Infraspinous fossa = a structural feature on the scapula, which is also known as the "shoulder blade" or "shoulder bone".
Location of infraspinous fossa:
The location on the scapula bone of the infraspinous fossa is indicated on the labelled diagram of the posterior (dorsal) surface of the left scapula bone shown below-right (highlighted in yellow).
The position on the scapula bone of the infraspinous fossa can be described in words as:
- a concave depression ("fossa" = "shallow depression")
- located in the area below the spine of scapula on the posterior = dorsal surface of the scapula bone only*
*So it won't be labelled on diagrams of the anterior = costal surface of the scapula.
The infraspinous fossa extends over a wide area covering most of the lower two-thirds of the dorsal surface of the scapula bone, that is - most of the area below the spine of the scapula. (Note that this is a much larger area than is covered by the supraspinous fossa which is also located on the dorsal surface of the scapula but above the spine of scapula.)
The area covered by the infraspinous fossa is approximately triangular, with the side forming the upper edge of the "triangle" along side but below the spine of scapula and the lower angle (or "apex") of the "triangle" tending towards the inferior angle of the scapula (as shown, right).
About the infraspinous fossa:
The infraspinous fossa is a shallow concave depression. Recall from general knowledge of the features and markings on bones that a fossa is typically a shallow depression.
The infraspinous fossa includes the surface of the scapula bone to which the infraspinatus muscle (sometimes written "infraspinalis" - one of the posterior muscles of the torso) is attached. So, remember that:
The infraspinous fossa is the part of the scapula (bone) to which the infraspinatus (muscle) is attached.
Where does the term "infraspinous fossa" come from ?
- "Infraspinous" comes from the Latin "infra" meaning below and "spine" which refers to the spine of the scapula (another feature on the scapula bone - also labelled in the diagram above).
- "Fossa" is also from a Latin word, in this case the verb "fodere" which means to dig. Hence "fossa" came to be used to refer to a trench, ditch or hole, i.e. features in the physical landscape that my be formed by digging.
In the past medical students were expected to have a good background in Latin (language) - it is easy to see how this helped.
For more information about this and related topics see the links to other features on the scapula bone listed on the left and the pages about the scapula bone and about bone markings and features on bones.