Surface anatomy & Abdominal wall

Question 1

What is the upper extent of the abdominal cavity?

Answer 1

Anteriorly the under surface of the diaphragm reaches the 5th intercostal space.

Question 2

Describe the 9 regions of the abdominal wall.

Answer 2

Draw two vertical lines down from the midpoint of the clavicles
Draw a horizontal line across the lowest point on the thoracic cage
Draw a horizontal line across the tubercles of the iliac crest
You now have nine abdominal areas. The three down the midline are; epigastrium,
umbilical and suprapubic from top down. The three lateral areas are hypo-chondrium, flank
and iliac fossa from top down

Question 3

Describe the nerve supply to the skin of the abdominal wall.

Answer 3

The dermatomes of the abdominal wall start at thoracic 5 in the upper epigastrium,
with thoracic 10 being at the umbilicus and thoracic 12 being just above the hair bearing
area in the lower suprapubic area. Each dermatome starts at the back at the level of the
named vertebra; the dermatomes run downwards as they pass round the trunk to the
front

foregut – greater splanchnic t5-t9
midgut – lesser splanchnic t10-t11
hindgut – lowest splanchnic t12

Question 4

How is the rectus sheath formed?

Answer 4

How is the rectus sheath formed?
In the upper 2/3 of the abdomen the aponeurosis of the external oblique muscle
passes in front of rectus abdominis and the aponeurosis of transversus abdominis passes
behind. The aponeurosis of internal oblique sends fibres both in front and behind rectus
abdominis. In the lower 1/3 of the abdomen all three aponeuroses pass in front of rectus
abdominis.

Question 5

What is the surface marking of the aortic bifurcation?

Answer 5

The level of the umbilicus

intertubercular plane – level of tubercles of iliac crests

Question 6

In which regions of the abdomen is pain from the three parts of the bowel felt?

Answer 6

Foregut; epigastrium
Midgut; umbilical
Hindgut; suprapubic

Question 7

7 Describe the anatomy of a ‘six pack’?

Answer 7

The rectus abdominis muscle runs vertically from the pubis up to the costal margin.
Along its length there are three places where it becomes a tendon. When exercised the
muscle hypertrophies (becomes bigger) but the tendinous part stays the same. The result is
three bulges (of muscle) between the tendons. This occurs on either side of the midline; six
bulges in all.

Question 8

The abdominal wall is formed from sheets of muscle and their corresponding sheets of tendon which we call

Answer 8

aponeuroses

Question 9

These muscles of the abdominal wall hold the abdominal viscera within the abdominal cavity and play an important part in… and How

Answer 9

rotating the body and in respiration, 
coughing, 
sneezing, 
micturition, 
defecation and 
childbirth 
by contracting to increase intra-abdominal pressure

Question 10

What is a Hernia

Answer 10

Weaknesses in the muscle wall are common and may allow the bowel (or other organs) to protrude out of the abdomen, this is called a Hernia

Question 11

Surgical access to the abdominal contents is done in such a way as not to

Answer 11

produce weakness nor interfere with the blood or nerve supply.

Question 12

Either side of the midline lies a pair of vertical muscles, the

Answer 12

rectus abdominis muscle

Question 13

What is the rectus abdominis muscle attached to and surrounded by

Answer 13

It is attached to the the sternum and costal margin superiorly and to the pubis inferiorly and is surrounded by the rectus sheath

Question 14

Lateral to the rectus sheath are three sheets of muscle which have fibres running in different directions;

Answer 14

1  obliquely downwards and inwards (external oblique), 
2 obliquely upwards and inwards (internal oblique) and 
3 transversely (transversus abdominis).

Question 15

As these three muscle layers pass forwards towards the rectus sheath the muscles become aponeurotic what does this do

Answer 15

and it is these aponeuroses that form the sheath for rectus abdominis

Question 16

Inferiorly the lowest most extent of the external oblique muscle is aponeurotic throughout its length and is attached to the

Answer 16

anterior superior iliac spine laterally and the pubic tubercle medially; this is the inguinal ligament

Question 17

Just above the inguinal ligament is the inguinal canal which, in the male,

Answer 17

ransmits all the structures to and from the testis, together these are the spermatic cord

Question 18

xiphisternum

Answer 18

the lowest part of the sternum

Question 19

Iliac Crest

Answer 19

the iliac crest is the curved superior border of the ilium

Question 20

The anterior superior iliac spine

Answer 20

The anterior superior iliac spine (abbreviated: ASIS) is a bony projection of the iliac bone
It refers to the anterior extremity of the iliac crest of the pelvis, which provides attachment for the inguinal ligament, and the sartorius muscle

Question 21

The pubic tubercle

Answer 21

The pubic tubercle is a prominent forward-projecting tubercle on the upper border of the medial portion of the superior ramus of the pubis. The inguinal ligament attaches to it.

