What passes through the triangular space?

The triangular space is an anatomic interval medial to the quadrangular space. Its borders are formed by the long head of the triceps laterally, the teres minor superiorly, and the teres major inferiorly. The circumflex scapular artery, a branch of the scapular artery, passes through the triangular space.

What runs through the triangular interval?

radial nerve

Contents. The radial nerve is visible through the triangular interval, on its way to the posterior compartment of the arm.

What nerve goes through the triangular space?

Triangular interval (lower triangular space)

The profunda brachii artery and the radial nerve pass through this space to enter the arm.

What passes through the quadrangular space?

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

Where is triangular space?


The lateral triangular space, also called the triangular interval or lower triangular space 1 or triceps hiatus, is a space connecting the axilla to the posterior compartment of the arm.

What muscles make up triangular space?

Triangular Space

  • Borders. inferior: teres major. lateral: long head of triceps. superior: lower border of teres minor.
  • Contents. scapular circumflex artery.

What is quadrilateral space syndrome?

Quadrilateral space syndrome (QSS) is a rare disorder characterized by axillary nerve and posterior humeral circumflex artery (PHCA) compression within the quadrilateral space. Impingement is most frequently due to trauma, fibrous bands, or hypertrophy of one of the muscular borders.

What are Intermuscular spaces?

The Triangular Intermuscular Space is defined by borders of the teres major, teres minor, and long head of the triceps. Through this space pass the descending circumflex scapular artery, vena comitants, and lymphatics.

What is quadrangular Intermuscular space?

The quadrangular space is an intermuscular space through which the axillary nerve and posterior circumflex humeral vessels pass through backwards to encircle the surgical neck of the humerus. It is bounded above by subscapularis and teres minor and below by teres major.

Why is the scapula triangular?

The scapula forms the back of the shoulder girdle. In humans, it is a flat bone, roughly triangular in shape, placed on a posterolateral aspect of the thoracic cage.

Muscle Direction Region
Trapezius insertion spine of scapula
Deltoid origin spine of scapula
Supraspinatus origin supraspinous fossa

How do you remember the quadrangular space?

Triangular space, Quadrangular Space- Scapula [Mnemonic]

  1. Triangular Space – TS (aka– Medial or Upper Triangular space, Foramen omotricipitale),
  2. Quadrangular Space – QS (aka– Quadrilateral space of Velpeau, Foramen humerotricipitale),
  3. Triangular Interval – TI (aka– Lateral or Lower Triangular space, Triceps hiatus).

What Innervates the teres major?

The subscapular nerve from C5 to C6 roots innervates the teres major muscle. The anterior thoracic nerve from the C5 to C8 roots innervates the pectoralis major and minor, and the thoracodorsal nerve from C6 to C8 roots innervates the latissimus dorsi muscle.

Does infraspinatus abduct?

Infraspinatus is the main external rotator of the shoulder joint. It assists in producing shoulder extension. With the arm fixed, it abducts the inferior angle of the scapula.

Are the rhomboids under the trapezius?

The rhomboid muscles, located on your upper back underneath the trapezius muscle, play a big part when it comes to posture. This is especially true if you have overdeveloped chest muscles or your shoulders pronate forward. The rhomboids are rhombus-shaped and are used to pull the shoulder blades together.

What Innervates the subscapularis?

Innervation. The subscapularis is innervated by both the upper subscapular nerve (USN) and lower subscapular nerve (LSN). Both the USN and LSN arise from the posterior cord of the brachial plexus.

What Innervates 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 osteofascial compartment of the forearm and the associated joints and overlying skin.

What is your underarm muscle called?

Pectoralis major: This large fan-shaped muscle stretches from the armpit up to the collarbone and down across the lower chest region. It connects to the sternum (breastbone). Pectoralis minor: The smaller of the pectoralis muscles, this muscle fans out from the upper ribs up to the shoulder area.