True/False: The Costal Cage provides the bony framework for protection of organs and vessels.
Ribs provide the structural integrity for respiration, but multiple rib fractures can lead to loss of rib function.
True
*paradoxical movement during lung inflation and deflation
Expansion of the costal cage during inhalation leads to _____ pressure within the thorax. This pulls in air, lymph, and venous drainage into the thoracic cavity and enhances flow.
Negative pressure
*sympathetic chain ganglia run along costovertebral joints – stimulated by motion
The Costovertebral joint is formed by the head of the rib. The head has two articular facets:
Atypical ribs are
1, 2, 10, 11, 12
Typical ribs have a head (w/ 2 articular facets), neck, tubercle, angle and shaft. List the typical ribs
All but 1, 2, 10, 11, 12
The shortest rib. It has a site for attachment of the anterior and middle scalenes. It is atypical because it only articulates with T1 and lacks an angle or a groove
Rib 1
Is a small atypical rib that has attachment sites for Serratus and Posterior scalene.
It has a large tuberosity on the shaft for the serratus anterior, but no non-articular tuburcle
Rib 2
________ is caused by Cervical Rib/Spasm of scalenus anterior muscle that compresses the subclavian artery and brachial plexus leading to ischemia and nerve pressure symptoms of the upper limb
Thoracic Outlet Syndrome
2. no neck, no tubercle
True/False: The ribs protect the organs, provide attachment sites for respiratory muscles, and support postural mechanics.
They are connected to the upper extremity by the clavicle
True
Most commonly caused by trauma (e.g. motor vehicle accidents, assault, sports, CPR, etc.)
Clinical presentation includes focal tenderness, crepitus and ecchymosis.
Rib fracture
*cancer, stress fractures
Complications:
–pneumothorax, flail chest, pneumonia, etc.
NOTE: start w/ X-ray; CT is gold standard
Inhalation involves the External Intercostals, Interchondral intercostals, and what accessory muscles?
*diaphragm: descends; elevates lower ribs
Pec minor
Serratus ant.
Latissimus dorsi
Exhalation occurs by passive recoil. However, forced expiration occurs by what muscles?
extrachondral internal intercostals and abdominals
The Diaphragm is the musculotendinous boundary between the negative pressure thoracic cavity and the positive pressure abdominal cavity.
It is innervated and supplied by
Phrenic nerve (C3-C5) Phrenic artery
*attaches to lower 6 ribs
Principle muscles of inhalation They originate on ribs 1-11 but insert on ribs 2-12.
They are responsible for elevation of the ribs and bending them open (expanding transverse dimensions of the thoracic cavity).
External Intercostals (elevate ribs; enlarge rib cage) and Intercatilaginous portion of Internal Intercostals (elevate ribs)
The diaphragm is divided intoperipheral andcentral attachments.
There are 3 Peripheral Attachments:
3. Xiphoid process
The Central attachments of the diaphragm are the R and L crura which arise from L1-L3 and their IVD’s.
The muscle fibers of the diaphragm combine to form a ______
central tendon
Accessory muscles involved in inhalation include the Scalenes and Sternocleidomastoid.
The Scalenes originate from C2-7 and insert on ribs ______.
The SCM originates on the manubrium and medial clavicle. It inserts onto the mastoid process and aids in ____
Scalenes: Ribs 1 and 2
SCM:
–insert: mastoid process
–lifts/elevates sternum
in addition to head sidebending towards/rotating away
Accessory muscles involved in inhalation include the Pectoralis Minor and Serratus Anterior
Pec minor: ribs 3-5
Serratus anterior: ribs 1-9
This is an accessory muscle to inhalation.
It originates at T7-L5, the Iliac crest and on Ribs 8-12.
It inserts on the floor of bicipital groove of humerus after spiraling around teres major
It functions in: extension, adduction and medial rotation of the arm, but its Costal attachment helps with deep inspiration.
Latissimus dorsi
True/False: Exhalation is usually quiet and passive. However, in active (forced exhalation) it involves the extrachondral internal intercostals and abdominal muscles.
True
During inhalation, the diameter increases in both the AP and transverse plane.
Anteriorly, there is upward motion of the _____ and _____. Posteriorly, there is caudal motion of the _____, and Laterally, there is upward and lateral motion of the ribs.