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Questions and Answers
What is the function of the sling-like loop of muscle fibers surrounding the esophageal orifice?
During inspiration, what happens to the central tendon of the diaphragm?
What is the function of the diaphragm in abdominal straining?
What is the thoracoabdominal pump?
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Which of the following nerves transmits through the caval opening?
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What is the location of the esophageal opening?
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What is the nerve supply of the parietal pleura and peritoneum covering the central surfaces of the diaphragm?
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What is the effect of paralysis of a single dome of the diaphragm?
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What is the motor nerve supply of the diaphragm?
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What is the function of the diaphragm in weight-lifting?
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Study Notes
Ribs and Costal Cartilages
- 6th to 10th costal cartilages articulate with each other along their borders through small synovial joints.
- 11th and 12th ribs have cartilages embedded in the abdominal musculature.
Joints of Ribs
Joints of Heads of Ribs
- 1st rib and 3 lowest ribs have a single synovial joint with their corresponding vertebral body.
- 2nd to 9th ribs: the head articulates with the corresponding vertebral body and the vertebra above it through a synovial joint.
Joints of Tubercles of Ribs
- Articulates with the transverse process of the corresponding vertebra through a synovial joint (absent in 11th and 12th ribs).
Joints of Ribs and Costal Cartilages
- Cartilaginous joints with no movement possible.
Superior Thoracic Opening (Thoracic Outlet)
- Communicates with the root of the neck through an opening bounded by:
- Posteriorly: T1
- Laterally: medial borders of 1st ribs and their costal cartilages
- Anteriorly: superior border of manubrium sterni
- Contents: apices of right and left lung; brachiocephalic, subclavian arteries and veins; trachea, esophagus; vagus nerves; sympathetic trunk; phrenic nerve.
Inferior Thoracic Opening
- Communicates with the abdomen through a large opening bounded by:
- Posteriorly: T12
- Laterally: curving costal margin
- Anteriorly: xiphisternal joint
- Through this large opening, the following pass:
- Esophagus, many large vessels and nerves, all piercing the diaphragm.
Thoracic Outlet Syndrome
- A group of disorders that occur when blood vessels or nerves in the space between the clavicle and 1st rib (thoracic outlet) become compressed.
- Common causes: physical trauma, repetitive injuries, certain anatomical defects, and pregnancy.
- Treatment: usually involves physical therapy and pain relief measures; in some cases, surgery may be recommended.
Symptoms of Thoracic Outlet Syndrome
- Numbness or tingling in the arm or fingers
- Pain in the neck, shoulder, or hand
- Weakening grip
- Weak or no pulse in the affected arm
- Pale color and coldness on the skin of the upper limb
Muscles of the Thorax
External Intercostal Muscle
- Most superficial layer
- Fibers directed downward and forward
- Origin: inferior border of the rib above
- Insertion: superior border of the rib below
- Extends forward from rib tubercle to costochondral junction
Intermediate Layer (Internal Intercostal Muscle)
- Fibers directed downward and backward
- Origin: subcostal groove of the rib above
- Insertion: superior border of the rib below
- Extends backward from sternum to angle of rib
Incomplete Muscle Layer (Innermost Intercostal Muscle)
- Divided into innermost intercostal, sternocostalis, and subcostalis muscles
- Related internally to endothoracic fascia and parietal pleura, and externally to intercostal nerves and vessels
Blood Vessels and Nerves
Intercostal Arteries
- Each space contains a single posterior intercostal and 2 anterior intercostal arteries
- Branches to muscles, skin, and parietal pleura
Intercostal Nerves
- 11 intercostal nerves: ventral (anterior) rami of the first 11 thoracic nerves
- Course and relations: enter intercostal space between parietal pleura and posterior intercostal membrane
- Types: typical, atypical (supplying chest wall and anterior abdominal wall)
- Branches: rami communicantes, collateral branch, lateral cutaneous branch, anterior cutaneous branch, muscular branches, pleural sensory branches, and peritoneal sensory branches
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Description
This quiz covers the anatomy of ribs and costal cartilages, including their joints and articulations. It's ideal for students of biology, medicine, or anatomy.
