Thoracic Wall and Cavities Flashcards
List the boundaries of the superior thoracic aperture
T1 vertebral segment, paired 1st ribs and superior manubrium
Superior Thoracic Aperture
communication between thorax and neck
-Contains trachea and esophagus, nerves and blood supply to head, neck and upper extremities
List the boundaries of the thoracic aperture
T12 vertebral segment, 11th and 12th ribs, 7th through 10th costal cartilages and xiphisternal joint
Inferior Thoracic Aperture (Thoracic Outlet)
- irregular communication between thorax and abdomen
- esophagus, inferior vena cava, aorta
Describe the three parts of the sternum
Manubrium,Body of Sternum
Xiphoid Process
Manubrium boundaries
- Suprasternal angle: top of manubrium
- Sternal angle: junction of manubrium and body
- Clavicular notch: articulates with clavicle
Body of Sternum
- Xiphoid/sternal joint attaches xiphoid to sternum
- Articulates with second to seventh costal cartilages
Costal Cartilages:
- 1-7:connect ribs to sternum
- 8-10: articulate with cartilage above them before connecting to sternum
Typical Ribs: (3-9)
-head, neck, body, tubercle
Atypical Ribs
- First Rib
- Second rib
- Tenth Rib
- Eleventh Rib
- Twelfth Rib
-First Rib
Head, scalene tubercle for insertion of scalene muscle, groove for subclavian V and A, broadest and shortest
-Second rib
longer than first, two articular facets to articulate with bodies of first and second thoracic vertebrae
-Tenth Rib
head with articular facet to articulate with 10th thoracic vertebrae
-Eleventh Rib
no head and neck, facet on head (false rib)
-Twelfth Rib
no head and neck, facet on head(false rib)
Most commonly fractured Ribs?
middle Ribs, at their weakest locus, just anterior to the Costal Angle. Rib fracture can damage internal organs and produce severe pain with respiration, coughing, laughing and sneezing
Supernumerary Ribs
Extra Ribs either in the Cervical region or Lumbar region
Cervical Ribs typically produce no symptoms; however, can produce neural and circulatory problems with based on their proximity to the Brachial Plexus and Subclavian A. Lumbar Ribs also often produce no symptoms; however, can result in confusion when reading radiographs and other diagnostic images.
three layers of intercostal muscles
External Intercostals,Internal Intercostals,Innermost Intercostals
External Intercostals
- Most superficial layer, extends from tubercles of ribs to junction of costal cartilages with bony ribs
- elevated upon contraction, fibers with inferomedial orientation
- An external intercostal membrane passes from the anterior margin of this muscle to the lateral border of the sternum
Internal Intercostals
- Middle layer of muscles, extends from sternum to mid axillary line
- An internal intercostal membrane passes from the lateral margin of this muscle to the region of the vertebral column to fuse with the superior costotransverse ligaments
- Upon contraction,ribs depressed, inferolateral orientation
Innermost Intercostals
- Deepest layer, extends from angles of ribs to anterior of mid axillary line
- An innermost intercostal membrane passes from the anterior border of this muscle to the lateral border of the transversus thoracis muscle
- The fibers have the same orientation and function as the internal intercostal
Transversus Thoracis
- Not a real intercostal muscle
- It extends from the posterior surface of the lower half of the body of the sternum and the xiphoid process to the costochondral junction of ribs 3-6
- Muscle functions to depress ribs
Nerves of thoracic wall and cavities
- Intercostal nerves, ventral primary rami of T1-T11
- cutaneous branches provide sensory innervation to the skin on the lateral and anterior surfaces of the thorax
- Intercostal nerves T1-T7 have branches that continue into the abdominal wall to provide both motor and cutaneous branches to the muscles and skin in this region
Posterior Intercostal arteries
- located between two deepest layers of intercostal muscles in intercostal spaces 3-11
- These arteries have muscular branches which supply the intercostal, pectoral and serratus anterior muscles.
- In intercostal spaces 3-5 their lateral branches supply the breasts in females.
Supreme Thoracic arteries:
- Supply intercostal spaces 1-2
- branches from axillary
Supreme Intercostal arteries:
- Supply intercostal spaces 1-2
- branches from costocervical trunk