Thorax Anatomy Flashcards: Ribs, Sternum, Musculature and Respiration

Flashcards covering thoracic anatomy: rib classification, sternum, rib articulations, intercostal muscles, diaphragm, respiration mechanics, and nerve/blood supply details.

What ribs are considered true ribs and what do they attach to?

Ribs 1–7; attach to the sternum via costal cartilages.

Which ribs are false ribs and how do 8–10 attach?

Ribs 8–12; 8–10 articulate with the costal cartilage of the rib above; 11–12 are floating.

Which ribs are the floating ribs?

Ribs 11–12.

What is the sternal angle and why is it important?

The junction between the manubrium and the body of the sternum; the second rib articulates there and serves as a key counting landmark.

What are the three parts of the sternum and their roles?

Manubrium, body, and xiphoid process; the manubrium articulates with rib 1 (and part of rib 2) and the clavicle, the body fuses with the manubrium to form the sternal angle, and the xiphoid process is the inferior tip.

What bones comprise the thoracic bony framework mentioned in the notes?

Clavicle, sternum, and true ribs (with scapular attachments via musculature).

With what does the head of a rib articulate?

The bodies of its own vertebra and the vertebra above (costovertebral joints).

What does the tubercle of a rib articulate with?

The transverse process of the same-numbered vertebra (costotransverse joint).

What is in the costal groove and what runs there?

The intercostal neurovascular bundle (vein, artery, nerve) runs in the costal groove from superior to inferior.

What is the angle of a rib?

The bend or curvature of the rib, located away from the vertebral column.

Sternal articulations: what type of joint is the 1st rib with the manubrium?

Synarthrosis (fused with the manubrium).

What type of joint is the 2nd rib at the sternal angle?

Synovial joint at the sternal angle.

Which ribs articulate with the body of the sternum via costal cartilages?

Ribs 3–7 (vertebrosternal ribs).

Which ribs articulate with the ribs above via their cartilage (8–10)?

Ribs 8–10 articulate with the costal cartilage of the rib above (indirect sternum connection).

Which ribs do not articulate fully with the sternum (11–12)?

Ribs 11 and 12; they are floating and do not form a full circle with the sternum.

What are the major components of a typical rib's anatomy (head, neck, tubercle, body, angle)?

Head articulates with the vertebral body of its own vertebra and the one above; neck; tubercle articulates with the transverse process; angle; body.

Which nerves form the intercostal nerves and what is their range?

The ventral rami of thoracic nerves 1–11 give rise to intercostal nerves.

What is contained in the costal groove during a rib?

Intercostal veins, arteries, and nerve (VAN) from superior to inferior.

What are the actions of the external intercostal muscles?

Elevate the ribs, increasing the vertical, A-P, and lateral dimensions of the thoracic cavity.

Where do the internal intercostal muscles originate, insert, and what is their action?

Origin: inferior border of ribs near the sternum; Insertion: superior surface of the rib below; Action: draw ribs together and, with support from above, elevate them.

What is the innervation for the intercostal muscles?

Adjacent intercostal nerves and vessels.

What is the innermost intercostal muscle and its function?

A muscle close to the inner surface of the thoracic wall; origin near the rib–transverse process articulation; insertion just anterior to the membranous portion of the internal intercostal; functions to draw ribs together; innervation similar to other intercostals.

What is the transversus thoracis, including origin, insertion, and action?

Origin: lower third of the body of the sternum; Insertion: lower borders of ribs 2–6; Action: draws ribs downward; Innervation: intercostal nerves.

What are the origin, insertion, and function of the diaphragm?

Origin: xiphoid process, lower ribs, lumbocostal arches, and bodies of L1–L2; Insertion: central tendon; Action: draws the central tendon downward to increase thoracic volume; Innervation: phrenic nerve (C3–C5).

Which arteries supply the diaphragm?

Musculophrenic artery (from the internal thoracic artery) and the inferior phrenic arteries (from the abdominal aorta).

How do the quiet and forced breathing patterns differ in terms of muscles involved?

Quiet breathing mainly uses the diaphragm and external intercostals with passive recoil for expiration; forced breathing uses sternocleidomastoid and scalene muscles (inspiration) and abdominal muscles plus intercostals for expiration.

Which muscles assist with forced inspiration beyond the diaphragm and external intercostals?

Sternocleidomastoid, scalene muscles, serratus posterior superior, levatores costorum, and erector spinae group; intercostals contract as well.

What nerve and vessel pathways are associated with the lateral thoracic wall and serratus anterior?

Long thoracic nerve and lateral thoracic artery supply serratus anterior; digitations of serratus anterior attach to the scapula.