Anterior Abdominal Wall

Anterior Abdominal Wall April 26, 2023 by Marksparks arkansas Leave a Comment (Edit)

Anterior Abdominal Wall Transpyloric plane (Addison’s plane)(Trans— across, pyloric—end of the stomach) Introduction: It is a horizontal plane passing through the pyloric end of the stomach.

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Anterior Abdominal Wall Transpyloric plane (Addison’s plane)(Trans—across, pyloric—end of the stomach) Sites of portocaval anastomoses Caput medusae (Caput—head, Medusae—Greek myth, female ^ with snaky hair.)

Inguinal ligament Rectus abdominis Lacunar ligament Attachments to pubic tubercle Superficial inguinal ring Deep inguinal ring Coverings of spermatic cord Spermatic cord Hesselbach’s (Trigonum inguinale—Inguinal trigone) Inguinal hernia External oblique muscle of anterior abdominal wall Transversus abdominis muscle:

1. Situation: 1. It lies midway between suprasternal notch and upper end of pubic symphysis.

2. It roughly corresponds with midpoint between xiphisternal joint and the umbilicus.

3. Anteriorly, it is at tips of 9th costal cartilages.

4. Posteriorly, it is at lower border of L1 (lower border of 1st lumbar vertebra) vertebra.

It is recollected by:

Read And Learn More: General Histology Question And Answers Association memory: Three vertical lines indicate “transpyloric plane” which is a horizontal plane 1. 1st vertical line indicates “L” of lower.

2. 2nd vertical line indicates the 1st.

3. 3rd vertical line indicates “L” of lumbar.

2. Structures at the transpyloric plane are: 1. Pyloric end of the stomach.

2. Lower end of spinal cord.

3. Origin of superior mesenteric artery.

4. Lateral aortic group of lymph node.

5. Hila of both kidneys.

6. Fundus of the gallbladder.

Visual memory: ATM: Above structures can be recollected by visualizing structures from posterior to anterior.

1. First analyze the word “Transpyloric”. The word “transpyloric” indicates a transverse plane present at pyloric end of stomach.

1. Spinal cord passes trough vertebral canal which ends at transpyloric plane.

2. Anterior to vertebra we have abdominal aorta. The artery arising from abdominal aorta at this plane is superior mesenteric artery.

3.. The lymph nodes surrounding the aorta are called para-aortic lymph nodes and they are present at this level.

4. On both sides of vertebrae, we have kidneys.

1. We know, right kidney is at lower level because of presence of liver on right side. The upper border of the hilum of right kidney is at this plane.

2. The left kidney is at higher level. Hence the lower border of hilum of left kidney is at this level.

3. On right side, we have part of the gallbladder below the inferior border of liver. It is the fundus of gallbladder.

Sites of portocaval anastomoses 1. Anterior abdominal wall 2. Posterior abdominal wall 3.Lower end of oesophagus 4. Lower end of rectum 5. Falciform ligament

Caput medusae (Caput—head, Medusae— Greek myth, female ^ with snaky hair.)

1. The umbilicus is one of the important sites of portocaval anastomosis.

2. There is anastomosis between tributaries of portal and tributaries of systemic veins.

The veins are paraumbilical veins in the falciform ligament (tributaries of portal vein) and Subcutaneous veins in the anterior abdominal wall (tributaries of epigastric veins which are tributaries of inferior vena cava) .

3. In case of portal hypertension, the blood from portal tributaries is directed into the caval tributaries causing their dilatation and tortuosity. This condition is referred to as ‘caput medusae’ because of its resemblance to the serpents on the head of Medusa, a mythical lady in Greek mythology.

Inguinal ligament Synonymous: Inguinal arch, arcus inguinalis, ligament of Poupart.

Introduction: It is a thickening of lower border of external oblique aponeurosis. It separates abdomen from thigh.

1. Extent: It extends from anterior superior iliac spine to pubic tubercle.

2. Features: 1. It is thickening of lower border of external oblique muscle.

2. It divides abdomen above and thigh below.

3. It extends from anterior superior iliac spine to pubic tubercle.

3. Attachments: 1. Upper surface gives attachments to 1. Internal oblique in lateral 2/3rd 2. Transversus abdominis in lateral 1/3rd 3. Cremaster muscle in middle part.

