Thoracic fascial planes

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Thoracic Fascia - The Body's Scaffolding

  • Pectoral Fascia: Superficial; invests the pectoralis major muscle, continuous with fascia of the anterior abdominal wall.
  • Clavipectoral Fascia: Deep to pectoral fascia; encloses subclavius and pectoralis minor muscles.
    • Pierced by: Cephalic vein, thoracoacromial artery & vein, and lateral pectoral nerve.
  • Endothoracic Fascia: Lines the thoracic cavity internally; attaches the costal parietal pleura to the thoracic wall.
    • Thickens over the lung apex as the Suprapleural membrane (Sibson's fascia).

⭐ The endothoracic fascia is continuous with the deep cervical fascia, allowing infections from the neck's "danger space" to track directly into the posterior mediastinum, leading to mediastinitis.

Pectoral & Clavipectoral Fascia - The Anterior Armor

  • Pectoral Fascia: A thin lamina investing the Pectoralis Major muscle.

    • Attachments: Superiorly to the clavicle and medially to the sternum.
    • Continuous inferiorly with the fascia of the anterior abdominal wall; laterally with the axillary fascia.
  • Clavipectoral Fascia: Strong fascial sheet deep to the pectoral fascia, enclosing the Subclavius and Pectoralis Minor muscles.

    • The portion between the two muscles is the costocoracoid membrane.
    • Inferiorly, it forms the suspensory ligament of the axilla (of Gerdy), which supports the axillary floor.

⭐ The clavipectoral fascia (specifically, the costocoracoid membrane) is famously pierced by several key structures superior to the pectoralis minor.

📌 Mnemonic (C-A-L-P) for structures piercing the fascia:

  • Cephalic Vein
  • Acromiothoracic Artery & Vein
  • Lateral Pectoral Nerve
  • Pectoral Lymphatics

Clavipectoral fascia and suspensory ligament of axilla

Endothoracic Fascia - The Inner Boundary

  • Location: A thin, fibro-areolar layer lining the internal surface of the thoracic cage, situated between the parietal pleura and the ribs/intercostal muscles.
  • Function: Acts as a natural cleavage plane, separating the thoracic wall from the delicate parietal pleura.
  • Key Relations & Continuations:
    • Superiorly: Thickens to form the suprapleural membrane (Sibson's fascia), covering the apex of the lung.
    • Costally: Lines the inner surface of the ribs and intercostal muscles.
    • Diaphragmatically: Blends with the fascia covering the diaphragm.
    • Mediastinally: Continuous with the connective tissue of the mediastinum.

Thoracic Wall Layers and Intercostal Neurovasculature

Surgical Pearl: The endothoracic fascia provides a critical plane for extrapleural surgical access. Surgeons dissect within this plane to approach thoracic structures (e.g., sympathetic chain, vertebral bodies) without incising the parietal pleura, thus avoiding pneumothorax.

Clinical Correlates - Pathways for Pathogens

  • Cervical fascial planes are potential conduits for the spread of infection (e.g., from dental abscesses, pharyngitis, or tonsillitis) from the neck to the mediastinum.
  • Retropharyngeal Space:
    • Infections can create abscesses, causing dysphagia, odynophagia, and neck pain.
  • "Danger Space":
    • Lies between the alar fascia and the prevertebral fascia.
    • This space provides a continuous path from the base of the skull to the diaphragm.
    • It is the most dangerous route for infection spread into the posterior mediastinum.

⭐ Infections reaching the posterior mediastinum via the "danger space" can cause acute necrotizing mediastinitis, a rapidly progressing condition with a mortality rate approaching 50%.

Neck fascial planes & infection routes (sagittal & axial)

High‑Yield Points - ⚡ Biggest Takeaways

  • The retropharyngeal space allows infection spread from the pharynx to the superior mediastinum.
  • The "danger space" is a direct route for infection from the skull base to the diaphragm.
  • Mediastinitis is a lethal complication of infections spreading through these planes, often from dental sources.
  • The carotid sheath contains the common carotid artery, internal jugular vein, and vagus nerve.
  • Ludwig's angina can cause fatal airway compromise by spreading into adjacent neck spaces.

Practice Questions: Thoracic fascial planes

Test your understanding with these related questions

A 66-year-old man is transferred from another hospital after 3 days of progressively severe headache, vomiting, low-grade fever, and confusion. According to his partner, the patient has been dealing with some memory loss and complaining about headaches for the past 2 weeks. He has a history of interstitial pulmonary disease that required lung transplantation 2 years ago. Upon admission, he is found with a blood pressure of 160/100 mm Hg, a pulse of 58/min, a respiratory rate of 15/min, and a body temperature of 36°C (97°F). During the examination, he is found with oral thrush and symmetric and reactive pupils; there are no focal neurological signs or papilledema. A lumbar puncture is performed. Which of the following features would be expected to be found in this case?

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Flashcards: Thoracic fascial planes

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Which layer(s) of spermatic fascia cover an indirect inguinal hernia? _____

TAP TO REVEAL ANSWER

Which layer(s) of spermatic fascia cover an indirect inguinal hernia? _____

All three

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