Ulnar and radial arteries. Deep view.
The cubital fossa or elbow pit is the triangular area on the anterior view of the elbow of a human or other hominid animal. It lies anteriorly to the elbow (Latin cubitus) when in standard anatomical position.
The cubital fossa contains four main vertical structures (from lateral to medial):
Several veins are also in the area (for example, the median cubital vein, cephalic vein, and basilic vein) but these are usually considered superficial to the cubital fossa, and not part of its contents.
Like other flexion surfaces of large joints (groin, popliteal fossa, armpit and essentially the anterior part of the neck), it is an area where blood vessels and nerves pass relatively superficially, and with an increased amount of lymph nodes.
During blood pressure measurements, the stethoscope is placed over the brachial artery in the cubital fossa. The artery runs medial to the biceps tendon. The brachial pulse may be palpated in the cubital fossa just medial to the tendon.
The area just superficial to the cubital fossa is often used for venous access (phlebotomy) in procedures such as injections and obtaining samples for blood tests. A number of superficial veins can cross this region. It may also be used for the insertion of a peripherally inserted central catheter.
Historically, when (venous) blood-letting was practiced, the bicipital aponeurosis (the ceiling of the cubital fossa) was known as the "grace of God" tendon because it protected the more important contents of the fossa (i.e. the brachial artery and the median nerve).
Statistically, the antecubital fossa is the least tender region for peripheral intravenous access, although it provides a greater risk for venous thrombosis.