Thoracic Wall chp 23/mediastinum chp 24 Flashcards
Sternum (breast bone)
Flat bone, anterior midline of thorax. Consists of manubrium, body, xiphoid process
Manubrium
Superior sternum, jugular notch, articulates w first 2 costal cartilage and clavicles
Body
middle sternum, long, narrow, thin, articulates w cc of ribs 2-7, has sternal angle (imp landmark for counting ribs)
Xiphoid process
small, variable, inferior sternum, has epigastric fossa - pit of stomach - ant. Has xiphisternal joint
Ribs (costae)
12 pairs, flat, course ant/inf - head to body, neck, tubercle to transverse process, body, angle, anterior end articulates w costal cartilage
Costal groove
Inf shaft of rib, VAN (sup to inf)
True/False/Floating
1-7 / 8-12 / 11-12
Costal margin / infrasternal angle
cc of 7 - 10 / intersection of costal margin at xiphisternal joint
Superior / inferior thoracic aperature
upper border of sternum and first ribs, great vessels and visceral ascend and descend btw thorax and neck / diaphragm, IVC, esophagus and aorta
External intercostal muscles
11, inf to sup, external intercostal membrane at costochondral jxn Elevation = Inspiration
Intercostal (T1-T6) and thoracoabdominal (T7-T11)
Internal intercostal muscles
sup to inf - internal intercostal membrane at intercostal spaces Expiration Intercostal (T1-T6) and thoracoabdominal (T7-T11)
Innermost intercostal muscles
11, same O, I, and N as internal, separated by internal vessels and nerves by neurovascular plane
Thoracic nerves
12, traverse intervertebral foramen, divide into ventral and dorsal rami
Dorsal rami
post, into medial and lateral branches
Ventral rami
largest, forward into intercostal spaces,
T1 - T6 = intercostal nerves (proper)
T7 - T11 = Thoracoabdominal nerves
T12 = subcostal nerve
Intercostal nerve course
below neck of numerical rib, in neurovascular plane, in costal groove VAN, lateral cutaneous branch (serratus ant into ant/post supplies skin of chest wall) and anterior cutaneous branch (pectoralis to skin of front of chest)
Mediastinum
interpleural space - space btw right/left pleura - all organs of thorax except lungs
extends ant from sternum to post vertebral column
extends from thoracic inlet sup to diaphragm inf
Pleura
thin serous membrane in thoracic cavity in left/right side - double layer = inner mesothelium, outer connective tissue
Visceral pleura
Covers lungs except hilus, dips into fissures btw lobes, few nerves, blood supply via bronchial arteries from des thoracic aorta
Parietal pleura
lining of thoracic wall, diaphragm, and mediastinum, rich nerve and vessel supply, derived from post intercostal and internal thoracic arteries.
4 subdivisions of parietal pleura
Costal parietal pleura = sternum, ribs, intercostal muscles
Cupolar (cervical) parietal pleura = over apex of lungs, up to neck of first rib
Diaphragmatic p p = upper surface of diaphragm
Mediastinal p p = forms lateral boundaries of mediastinum
Recesses
where 2 parts of P P join - not occupied by lung =
costomediastinal recess - jxn of costal and mediastinal, ant border of lung fills during strenuous breathing
Costodiaphragmatic recess - jxn of costal and diaphragmatic, inf border of lung fills during strenuous breathing
Pleural Cavity
space btw parietal and visceral pleura
capillary thickness, thin film of fluid, negative pressure (keeps visceral pleura (lungs) by parietal pleura (thoracic chest wall and diaphragm)). So if diaphragm moves, so does lung = breathing
Atelectasis
Collapse of lung
