Anatomy Respiration II - Thorax

Posterior wall of the thorax formed by _____

thoracic vertebrae

Arterial supply to the thoracic wall

Derives from: 1. Arota - posterior intercostal and subcostal artery 2. Subclavian - internal thoracic, which then gives rise to the anterior intercostal artery 3. Axillary - superior intercostal artery (More branches... mi naahh know)

Parts of the intervertebral disk

1. Anulus fibrosus - outer ring of fibrocartilage 2. Nucleus pulposus

Parts of the vertebrae

1. Body 2. Transverse process 3. Articular process 4. Vertebral arch: Consists of two laminae and two pedicles. 5. Spinous process

Different intercostal muscles and their function

1. External: Run anteriorly from the tubercle of each rib to the costochondral junction. It also attaches to the inferior border of one rib to the superior border of the next. Elevate ribs during forced inspiration. 2. Internal: Run at right angles to the external intercostals, from the floor of the costal groove to the superior border of the rib below. Depresses ribs to aid in forced expiration. 3. Innermost: Helps with respiration. Has 3 parts. - Transverse thoracic muscle (sternocostal): Runs from the posterior aspect of the lower part of the sternum to the costal cartilages 2-6. - Intercostalis intimus: Runs from the costal groove to the superior border of the rib below. - Subcostalis: Runs from the inner surface of the rib near the sternal angle and attaches to the inner surface of lower ribs after crossing one or two spaces.

Characteristic features to identify thoracic vertebrae

1. Tansverse costal facet on the transverse process - this is where the tubercle of the rib articulates with the vertebrae. 2. Articular facet on the articular process

Parts of the sternum

Manubrium: Widest, thickest part. The superior border of the manubrium, the jugular notch, can be easily palpated Body: Connects to the manubrium through the manubriosternal angle. Clinical correlate: Marks the second costal cartilages. Xiphoid process: Connects to the manubrium through the xiphisternal joint.

Parts of the ribs

Neck: Connects the head of the rib with the body at the level of the tubercle Tubercle: At the junction between the head and the body Shaft: Thin, flat and curved, mostly at the costal angle.

Clinical correlate of the nucelus pulposus

Normally during flexion of the vertebral column the disks are compressed anteriorly. If the the annular fibrosis has degenerated herniation of the nucleus pulposus into the vertebral canal can result. This compress the spinal nerve.

Branches of the intercostal nerve (5)

Runs anteriorly along the costal groove. - Posterior ramus - Rami communicantes: Connect each intercostal nerve to the sympathetic trunk - Around the costal angle it splits into lateral cutaneous branch, which further branches into the posterior and anterior branch. - Collateral branch runs parallel to the main nerve and either rejoins it or becomes anterior cutaneous nerve. It runs along the superior margin of the lower rib. - Muscular branches

What does the nerovascular bundle consist of and where is it

The intercostal nerve run inferior to intercostal arteries, which in turn run inferiorly to the veins, in or just below the costal groove

Which nerves are typical and atypical

Typical nerves are found along ribs 4-6. Atypical supply everything else.

Difference between typical and atypical ribs

Typical ribs: - ribs 3-9 - C: Costal grove of the concave interior border of the rib - A: Tubercle has a facet which articulates with the transverse process of the vertebra - T: Twisting of the rib: The rib twists anterolaterally, especially at the costal angle and behind the costal angle the rib twists medially upward. Atypical ribs: - First rib: Shortest, most curved rib. Has a single facet on its head for articulation with the T1 vertebrae. Has two transverse grooves for the subclavian vessels to run through and also a scalene tubercle for muscle attachment. - Second rib: Has two facets on the head. Atypical feature is the rough surface on its body. - 10-12th: Have only one facet and articulate with one vertebrae - 11-12th: Short and have no neck or tubercle

Which vertebrae are typical and atypical

Typical: 2-8 Atypical: 1, 9-12

Difference between true, false and floating ribs

Vertebrosternal (1-7): They attach to the sternum through their own costal cartilages Vertebrochondral (8-10): Attach to the sternum through the costal cartilage of the rib above forming a continuous costal margin Their attachment is indirect. Vertebral (11,12): Attachment to the sternum does not occur.

The nucleus pulposus is a geletinous remnant of the _________

notochord