Posterior Abdominal Wall

Question 1

Summarise the contents of the posterior abdominal wall

Answer 1

• 5 lumbar vertebrate and IV discs, - IVC and aorta, - Paravertebral gutters (Muscles and kidneys)

Question 2

Name the posterior abdominal wall muscles

Answer 2

• Psoas major, - Psoas minor, - Iliacus, - Quadratus Lumborum - (diaphragm)

Question 3

Name the origins and insertions of Quadratus Lumborum

Answer 3

O - Inferior boarder of 12th rib and the transverse processes of L1-4 vertebrae. I - Iliolumbar ligament and Iliac crest

Question 4

Describe the action of Quadratus lumborum and its nerve innervation

Answer 4

Action - Pulls down the 12th rib which helps with the descent of the diaphragm in inspiration and lateral flexion. N - T12 to L4

Question 5

Name the origins and insertions of psoas major

Answer 5

Origins - Transverse processes of lumber vertebrate, bodies of T12-L4 and the IV disks. Insertion - Lesser trochanter

Question 6

Name the actions and innervation of psoas major

Answer 6

Action - Flexion of the thigh and trunk and lateral flexion of the vertebral column. N - L1 to L3

Question 7

Name the origin, insertion and innervation of psoas minor

Answer 7

Origins - Bodies of T12 to L1, Insertions - Pectineal line and iliopectineal eminence. N - L1

Question 8

Name the origins, insertions, action and innervation of Iliacus muscle

Answer 8

Origins - Iliac fossa, Iliac crest and anterior sacroiliac ligament. Inserts - Lesser trochanter, Action - Femoral flexion of the thigh, Innervation - Femoral nerve (L2-4)

Question 9

What is the function of the femoral sheath and what is it continuous with?

Answer 9

It is a continuous with transversalis and iliac fascia. Its function is to separate the space between the inguinal ligament and hip bone into muscular and vascular compartments

Question 10

What is the function of the muscular and vascular compartments?

Answer 10

Muscular compartment transmits psoas major, iliacus muscles and femoral nerve. Vascular - Transmits femoral vessels

Question 11

Name the boundaries of the femoral canal

Answer 11

Anterior - Inguinal Ligament, Posterior - pectineus Medial - Lacunar ligament, Lateral - Femoral vein. It is then closed by extraperitoneal tissue

Question 12

Explain why femoral hernias occur

Answer 12

The femoral ring is a weak area and so is often associated with abnormal protrusion of the abdominal organs into the femoral canal. Femoral hernias are more prone to strangulation than inguinal hernia

Question 13

Why are femoral hernias more common in women?

Answer 13

Because the in men the inguinal canal is larger due to the spermatic cord and descent of the testies.

Question 14

What are dermatomes and mytomes?

Answer 14

Dermatome - Strip of skin supplied by specific spinal nerve Myotome - Froup of muscle fibres supplied by a specific spinal nerve

Question 15

What is the nerve supply of the abdominal wall?

Answer 15

T7 - L1 spinal nerves. They pass between internal oblique and transversus abdominis

Question 16

Describe where referred pain is from when pain presents in the epigastrium, the umbilicus and the pubic region

Answer 16

T6-7 (epigastrium) - Pain from stomach and oesophagus. T10 (umbilicus) - Appendix, gonads and small intestine. T12 (pubic region) - Lower colon, bladder and uterus

Question 17

Describe the appearance of herpes zoster (shingles)

Answer 17

The rash can form a band along the course of a nerve/dermatome as the virus remains inactive in nerve cells. Reactivation of the virus causes shingles

Question 18

Label the branches of the lumbar plexus

Answer 18

1) Iliohypogastric (L1), 2) Ilioinguinal (L1), 3) Genitofemoral (L1,L2) 4) Lateral femoral cutaneous , 5) Obturator (L2,3,4), 6) Femoral (L2,3,4) 7) To lumbrosacral trunk

Question 19

Where does the lumbar plexus form and what does it supply?

Answer 19

It forms in the psoas major muscle and goes on to supply abdominal muscles and extensor and adductor compartments of the thigh

Question 20

Describe the arterial supply

Answer 20

1. Intercostal arteries, 2. Lumbar arteries (branches of abdominal aorta) 3. Superior epigastric arteries (branch of ITA and descends behind rectus abdominis) 4. Inferior epigastric artery, 5. Superior epigastric artery. 6. Superficial circumflex iliac artery. 7. Deep circumflex iliac artery

Question 21

Describe the venous drainage of the abdomen

Answer 21

Veins radiate from the umbilicus. They eventually drain into femoral and external iliac veins inferiorly and the internal thoracic and axillary veins superiorly. Superficial epigastric and circumflex iliac drain to great saphenous

Question 22

Desribe the anterior superficial lymphatic drainage

Answer 22

Above umbilicus - Anterior axillary nodes. Below umbilicus - Superficial inguinal nodes

Question 23

Describe the posterior superficial lymphatic drainage

Answer 23

Above iliac crests - Posterior axillary nodes. Below iliac crests - Superficial inguinal nodes

Question 24

Describe the deep lymphatic drainage

Answer 24

Drain alongside epigastric vessels either superiorly to parasternal nodes then to mediastinal nodes or inferiorly to external iliac and then para-aortic nodes.

Question 25

Describe the presentation of psoas abscess

Answer 25

Infection passes into psoas muscle sheath and spreads within the muscle sheath. May appear as mass below inguinal lig

Question 26

What is Meralgia paresthetica

Answer 26

characterized by tingling, numbness and burning pain in the outer part of your thigh caused by compression of the lateral femoral cutaneous nerve