2. Fascia lata to lower border.

4. Relations: 1. Upper grooved part forms the floor of inguinal canal.

2. Its lodges

1. Spermatic cord in male 2. Round ligament of uterus in female

5. Extension:

1.Pectineal part of the inguinal ligament.:It is called lacunar ligament. It is lar in shape.

1. Anteriorly: It is attached to the medial end of the inguinal ligament.

2. Posteriorly: It is attached to the pecten pubis. It is horizontal in position and supports the spermatic cord.

3. Apex is attached to the pubic tubercle.

2. Pectineal ligament (ligament of Cooper): It is an extension of the inguinal ligament.

It extends from posterior part of base of lacunar ligament. It is attached to the pecten pubis.

3. The reflected part of inguinal ligament: Extends from inguinal ligament to linea alba.

Rectus abdominis 1. Proximal attachments: It arises by two tendinous heads as follows 1. Lateral head from the lateral part of the pubic crest.

2. Medial head from the anterior pubic ligament.

3. The direction of the fibres is vertically and upwards.

2. Distal attachments: It is inserted along a horizontal line extending from the xiphoid process to the 7th, 6th and 5th costal cartilages.

3. Nerve supply : Intercostal nerves (lower 6 or 7 thoracic spinal nerves).

4. Action: Flexion of the trunk (lumbar spine).

Question – 1: Describe rectus sheath under following heads 1. Formation 2. Contents, and

3. Applied anatomy.

Answer: Introduction: It is an aponeurotic sheath enclosing rectus abdominis and pyramidalis muscles.

1. Formation 1. Number: It is one on each side.

2. Features: Given in table Formation of rectus sheath:

2. Contents 1. Muscles: 1. Rectus abdominis 2. Pyramidalis.

2. Arteries: 1. Superior epigastric artery, branch of internal thoracic artery.

2. Inferior epigastric artery, branch of external iliac artery.

3. Veins: 1. Superior epigastric vein > internal thoracic vein > subclavian vein > superior vena cava.

2. Inferior epigastric vein > external iliac vein > common iliac vein > inferior vena cava.

4. Nerves: Lower 5 intercostal nerves and subcostal nerve.

3. Applied anatomy 1. Divarication of recti: In multiparous women and chronic weak children, the upper part of linea alba becomes stretched and gap is produced between two recti.

2. Supraumbilical median incisions: Advantages: It is bloodless area hence there is less bleeding during operation.

Disadvantages: 1. It leaves a postoperative big scar.

2. There is a delay in healing of the wound.

3. Infraumbilical median incisions: Advantages: It prevents ventral hernia.

Disadvantages: 1. There is delay in healing of the wounds because of the less blood supply.

2. Big scar is formed.

4. Advantage of paramedian incision: There is an early healing of wound because of rich blood supply.

5. Incisional hernia: Hernia through the incision taken for the surgery is called incisional hernia. It may be because of injury to spinal nerves.

Question – 2: Name the contents of inguinal canal in male Answer:

1. Spermatic cord in male : It enters through the deep inguinal ring and comes out through the superficial inguinal ring of inguinal canal.

2. Ilioinguinal nerve (L1): It lies outside the spermatic cord but inside inguinal canal.

Question – 2: Name the contents of inguinal canal in female 1. Round ligament of uterus.

2. Ilioinguinal nerve.

Question – 3: Describe inguinal canal under following heads 1. Gross anatomy 2. Development, and 3. Applied anatomy.

Answer: Introduction: It is an oblique passage or canal present in the lower part of anterior abdominal wall for the passage of

1. Spermatic cord in male

or

2. Round ligament of uterus in female 1. Gross anatomy

Situation: It is situated just U” above the midpoint of inguinal ligament.

Extent: It extends from the deep inguinal ring to the superficial inguinal ring Length: 1.5″ (4 cm) Direction: Oblique, downwards, forwards and medially (same as the direction of fibres of external oblique muscle)

Gender variation: The canal is larger in male of larger dimensions of testis in male

than females

. This is because

.

Boundaries: 1. Roof: Roof is formed by lower arched fibres of internal oblique and transversus abdominis.

2. Floor: Laterally: Grooved surface of inguinal ligament.

Medially: 1. The grooved surface of inguinal ligament.

