Abdomen Flashcards
What are the layers of the anterior abdominal wall (superficial to deep)?
- Skin
- Superficial fascia
- Anterior abdominal wall muscles
- Transversalis fascia
- Extraperitoneal connective tissue
- Peritoneum
What are the layers of superficial fascia in the anterior abdominal wall (superficial to deep)? Describe the layout.
- Superficial fatty layer - fascia of Camper’s
- Deep membranous layer - fascia of Scarpa’s
Above the umbilicus, the superficial fascial layer is only fat. Below the umbilicus, the other two layers arise.
What are the 6 muscles of the anterior abdominal wall?
Anterolateral:
- External oblique
- Internal oblique
- Transversus abdominis
Midline:
- Rectus abdominis
- Pyramidalis
- Cremaster muscle
What is the origin of external oblique?
- Ribs (5-12)
What is the insertion of external oblique?
- Pubic tubercle
- Linea alba
- Iliac crest
What is the origin of internal oblique?
- Iliac crest
- Thoracolumbar fascia
- Inguinal ligament
What is the insertion of internal oblique?
- Ribs (10-12)
- Linea alba
- Pubis
What is the origin of transversus abdominis?
- Thoracolumbar fascia
- Inguinal ligament
- Iliac crest
- Ribs (7-12)
What is the insertion of transversus abdominis?
- Linea alba
- Pubic crest
- Pecten pubis
What are the functions of external oblique, internal oblique, and transversus abdominis?
All: Compress and support abdominal viscera
Obliques only: Flexion and rotation of trunk
What is the origin of rectus abdominis?
- Pubic symphysis
2. Pubic crest
What is the insertion of rectus abdominis?
- Ribs (5-7)
2. Xiphoid process
What is the function of rectus abdominis?
Compression of abdominal viscera
What is the origin of pyramidalis?
- Body of pubis
What is the insertion of pyramidalis?
- Linea alba
What is the function of pyramidalis?
Tenses linea alba
What is the origin of cremaster?
- Internal oblique muscle
2. Inguinal ligament
What is the insertion of cremaster?
- Crest of pubis
2. Pubic tubercle
What is the function of cremaster?
Moves the testes
What is the rectus sheath?
Aponeurotic sheath formed by the fusion of the aponeuroses of external oblique, internal oblique, and transversus abdominis.
What are the muscular contents of the rectus sheath?
- Rectus abdominis
2. Pyramidalis
What are the vascular and nerve contents of the rectus sheath?
- Inferior epigastric
- Superior epigastric
- Lower 6 intercostal nerves
Describe the walls of the rectus sheath above the arcuate line.
The anterior layer of the rectus sheath above the arcuate line contains the aponeuroses of the external and internal obliques. The posterior layer of the rectus sheath contains the aponeuroses of the internal oblique and transversus abdominis.
Describe the walls of the rectus sheath below the arcuate line.
The rectus sheath below the arcuate line contains the aponeuroses of the external oblique, internal oblique, and transversus abdominis. The rectus abdominis is not within the rectus sheath; it is in contact with the transversalis fascia.
What are the three lines in the abdomen? Describe them.
- Linea semilunaris - curved tendinous intersection on either side of rectus abdominis
- Linea alba - runs down the midline of the abdomen
- Arcuate line - demarcates the lower limit of the posterior layer of the rectus sheath; where inferior epigastric vessels perforate the rectus abdominis
The inguinal canal is formed in relation to the relocation of the ___ during fetal development.
Gonads
What is a fibrous band that extends from the caudal part of the testis and plays a role in the descent of the testis?
Gubernaculum
What does the gubernaculum do?
Forms a path through the anterior abdominal wall for the processus vaginalis to follow during the formation of the inguinal canal; it then anchors the testis to the scrotum.
What are the layers of the scrotum?
- Skin
2a. Dartos fascia
2b. Dartos muscle - External spermatic fascia
- Cremaster muscle
- Cremasteric fascia
- Internal spermatic fascia
- Tunica vaginalis (parietal and visceral layers)
What is each layer of the scrotum derived from?
- Skin from skin
2a. Dartos fascia from Camper’s fascia
2b. Dartos muscle from Scarpa’s fascia - External spermatic fascia from external oblique
- Cremaster muscle from internal oblique
- Cremasteric fascia (n/a)
- Internal spermatic fascia from transversalis fascia
- Tunica vaginalis from peritoneum
Which part of the abdominal wall does not become a part of the scrotum?
Transversus abdominis
The ___ is an oblique passage in the lower part of the anterior abdominal wall just above the medial half of the inguinal ligament.
Inguinal canal
How long is the inguinal canal?
4cm
In what three directions is the inguinal canal directed?
Downward, forward, medially
In which sex is the inguinal canal larger?
Male
Where is the deep inguinal ring located?
Transversalis fascia
What passes through the deep inguinal ring to enter the inguinal canal?
Spermatic cord (males), round ligament of uterus (females)
What is the other name for the inguinal triangle?
Hesselbach’s triangle
What are the medial, lateral, and inferior boundaries of Hesselbach’s triangle?
- Medial: linea semilunaris
- Lateral: inferior epigastric vessels
- Inferior: inguinal ligament
What is a common site of a direct inguinal hernia? Why?
Hesselbach’s triangle; it is an area of potential weakness
Which abdominal muscle has low arching fibers?
Internal oblique
Which abdominal muscle has high arching fibers?
Transversus abdominis
What forms the conjoint tendon?
Internal oblique and transversus abdominis
What contains the superficial inguinal ring?
External oblique aponeurosis
What forms the inguinal ligament?
External oblique
What structures pass through the superficial inguinal ring?
Spermatic cord (males) or round ligament (females), and ilioinguinal nerve
Describe the boundaries of the inguinal canal (roof, floor, anterior wall, posterior wall)
- Roof: internal oblique and transversus abdominis
- Floor: inguinal ligament
- Anterior wall: external oblique aponeurosis and internal oblique fibers (lateral 1/3)
- Posterior wall: transversalis fascia and conjoint tendon (medial 1/3)
What are the three coverings of the spermatic cord?
- External spermatic fascia
- Cremaster muscle and fascia
- Internal spermatic fascia
What are the three arteries of the spermatic cord?
- Testicular artery
- Cremasteric artery
- Artery of vas
What are the three “V” structures of the spermatic cord?
- Vas deferns
- Pampiniform venous plexus
- Vestiage of processus vaginalis
What are the three nerves of the spermatic cord?
- Genital branch of genitofemoral nerve
- Sympathetic plexus around testicular artery
- Sympathetic plexus around artery of vas