Brachial fascia !
The brachial fascia is the sleeve of connective tissue around the upper arm; it holds the arm muscles in a front and a back compartment.
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What it is
The sleeve of deep fascia around the upper arm muscles.
What it does
Holds the arm muscles in their compartments.
Key facts
- Where
- Deep fascia sleeve around the arm
- Function
- Encloses the arm muscles; with the septa forms the anterior and posterior compartments
Relations
- Contents
- The two compartments; along the medial septum runs the bundle of the brachial artery, the median nerve and, in the upper arm, the ulnar nerve
- Superficial
- Cephalic vein on the lateral side, the lower basilic vein on the medial side, and the arm skin nerves
- Above
- Continuous with the deltoid and pectoral fasciae and the axillary fascia
- Below
- Continues into the antebrachial fascia; the bicipital aponeurosis joins it at the elbow
How to find it
It is not felt as such: it is the tough layer under the skin and fat in any approach to the arm. The cephalic vein lies on it laterally; the basilic vein dives through it medially at about mid-arm.
On imaging
A thin bright (hyperechoic) line around the arm muscles on ultrasound, and a thin dark line on MRI. Imaging does not diagnose compartment syndrome of the arm: examination and compartment pressure do. In necrotising fasciitis, soft-tissue gas on radiographs or CT is a warning sign and MRI shows fluid and thickening along the fascia; neither should delay surgery.
Clinical notes
- Arm compartment syndrome (crush, prolonged lying on the arm, humeral fractures, bleeding) is released by opening both compartments
- For dialysis access, the basilic vein is freed from beneath the fascia and moved to a superficial position (basilic vein transposition)
- The basilic vein and the medial antebrachial cutaneous nerve go through the fascia together on the medial arm, so the nerve is at risk when the vein is harvested or transposed
Test yourself
Think of the answer, then tap the question to see it.
What are the contents of the two compartments enclosed by the brachial fascia?
Anterior: biceps, brachialis, coracobrachialis and the musculocutaneous nerve; posterior: triceps and the radial nerve.
Which structures pierce the brachial fascia on the medial side of the arm?
The basilic vein and the medial forearm skin nerve, about halfway up the arm.
How is arm compartment syndrome released?
By opening both the anterior and posterior compartments of the brachial fascia; it is much rarer than forearm compartment syndrome.
Educational information, not medical advice. For any symptom, see a health professional.
Its names
- Official Latin (TA2)
- fascia brachii TA2 2541
- Official Spanish (DeCS)
- Fascia del brazo
- English (TA2)
- Brachial fascia
Related
Sources: Terminologia Anatomica (TA2); Anatomy, Shoulder and Upper Limb, Arm Muscles.
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Representative model, for educational purposes only.