2. Upper surface of lacunar ligament.

3. Attachment of fascia transversalis with the inguinal ligament.

3. Anterior wall: 1. Laterally 1. Skin 2. Superficial fascia 3. External oblique aponeurosis 4. Internal oblique 2. Medially 1. Skin.

2. Superficial fascia 3. External oblique aponeurosis 4. Posterior wall: 1. Laterally 1. Interfoveolar ligament: It is a thickening in the fascia transversalis. It is present on the medial side of deep inguinal ring. It is connected above to the transversalis muscle and below 2. Fascia transversalis.

3. Extraperitoneal connective tissue.

4. Parietal peritoneum.

2. Medially 1. Reflected part of inguinal ligament.

2. Fascia transversalis.

3. Conjoint tendon formed by internal oblique and transversus abdominis.

4. Extraperitoneal connective tissue.

5. Parietal peritoneum.

Direction of muscles of anterior abdominal wall. “The directions are shown by hands of the clock. 3 o’clock indicates direction of the transversus abdominis, 4 o’clock indicates direction of external oblique, 11 o’clock indicates direction of internal oblique

7. Contents: 1. Spermatic cord: In male and round ligament of uterus in female It enters through the deep inguinal ring and passes out through the superficial inguinal ring of inguinal canal.

2. Ilioinguinal nerve: It is derived from 1st lumbar nerve. In the anterior abdominal wall, it lies in the neurovascular plane between the internal oblique and transversus abdominis muscles.

It is content of inguinal canal but it does not enter the canal through deep inguinal ring.

It pierces internal oblique muscle and enters the inguinal canal.

It passes in front of the spermatic cord and leave the canal through superficial inguinal ring. It supplies the skin of the root of the penis and anterior 1/3rd of the scrotum in male

and labium majus in female.

It also supplies small area of thigh below the medial end of the inguinal ligament.

8. Defensive mechanism of inguinal canal: It is the mechanism by which the abdominal contents normally are prevented from entering the inguinal canal.

These are as follows 1. Flap valve mechanism: The increased intra-abdominal pressure approximates anterior and posterior walls and obliterates the inguinal canal.

.

2. Slit valve mechanism: The contraction of external oblique approximates two cruris of the superficial inguinal ring

.

3. Shutter mechanism: The contraction of the internal oblique closes the inguinal

canal as a shutter

.

4. Ball valve mechanism: The cremaster muscle contracts and draws upwards the constituents of the spermatic cord. These constituents aggregate at the superficial inguinal ring and act as a plug for the superficial inguinal ring 5. Superficial: Inguinal ring is guarded by conjoint tendon and reflected part of inguinal ligament.

6. Deep: Inguinal ring is guarded by fibres of internal oblique.

7. Hormones: Play an important role in maintaining tone of inguinal musculature.

2. Development The canal is (developmentally) formed by the descent of gubernaculum of testis or ovary. In fetal life, the round ligament of uterus is accompanied by a process of peritoneum. It usually disappears after birth. In female called canal of Nuck.

3. Applied anatomy

, if it persists after birth, it is

1.The inguinal canal is a region of potential weakness in the lower part of anterior abdominal wall. Protrusion of abdominal contents through inguinal canal is called inguinal hernia 2. If contents are pushed out indirectly through deep inguinal ring > inguinal canal.

3. Superficial inguinal ring > scrotum, it is called indirect inguinal hernia It enters the inguinal canal through the deep ring lateral to the inferior epigastric artery.

4. If the contents are pushed out directly forwards through posterior wall of inguinal canal . Superficial inguinal ring > scrotum, it is called ‘direct inguinal hernia’. The direct inguinal hernias pass medial to the inferior epigastric artery and lie medial to the spermatic cord.

1. Medial direct inguinal hernia, and 2. Lateral indirect inguinal hernia.

5. Inguinal hernias lie superior and medial to the pubic tubercle. This is in contrast to the femoral hernias which lie inferior and lateral to the pubic tubercle 6. Direct inguinal hernias are more frequent in old persons. In old age, muscles become lax due to loss of tone and power. The lax muscles yield easily following a 1. Heavy strain 2. Chronic cough 3. Constipation, and 4. Bladder Outlet Obstruction. It is commonly called BOO are 1. Stricture of urethra 2. Meatal stenosis

3. Cancer of bladder 4. Prostatitis, and 5. Prostatic abscess.

Lacunar ligament Introduction: Lacunar ligament is pectineal part of inguinal ligament.

