The quadrangular space, also known as the quadrilateral space (of Velpeau) and the foramen humerotricipitale, is one of the three spaces in the axillary space. The other two spaces are: triangular space and triangular interval.

Structure

The quadrangular space is one of the three spaces in the axillary space.

Boundaries

The quadrangular space is defined by: - "Scapular Region: Quadrangular Space of Scapular Region" * ''above/superior:'' teres minor muscle. * ''below/inferior:'' teres major muscle. * ''medially:'' long head of the triceps brachii muscle (lateral margin). * ''laterally:'' surgical neck of the humerus. * ''anteriorly:''

subscapularis muscle The subscapularis is a large triangular muscle which fills the subscapular fossa and inserts into the lesser tubercle of the humerus and the front of the capsule of the shoulder-joint. Structure The subscapularis is covered by a dense fasci ...

The quadrangular space transmits the axillary nerve, the posterior humeral circumflex artery and the posterior circumflex humeral vein.

Clinical significance

The quadrangular space is a clinically important anatomic space in the arm as it provides the anterior regions of the

axilla The axilla (: axillae or axillas; also known as the armpit, underarm or oxter) is the area on the human body directly under the shoulder joint. It includes the axillary space, an anatomical space within the shoulder girdle between the arm a ...

a passageway to the posterior regions. In the quadrangular space, the axillary nerve and the posterior humeral circumflex artery can be compressed or damaged due to space-occupying lesions or disruption in the anatomy due to trauma. Other common causes of axillary nerve compression at the quadrangular space include local compression due to

osteophytes Osteophytes are exostoses (bony projections) that form along joint margins. They are distinct from enthesophytes, which are bony projections that form at the attachment of a tendon or ligament. Osteophytes are not always distinguished from exost ...

which are common in

osteoarthritis Osteoarthritis is a type of degenerative joint disease that results from breakdown of articular cartilage, joint cartilage and underlying bone. A form of arthritis, it is believed to be the fourth leading cause of disability in the world, affect ...

, shoulder dislocations, fractures of the humeral neck, repetitive use, and external pressure (such as from crutches).

Symptoms Signs and symptoms are diagnostic indications of an illness, injury, or condition. Signs are objective and externally observable; symptoms are a person's reported subjective experiences. A sign for example may be a higher or lower temperature ...

of axillary nerve compression include axillary nerve related weakness of the

deltoid muscle The deltoid muscle is the muscle forming the rounded contour of the shoulder, human shoulder. It is also known as the 'common shoulder muscle', particularly in other animals such as the domestic cat. Anatomically, the deltoid muscle is made up o ...

(shoulder abduction) and teres minor (external rotation of the arm) as well as numbness of the lateral shoulder. The quadrangular space is the most common site of axillary nerve compression.

History

The quadrangular space is so named because the three

skeletal muscles Skeletal muscle (commonly referred to as muscle) is one of the three types of vertebrate muscle tissue, the others being cardiac muscle and smooth muscle. They are part of the somatic nervous system, voluntary muscular system and typically are a ...

and one

long bone The long bones are those that are longer than they are wide. They are one of five types of bones: long, short, flat, irregular and sesamoid. Long bones, especially the femur and tibia, are subjected to most of the load during daily activities ...

that form its boundaries leave a space in the shape of a

complete quadrangle In mathematics, specifically in incidence geometry and especially in projective geometry, a complete quadrangle is a system of geometric objects consisting of any four points in a plane, no three of which are on a common line, and of the six ...

. The quadrangular space is also known as the quadrilateral space, the quadrilateral space of Velpeau, and the foramen humerotricipitale.

Additional images

File:Gray412-spaces.png, Muscles on the dorsum of the scapula, and the triceps brachii.

References

External links

*
Photo at umich.edu

Diagram at wustl.edu

Photo at ithaca.edu
Upper limb anatomy {{Portal bar, Anatomy