What anatomy should I know for a mass excision over the left scapula?

Surgical Anatomy for Mass Excision Over the Left Scapula

For a mass excision over the left scapula, you should understand the layered anatomy and neurovascular structures to ensure complete tumor removal while preserving critical structures. The surgical approach requires knowledge of both superficial and deep anatomical structures to achieve appropriate margins while minimizing morbidity.

Superficial Anatomical Layers

• Skin and subcutaneous tissue: Contains superficial vessels and nerves
• Superficial fascia: Contains cutaneous nerves and vessels
• Deep fascia: Important resistant anatomical barrier that should be identified during dissection 1
• Muscular layer: Contains the trapezius muscle superficially

Muscular Anatomy

• Superficial muscles:

  • Trapezius: Originates from the occipital bone, ligamentum nuchae, and spinous processes of vertebrae; inserts on the lateral third of clavicle, acromion, and scapular spine
  • Deltoid: Originates from lateral third of clavicle, acromion, and scapular spine; inserts on deltoid tuberosity of humerus

• Intermediate muscles:

  • Rhomboid major and minor: Connect the medial border of scapula to the spinous processes
  • Levator scapulae: Connects the superior angle of scapula to the transverse processes of C1-C4

• Deep muscles:

  • Subscapularis: Located on the anterior (costal) surface of the scapula
  • Infraspinatus and supraspinatus: Located on the posterior surface of the scapula

Critical Neurovascular Structures

• Dorsal scapular nerve: Typically arises from C5 nerve root, but can have dual origin from C5 and C6 2. Supplies the rhomboid muscles and levator scapulae

• Long thoracic nerve: Courses along the lateral chest wall to innervate the serratus anterior muscle

  • Located at least 6.0 cm (males) and 5.5 cm (females) anterior to the scapular tip in posterolateral positioning 3
  • Injury can cause scapular winging and dysfunction

• Suprascapular nerve: Passes through the suprascapular notch to supply the supraspinatus and infraspinatus muscles

• Thoracodorsal neurovascular bundle: Supplies the latissimus dorsi muscle

• Axillary vessels: Located anteriorly and superiorly to the scapula

Surgical Considerations

• Margin requirements: The surgical approach should involve en bloc excision with appropriate margins 1

  • For benign lesions: Marginal excision may be acceptable
  • For suspected sarcomas: Wide excision with tumor-free margins (R0) is standard 4

• Fascial planes: The deep muscular fascia serves as an important resistant anatomical barrier 1

  • For superficial masses: Remain above the fascia
  • For deep masses: Incise the fascia and identify muscular planes

• Surgical marking: Place surgical clips to mark the periphery of the surgical field to guide potential future radiation therapy 4

Potential Complications to Avoid

• Nerve injury: Damage to the dorsal scapular or long thoracic nerves can cause scapular winging and dysfunction 2, 5

• Vascular injury: The suprascapular and thoracodorsal vessels require careful identification

• Functional impairment: Excessive muscle resection can lead to shoulder weakness and limited range of motion

• Incomplete resection: Inadequate margins may necessitate re-excision or adjuvant therapy 4

By understanding these anatomical considerations, you can perform a safe and effective mass excision over the left scapula while minimizing the risk of complications and preserving shoulder function.