1. Features:

1. It is lar.

2. It forms the medial boundary of femoral ring.

3. It is strengthened by 4. Pectineal fascia, and 5. Linea alba.

2. Attachments: 1. Anteriorly to medial end of inguinal ligament.

2. Posteriorly to pectin pubis 3. Apex is attached to pubic tubercle.

3. Function: It supports spermatic cord.

Attachments to pubic tubercle

1. Medial end of inguinal ligament 2. Medial ends of the loop of cremaster

Superficial inguinal ring 1. Location: It is situated 1 cm above the pubic tubercle.

2. Formation: It is formed in the external oblique muscle.

3. Shape: It is 4. Axis: It is oblique.

lar in shape.

5. Dimension: 1. Length: 1 2. Breadth: ½ 6. Relations: 1. Anterior: 1. Skin, and 2. Superficial fascia.

2. Medial: Pubic tubercle.

3. Lateral: Inferior crus of external oblique muscle which is attached to pubic tubercle.

4. Posterior: 1. Conjoint tendon.

2. Reflected part of the inguinal ligament.

7. Contents: 1. Ilioinguinal nerve.

2. Spermatic cord or round ligament of uterus.

Deep inguinal ring 1. Location: It is situated 1 cm above the mid-inguinal point.

2. Formation: It is present in the fascia transversalis.

3. Shape: It is oval ‘ hi shape.

4. Axis: It is vertical.

5. Relations: 1. Anterior: Arched fibres of transversus abdominis.

2. Medial: Inferior epigastric artery.

Coverings of spermatic cord Coverings of spermatic cord: These are described from superficial to deep.

1. External spermatic fascia: It is formed by external oblique. It covers the cord below the superficial inguinal ring.

2. Cremasteric fascia: It is derived from internal oblique and transversus abdominis muscle.It covers the cord below the level of these muscles.

3. Internal spermatic fascia: It is derived from fascia transversalis. It covers the cord in the whole extent.

Spermatic cord Introduction: Each testis develops in the lower thoracic and upper lumbar regions. It migrates into the scrotum. During its descent, it carries “vas deferens” with its vessels, nerves, etc. It is one on each side.

1. Gross 1. Length: 7 cm.

2. Extent: It extends from upper pole of testis to the deep inguinal ring.

3. Course: It ascends in the scrotum and enters the inguinal canal to the superficial inguinal ring. It passes through the inguinal canal and ends at the deep inguinal ring.

2. Constituents are grouped as 1. Deep to internal spermatic fascia “Vas deferens”: It starts at the tail of epididymis. At the upper pole of the testis, it is accompanied by other constituents of the spermatic cord. At the deep inguinal ring, it leaves all the structures and enters the abdomen.

Artery to vas: It is a branch of inferior or superior vesical artery, which is a branch of anterior division of internal iliac artery.

Structures in relation to testis: 1. Testicular artery: It is a branch of abdominal aorta.

2. Testicular sympathetic plexus: It is formed by renal and aortic plexus.

3. Testicular lymph vessels: They drain into the lateral aortic group of lymph nodes.

4. Pampiniform plexus Genital: Branch of genitofemoral nerve supplies cremaster muscle.

2. Between external and internal spermatic fascia: Artery to cremaster, a branch of inferior epigastric artery.

3. Out side spermatic cord: Ilioinguinal nerve

3. Applied anatomy 1. Vasectomy: It is surgical removal of “vas deferens” or portion of it. It is one of the commonest operations done for family planning.

2. Varicocele: The dilatation and tortuosity of pampiniform plexus in the spermatic cord is called varicocele. It mainly occurs on left side.

3. Torsion of spermatic cord: Torsion (twisting) of the spermatic cord results in death of testis. Hence, it is a surgical emergency.

Hesselbach’s (Trigonum inguinale—Inguinal trigone) Introduction: It is a

lar area presents on the anteroinferior wall of abdomen.

