Anatomy of the Thoracic Wall Flashcards
What is the purpose of the Thorax?
- Provides protection for underlying structures and organs
- Assists in respiration by resisting negative intra-thoracic pressure
- Provides attachments for muscles
- Haematopoiesis - especially in the sternum
- Connects to the neck, upper limbs and abdomen
What makes up the Thoracic Cage?
- Sternum
- 12 Pairs of Ribs
- Costal Cartilages
- 12 Thoracic Vertebrae and their Intervertebral disks
What makes up the Thoracic Wall?
- Thoracic Cage
- Skin and subcutaneous tissue
- Thoracic muscles and fascia
- Intercostal Muscles - 3 layers
- Mammary Glands/Breast Tissue
Describe the movements permitted by the Thoracic Vertebrae
Some rotation due to arcuate arangement of articular facets, but no flexion
What is the purpose of Costal Cartilage?
Provides Mobility and Elasticity
What are the True Ribs?
Ribs 1-7 which attach to the Sternum directly through their own Costal Cartilage
What are False Ribs?
Ribs 8-10 which attach to the Sternum indirectly through Costal Cartilage of Rib 7
What are Floating Ribs
Ribs 11-12 which don’t articulate with Sternum
Describe the structure of a typical Rib
Consists of a Head with two articular facets divided by a Ridge, a neck, a tubercle with an articular surface, the angle - the sharpest curve of the rib, vulnerable to breakage, and the shaft. A Costal Groove is present on the inner inferior border of the rib and covers the intercostal nerves and vessels.
Which Ribs are classified as ‘typical’?
Ribs 2-9
Describe the structure of the First Rib
Head has only one articular facet, articulates with T1 only. Scalene tubercle present on superior surface divides the groove for the subclavian vein and groove for subclavian artery and inferior trunk (C8 and T1) of the brachial plexus.
Describe the structure of the 11th and 12th Ribs
Head has only one articular facet, articulate only with corresponding vertebrae. No Tubercle as they do not articulate with transverse precesses. Are not attached to Sternum
Describe the structure of the Sternum
Made up of 3 parts:
* Manubrium
* Body
* Xiphoid Process
What is the sternal angle?
Joint between Manubrium and Sternal Body
What occurs at the level of the Sternal Angle?
- 2nd Costal Cartilage joins Sternum
- Intervertebral disk between T4 and T5 vertebrae
- Beginning and End of Aortic Arch
- Bifurcation of the Trachea (Carina)
- Superior limit of the Pulmonary Trunk
- Azygos Vein opening to the Superior Vena Cava
- Ligamentum Ateriosum
What useful surface feature can be found at the Xiphosternum?
T6 Dermatome
Name the Joint that occurs between a Vertebra and a Rib
Costovertebral Joint