The suprapleural membrane, eponymously known as Sibson's fascia, is a structure described in human

anatomy Anatomy () is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old science, having i ...

. It is named for Francis Sibson.

Anatomy

It refers to a thickening of

connective tissue Connective tissue is one of the four primary types of animal tissue, along with epithelial tissue, muscle tissue, and nervous tissue. It develops from the mesenchyme derived from the mesoderm the middle embryonic germ layer. Connective tiss ...

that covers the

apex The apex is the highest point of something. The word may also refer to: Arts and media Fictional entities * Apex (comics), a teenaged super villainess in the Marvel Universe * Ape-X, a super-intelligent ape in the Squadron Supreme universe *Apex, ...

of each human

lung The lungs are the primary organs of the respiratory system in humans and most other animals, including some snails and a small number of fish. In mammals and most other vertebrates, two lungs are located near the backbone on either side of ...

. It is an extension of the

endothoracic fascia The endothoracic fascia is the layer of loose connective tissue deep to the intercostal spaces and ribs, separating these structures from the underlying pleura. This fascial layer is the outermost membrane of the thoracic cavity. The endothor ...

that exists between the

parietal pleura The pulmonary pleurae (''sing.'' pleura) are the two opposing layers of serous membrane overlying the lungs and the inside of the surrounding chest walls. The inner pleura, called the visceral pleura, covers the surface of each lung and dips be ...

and the

thoracic cage The rib cage, as an enclosure that comprises the ribs, vertebral column and sternum in the thorax of most vertebrates, protects vital organs such as the heart, lungs and great vessels. The sternum, together known as the thoracic cage, is a sem ...

. Sibson muscular part is originated from scalenus medius muscle. Fascial part is originated from Endothoracic Fascia. It attaches to the internal border of the first

rib In vertebrate anatomy, ribs ( la, costae) are the long curved bones which form the rib cage, part of the axial skeleton. In most tetrapods, ribs surround the chest, enabling the lungs to expand and thus facilitate breathing by expanding the ches ...

and the transverse processes of

vertebra The spinal column, a defining synapomorphy shared by nearly all vertebrates, Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristi ...

C7. It extends approximately an inch more superiorly than the

superior thoracic aperture The superior thoracic aperture, also known as the thoracic outlet, or thoracic inlet refers to the opening at the top of the thoracic cavity. It is also clinically referred to as the thoracic outlet, in the case of thoracic outlet syndrome. A low ...

, because the lungs themselves extend higher than the top of the ribcage.

Clinical significance

*The function of the suprapleural membrane is to protect the apex of the lung (as some of the part which extends outside the rib cage) and to protect the cervical fascia. This helps in resisting intrathoracic pressure changes therefore preventing inflation and deflation of the neck during expiration and inspiration respectively and also providing rigidity to the thoracic inlet. *Herniation of the cervical fascia may result due to injury to suprapleural membrane. **"The thoracic duct traverses Sibson's Fascia of the thoracic-inlet up to the level of C7 before turning around and emptying into the left (major) duct. The right (minor duct) only traverses the thoracic inlet once."p. 86, p 210, Kuchera, WA.

References

Thoracic cavity Pleura {{anatomy-stub