Connective tissue (Fascia and function)

• Fascia

  • is a layer of connective tissue lying deep to the dermal portion of the skin.
  • The connective tissues are responsible for providing & maintaining form in the body by supporting, binding tissue parts.
  • It contains collagen & elastic fibers
  • Basically 2 layers: 1. Superficial fascia 2. Deep fascia
• Superficial fascia

  a.k.a subcutaneous tissue / Hypodermis / subcutis

  1. Lies under the dermis of skin
  2. Fibers are less organized and run in all directions
  3. Present throughout the body.
  4. Lies superficial to deep fascia
  5. Contains fat (storage)
  6. Store water
• Superficial fascia

  Functions

  1. Storage - Fats
  2. Conduction – vessels & nerves
  3. Protective cushion – against shock
  4. Thermal insulation – barrier against heat loss (body heat)

  Distribution of Fat in this Fascia:

  • Fat is abundant in the gluteal region (buttocks), front of the thighs, mammary gland.
  • In females, fat is more abundant and is more evenly distributed than in males.
  • Fat is absent -eyelids, external ear, penis, and scrotum.
  • The subcutaneous layer of fat - panniculus adiposus.
• Clinical insight

  Subcutaneous Injections

  • Some drugs are administered in subcutaneous tissue, especially where slow absorption is desirable.
  • The most common example of subcutaneous injection is insulin.
  • The local anesthetics are also injected subcutaneously.
• Deep fascia

  a.k.a. packing material

  1. Covers deeper structures
  2. Fibers are more organized and run in parallel fibers
  3. Lies deep to s/f fascia
  4. Contains little or no fat
  5. Do not store water
  6. Absent in face, abdomen skin and scrotum.
• Functions of deep fascia

  • Neuro-vascular sheath provides pathways for the passage of vessels & nerves; surrounding these structures in a common sheath called “neuro-vascular bundle”
  • Muscles wrapped in deep fascia provide mobility, elasticity and slipperiness to glide freely over one another.
• Functions of deep fascia

  • Fascial investment of muscles prevent them from bulging during contraction. This makes muscular contraction more efficient in pumping blood into the veins and aid in venous return to the heart.
  • Muscles or groups of muscles are generally separated by inter-muscular septum which are deep prolongations of deep fascia.
• Functions of deep fascia

  • Deep fascia provides origin & insertions for muscles.
  • Prolongations of fascial septum in certain areas [e.g. fascial spaces of neck , palmar spaces of palm] prevent the spread of infection by limiting areas and thus controlling pus or fluid from tracking freely to other sites.
• Functions of deep fascia

  • It forms special retaining bands or reticulum which prevent bow-stringing of tendons of wrist & ankle.
  • Strips of deep fascia are sometimes used to repair tendinous or aponeurotic defects e.g. repair of hernia apertures.
• Functions of deep fascia

  • If forms fibrous synovial sheaths for tendons so that they may move freely over one another frictionlessly.
  • Fascia has numerous proprioceptive endings. Therefore it has kinesthetic as well as mechanical
• Lines of cleavage (Langer’s Lines)

  • direction of collagen fibers in the dermis; assist the surgeon to get the minimal scar if incision line is parallel to Langer’s line.

  
• Sites with abundant fat in superficial fascia

  • Breasts, buttocks, flanks, anterior abdominal wall

  (below umbilicus)
• Sites where fat is absent in superficial fascia

  • Eyelids, penis, scrotum
• Most common tumor arising from subcutaneous tissue

  • Lipoma
• Ideal sites for subcutaneous injections

  • Posterior aspect of arm, anterior aspect of forearm, anterior abdominal wall, anterior aspect of thigh
• Toughest deep fascia in the body

  • Temporal fascia, fascia lata
• Sites where deep fascia is absent

  • Face, external genitalia