Fascia, vessels and nerves of the upper limb

The upper limb contains an intricate metro system of blood vessels, muscles, and nerves.

These structures are wrapped up and organized into different compartments by superficial and deep fascia layers, and together they form the multifunctional upper limbs we know and love.

So let’s start with the fascia. You can think of fascia as a pair of thin stockings made of connective tissue that support and bind together different parts of the body, including the lower limbs.

Now, each upper limb actually has two pairs of stockings on top of each other: the superficial fascia, which sits right underneath our skin, and the deep fascia, which is deep to or beneath the superficial fascia, and it sits on top of muscles, organizing them into compartments.

In the upper limb, there are six fasciae to remember. We have the pectoral fascia, the clavipectoral fascia, the axillary fascia, the deltoid fascia, the brachial fascia, and antebrachial fascia.

The wrist and the hand also have fibrous band-like structures called the flexor retinaculum, the extensor retinaculum, and the palmar aponeurosis.

OK, let’s start with the pectoral fascia, which is a broad thin sheath of connective tissue surrounding the pectoralis major muscle, from which it gets its name. Medially, the pectoral fascia is attached to the sternum along with the pectoralis major’s origin.

Superiorly, it attaches to the clavicle, and superolaterally, this fascia passes over this narrow trench called the deltopectoral groove to blend with the deltoid fascia covering the deltoid muscle around the shoulder.

The deltopectoral groove serves as a passageway for the cephalic vein when it is traversing from the arm to enter the lateral aspect of the chest.

Inferiorly, the pectoral fascia spreads downwards and becomes continuous with the fascia of the anterior abdominal wall, while on the lateral side, the fascia curves around the lateral border of the pectoralis major to become continuous with the axillary fascia in the floor of the axilla.