Synechiae

Synechiae (singular: synechia, alternative plural: synechias) are another term for adhesions, which in radiological contexts usually relates to bands of scar tissue between structures, e.g. within the abdominal cavity or pleural cavity or within the uterus.

Pathology

Synechia can be found throughout the body:

• nasal synechiae

  • adhesions between the lateral and medial (septal) walls of the nostril and usually occur post-surgery (e.g. FESS) or due to physical trauma

  • additional causes include chronic and recurrent nasal infections, nasogastric tube insertions, and post-cauterisation for bleeding

• ocular synechiae: iris adheres to the trabecular meshwork (anterior synechiae) or anterior lens (posterior synechiae), usually as a result of inflammation

• penile synechiae: tight attachment of the penile foreskin to the glans penis often a physiological and normal phenomenon in newborn infants and up to three years of age

• uterine synechiae

  • may occur due to curettage (repeated), chronic infections, caesarian delivery or myomectomy

  • Asherman syndrome is characterised by dysmenorrhoea, infertility and placental abnormalities and occurs due to uterine scarring and synechiae

• venous synechiae: develop post-deep venous thrombosis following recanalisation and remodelling of the thrombus with the identification of a residual fibrous membrane or band within the lumen

• vocal cord synechiae: scar tissue that prevents vocal cord function due to tethering and bridging of the vocal cords

• vulvar synechiae: bridge(s) of tissue (skin) uniting the labia minora of the vulva; it is theorised that this condition occurs due to low oestrogen in prepubertal girls; poor hygiene and chronic dermal irritation may also predispose to developing vulvar synechaie

History and etymology

While adhesions have a Latin origin meaning 'sticking to' (compare the common English word 'adhesive'), synechiae are essentially the Greek equivalent, where συνέχεια/sunekheia means to hold (ἔχειν/ekhein) together (σύν/sun). Interestingly, the English word synechia is a Latinised version of the original Greek with one of the accepted plurals (synechiae) following the pattern of a first declension female Latin word – the actual Greek plural would be synechies (συνέχειες). This is a pattern that can be seen in other terms with non-Latin origins.