posterior abdominal walls

Question 1

What are the cavities in the body?

Answer 1

2x pleural, 1x pericardial, 1x abdominal/pelvic

Question 2

What are cavities lined with?

Answer 2

Serous membrane (simple squamous epithelium + connective tissue)

Question 3

What do the cavities contain?

Answer 3

Fluid & isolated cells.

Question 4

What structure separates the pleural cavities?

Answer 4

The mediastinum

Question 5

Where is the pericardial cavity located?

Answer 5

Within the mediastinum

Question 6

How is the thorax separated from the abdomen?

Answer 6

The diaphragm

Question 7

Divisions of the medistinum?

Answer 7

Superior
Inferior
- anterior
- middle
- posterior

Question 8

Where is the superior and inferior mediastinum divided?

Answer 8

Sternal angle (body of T4/ at level of disc between T4/T5)

Question 9

What does the superior mediastinum contain?

Answer 9

Upper thymus, arch of aorta + it’s immediate branches, SVC, brachicephalic veins, upper oesophagus

UTABES

Question 10

What does the inferior posterior mediastinum contain?

Answer 10

DATE

Descending aorta, azygos vessels, thoracic duct, oEsophagus (to t12)

Question 11

What does the anterior mediastinum contain?

Answer 11

Lower thymus

Question 12

What does the middle mediastinum contain?

Answer 12

T4-T8.

Pericardium & contents - heart & assoc vessels, phrenic nerves passing through fibrous parietal pericardium

Question 13

Serous mebrane adjacent to outer wall of cavity is?

Answer 13

Parietal

Question 14

Diaphragm features.

Answer 14

MUSCULAR left and right domes & FIBROUS central tendon.

Question 15

Where does the central tendon attach to?

Answer 15

The base of the pericardial cavity.

Question 16

What are the attachments of the diaphragm?

Answer 16

Sternal: Back of xiphoid process
Costal: Lower 6 costal cartilages and ribs and transversus abdominus.
Lumbar:
- left & right crura (median arcuate ligament)
- Medial arcuate ligamet
- Lateral arcuate ligament

Question 17

Where does the medial arcuate ligament come from?

Answer 17

Thickening of the fascia overlying psoas major (and minor if present).

Question 18

Where does the lateral arcuate ligament lie?

Answer 18

Arching over quadratus lumborum.

Question 19

Where do the splanchnic nerves enter the abdominal cavity?

Answer 19

Through the crura.

Question 20

Where does the right phrenic nerve enter the abdominal cavity?

Answer 20

Can pass through aperture of IVC (T8 - at edge of right dome near junction of muscle and central tendon)

Question 21

What is the blood supply to the diaphragm?

Answer 21

Superior surface: Musculophrenic arteries (branches of internal thoracic artery)
Inferior surface: Inferior phrenic branches of aorta.

Question 22

What is the innervation of the diaphragm?

Answer 22

Phrenic nerve

Question 23

Where does the phrenic nerve originate?

Answer 23

cervical spinal nerves C3-C5 (but mainly C4)

Question 24

Aperture for IVC?

Answer 24

T8 - edge of the right dome near central tendon.

Question 25

Aperture for left phrenic nerve?

Answer 25

Muscular diaphragm just to left of central tendon.

Question 26

Aperture in diaphragm for oesophagus? What passes through with it?

Answer 26

T10 - vagus nerves.

Above, in front of and to the left of aperture for aorta.

Question 27

What passes trough the aperture for the aorta?

Answer 27

T12 - thoracic duct, azygos vessels, sympathetic trunks.

Question 28

What are the 3 possible pairs of thoracic splanchnics? Where do they arise from?

Answer 28

Greater - always present. 5th - 9th thoracic splanchnic ganglia
Lesser - 90% of individuals - 10th - 11th thoracic splanchnic ganglia
Least - 50% of individuals - 11th thoracic splanchnic ganglia

Question 29

Function of thoracic splanchnics?

Answer 29

Carry preganglionic sympathetic fibres which will synapse in sympathetic ganglia in the abdomen.

Question 30

Path of the phrenic nerves:

Answer 30

• cross anterior surface of scalenus anterior and enter thorax
• descend ANTERIOR to the root of lung
• pass through fibrous pericardium to diaphragm

Question 31

Function of phrenic nerves?

Answer 31

Motor - sole somatic motor supply to diaphragm
Sensory - to pericardium, parietal pleura, diaphragm, liver ligaments (coronary & falciform), suprarenal, IVC & gall bladder

Question 32

Path of vagus nerve?

Answer 32

• Descends through jugular foramen, travels down side of the neck with internal jugula & internal and common carotid arteries
• LEFT side: passes anterior to arch of aorta gives of L recurrent larygneal branch which then passes BEHIND aorta arch & back up neck to larynx.
• RIGHT side: anterior to subclavian artery (gives of r. recurrent larngeal branch)
• both vagi then pass POSTERIOR to roots of lung

Question 33

Function of vagus nerve?

Answer 33

• Supplies pharynx, larynx, soft palate (motor & sensory),
  thoracic viscera & fore & midgut (parasympathetic and sensory)

Question 34

Quadratus lumborum? Attachment? Function?

Answer 34

Rib 12 & bodies of L1-4 to iliac crest.
Muscle on one side - lateral spine flexor
Both muscles contracting - extend lower back.
Breathing - stabilise rib position

Question 35

Posas minor attachment. ACTION.

Answer 35

(absent in 40% individuals)
Bodies T12 & L1 to PECTIN PUBIS.
- Weak trunk flexor

Question 36

Psoas major attachment.

Answer 36

Transverse process & bodies of lumbar vertebra via common tendon with iliacus to upper femur.

Question 37

Iliacus attachment

Answer 37

iliac fossa to upper femur

Question 38

Function of illiacus and psoas?

Answer 38

Flex thigh on pelvis.

Bend trunk & pelvis forward against resistance. (e.g. rising from a sitting position)