Anterior Arm, Forearm and Cubital Fossa

Question 1

What are the three muscles of the anterior arm?

Answer 1

Biceps brachii, coracobrachialis, brachialis

Question 2

What makes up the biceps brachii?

Answer 2

Comprises a long and short head and two distal tendons (biceps tendon and bicipital aponeurosis)

Question 3

What is the most anteriorly positioned muscle of the anterior arm?

Answer 3

The biceps brachii

Question 4

What are the proximal attachments of the biceps brachii?

Answer 4

Via long head = supraglenoid tubercle of scapula

Via short head = coracoid process of the scapula

Question 5

What muscles attach to the coracoid process?

Answer 5

Pectoralis minor, coracobrachialis, short head of biceps brachii

Question 6

Where does the tendon of the long head of the biceps brachii pass?

Answer 6

Passes superiorly in the intertubercular groove/sulcus of the humerus, then becomes enclosed within fibrous layer of the shoulder joint capsule to reach supraglenoid tubercle of the scapula

Question 7

What causes biceps tendinitis?

Answer 7

Movement of the tendon of the long arm of the biceps brachii within the intertubercular groove of the humerus

Question 8

What are the distal attachments of the biceps brachii?

Answer 8

Biceps tendon = attaches to radial tuberosity

Biceps aponeurosis = blends distally with deep (antebrachial) fascia on medial side of proximal forearm

Question 9

What is the biceps deep tendon (myotactic) reflex?

Answer 9

Deep tendon reflex performed in neurological examinations

Question 10

How is the biceps deep tendon reflex elicited?

Answer 10

By placing examiners thumb on biceps tendon (within the cubital fossa) and then striking briskly on the thumb with a tendon hammer

Question 11

What should be the result of the biceps deep tendon reflex?

Answer 11

Conveys sudden stretch to biceps tendon and should cause involuntary contraction of muscle = patient will flex forearm at the elbow

Question 12

Where is the coracobrachialis located?

Answer 12

Attaches from coracoid process of scapula to humerus, deep to biceps brachii and medial to brachialis

Question 13

What separates coracobrachialis from the triceps?

Answer 13

Medial intermuscular septae

Question 14

Where is brachialis located?

Answer 14

Attaches from humerus to coronoid process of ulna, deep to biceps brachii and lateral to coracobrachialis

Question 15

What separates brachialis from the triceps?

Answer 15

Lateral intermuscular septae

Question 16

Where do the muscles of the anterior arm span?

Answer 16

The shoulder joint and elbow joint, biceps brachii also spans the proximal radioulnar joint

Question 17

What is the most powerful supinator of the forearm?

Answer 17

Biceps brachii

Question 18

What innervates the anterior compartment of the forearm?

Answer 18

All supplied by median nerve except for flexor carpi ulnaris and medial part (to digits 4 and 5) of flexor digitorum profundus

Question 19

What nerves supply the flexor carpi ulnaris and medial part of flexor digitorum profundus of the anterior forearm?

Answer 19

Ulnar nerve

Question 20

What are the actions of the muscles of the anterior forearm?

Answer 20

Flexion, abduction and adduction of wrist (carpus)
Flexion of fingers (digits 2-5)
Flexion of thumb (digit 1)
Pronation of forearm at proximal and distal radioulnar joints

Question 21

What are the three layers of muscle in the anterior forearm?

Answer 21

Layer 1 = superficial muscles
Layer 2 = intermediate muscles
Layer 3 = deep muscles

Question 22

Where do the superficial muscles of the anterior forearm attach proximally?

Answer 22

To medial epicondyle of humerus by common flexor tendon

Question 23

What muscles make up the superficial layer of the anterior forearm?

Answer 23

Pronator teres
Palmaris longus = attaches distally to palmar aponeurosis
Flexor carpi radialis = attaches distally to metacarpals on radial side
Flexor carpi ulnaris - attaches distally to metacarpals on ulnar side

Question 24

Where do the intermediate muscles of the anterior forearm attach proximally?

Answer 24

Medial epicondyle of humerus, coronoid process of ulna and radial head

Question 25

What muscle makes up the intermediate layer of the anterior forearm?

Answer 25

Flexor digitorum superficialis = four muscle bellies/tendons for the medial four digits

Question 26

What is the proximal attachment of the deep muscles of the anterior forearm?

Answer 26

Anterior surfaces of radius or ulna

Question 27

What muscles make up the deep layer of the anterior forearm?

Answer 27

Flexor digitorum profundus = attaches distally to digits 2-5 Flexor pollicis longus = attaches distally to thumb Pronator quadratus = attaches between distal anterior surfaces of radius and ulna

Question 28

Where are the muscle bellies of the anterior forearm muscles found?

Answer 28

Exclusively in the anterior compartment of the forearm

Question 29

Where do the long tendons of the anterior forearm muscles pass to?

Answer 29

The wrist and hand

Question 30

What holds the long tendons of the anterior forearm muscles in place at the wrist joint or carpus?

Answer 30

Wrist joint = palmar carpal ligament | Carpus = flexor retinaculum

Question 31

Where does the common flexor origin attach proximally?

Answer 31

To the medial epicondyle of the humerus

Question 32

What causes Golfers elbow?

Answer 32

Tendonitis of the common flexor tendon causing pain felt in the area of the medial epicondyle

Question 33

What are the boundaries of the cubital fossa?

Answer 33

``` Superior = transvers line between epicondyles of humerus Medial = pronator teres Lateral = brachioradialis ```

Question 34

What are the superficial contents of the cubital fossa?

Answer 34

Median cubital vein, cephalic vein, basilic vein

Question 35

What structures are palpable in the cubital fossa?

Answer 35

Distal tendon (deep and lateral) and aponeurosis (medial) of biceps brachii

Question 36

What are the deep contents of the cubital fossa?

Answer 36

``` Median nerve (medially) = continues into anterior forearm Brachial artery Radial nerve (laterally) ```

Question 37

Where does the brachial artery bifurcate into the radial and ulnar arteries?

Answer 37

At apex of cubital fossa

Question 38

Where does the radial nerve divide?

Answer 38

Divides into superficial and deep branches deep to brachialis, deep branch pierces supinator to enter posterior forearm

Question 39

What is the cubital fossa?

Answer 39

Triangular space between skin and anterior aspect of elbow capsule

Question 40

What supplies the skin and fascia of the cubital fascia?

Answer 40

Cutaneous nerves of arm and forearm

Question 41

What can the superficial veins of the cubital fossa be used for?

Answer 41

Venapuncture and siting of peripheral venous cannulas (deep contents may be damaged)

Question 42

Where can the ulnar nerve be palpated?

Answer 42

Where it crosses the posterior surface of the medial epicondyle of the humerus (readily injured at this site)

Question 43

What does the ulnar nerve pass through to reach the anterior forearm?

Answer 43

Passes through flexor carpi ulnaris (in cubital tunnel)