1. Boundaries: It is bounded.

1. Medially by the lateral border of rectus abdominis muscle.

2. Laterally by the inferior epigastric artery.

3. Base by the inguinal ligament.

4. Floor by the posterior wall of inguinal canal .

2. Distribution: Inguinal hernia is divided into two types depending upon the relation in the Hesselbach’s 1. If hernia is passing lateral to the Hesselbach’s hernia. ingunial hernia.

it is called indirect

2. If hernia is passing through the Hesselbach’s , it is called direct inguinal hernia (i.e. medial to inferior epigastric artery). Direct inguinal hernia is again subdivided into.

1. Lateral direct inguinal hernia: It lies lateral to obliterated umbilical artery. The contents of direct hernia enter through medial inguinal fossa.

2. Medial direct inguinal hernia: It lies medial to obliterated umbilical artery. The contents of the hernia enter through the supravesical fossa.

3. Characters:

Inguinal hernia passing through Hesselbach’s 1. It is acquired.

2. It is usually bilateral and occurs in old age.

4. Applied anatomy: 1. In long-standing hernia, inferior epigastric artery helps to differentiate between direct and indirect inguinal hernias .

2. It is anatomical landmark to 1. Differentiate between direct and indirect hernias, and 2. Recognize neck of hernial sac.

Question – 4 : What is inguinal hernia?

The inguinal canal is a region of potential weakness in the lower part of anterior abdominal wall. Therefore, following an increased intra-abdominal pressure, the abdominal contents are pushed out through inguinal canal called inguinal hernia.

Inguinal hernia Introduction: It is an abnormal protrusion of abdominal contents through the weak point of abdominal wall.

1. Classification: 1. Based upon the situation of the contents of hernia.

Direct (old age): If the contents are pushed out directly forwards through posterior wall of inguinal canal > superficial inguinal ring > scrotum, it is called ‘direct inguinal hernia’.

If the hernia is medial to inferior epigastric artery, it is diagnosed as direct inguinal hernia. These are subdivided depending upon the relation to the obliterated umbilical artery.

1. Medial: Contents of hernia are medial to obliterated umbilical artery.

2. Lateral: Contents of hernia are lateral to obliterated umbilical artery.

Indirect (oblique): If contents are pushed out indirectly through deep inguinal ring> inguinal canal > superficial inguinal ring into the scrotum, it is called indirect inguinal hernia. Indirect inguinal hernias enter the inguinal canal through the deep ring.

It is lateral to the inferior epigastric artery and lies within the spermatic cord.

1. Congenital.

2. Acquired.

2. Features: 1. Inguinal hernia lies superior and medial to the pubic tubercle. This is in contrast to the femoral hernias.

2. Direct inguinal hernias are more frequent in old persons. In the old age, muscles become lax due to loss of tone and power. The lax muscles yield easily following a heavy strain, as in chronic cough and constipation.

3. Difference between direct and indirect hernias.

External oblique muscle of anterior abdominal wall 1. Proximal attachments: 1. Middle part of shaft of lower 8 ribs.

2. Upper 4 slips get merged with the lower 4 digitations of serratus anterior.

3. Lower fibres get merged with the upper fibres of latissimus dorsi.

4. Direction of fibres: Downwards, medially and forwards.

2. Distal attachments: Fibres of the muscles are fleshy in proximal attachments and end in aponeurosis. The aponeurosis ends in 1. Xiphisternum 2. Linea alba 3. Pubic symphysis 4. Pubic crest, and 5. Pectinate line of pubis

3. Actions: 1. Lateral bending of back 2. With opposite internal oblique, it brings rotation.

4. Nerve supply: Lower 6 thoracic spinal nerves

Transversus abdominis muscle: 1. Proximal attachments: Fibres of the muscles are fleshy in proximal attachments and end in aponeurosis. The fleshy part arises from

1. Lateral 1/3rd of inguinal ligament 2. Anterior 2/ 3rd of outer lip of ventral segment of iliac crest.

3. Thoracolumbar fascia, and 4. Inner surface of lower 6 costal cartilages.

2. Direction of fibres: Runs horizontally 3. Distal attachments: Along a line of 1. Xiphoid process 2. Linea alba 3. Pubic crest, and 4. Pectineal line of the pubis 4. Nerve supply : Lower 6 thoracic nerves and first lumbar nerve.