Cubital Fossa: Anatomy

Boundaries

The cubital fossa is the transitional area between the upper arm Arm The arm, or “upper arm” in common usage, is the region of the upper limb that extends from the shoulder to the elbow joint and connects inferiorly to the forearm through the cubital fossa. It is divided into 2 fascial compartments (anterior and posterior). Arm: Anatomy and the forearm Forearm The forearm is the region of the upper limb between the elbow and the wrist. The term “forearm” is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles. Forearm: Anatomy anterior to the elbow joint Elbow joint The elbow is the synovial hinge joint between the humerus in the upper arm and the radius and ulna in the forearm. The elbow consists of 3 joints, which form a functional unit enclosed within a single articular capsule. The elbow is the link between the powerful motions of the shoulder and the intricate fine-motor function of the hand. Elbow Joint: Anatomy. The cubital fossa is defined by the following anatomical boundaries:

Contents

The important structures of the cubital fossa can be organized from lateral to medial and include all the important neurovascular structures except for the ulnar nerve Ulnar Nerve A major nerve of the upper extremity. In humans, the fibers of the ulnar nerve originate in the lower cervical and upper thoracic spinal cord (usually C7 to T1), travel via the medial cord of the brachial plexus, and supply sensory and motor innervation to parts of the hand and forearm. Axilla and Brachial Plexus: Anatomy, which runs posterior to the medial epicondyle Medial epicondyle Arm: Anatomy.

Structures deep within the cubital fossa (lateral to medial)

• Radial nerve Radial Nerve A major nerve of the upper extremity. In humans the fibers of the radial nerve originate in the lower cervical and upper thoracic spinal cord (usually C5 to T1), travel via the posterior cord of the brachial plexus, and supply motor innervation to extensor muscles of the arm and cutaneous sensory fibers to extensor regions of the arm and hand. Axilla and Brachial Plexus: Anatomy: located below or posterior to the brachioradialis Brachioradialis Forearm: Anatomy, and therefore not always included in the description of the cubital fossa 
• Distal biceps Biceps Arm: Anatomy tendon: attaches at the radial tuberosity
• Brachial artery: bifurcates into the radial and ulnar arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology at the distal end of the cubital fossa or apex of the fossa
• Median nerve: exits the cubital fossa beneath the pronator teres Pronator teres Forearm: Anatomy muscle

Structures within the superficial fascia Fascia Layers of connective tissue of variable thickness. The superficial fascia is found immediately below the skin; the deep fascia invests muscles, nerves, and other organs. Cellulitis of the cubital fossa

• Median cubital, cephalic, and basilic veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins: Histology
• Lateral and medial cutaneous nerves of the forearm Forearm The forearm is the region of the upper limb between the elbow and the wrist. The term “forearm” is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles. Forearm: Anatomy
• Lymphatics: epitrochlear lymph Lymph The interstitial fluid that is in the lymphatic system. Secondary Lymphatic Organs nodes (cubital lymph Lymph The interstitial fluid that is in the lymphatic system. Secondary Lymphatic Organs nodes)
  • Within subcutaneous fat Subcutaneous fat Fatty tissue under the skin throughout the body. Erythema Nodosum above the medial epicondyle Medial epicondyle Arm: Anatomy of the humerus Humerus Bone in humans and primates extending from the shoulder joint to the elbow joint. Arm: Anatomy
  • Drains into the axillary lymph Lymph The interstitial fluid that is in the lymphatic system. Secondary Lymphatic Organs nodes

Clinical Relevance

The following are important clinical concepts related to the structures found within the cubital fossa:

• Brachial pulse: The brachial pulse (brachial artery) can be palpated immediately medial to the biceps Biceps Arm: Anatomy tendon in the cubital fossa.
• Blood pressure: The cubital fossa is a site for placement of the diaphragm Diaphragm The diaphragm is a large, dome-shaped muscle that separates the thoracic cavity from the abdominal cavity. The diaphragm consists of muscle fibers and a large central tendon, which is divided into right and left parts. As the primary muscle of inspiration, the diaphragm contributes 75% of the total inspiratory muscle force. Diaphragm: Anatomy of the stethoscope during blood pressure measurement over the brachial artery.
• Venipuncture: the process of obtaining intravenous access, most commonly performed to obtain venous blood for testing or to acquire intravenous access. The cubital fossa is a common site for venipuncture because of the prominence and accessibility of the veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins: Histology, especially the median cubital vein located superficially within the roof of the cubital fossa.