Chapter 1 - Anterior Abdominal Wall (until pyramidalis) Flashcards
(42 cards)
1
Q
Definition and position of umbilicus
A
- Normal scar on anterior abdominal wall
- Remnants of root of umbilical cord
- in anterior median line
- level of L3-L4
- lower in infants and persons with pendulous abdomen
2
Q
Anatomical importance of umbilicus
A
- Lymph and venous blood flow upwards above umbilical plane and downwards below
- Skin around by T10 segment of spinal cord
- Portal veins anastamose with systemic veins
3
Q
Embryological importance of umbilicus
A
- Meeting point of 4 folds of embryonic plate - 2 lateral, head, tail
- Meeting point of digestive, excretory, vascular system
4
Q
Persistence of vitellointestinal duct
A
Patent - faecal fistula at umbilicus
Proximal part - Meckel’s diverticulum
Middle part - enterocoele
- May form raspberry red or cherry red tumors
5
Q
Layers of superficial fascia
A
- Superficial, fatty layer - fascia of Camper
2. Deep, membranous layer - fascia of Scarpa
6
Q
Fatty layer of superficial fascia
A
- continuous with superficial fascia of nearby parts
- in penis, devoid of fat
- in scrotum, replaced by dartos muscle
7
Q
Membranous layer of superficial fascia
A
- continuous with membranous layer of superficial fascia of perineum - Colles fascia
- prevents passage of extravasted urine backwards into ischiorectal fossa due to rupture of urethra
- thickened in median plane to form suspensory ligament, fundiform ligament of penis/clitoris
- Above umbilicus, it merges with fatty layer
8
Q
Line of attachment of membranous fascia
A
- Holden’s line
- Pubic tubercle
- Body of pubis
- Pubic arch
- Posterior border of perineal membrane
9
Q
Anterior cutaneous N of AAW
A
Thoracic N - T7-T12, L1
- Enter abdominal wall from intercostal spaces
- pass b/w internal oblique and transversus
- pierce posterior lamina of internal oblique aponeurosis
- enter rectus sheath
- pierce rectus muscles
- divide into medial and lateral branches
- Iliohypogastric and ilioinguinal do not enter rectus sheath
- Subcostal supplies pyramidalis
10
Q
Lateral cutaneous N of AAW
A
T10-T11 intercostal N
- pierce external intercostal
- divide into anterior andposterior branches
- supply skin on side of abdomen
lateral cutaneous branches of subcostal and iliohypogastric N (T12, L1)
- descend over iliac crest
- supply skin of gluteal region
11
Q
Cutaneous A of AAW
A
- Anterior cutaneous A - from superior, inferior epigastric A
- Lateral cut. A - from lower intercostal A
- Superficial inguinal A - from femoral
- Superficial epigastric A - skin upto umbilicus
- Superficial external pudendal A - skin of external genitalia
- Superficial circumflex iliac A - skin of abdomen, thigh
12
Q
Superior vena caval blockage vein path
A
Brachiocephalic -> Subclavian -> Axillary -> Lateral thoracic -> Thoracoepigastric -> Superficial epigastric -> Great saphenous -> Femoral -> IVC
13
Q
Caput Medusae
A
- When portal vein, SVC or IVC are obstructed, superficial abdominal V dilate to provide collateral circulation
- Dilated V radiate from umbilicus forming caput medusae
- Mainly seen in portal obstructions
14
Q
Origin of external oblique M
A
- As 8 slips from outer surface of shafts of lower 8 ribs
- Downward, forward, medially
15
Q
Insertion of external oblique M
A
-Aponeurosis Xiphoid process Linea alba Pubic symphysis Pubic crest
16
Q
Nerve supply of external oblique M
A
Lower 6 thoracic N
17
Q
Properties of external oblique M
A
- Upper 4 slips interdigitate with serratus anterior, lower 4 with latissimus dorsi
- aponeurosis has free margin which forms inguinal ligament
- aponeurosis forms anterior wall of rectus sheath
- forms triangular superficial inguinal ring above pubic crest
18
Q
Origin of internal oblique M
A
- Lateral 2/3 of inguinal ligament
- Anterior 2/3 of iliac crest
- Thoracolumbar fascia
- Upwards, forwards, medially
19
Q
Insertion of internal oblique M
A
- Uppermost directly into lower 4 ribs
- Aponeurosis into:
- 7, 8, 9 costal cartilages
- xiphoid process
- linea alba
- pubic crest
- pectineal line of pubis
20
Q
Nerve supply of internal oblique M
A
- Lower 6 thoracic N
- L1 N
21
Q
Properties of internal oblique M
A
- In upper 3/4 aponeurosis splits into anterior, posterior lamina
- Anterior lamina passes in front of rectus abdominis and posterior lamina behind.
