Internal Mammary Vein Valves: A Histological Study.

Area of Science:

• Anatomy
• Vascular Biology
• Histology

Background:

• The internal mammary vein (IMV) is commonly believed to be valveless.
• Limited anatomical studies exist regarding the presence of valves within the IMV.

Purpose of the Study:

• To investigate the hypothesis that the IMV is valveless.
• To anatomically characterize any potential valves within the IMV.

Main Methods:

• Microscopic histological examination of internal mammary vein (IMV) samples from 10 human fresh frozen cadavers.
• Comparison with valves from the small saphenous vein (SSV) as a control.
• Histological staining and microscopic analysis of valve structure.

Main Results:

• Venous valves were identified in 8 out of 20 examined IMVs.
• IMV valves possessed a bipartite leaflet structure: a thick, muscularized part and a thin, non-muscularized part.
• The thick part of IMV valves was smaller than that of SSV valves, while the thin part showed no size difference.

Conclusions:

• The internal mammary vein (IMV) does contain valves, contradicting the prevailing assumption.
• The presence of valves in less than half of IMVs and their smaller leaflet size suggest they may be rudimentary.
• Further research is needed to understand the functional significance of these IMV valves.