The axillary spaces are anatomic spaces. through which axillary contents leave the axilla. They consist of the

quadrangular space 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 ...

triangular space The triangular space (also known as the medial triangular space, upper triangular space, medial axillary space or foramen omotricipitale) is one of the three spaces found at the axillary space. The other two spaces are the quadrangular space a ...

, and

triangular interval The triangular interval (also known as the lateral triangular space, lower triangular space, and triceps hiatus) is a space found in the axilla. It is one of the three intermuscular spaces found in the axillary space. The other two spaces are: q ...

. It is bounded by

teres major The teres major muscle is a muscle of the upper limb. It attaches to the scapula and the humerus and is one of the seven scapulohumeral muscles. It is a thick but somewhat flattened muscle. The teres major muscle (from Latin ''teres'', meanin ...

teres minor The teres minor (Latin ''teres'' meaning 'rounded') is a narrow, elongated muscle of the rotator cuff. The muscle originates from the lateral border and adjacent posterior surface of the corresponding right or left scapula and inserts at both the ...

, medial border of the

humerus The humerus (; : humeri) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius (bone), radius and ulna, and consists of three sections. The humeral upper extrem ...

, and long head of

triceps brachii The triceps, or triceps brachii (Latin for "three-headed muscle of the arm"), is a large muscle on the back of the upper limb of many vertebrates. It consists of three parts: the medial, lateral, and long head. All three heads cross the elbow jo ...

. They should not be confused with the true "axillary space" within the borders of the axilla.

Structure

Axilla

The true axilla is a conical space with its apex at the Cervico-axillary Canal, Base at the axillary fascia and skin of the armpit. When viewed in an axillary plane (axillary cut), it is more triangle with: Medial Wall: Serratus Anterior, Anterior Wall: pectoral muscles, Posterior Wall: subscapularis muscle, where the "apex" of the triangle is the humerus

Quadrangular space

This space is in the posterior wall of the axilla. It is a quadrangular space bounded laterally by surgical neck of the humerus, medially by long head of triceps brachii and inferiorly by

. It is bounded superiorly by

subscapularis 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 Glenohumeral joint, shoulder-joint. Structure The subscapularis is covere ...

in front, capsule of the shoulder joint in the middle, and behind by

. The

axillary nerve The axillary nerve or the circumflex nerve is a nerve of the human body, that originates from the brachial plexus ( upper trunk, posterior division, posterior cord) at the level of the axilla (armpit) and carries nerve fibers from C5 and C6. ...

and

posterior humeral circumflex artery The posterior humeral circumflex artery (posterior circumflex artery or posterior circumflex humeral artery) arises from the third part of the axillary artery at the distal border of the subscapularis. Anatomy Course and relations It passes p ...

and vein pass through this space.

Triangular space

This space (sin. ''medial triangular space'') is also in the posterior wall of the axilla. It is a triangular space bounded medially by teres minor, laterally by long head of triceps brachii, and inferiorly by teres major. The

scapular circumflex artery The circumflex scapular artery (scapular circumflex artery, dorsalis scapulae artery) is a branch of the subscapular artery and part of the scapular anastomoses. It curves around the axillary border of the scapula, traveling through the anato ...

and scapular circumflex vein pass through this space.

Triangular interval

This space (a.k.a. ''lateral triangular space'') is in the inferior to the posterior wall of the axilla. The

is bounded medially by long head of triceps brachii, laterally by medial border of humerus (some say the lateral head of the triceps), and superiorly by teres major. The

radial nerve The radial nerve is a nerve in the human body that supplies the posterior portion of the upper limb. It innervates the medial and lateral heads of the triceps brachii muscle of the arm, as well as all 12 muscles in the Posterior compartment of the ...

and

profunda brachii artery The deep artery of arm (also known as deep brachial artery) is a large artery of the arm which arises from the brachial artery. It descends in the arm before ending by anastomosing with the radial recurrent artery. Structure Origin The deep ...

and vein passes through this space.

References

External links

Dissector Answers - Axilla & Arm
* http://sarcoma.org/publications/OTOS_Book/13282_ON-13.pdf. This article defines the true "axillary space" in relation to Axillary Space Exploration and Resections. {{Muscles of upper limb Muscular system