CUBITAL FOSSA Anatomy

Cubital Fossa

Definition: A triangular hollow situated in front of the elbow. It is homologous to the Popliteal fossa of the lower limb.

Fig 1: Boundaries and contents of the cubital fossa

Boundaries

Fig 2: Muscles forming the floor of cubital fossa (Anterior & Cross-section)

Boundary	Formed By
Lateral	Medial border of Brachioradialis muscle.
Medial	Lateral border of Pronator Teres muscle.
Base	Imaginary horizontal line joining the two epicondyles.
Apex	Meeting point of Brachioradialis & Pronator Teres.

Floor: Formed by Brachialis (upper part) and Supinator (lower part).
Roof (Superficial to Deep):
1. Superficial fascia containing:
  - Median Cubital Vein (connects Cephalic & Basilic).
  - Medial & Lateral cutaneous nerves of forearm.
2. Deep fascia (strengthened by Bicipital Aponeurosis).

Note: Contents are best displayed when the elbow is flexed and margins are pulled apart.

Fig 3: Structures in the roof of cubital fossa

Mnemonic: M - B - B - S
(From Medial to Lateral)

Structure	Description
1. Median Nerve	Leaves fossa between two heads of Pronator Teres.
2. Brachial Artery	Divides into Radial & Ulnar arteries at neck of radius.
3. Biceps Tendon	Passes backwards to attach to Radial Tuberosity.
4. Radial Nerve	Lies between Brachialis & Brachioradialis. (Superficial branch).

Note to Self:

1. Venipuncture: The Median Cubital Vein is the vein of choice for IV injections (it's fixed by the aponeurosis!).

2. BP Measurement: The Brachial Pulse is auscultated medial to the Biceps tendon.

3. Danger Zone: In Supracondylar fractures, the Brachial artery is vulnerable (Volkmann's Ischemia).

📚 Ref: Vishram Singh - Upper Limb and Thorax