Question 22

Pubic Symphysis

Answer 22

The pubic symphysis is a secondary cartilaginous joint (a joint made of hyaline cartilage and fibrocartilage) located between the left and right pubic bones near the midline of the body. More specifically, it is located above any external genitalia and in front of the bladder.

Question 23

The 9 regions are delineated by two vertical and two horizontal lines. The vertical line on each side extends from

Answer 23

from the mid-clavicular point (half way along the clavicle) to the mid-inguinal point (midway between pubic symphysis and anterior superior iliac spine)

Question 24

The lower transverse line is drawn between the

Answer 24

tubercles of the iliac crests (intertubercular plane) and the upper transverse line is the subcostal plane (line joining the lowest part of the costal margins on both sides).

Question 25

The three central regions, from superior to inferior are:

Answer 25

epigastric, umbilical and suprapubic (or hypogastric)

Question 26

The three lateral regions are

Answer 26

hypochondrium, flank and iliac fossa

Question 27

Extending towards the back from the flank is the

Answer 27

loin and further still the lumbar region

Question 28

Transpyloric plane of Addison

Answer 28

This plane passes horizontally across the epigastrium and reaches the costal margin at the most lateral part of the rectus abdominis muscle. This is at the tip of the 9th costal cartilage and where the midclavicular line crosses the costal margin.

Question 29

What lies on the Transpyloric plane of Addison

Answer 29

The gall bladder, pancreas, pylorus of the stomach and duodeno-jejunal flexure all lie on this plane.

Question 30

Sub-costal Plane

Answer 30

This plane lies at the lowest points of the costal margin.

Question 31

McBurney’s point

Answer 31

This point lies 2/3 of the way along a line joining the umbilicus to the right anterior superior iliac spine. It marks the usual site of the base of the appendix. It also gives a guide to the position of the caecum during clinical examination of the abdomen.

Question 32

Umbilicus

Answer 32

This variable and usually unreliable landmark marks the point of insertion of the umbilical cord during embryonic life and (only in the thin recumbent patient) the level of the L3 vertebra.

Question 33

Intertubercular plane

Answer 33

This is a plane which lies at the level of the tubercles of the iliac crests and marks the position of the bifurcation of the abdominal aorta.

Question 34

Intercristal plane

Answer 34

This plane lies across the highest point of the pelvis, it cannot be felt with the patient lying on their back. It is used for examinations and procedures on the back whilst the intertubercular plane is used for the front.

Question 35

The foregut is supplied by the greater splanchnic nerve which arises from

Answer 35

T5 to T9

Question 36

pain from the foregut is usually felt

Answer 36

anteriorly in the midline at this level (T5-T9), i.e. in the epigastrium

Question 37

Midgut pain, supplied by the lesser splanchnic nerve this arises from where and is felt where?

Answer 37

(T10 and T11) is referred to the periumbilical area

Question 38

pain from the hind gut

Answer 38

(lowest splachnic nerve, T12) to the suprapubic area.

Question 39

Why is a disease process involves the abdominal wall is it felt very directly

Answer 39

The peritoneum covering the inside if the abdominal wall has the same sensory nerve supply as the skin overlying the same area of the abdominal wall. If a disease process involves the abdominal wall, such as an inflammed appendix the pain is felt very precisely directly over the appendix.

Question 40

The under surface of the diaphragm is supplied by sensory nerves from the

Answer 40

the phrenic nerve (cervical 3,4,5 nerve roots),

Question 41

diseases which may irritate the diaphragm, such as
7

cholecystitis (inflammation of the gall bladder), may be felt as referred pain in the

Answer 41

C3, C4, C5 distribution,The pain is felt in the shoulder, despite the disease being in the abdomen.

Question 42

The sensory innervation of the kidney is via the sympathetic plexus which accompanies the … at what vertebrae

Answer 42

renal artery (T10, 11, 12), the same plexus supplies the gonad

Question 43

Pain from the kidney can be referred along the cutaneous nerves of… how is the pain described as

Answer 43

of T10, 11, 12, most commonly T12, the pain is often described as radiating from the loin to the groin. Renal pain can also be felt in the gonadal area and conversely gonadal pain can be felt in the loin.

Question 44

Infection in the abdomen is common and can arise from a variety of sources;

Answer 44

the appendix, gall bladder, uterine tudes or divirticular disease of the colon etc

Question 45

Once bacteria are in the cavity

they can spread rapidly and widely. They tend to ‘gravitate’ to the lowest place which is

Answer 45

behind the right lobe of the liver when lying flat and into the pelvis when upright. Tumours may also spread through the cavity.