
－lies within tonsillar fossa
The Pharynx 咽
Laryngopharynx 喉咽－posterior


to larynx
Extends from upper border of
epiglottis to the level of lower
border of C6
Piriform recess 梨状隐窝 －a deep
depression on each side of
aperture of larynx, common side
for lodgement of foreign bodies (for
example, fish bones)
The Pharynx 咽
Lymphatic ring


Consists of

Pharyngeal tonsil

tubal tonsil

Palatine tonsil

lingual tonsil
Forming a circular band of
lymphoid tissue at
oropharyngeal isthmus
The Esophagus 食管

General features
－ a muscular tuber about
25cm long, connecting the
pharynx at level of C6 vertebra,
passes through the diaphragm
at level of T10 vertebra and
after 1~2 cm enters the
stomach

Division



Cervical part
Thoracic part
Abdominal part
The Esophagus 食管
★Three constrictions
1. Where it beginning, 15cm from
incisors, lies at level of C6, is the
narrowest part of the esophagus
2. Where it is crossed by left
principal bronchus, 25cm from
incisors, lies at level of intervertebral
disc between T4 and T5.
3. Where it passes through the
esophageal hiatus of diaphragm,
40cm from incisors, at level of T10
The Stomach 胃
Shape



Two surface: anterior and posterior
Two curvatures
 Lesser curvature 胃小弯 : short, concave and
directed to the right and upward, near its lower
part is angular incisure 角切迹
 Greater curvature 胃大弯: long, convex and
directed to the left and downward, at the
junction of left margin of esophagus and
greater curvature is cardiac incisure 贲门切迹
Two openings
 Cardia 贲门
 Pylorus 幽门
The Stomach 胃

Four parts




Cardiac part 贲门部
Fundus of stomach 胃底
Body of stomach 胃体
Pyloric part 幽门部


Pyloric antrum 幽门窦
Pyloric canal 幽门管
Fundus of stomach 胃底
Cardiac part 贲门部
Body of stomach 胃体
Pyloric canal 幽门管
Pyloric antrum 幽门窦
Pyloric part 幽门部
The Stomach 胃
Structure of stomach wall



－consists of four usual layers
Mucous membrane
Submucous ( loose areolar tissue
connecting the mucous and
muscular layer)
Muscular layer contains:
 The most superficial longitudinal
fibers
 Inner circular fibres


幽门括约肌
Innermost oblique fibres
Serous (visceral peritoneum)


Sphincter of pylorus
Pyloric valve 幽门瓣
The Stomach 胃
Location



Mainly parts is situated in the left
hypochondriac region
Small in the epigastric region
The cardia is situated to the left of T11, the
pylorus lies to the right of L1
Variations in position of stomach
The Small Intestine小肠
Duodenum

About 5-7m long

Division:



Duodenum 十二指肠
Jejunum 空肠
Ileum 回肠
Jejunum
Ileum
Duodenum 十二指肠
Four parts

Superior part 上部

Duodenal cap

Superior duodednal flexure
十二指肠球
十二指肠上曲

Descending part 降部

Inferior duodenal flexure
十二指肠下曲

Horizontal part 水平部

Ascending part 升部

Duodenojejunal flexure
十二指肠空肠曲
Duodenum 十二指肠
Descending part 降部

Longitudinal fold of duodenum
十二指肠纵襞

Major duodenal papilla
十二指肠大乳头 the common opening
of the common bile duct and
pancreatic duct, 75cm from
incisors

Minor duodenal papilla
十二指肠小乳头

Contrast radiographic
appearance of the duodenum
showing a distended
duodenal cap and the
remainder of the duodenum
up to the duodenojejunal
flexure
Duodenum 十二指肠

Suspensory muscle of duodenum 十二指肠悬肌
(ligament of Treitz), a surgical landmark, descends from the right
crus of diaphragm to duodenal termination.
Jejunum and ileum
Characteristic
Jejunum
Ileum
Position
Upper 2/5, upper left
Lower 3/5, lower right
part of abdominal cavity part of abdominal cavity
Diameter
Greater
Less
Wall
Thicker
Thin
Circular folds
Larger, numerous and
large villi
Fewer，smaller and
less abundant villi
Vascularity
Greater
Less
Vasa recta
Long
Short
Color
Deeper red
Paler pink
Lymphatic follicles
Solitary
Aggregated
Fat in mesentery
Less
More
Jejunum and ileum


