Quadrangular space facts for kids

The quadrangular space is a small area found deep inside your arm, near your shoulder. Think of it like a secret "room" or "tunnel" formed by different muscles and bones working together. It's important because some key nerves and blood vessels pass through it to reach other parts of your arm and shoulder.

What is the Quadrangular Space?

The quadrangular space gets its name because it's shaped a bit like a square or rectangle. It's not an empty space, but rather a pathway for important structures.

Where is it Located?

This space is located in the upper part of your arm, close to your shoulder. It's surrounded by:

• Above: Two muscles called the subscapularis (in front) and the teres minor (behind).
• Below: A muscle called the teres major.
• Inside (towards your body): The long head of the triceps muscle, which is a big muscle at the back of your upper arm.
• Outside (away from your body): The humerus bone, specifically a part called the surgical neck of the humerus. This is the long bone in your upper arm.

What's Inside the Space?

Even though it's small, the quadrangular space is like a busy highway for two important things:

• The axillary nerve: This nerve helps control some of the muscles in your shoulder and gives feeling to the skin over your shoulder.
• The posterior humeral circumflex artery: This is a blood vessel that carries blood to the shoulder joint and some of the surrounding muscles.

So, this little space is super important for making sure your arm and shoulder can move and feel things properly!

Images for kids

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  Muscles on the dorsum of the scapula, and the Triceps brachii.

See also

In Spanish: Cuadrilátero humerotricipital para niños