Chapter 25: Surgery and Anatomy

ANATOMIC REVIEW OF ARTERIES AND VEINS AND LYMPHATICS

Arteries of the Head and Neck

• Blood supply to the head and neck (Fig. 25-1, Table 25-1)

• The internal carotid artery (ICA)

• External carotid artery (ECA) and their branches

• Intimate anastamoses between ICA and ECA in the region of the upper central face (nose, glabella, periorbital, and forehead)

• These connections are important clinically in that

  • Infections in this area may extend intracranially via ICA

  • Steroid injections in the periorbital skin may embolize to the retinal artery and cause blindness

• Named arteries give rise to unnamed branches and perforators that nourish overlying muscles, fascia, subcutaneous fat, and skin

  • Septocutaneous arteries: travel through septa to skin

  • Musculocutaneous arteries: perforate muscles to skin

  • Subdermal plexus arteries: at the junction of the subcutaneous fat and the deep reticular dermis

    • – Arise from septocutaneous and musculocutaneous arteries

    • – Main blood supply to the skin

    • – Undermine at least below midfat to preserve the subdermal plexus as immediate subdermal undermining may compromise the subdermal plexus

Venous System of the Lower Extremities

• Consists of the superficial (above muscular fascia) and deep (below muscular fascia) venous system (Fig. 25-2, Table 25-2)

• The superficial and deep systems are connected via perforator veins

• Flow is unidirectional due to bicuspid valves in veins

  • Superficial veins drain into the deep veins via the perforators

  • Deep veins merge to form the common femoral vein

  • Venous valves permit only one-way flow (upward), when competent

  • Greatest density in the calf and progressively fewer valves in the thigh

• Calf muscles act as a muscular pump to propel venous blood upward

  • Venous blood is moved only during muscle contraction

  • Lying still or standing still does not drain the venous system