posterior abdominal walls Flashcards
What are the cavities in the body?
2x pleural, 1x pericardial, 1x abdominal/pelvic
What are cavities lined with?
Serous membrane (simple squamous epithelium + connective tissue)
What do the cavities contain?
Fluid & isolated cells.
What structure separates the pleural cavities?
The mediastinum
Where is the pericardial cavity located?
Within the mediastinum
How is the thorax separated from the abdomen?
The diaphragm
Divisions of the medistinum?
Superior Inferior - anterior - middle - posterior
Where is the superior and inferior mediastinum divided?
Sternal angle (body of T4/ at level of disc between T4/T5)
What does the superior mediastinum contain?
Upper thymus, arch of aorta + it’s immediate branches, SVC, brachicephalic veins, upper oesophagus
UTABES
What does the inferior posterior mediastinum contain?
DATE
Descending aorta, azygos vessels, thoracic duct, oEsophagus (to t12)
What does the anterior mediastinum contain?
Lower thymus
What does the middle mediastinum contain?
T4-T8.
Pericardium & contents - heart & assoc vessels, phrenic nerves passing through fibrous parietal pericardium
Serous mebrane adjacent to outer wall of cavity is?
Parietal
Diaphragm features.
MUSCULAR left and right domes & FIBROUS central tendon.
Where does the central tendon attach to?
The base of the pericardial cavity.
What are the attachments of the diaphragm?
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
Where does the medial arcuate ligament come from?
Thickening of the fascia overlying psoas major (and minor if present).
Where does the lateral arcuate ligament lie?
Arching over quadratus lumborum.
Where do the splanchnic nerves enter the abdominal cavity?
Through the crura.
Where does the right phrenic nerve enter the abdominal cavity?
Can pass through aperture of IVC (T8 - at edge of right dome near junction of muscle and central tendon)
What is the blood supply to the diaphragm?
Superior surface: Musculophrenic arteries (branches of internal thoracic artery)
Inferior surface: Inferior phrenic branches of aorta.
What is the innervation of the diaphragm?
Phrenic nerve
Where does the phrenic nerve originate?
cervical spinal nerves C3-C5 (but mainly C4)
Aperture for IVC?
T8 - edge of the right dome near central tendon.
Aperture for left phrenic nerve?
Muscular diaphragm just to left of central tendon.
Aperture in diaphragm for oesophagus? What passes through with it?
T10 - vagus nerves.
Above, in front of and to the left of aperture for aorta.
What passes trough the aperture for the aorta?
T12 - thoracic duct, azygos vessels, sympathetic trunks.
What are the 3 possible pairs of thoracic splanchnics? Where do they arise from?
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
Function of thoracic splanchnics?
Carry preganglionic sympathetic fibres which will synapse in sympathetic ganglia in the abdomen.
Path of the phrenic nerves:
- cross anterior surface of scalenus anterior and enter thorax
- descend ANTERIOR to the root of lung
- pass through fibrous pericardium to diaphragm
Function of phrenic nerves?
Motor - sole somatic motor supply to diaphragm
Sensory - to pericardium, parietal pleura, diaphragm, liver ligaments (coronary & falciform), suprarenal, IVC & gall bladder
Path of vagus nerve?
- 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
Function of vagus nerve?
- Supplies pharynx, larynx, soft palate (motor & sensory),
thoracic viscera & fore & midgut (parasympathetic and sensory)
Quadratus lumborum? Attachment? Function?
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
Posas minor attachment. ACTION.
(absent in 40% individuals)
Bodies T12 & L1 to PECTIN PUBIS.
- Weak trunk flexor
Psoas major attachment.
Transverse process & bodies of lumbar vertebra via common tendon with iliacus to upper femur.
Iliacus attachment
iliac fossa to upper femur
Function of illiacus and psoas?
Flex thigh on pelvis.
Bend trunk & pelvis forward against resistance. (e.g. rising from a sitting position)
