The Arm & Cubital Fossa

Question 1

What is the floor of the cubital fossa formed by?

Answer 1

Proximally brachialis and distally by the supinator muscle

Question 2

What does the roof of the cubital fossa consist of?

Answer 2

Skin and fascia, which is reinforced by bicepal aponeurosis. Within the roof runs the median cubital vein which can be accessed via venopuncture.

Question 3

What are the three anterior arm muscles and what motion do they assist with?

Answer 3

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Biceps brachii
Brachialis
Corochobrachialis

All aid in flexion of the forearm

Question 4

What nerve innervates the anterior arm muscles?

Answer 4

The muscularcutaneous nerve

Question 5

What is the origin and insertion of the biceps brachii?

Answer 5

Origin- long head=supraglenoid tuburcle of the scapula
Short head= corocoid process of the scapula

Insertion- radial tuberosity

Question 6

What is the origin and insertion of the brachialis muscle?

Answer 6

Origin- medial and lateral surfaces of the humeral shaft

Insertion- tuberosity of the ulna

Question 7

What is the origin and insertion of the corocobrachialis muscle?

Answer 7

Origin- corocoid process

Insertion- deltoid tuburcle

Question 8

What are the contents of the cubital fossa?

Answer 8

Radial nerve
Biceps tendon
Brachial artery
Median nerve

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Question 9

Name what order the biceps brachi tendon, the medial nerve, and the brachial artery lie laterally to medial:

Answer 9

Lateral to medial:
Biceps brachi (tendon)
Brachial Artery
Medial nerve

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Question 10

What movement does the triceps brachi aid in? And what part of the arm is it in?

Answer 10

Extension of the forearm and it is in the posterior compartment of the arm.

Question 11

What is the origin and insertion of the triceps brachi?

Answer 11

Origin- long head= infraglenoid tuburcle of the scapula
Medial head= posteria surface of the humerus inferior to the radial groove
Lateral head= posterior surface of the humerus, superior to the radial groove.

Insertion= proximal end of the olecranon of the ulna

Question 12

What nerve innervates the triceps brachi?

Answer 12

The radial nerve

Question 13

Which 4 main nerve run through the arm?

Answer 13

The median nerve
The ulna nerve
The musculocutaneous nerve
The radial nerve

Question 14

What is the main pathway of the median nerve in the arm?

Answer 14

• Formed in the Axilla by the Union of the medial and lateral roots of the brachial plexus
• runs distally down the arm, initially on the lateral side of the brachial artery until it reaches the middle where it cross to the medial side.
• here it contacts the brachialis
• it descends into the cubital fossa, where it lies deep to biceps aponeurosis and median cubital vein

Question 15

What is the pathway of the ulnar nerve in the arm?

Answer 15

• The ulnar nerve arises from the medial cord of the brachial plexus
• it passes distally, anterior to the insertion of the teres major and the long head of the triceps, on the medial side of the brachial artery
• around the middle of the arm it pierces the medial intermuscular septum with the superior ulnar collateral artery and descends between the septum and medial head of the triceps.

The ulnar nerve passes posterior to the medial epicondyle of the humerus to enter the forearm

Question 16

What is the main pathway of the musculocutaneous nerve in the arm?

Answer 16

Arises from the lateral cord of the brachial plexus.

• it pierces the corocobrachialis and then continues distally between the brachialis and the biceps.
• after supplying all 3 muscles of the anterior compartment of the arm, it then emerges lateral to the biceps brachii as the LATERAL CUTANEOUS NERVE OF THE FOREARM.

Question 17

What is the main pathway of the radial nerve in the arm?

Answer 17

The radial nerve enters the arm posterior to the brachial artery, medial to the humerus and anterior to the long head of the triceps.

The radial nerve descends inferolaterally with the profunda brachii artery and curves around the humeral shaft in the radial groove.

In the cubital fossa it divides into deep and superficial branches.

Question 18

What is the pathway of the brachial artery of the arm?

Answer 18

The brachial artery supplies the main arterial supply to the arm and is the continuation of the Axillary artery.

It begins at the inferior border of the teres major and ends in the cubital fossa opposite the neck of the radius under cover of the bicipital aponeurosis where it divides into the radial and ulnar arteries.

It lies medial to the humerus where it is palpable in the medial bicipital groove

Question 19

What are the main veins of the arm?

Answer 19

There are two sets of veins in the arm- the superficial veins and the deep veins.

Superficial- cephalic and basilic

Paired deep veins making the brachial vein- begins at the elbow by union of the veins accompanying the ulnar and radial arteries and ends by merging with the basilic vein to form the Axillary vein.

Question 20

What are the borders of the cubital fossa and what lies at each border?

Answer 20

1. Lateral border- the medial border of the brachialis muscle
2. Medial border- the lateral border of the pronator teres muscle
3. Superior border- an imaginary line connecting the medial and lateral epicondyles