Thoracic Cage Dynamics

University:
The University Of Western Ontario
Course:
ANAT 2200B | Systemic Anatomy of the Human Body
Academic year:

2022
Views:

221

Pages:

2
Author:

Kyuwon J.

Thoracic Cage Dynamics ● Pump-handel movements ○ Upper ribs 2-6 ■ Upper ribs elevates ■ Anterior ends move up ● Passes on costovertebral + costo-transvers joints ● Lifting handles for water pump ● Anterior posterior diameter increases thoracic cavity ● Sternum rises ● Ribs pivot on costal cartilages ● Bucket handle movement ○ (Lower ribs 7-10) ■ Middle shaft swings outward (while elevated) ■ Bucket handel lifting laterally ○ Increase in transverse diameter in thoracic cavity ○ Costovertebral + sternocostal joints ● Vertical Diameter ○ Diaphragm Descent ○ Abdominal are displaced ○ Abdominal wall expansion (outwards, towards accommodate)increase in vertical dimensions on thoracic cavity ● Combined Effect ○ Quit vs Forced Respirations ■ Quite ● Mainly diaphragm ● Minimal rib movements ■ Forced Respirations ● Diaphragm ● Intercostals ● Accessory muscles ○ Forced expirations ■ Passive recoil ■ Abdominal muscle contractions ● Clinical Imaging ○ Pump-handle ■ Movement could be seen in lateral chest X-ray ○ Bucket handles ■ Movement better in AP view ● Ribcage widens ○ Diaphragm descent ■ Fluoroscopy ■ Sniff test for diaphragamatic Movement / Mechanism Pump-handle (upper ribs) Bucket-handle (lower ribs) Vertical (diaphragm descent) Combined movements Clinical Correlation Explanation / Consequence Sternocostal joint ankylosis (elderly, arthritis) ↓ mobility of upper ribs → impaired ↑ anterior–posterior diameter, reduced ventilation efficiency Costosternal pain (e.g., Tietze syndrome) Localized chest wall pain during rib elevation Costochondritis Inflammation at costochondral junction → pain with lateral expansion Rib fractures Pain + mechanical instability → ↓ transverse diameter expansion, risk of flail chest Phrenic nerve injury (C3–C5) Hemidiaphragm paralysis → paradoxical upward motion on inspiration, reduced lung expansion Diaphragmatic hernia (Bochdalek, hiatal) Abdominal contents move into thorax → ↓ vertical capacity of thoracic cavity Neuromuscular disorders (e.g., ALS, muscular dystrophy) Weak diaphragm + intercostals → impaired pump, bucket, and vertical expansion Trauma / flail chest Paradoxical rib motion → inefficient ventilation ● Pump-handle = anterior posterior issue ● Bucket handles = transverse diameter issues ● Vertical = diaphragm, phrenic nerve problem