Infraespinous

Infraespinous is a rarely used or nonstandard anatomical term that appears in some texts as an alternative spelling or descriptor indicating a location below a spine. In modern anatomical nomenclature, the form infraspinous is preferred. The root infra- means below, and spinous relates to a spine or spinous process on a bone such as the scapula.

Infraspinous is used in established anatomical phrases to denote structures situated beneath the spine of a bone. The most common usage is with the scapula: the infraspinous fossa, a broad surface on the posterior aspect of the scapula below the spine, and the infraspinatus muscle that occupies this region.

The infraspinous fossa borders are defined by the spine of the scapula above and the lateral border below; it contains the infraspinatus muscle and is traversed by the suprascapular nerve and vessels. The infraspinatus is one of the rotator cuff muscles and primarily performs external rotation of the humerus and stabilization of the glenohumeral joint.

Clinical relevance: injury or pathology involving the infraspinatus muscle or suprascapular nerve, such as tendinopathy or nerve entrapment, can lead to weakness in external rotation and shoulder pain. The term infraespinous, when encountered, is typically considered a nonstandard variant rather than a defined anatomical structure.

See also: infraspinous fossa; infraspinatus; suprascapular nerve; rotator cuff.