Arm and Cubital Fossa

Question 1

What are the compartments of the arm?

Answer 1

Anterior compartment also called flexor compartment Posterior compartment also called extensor compartment

Question 2

What muscles are found in the flexor compartment (front of the arm)?

Answer 2

Coracobrachialis
Biceps brachii
Brachialis

Question 3

Which muscle is found in the extensor compartment (back of the arm)?

Answer 3

Triceps brachii

Question 4

Origin of the coracobrachialis

Answer 4

Apex of coracoid process

Question 5

Insertion of coracobrachialis

Answer 5

Mid-shaft of the humerus on medial side

Question 6

Nerve supply of coracobrachialis

Answer 6

Musculocutaneous nerve (C5, C6, C7)

Question 7

Action of coracobrachialis

Answer 7

Flexion of the arm (shoulder)

Question 8

Origin of the biceps brachii

Answer 8

Two heads:
* Long head (lateral head): Supra-glenoid tubercle of scapula
* Short head (medial head): Apex of coracoid process

Question 9

Insertion of the biceps brachii

Answer 9

Radial tuberosity & bicipital aponeurosis in the skin

Question 10

Nerve supply of biceps brachii

Answer 10

Musculocutaneous nerve (C5,C6,C7)

Question 11

Action of the biceps brachii

Answer 11

Flexion of the arm (at shoulder joint)
Flexion of the forearm (at the elbow)
Supination in mid-prone position

Question 12

Origin of the brachialis

Answer 12

Lower part of the anterior surface of humerus

Question 13

Insertion of the brachialis

Answer 13

Ulnar tuberosity

Question 14

Nerve supply of the brachialis

Answer 14

Musculocutaneous nerve (C5,C6,C7)

Question 15

Action of the brachialis

Answer 15

Flexion of the forearm (at the elbow joint)

Question 16

Origin of the triceps brachii

Answer 16

Three heads
* Long head: Infra-glenoid tubercle of scapula
* Medial head: Posterior surface of humerus, below the radial groove
* Lateral head: Posterior surface of humerus, above the radial groove

Question 17

Insertion of the triceps brachii

Answer 17

Superior surface of the olecranon of the ulna

Question 18

Nerve supply of the triceps brachii

Answer 18

Radial nerve

Question 19

Action of triceps brachii

Answer 19

Extension of the forearm (at elbow joint)

Question 20

What is the brachial artery?

Answer 20

Continuation of axillary artery at the lower border of teres major muscle
Main arterial supply to arm

Extends to the neck of the radius where it divides into radial & ulnar arteries

Question 21

Branches of brachial artery

Answer 21

Profunda brachii
Superior ulnar collateral
Inferior ulnar collateral
Radial
Ulnar

Question 22

What is the cubital fossa?

Answer 22

Triangular depression located anterior to the elbow joint

Question 23

Boundaries of the cubital fossa

Answer 23

Laterally: Brachioradialis muscle
Medially: Pronator teres muscle
Base: Imaginary horizontal line between medial and lateral condyle

Question 24

What structures form the roof of the cubital fossa?

Answer 24

Skin
Superficial fascia
Median cubital vein
The bicipital aponeurosis

Question 25

What structures form the floor of the cubital fossa?

Answer 25

Brachialis & supinator muscles

Question 26

Contents of the cubital fossa

Answer 26

Radial nerve laterally
Biceps tendon
Brachial artery with its terminal branches (radial & ulnar arteries)
Median nerve medially

Question 27

What are the applied aspects of the cubital fossa?

Answer 27

Venipuncture: Median cubital vein is used in gathering blood samples and for intravenous injections
Brachial pulse & blood pressure: Easily felt medial to the biceps tendon for recording blood pressure