AAW: Muscles of the anterior abdominal wall

Question 1

Common Nerve supply of anterior Abdominal wall muscles

Answer 1

Lower 5 intercostal N (T6-T11) & subcostal N (T12)
* Internal Abdomenal Oblique & transversus abdominus recieve additional innervation from 1st Lumbar N (ilo-inguinal N & ilo-hypogastric N)

Question 2

Common action of Anterior abdominal wall muscles

Answer 2

• Increase intra-abdominal pressure
• Protect viscera
• Oblique muscle bend trunk laterally
• rectus abdominis flex trunk (mainly from supine position)
• Lateral rotation of trunk (external AO of same side & Internal AO of opposite site)

Question 3

Origin of External Abdominal Oblique muscles

Answer 3

by eight fleshy digitations from lower 8 ribs (outer surface) = 5-12

interdigiating with latissimus dorsi & Serratus anterior

Question 4

Insertion of External Abdominal Oblique

Answer 4

• Fleshy fiber: into outer lip of iliac crest (ant. 1/2)
• Aponeurosis (at the front) : Xiphoid process, symphysis pubis, linea Alba, pubic crest
• lower free border: forms Inguinal ligament

Question 5

Direction of external Abdominal oblique muscle fibers

Answer 5

Downwards, forewards and medial

Question 6

External Abdominal oblique muscle forms which border of the Posterior lumbar triangle

Answer 6

Anterior boundary

Question 7

Where does External Abdominal Oblique muscle becomes aponeurotic

Answer 7

below a line between ASIS & umbilicus

Question 8

opening in the aponeurosis of the External Abdominal Oblique muscle forms ….

Answer 8

Superficial/ External Inguinal ring

Question 9

Prolongation of The aponeurosis of the External Abdominal oblique muscle at the External/superficial inguinal Ring is called ……

Answer 9

External Spermatic fascia

Question 10

Origin of Internal Abdominal Oblique muscle

Answer 10

• Thoracolumbar fascia
• Anterior 2/3 of intermediate lip of Iliac crest
• lateral 2/3 of upper surface of Inguinal Ligament

Question 11

Insertion of Internal Abdominal Oblique Muscles

Answer 11

Fleshy fibers:
Lower border of Lower 3 Ribs

Aponeurosis:
* xyphoid process
* Linea Alba
* Symphysis pubis
* 7th, 8th & 9th Costal Cartilages
* Conjoint tendon (into pubic crest & pectineal line)

Question 12

Direction of internal Abdominal Oblique muscle

Answer 12

Upwards, forewards and medially

Question 13

Describe the relations of the Lower fibers of the Internal Abdominal Oblique muscle to the spermatic cord/ abdominal Canal

Answer 13

1. Anterior to the spermatic cord: makes up lateral 1/2 of Anterior wall of inguinal Canal
2. Arches above the spermaric cord: makes up the roof of inguinal Canal
3. Behind the cord/ round lig. of uterus (as conjoint tendon): it makes up the medial 1/2 of posterior wall of inguinal Canal

Question 14

Relation between Aponeurosis of Internal Abdominal Oblique muscle and Rectus Abdominis muscle

Answer 14

Aponeurosis splits at lateral border of rectus Abdominis to Anterior and posterior laminae, behind and in front of the rectus abdominis respectively

Question 15

another name for conjoint tendon

Answer 15

Falx Inguinalis

Falx meaning the sickle shape of the tendon

Question 16

Conjoint tendon is formed of Aponeurosis of which muscles

Answer 16

Internal Abdominal Oblique & Transversus abdominus

Question 17

Base of conjoint tendon is inserted into

Answer 17

Pubic tubercle and pectineal Line

Question 18

Innervation of conjoint tendon

Answer 18

Ilio-inguinal N (1st Lumbar N)

Question 19

Origin of Cremastric Muscle

Answer 19

Extension of the origin of the Internal Abdominal Oblique muscle: from upper concave surface of inguinal Ligament

Question 20

Insertion of the Cremastric Muscle

Answer 20

Loops around spermatic cord & Testis and inserts into pubic tubercle

Question 21

Nerve supply of cremastric Muscle

Answer 21

Genital Branch of genito-femoral N

Question 22

Action of Cremastric muscle

Answer 22

• supporting of weight of testis
• Elevation of testis during Ejaculation & increased intra-abdominal pressure
• Cremastric reflex

Question 23

Origin of Transversus abdominis Muscle

Answer 23

• Thoracolumbar fascia
• Anterior 2/3 of Inner lip of iliac crest
• Lateral 1/3 of Inguinal Ligament
• Inner surface of lower 6 costal Cartilages, interdigiating with Diaphragm

Question 24

Insertion of the Transversus Abdominus

Answer 24

• Aponeurosis: xyphoid process, linea Alba, symphysis pubis
• Lower most fibers: Conjoint tendon (into pubic crest & pectineal Line)

Question 25

Direction of Trasversus Abdominus Muscle fibres

Answer 25

Trasversely , except for the lower fibers which run downwards and medially to share in formation of Conjoint tendon

Question 26

Explain what happens to Aponeurosis of transversus abdominus

Answer 26

At level of Arcuate line horizontaly, Aponeurosis splits into:
* Upper part: which extends behind rectus Abdominis and shares in formation of posterior wall of Rectus sheath
* Lower part: extends anterior to rectus abdominis, unite with Internal Abdominal Oblique and form conjoint tendon

Question 27

Origin of Rectus Abdominus

Answer 27

Pubic crest & Symphysis pubis

Question 28

Insertion of Rectus Abdominis

Answer 28

Outer surface of 5th, 6th and 7th Costal Cartilages + xiphoid process

Question 29

Shallow groove formed by lateral convex surface of Rectus Abdominus is called

Answer 29

linea semilunaris

Question 30

Explain why Rectus Abdominus Muscle is divided into segments of 3-4 tendinous intersections

Answer 30

The muscle was formed by fusion of many myotomes

Question 31

Sites of Tendinous intersections of Rectus Abdominis

Answer 31

• Level of Xiphoid process
• Midway between xiphoid process and umbilicus
• Level of umbilicus
• Below Umbilicus

Question 32

origin of pyramidlis muscle

Answer 32

Pubic crest

Question 33

Insertion of pyramidalis Muscle

Answer 33

Lower part of Linea Alba

Question 34

Nerve supply of Pyramidalis Muscle

Answer 34

Subcostal N

Question 35

Action of Pyramidalis Muscle

Answer 35

makes linea Alba tense