Barium studies of the
jejunum and ileum.
Small bowel enema
(enteroclysis). The plicae
circulares are clearly
demonstrated by this
technique.
Jejunum and ileum
Meckel’s diverticulum




Persistence of proximal portion of
yolk sac (vitelline duct,
omphalomesenteric duct)
Common malformation of
digestive tract (2－4%) － more
prevalent in males
About 2－5cm long and located
30－100cm from ileocecal valve
Usually asymptomatic but:


May become inflamed (mimicking
appendcitis) or bleed
May be attached to umbilicus by a
fibrous cord (distal end of yolk stalk)
and cause intestinal obstruction by
compressing adjacent intestinal loops
Large Intestine 大肠


Approximately 1.5m long,
Five parts:





Cecum 盲肠
Vermiform appendix 阑尾
Colon 结肠
Rectum 直肠
Canal 肛管
Large Intestine 大肠
Features



Colic bands 结肠带
Haustra of colon 结肠袋
Epiploic appendices 肠脂垂
Cecum 盲肠


Position: lies in right iliac fossa
Shape:


Blind sac, first part of large intestine,
with largest diameter and thinnest
wall
The ileum enters the cecum obliquely,
and partially invaginates into it,
forming the ileocecal valve 回盲瓣
 Consists of two folds
 Probably delays flow of ileal
contents into large intestine
Vermiform appendix 阑尾



Blind worm-like tube, 6－8cm
long, about 0.5cm in diameter
Opens into posteromedial aspect
of cecum，about 2 cm below
ileoceal orifice
The base of the appendix lies at
the point of convergence of three
colic bands (used as a guide to
find the appendix during
operation)
Vermiform appendix 阑尾

Surface marking of the base
is at the so-called
McBurney’s point which is
at junction of lateral and
middle thirds of line joining
right anterior superior iliac
spine and umbilicus
Vermiform appendix 阑尾






Tip variable in position
Preileal －7%
Pelvic－41%
Retrocecal －29%
Retroileal－4%
Subcecal－17%
Vermiform appendix 阑尾
Mesoappendix 阑尾系膜


Triangular mesentery－
extends from terminal part
of ileum to appendix
Appendicular a. runs in free
margin of the
meseoappendix then along
wall of appendix
Double contrast barium enema appearance of the caecum
and ileocaecal valve.
Colon 结肠

Ascending colon 升结肠


Transverse colon 横结肠


right colic flexure 结肠右曲
left colic flexure 结肠左曲
Descending colon 降结肠
descends almost vertically
from left colic flexure to
sigmoid colon at left iliac
crest.

Sigmoid colon乙状结肠
－extends from descending
colon to rectum at level of S3.
Appearance of the abdominal colon on double contrast barium
enema examination demonstrating the transverse colon,
hepatic and splenic flexures.


Barium studies of the
jejunum and ileum.
Barium follow-through. The
feathery appearance of the
small intestine is due to the
plicae circulares, this is
most prominent in the
jejunum. The constrictions
are the result of peristalsis.
Rectum 直肠

Position: within pelvic cavity, extends
from S3 to pelvic diaphragm.

Curves

Sagittal plane



Coronal plane



Sacral flexure 直肠骶曲: convex backward
Perineal flexure 直肠会阴曲: convex
forward.
Upper and lower part－convex to the right.
Middle part－convex to the left.
Lower part of rectum dilated, to from
ampulla of rectum 直肠壶腹

Three transverse folds of rectum 直肠横襞
Sagittal T2-weighted MRI of
the rectum in the male.
Sagittal T2-weighted MRI of
the rectum in the female.
Anal canal 肛管





Anal columns 肛柱: 6 － 11 in number
Anal valves 肛瓣
Anal sinuses 肛窦
Anorectal line 肛直肠线
Dentate line 齿状线
Above line, of endodermal origin
 Below line, of ectodermal origin
Anal pecten 肛梳
White line 白线 (Hilton’s line)
Anus 肛门
Anal sphincters 肛门括约肌
 Sphincter ani internus 肛门内括约肌
 Sphincter ani externus 肛门外括约肌





Anterior coronal MRI endocoil section
in a woman showing the transverse
perineii (TP) joining the external anal
sphincter anteriorly (between arrows).
EAS, external anal sphincter; IAS,
internal anal sphincter; PR,
puborectalis.