Week 16 Anatomy - Abdomen + Large Vessels Flashcards
What are the special layers of fascia in the anterior abdominal wall?
**Below level of umbilical, superficial fascia consists of Camper’s Fascia (anteriorly) and Scarpa’s Fascia (posteriorly)
Scarpa’s Fascia is continuous with fascia lata of lower limb.
What are the 3 layers of lateral abdominal wall muscles?
External oblique
Internal oblique
Transversus abdominus
What is the origin and insertion of the external oblique muscle?
Originates from Ribs 5-12, around to linea alba, to the pubic tubercle and anterior iliac crest
Fibres run anteriorly and inferiorly
What is origin an insertion of internal oblique muscles?
Fibres run anteriorly and superiorly, from iliac crest. thoracolumbar fascia to costal cartilages of 10-12 and linea alba, and pubis bone.
What is the origin and insertion of traversus abdominus muscle?
From thoracolumbar fascia to costal cartilages of 7-12, anterior iliac crest, linea alba
What is the origin and insertion of the rectus abdominus?
From costal cartilages and xiphoid process down to pubis, with transverse bands of tendinous connective tissue, and joined on the R + L by linea alba
Describe the aponeurosis of the lateral abdominal wall muscles:
External forms an aponeurosis at the lateral margin of the rectus abdominus, which travels anteriorly to the rectus abdominus
Internal forms aponeurosis at the same margin, but splits to form an anterior and posterior aspect which encases the rectus abdominus.
Transversus abdominus does the same, but remains posterior to the rectus abdominus
What does the sum of the different aponeuroses of the abdominal wall form?
Rectus abdominus sheath
What muscle is responsible for the formation of the inguinal canal? What are the other components?
External oblique: forms the inguinal ligament by looping back on itself to form the inferior part of the canal. The transversalis fascia forms the rest of the canal.
**Internal oblique and tranversus abdominus form a hiatus with their attachments, and don’t directly contribute to the canal.
Where is the deep inguinal ring?
Deep (internal) ring:
Marks the internal opening of the inguinal canal
Found above the midpoint of the inguinal ligament (lateral to the epigastric vessels).
The ring is created by the transversalis fascia, which invaginates to form a covering of the contents of the inguinal canal.
Where is the superficial inguinal ring?
Marks the external end of the inguinal canal
Lies just superior to the pubic tubercle.
It is a triangle shaped opening, formed by the invagination of the external oblique, which forms another covering of the inguinal canal contents.
What is the difference between direct and indirect inguinal hernia?
Direct = directly though abdominal wall musculature
Indirect = through inguinal canal into scrotum
What are the fascial coverings of the spermatic cord?
- External spermatic fascia (derived from the aponeurosis of the external oblique muscle)
- Cremaster muscle and fascia – derived from the internal oblique muscle.
- Internal spermatic fascia – derived from the transversalis fascia.
What are the contents of the spermatic cord?
Blood vessels:
1. Testicular artery
2. Cremasteric artery and vein
3. Artery to vas deferens
4. Pampiniform plexus
Nerves:
1. Genital branch of the genitofemoral nerve – supplies the cremaster muscle.
2. Autonomic nerves
Other:
1. Vas deferens
2. Processes vaginalis
What are the first branches of the aorta?
The right and left coronary arteries, from the sinuses that form just above the cusps of the aortic valve.
What are the branches of the aortic arch?
- Brachiocephalic artery
- Left common carotid artery
- Left subclavian artery
What are the main functions/branches of the descending thoracic aorta?
Oesophageal arteries
Intercostal arteries
Bronchial arteries
Phrenic arteries
How does the aorta pass into the abdomen? What does the aorta get names?
Between the crura of the diaphragm (I.e. there is no hiatus in diaphragm for aorta)
Becomes abdominal aorta
What are the first branches of the abdominal aorta?
Inferior phrenic arteries
What are the 3 anterior branches of the abdominal aorta that supply the GI tract?
- Coeliac trunk
- Superior mesenteric artery
- Inferior mesenteric artery
What structures does the coeliac trunk supply?
Lower 1/3 of oesophagus
Stomach
First half of duodenum
What does the superior mesenteric artery supple?
From later part of duodenum to transverse colon
What does the inferior mesenteric artery supply?
The rest of colon from last part transverse colon to anal canal
What are the corresponding embryological origins/structures of the bowel blood supply?
Coeliac trunk –> foregut
SMA - midgut
IMA - hind gut
What are the paired lateral arteries of the abdominal aorta?
Renal arteries
Gonadal arteries
**Adrenal glands often supplied by renal arteries
Lumbar arteries
Where does the abdominal aorta end?
Where it bifurcates into the common iliac arteries
What veins combine to form the superior vena cava?
Left and right brachio-cephalic veins (left is longer as it travels across to merge
What veins combine to form the inferior vena cava?
Left and right common iliac veins
Why does the inferior vena cava not have equivalents of the coeliac trunk, SMA, IMA?
All venous blood from GI tract travels via portal vein to the liver prior to entry into the IVC just inferior to the diaphragm
What are the the muscles of the posterior abdominal wall?
Diaphragm
Psoas major
Iliacus
Quadratus lumborum