- Posterior lamina ends to form linea semicircularis/ arucate line
- Lower 1/4 aponeurosis is single layer
- Forms conjoint tendon and cremaster muscle
22
Q
Origin of transversus abdominis M
A
- Lateral 1/3 of inguinal ligament
- Anterior 2/3 of iliac crest
- Thoracolumbar fascia
- Inner surface of lower 6 costal cartilages
- Horizontally forwards
23
Q
Insertion of transversus abdominis M
A
-Aponeurosis Xiphoid process Linea alba Pubic crest - Lowest fibres + internal oblique form conjoint tendon
24
Q
Nerve supply of transversus abdominis M
A
- Lower 6 thoracic N
- L1 N
25
Properties of transversus abdominis M
1. In upper 3/4, aponeurosis passes behind rectus muscle
2. Lower edge contributes to arcuate line
3. Lower 1/4, aponeurosis forms anterior wall of rectus sheath.
26
Origin of rectus abdominis M
1. Lateral head - lateral part of pubic crest
2. Medial head - Medial pubic crest, anterior pubic ligament
- Vertically upward
27
Insertion of rectus abdominis M
Xiphoid process
| 7th, 6th, 5th costal cartilages
28
Nerve supply of rectus abdominis M
Lower 6 thoracic N
29
Properties of rectus abdominis M
1. It has 3 transverse fibrous bands that divide it into small parts
a. opp. umbilicus
b. opp. free end of xiphoid
c. b/w both
2. They make muscle powerful
30
Actions of muscles of AAW
1. Tone of M provide firm, elastic support for abdominal viscera against gravity
2. Can compress viscera for expulsive acts like vomiting, micturition, defecation, paturition
3. External oblique and depress/compress lower thorax for forceful expiration, sneezing, coughing
4. Movements of trunk:
a. Flexion of trunk/spine - rectus abdominis
b. Lateral flexion of trunk - obliques
c. Rotation of trunk - ext. oblique + opp. int. oblique
31
Formation and attachments of inguinal ligament
```
FORMATION
- by lower border of ext. oblique
- aponeurosis is thickened and folded upon itself
- from anterior superior iliac spine to pubic tubercle
ATTACHMENTS
- Lower border - fascia lata
- Lat 2/3 - Int. oblique
- Lat 1/3 - transversus abdominis
- Middle - Cremaster
```
32
Relations of inguinal ligament
Upper surface forms floor of inguinal canal
| Lodges spermatic cord and round ligament of uterus
33
Extensions of inguinal ligament
1. Lacunar ligament
2. Ligament of Cooper
3. Reflected part of inguinal ligament
4. Intracrural fibres that arise from middle and arch over superficial inguinal ring
34
Lacunar ligament
- Triangular
- Ant: Medial end of inguinal ligament
- Post: pecten pubis
- Horizontal
- Supports spermatic cord
- Forma medial boundary of femoral ring
35
Ligament of Cooper
- Extension from post. part of lacunar ligament
| - Attached to pecten pubis
36
Reflected part of inguinal ligament
- fibres pass upwards and medially from superficial inguinal ring(SIR)
- lies behind SIR and in front of conjoint tendon
37
Conjoint tendon
- fusion of lowest fibres of int. oblique and transversus
- attached to pubic crest, pecten pubis
- Medially, continuous with anterior wall of rectus sheath
- Laterally, free
- Strengthens abdominal wall at site where it is weakened by SIR
38
Cremaster muscle
- muscle fasiculi embedded in cremasteric fascia
- fasiculi form superficial loops from upper surface of inguinal ligament
- form deep loops from pubic crest, conjoint tendon
- fully developed only in male
- lies deep to external spermatic fascia
39
Nerve supply of cremasteric muscle
Genital branch of genitofemoral N
40
Action of cremaster
Helps suspend and elevate testes
| Closes SIR when intra-abdominal pressure increases
41
Cremasteric reflex
- On stroking upper part of medial side of thigh, cremaster reflexively contracts
- More brisk in children
- In upper motor N leisions abover L1, reflex is lost
42
Pyramidalis
- small triangular
- from anterior surface of body of pubis
- fibres - upwards, medially
- inserted into linea alba
- supplied by subcostal N T12
- tensor of linea alba
