Arm and Cubital Fossa: Laboratory Identifications and Relationships

Arm

• Brachial artery
  • continuation of the axillary artery at inferior boundary of teres major
• Medial epicondyle humerus
  • common flexor tendon
• Ulnar groove of the humerus
  • subcutaneous ulnar nerve, ulnar collateral ligament, Joe Montana and nerve entrapment
• Lateral epicondyle humerus
  • common extensor tendon
• Olecranon fossa
  • receives olecron process on extension, stability on extenson
• Trochlea of humerus
  • articulates with trochlear notch of ulna
• Capitulum of humerus
  • articulates with head of radius
• Supracondyler ridge of humerus
  • fractures of this region threaten contents of cubital fossa
• Head of radius
  • secured to ulna by annular ligament of elbow
• Radial tuberosity
  • site of insertion for biceps tendon
  • Radial notch of ulna
  • stabilizes radial head
• Coronoid process of ulna
  • site of insertion for brachialis
• Olecranon process of ulna
  • site of insertion for triceps
• Lateral intermuscular septum
  • lateral fascial separation between anterior and posterior compartments of arm, brachialis anterior and lateral head triceps posterior
• Medial intermuscular septum
  • medial fascial separation between anterior and posterior compartment of arm, biceps anterior and medial/long head triceps posterior
• Corocoid process
  • site of origin for two muscles (short head biceps, coracobrachialis) and site of insertion for one muscle (pectoralis minor)
• Musculocutaneous nerve
  • piercing coracobrachialis and runing deep to biceps on anterior surface of brachialis
• Lateral antebrachial cutaneous nerve
  • terminal branch of musculocutaneous nerve, relation to cephalic vein along forearm
• Medial antebrachial cutaneous nerve
  • from medial cord in axilla, related to basilic vein
• Median nerve
  • enters arm on lateral aspect of brachial artery, crosses to medial side of artery just before entering cubital fossa
• Profunda brachii artery
  • branches from the brachial artery and crosses the posterior humerus along the spiral (radial) groove with the radial nerve
• bicipital aponeurosis
  • intervening between the brachial artery and the median cubital vein, protects artery during IV placement
• Transverse humeral ligament
  • securing the tendon of the long head of the biceps within the intertubercular groove
• Coracobrachialis muscle
  • adduction, flexion, and medial rotation of the arm, pierced by the musculocutaneous nerve
• Long head triceps
  • origin at infraglenoid tubercle, medial border of quadrangular space
• Spiral (radial) groove
  • an interosseous groove of the posterior humerus with the lateral head of the triceps taking origin lateral and superior to the groove and the medial head of the triceps taking origin medial and inferior to the groove, radial nerve and profunda brachii artery on the groove
• Triangular space
  • circumflex scapular artery, medial: subscapularis, lateral: long head triceps, inferior: teres major, superior: teres minor
• Quadrangular space
  • axillary nerve and posterior humeral circumflex artery, superior: joint capsule (teres minor), inferior: teres major, lateral: surgical neck humerus, medial: long head triceps
• Triangular interval
  • radial nerve and profunda brachii artery, superior: teres major, inferior: triceps and humerus crossing, lateral: humerus, medial: long head triceps
• Ascending branch of profunda brachii artery
  • appreciate the contribution of the artery to the acromial (shoulder) anastomosis (note: the shoulder anastomosis and the scapular anastomosis are not the same) * Anconeus - lateral epicondyle of humerus to olecranon and lateral superior ulna, deep to anconeus is the interosseous recurrent artery

Elbow Anastomosis

1. Superior ulnar collateral artery
   • arises from superior brachial artery and passes posterior to elbow joint in the ulnar groove with the ulnar nerve
2. Inferior ulnar collateral artery
   • arises from brachial artery inferior to the superior ulnar collateral artery and passes anterior to elbow joint between brachialis and pronator teres
3. Anterior ulnar recurrent artery
   • arises from ulnar artery and recurs anterior to elbow joint to anastomose with inferior ulnar collateral artery
4. Posterior ulnar recurrent artery
   • arises from ulnar artery (sometimes has common trunk with anterior ulnar artery) and recurs posterior to elbow joint to anastomose with the superior ulnar collateral artery
5. Radial collateral artery
   • terminal branch of profunda brachii artery, travels with radial artery to pierce the lateral intermuscular septum and then crosses anterior to the elbow joint between brachialis and brachioradialis
6. Middle collateral artery
   • terminal branch of profunda brachii artery, passes inferior within the lateral head of the triceps to cross posterior to the lateral aspect of the elbow joint
7. Radial recurrent artery
   • recurs anterior to the elbow joint to anastomose with the radial collateral artery
8. Interosseous recurrent artery
   • recurs posterior to the lateral side of the elbow joint (deep to anconeus) to anastomose with the middle collateral artery

Cubital fossa boundaries

1. Lateral
   • brachioradialis (the branching of the radial nerve into superficial and deep branches is often described as occuring with cubital fossa)
2. Medial
   • pronator teres
3. Superior
   • horizontal line marking the medial and lateral epicondyles of the humerus
4. Anterior
   • bicipital aponeurosis (Despite this traditional boundary, the median cubital vein is sometimes incorrectly described as a content of the cubital fossa. It is superficial to the cubital fossa.)
5. Posterior
   • brachialis and supinator
6. Inferior - crossing of the brachioradialis and the pronator teres

Key relations within the cubital fossa (non-exhaustive)

• Lateral to medial:
  • radial nerve and terminal branches (superficial and deep)
  • radial collateral artery
  • biceps tendon, brachial artery (radial and ulnar branches)
  • median nerve
  • inferior ulnar collateral artery