Advanced Subcostal Muscles Quiz

Q1. Which description best characterizes the attachment pattern of a typical subcostal muscle?

• From the clavicle to the first rib
• From a vertebral body directly to the diaphragm
• From the sternum to the immediately adjacent rib
• From a rib near its angle to a rib two or three levels below

Q2. Why do subcostal muscles cross more than one intercostal space?

• They attach to the vertebral discs
• They pass through the pleural cavity
• Their insertions are several rib levels below their origins
• They attach directly to the sternum

Q3. Which location most clearly distinguishes subcostals from transversus thoracis?

• Lateral surface of the lung
• Anterior surface of the sternum
• Superior surface of the diaphragm
• Posterior internal thoracic wall

Q4. Which three muscle groups are commonly associated with the deepest plane of the thoracic wall?

• Innermost intercostals, subcostals, and transversus thoracis
• External intercostals, pectoralis major, and diaphragm
• Internal intercostals, trapezius, and latissimus dorsi
• Scalenes, serratus anterior, and pectoralis minor

Q5. Which feature of subcostal fiber orientation supports their role in rib depression?

• Their fibers run like external intercostals
• Their fibers attach directly to the lungs
• Their fibers resemble those of internal intercostals
• Their fibers are circular around the thorax

Q6. Which nerves provide motor supply to subcostal muscles?

• Phrenic nerves
• Greater splanchnic nerves
• Intercostal nerves
• Recurrent laryngeal nerves

Q7. Why are subcostal muscles usually more prominent in the lower thorax?

• They originate from the diaphragm
• They are extensions of abdominal muscles
• They occur only below the twelfth rib
• They are best developed in lower posterior intercostal spaces

Q8. Which tissue lies between the deepest thoracic wall muscles and the costal parietal pleura?

• Fibrous pericardium
• Visceral pleura
• Superficial fascia
• Endothoracic fascia

Q9. Which anatomical feature most clearly distinguishes a subcostal muscle from a typical intercostal muscle?

• It can span multiple intercostal spaces
• It contains smooth muscle fibers
• It lies outside the rib cage
• It is innervated by the vagus nerve

Q10. Which description best summarizes the subcostal muscles?

• Mediastinal muscles that constrict the bronchi
• Deep posterior thoracic muscles that span ribs and assist rib depression
• Superficial anterior muscles that elevate the clavicle
• Pleural muscles that directly expand the lungs