3 divisions of hypaxial muscles
- body wall muscles: between celom and skin
- limb muscles
- Prevertebral muscles (neck)
Body wall muscles (lateral)
Neck: scalenes
Thorax: external intercostals, internal intercostals, “scattered deep bits”
Abdomen: external oblique, internal oblique, transverse abdominus
Body wall muscles (anterior)
Neck: rectus cervicis muscles
Thorax: none
Abdomen: rectus abdominus, pyramidalis
External intercostal muscles
- Most external muscle of body wall
- deficient anteriorly, made up of fascia and called the external intercostal membrane
Internal thoracic muscles
- deep to external intercostal muscles
- deficient posteriorly
- fascia is called internal intercostal membrane
Scattered deep bits
- posterior: subcostal muscle fibers span to intercostal spaces
- laterally: innermost intercostal muscles
- anterior: transverse thoracis- spans several spaces from the ribs to the sternum
Deepest layers of thorax (muscle and connective tissue)
- scattered deep bits
- loose connective tissue: endothoracic fascia
- parietal pleura
VAN
- superficial to scattered deep bits
Vein: posterior intercostal vein
Artery: posterior intercostal artery (comes of aorta)
Nerve: intercostal nerve–> thoracic ventral rami
How many intercostal nerves are there?
11
Intercostal nerves span from….
T1-T11
What happens to T12?
Subcostal nerve
Sympathetic trunk
White rami communicans–>sympathetic trunk–>
Input: T1- L2 through white rami
Posterior intercostal artery
- 11 of them
- Intercostal spaces 3-11
- comes off the aorta
Internal thoracic artery
Gives off anterior intercostal artery (1-6)
- anterior intercostal artery branches into: (after 6th intercostal space)
- superior epigastric artery
- musculophrenic artery (7,8,9)
Anastemosis in thorax
- Posterior intercostal artery and anterior intercostal artery
- Superior epigastric artery and inferior epigastric artery
- with in rectus abdominus
Autonomics
– motor only to…
Smooth muscle
Cardiac muscle
Glands
Common features of autonomics
2 neuron chain from CNS to target
Neuron in CNS—-(passes thru PNS)—goes to ganglion— target
Parasympathetics
Thorax: vagus- ganglion in walls of target
Abdomen: vagus- left colic flexure
– below LCF and pelvis: S2, S3, S4- pelvic splanchnic nerves
Only parasympathetic in the perineum is erectile tissue of the clitoris and penis
Autonomics of T1-T5
Lateral horn- preganglionic sympathetics
- goes to sympathetic trunk and then to sympathetic ganglion
- -To white ramus communicans
- -Then to cardiac nerve (post ganglionic)
- -to target: thoracic viscera
What are the different parts of the mediastinum in the thoracic cavity
Superior mediastinum Inferior mediastinum -anterior mediastinum -posterior mediastinum - middle mediastinum
Where is the mediastinum located and what does it contain?
Region between pleural sacs
Contains all structures in thoracic cavity except lungs
Superior mediastinum
- where is it located (inferior and superior limits)
- what it contains
- inferior limit: plane from sternal angle to inferior lip of body of T4
- superior limit is thoracic inlet (body of t1, 1st ribs and manubrium)
- contains remnants of thymus gland, brachiocephalic veins, superior vena cava, aortic arch and branches, lower trachea, phrenic nerves, vagus nerves, left recurrent laryngeal nerve, thoracic duct
Inferior mediastinum
- anterior mediastinum
- –where is it located and what does it contain
Smallest part
Anterior limit: sternum
Posterior limit: anterior surface of fibrous pericardial sac
Contains: fat, sternopericardial ligaments, internal thoracic artery and vein, lymph nodes
Posterior mediastinum
- where is it located
- what does it contain
Posterior limit is vertebral bodies T4-T12
Anterior limit is posterior surface of fibrous pericardial sac
Contains: esophagus, vagus nn, thoracic duct, azygous venous system, thoracic aorta, sympathetic trunk, splanchnic nn, lymph nodes
