Lecture 10 - Brachium, Cubital Fossa

Question 1

What are the fascial membranes of the brachium and how do they divide the brachium?

Answer 1

• medial intermuscular septum
• lateral intermuscular septum

-divides the brachium into anterior and posterior compartments

Question 2

What muscles are located in the anterior compartment of the arm? What general functions do they have?

Answer 2

Muscles:

• bicep brachii
• coracobrachialis
• brachialis

Function:

• flexion of the forearm
• biceps supinates forearm

Question 3

What nerves are present in the anterior brachial compartment? Which nerve(s) innervate the compartment?

Answer 3

Nerves:

• musculocutaneous nerve (innervates)
• median nerve (non-innervating)
• ulnar nerve (non-innervating)

Question 4

What are the main vascular components of the anterior brachial compartment?

Answer 4

Arterial:
-brachial artery

Venous:
-basilic vein and venae comitantes

Question 5

What muscles are located in the posterior compartment of the arm? What general functions do they have?

Answer 5

Muscles:

• triceps brachii
• anconeus

Functions:

• forearm extension
• shoulder extension (long head triceps brachii)
• synergism in forearm supination

Question 6

What nerves are present in the posterior brachial compartment? Which nerve(s) innervate the compartment?

Answer 6

Nerve:

-radial nerve (innervates)

Question 7

What cutaneous nerves are present in the brachium and what is their origin?

Answer 7

• superior lateral cutaneous nerve of arm (axillary nerve)
• medial brachial cutaneous nerve (medial cord)
• medial antebrachial cutaneous nerve (medial cord)
• lateral antebrachial cutaneous nerve (termination of musculocutaneous nerve)
• posterior cutaneous nerve of arm (radial nerve)
• posterior cutaneous nerve of forearm (radial nerve)

Question 8

What does the median nerve do in the brachium?

Answer 8

• does not innervate brachium
• travels with the brachial artery; initially laterally but ends up medially
• crosses cubital fossa

Question 8

What does the ulnar nerve do in the brachium?

Answer 8

• does not innervate brachium
• travels medially to brachial artery
• travels with superior ulnar collateral artery
• pierces medial intermuscular septum
• passes around medial epicondyle
• passes between heads of flexor carpi ulnaris

Question 8

What does the radial nerve do in the brachium?

Answer 8

• supplies extensor muscles in the brachium (triceps and anconeus)
• supplies brachioradialis
• descends posterior to the axillary artery with the deep brachial artery
• pierces lateral intermuscular septum distal to deltoid insertion
• passes into forearm medially to brachialis and laterally to brachiordialis
• divides into superficial and deep branch near lateral epicondyle

Question 9

Where does the radial nerve branch in the brachium and what do these nerves supply?

Answer 9

Axilla, upper third of arm:

• long head of triceps
• medial head of triceps
• posterior brachial cutaneous nerve

Radial groove, mid third of arm:

• lateral head of triceps
• medial head of triceps
• anconeus
• lower lateral brachial cutaneous nerve
• posterior cutaneous nerve of the forearm

Distal third of arm:

• brachioradialis
• extensor carpi radialis longus
• articular branches of elbow

Question 10

What does the musculocutanous nerve do in the brachium?

Answer 10

-innervates anterior brachial compartment

• pierces coracobrachialis in upper third of brachium
• pierces fascia lateral to biceps tendon
• terminates as lateral cutaneous nerve to the forearm

Question 11

What anastomoses are present in the brachium?

Answer 11

Brachial artery with ulnar artery:

• superior ulnar collateral to posterior ulnar recurrent
• inferior ulnar collateral to anterior ulnar collateral

Brachial artery with radial artery:

• radial collateral artery with radial recurrent artery
• middle collateral artery with interosseous recurrent artery

Question 12

What veins are present in the brachium?

Answer 12

• cephalic vein
• basillic vein
• median cubital vein
• venae comitantes

Question 13

What is the path of the cephalic vein?

Answer 13

• lateral continuation of dorsal venous arch
• ascends in superficial fascia of lateral FA and arm
• passes through deltopectoral triangle
• empties into axillary vein

Question 14

What is the path of the basilic vein?

Answer 14

• medial continuation of dorsal venous arch
• ascends in medial superficial fascia of arm and forearm
• pierces deep fascia and ascends in upper arm
• joins venae comitantes to form axillary vein (inferior border of teres major)

Question 15

What path does the median cubital vein take?

Answer 15

• drains from palmar hand via median antebrachial vein
• connects cephalic and basilic vein
• extends diagonally at the bicipital aponeurosis

Question 16

What are venae comitantes?

Answer 16

• veins that run parallel to arteries
• usually in pairs
• countercurrent heat exchange; absorb heat from the artery

Question 17

What are the boundaries of the cubital fossa?

Answer 17

Lateral:
-brachioradialis

Medial:
-pronator teres

Superior:
-line between humeral epicondyles

Floor:
-supinator and brachiallis

Roof:
-skin, superficial and deep faschia

Question 18

What are the contents of the cubital fossa?

Answer 18

• biceps (T)endon
• brachial (A)rtery
• median (N)erve

TAN (lateral to medial)