arm

Question 1

Compartments of the arm

Answer 1

• The deep fascia of the arm.
• The humerus.
• The lateral and medial intermuscular septa

Question 2

Muscles of the arm

Answer 2

four major arm muscles, three flexors (biceps
brachii, brachialis, and coracobrachialis) are in the
anterior (flexor)compartment , musculocutaneous nerve

one extensor (triceps
brachii) is in the posterior compartment, supplied by
the radial nerve

Question 3

who are
stonger ant or
post

Answer 3

The flexor muscles of the anterior
compartment are almost twice as strong as the
extensors in all positions; consequently, we are
better pullers than pushers

Question 4

Coraco-brachialis
• Origin:

Answer 4

Tip of coracoid process of
scapula (with the short head of
biceps brachii)

Question 5

Coraco-brachialis insertion & innervation

Answer 5

Insertion: Middle of medial
aspect of humerus.
• Nerve supply: Musculocutaneous
nerve (C5, C6, C7)

Question 6

Coraco-brachialis
action

Answer 6

Action: It helps in flexion and
adduction of the arm.

Question 7

Biceps brachii
▪ Origin:

Answer 7

by 2 heads
• Short head: from the tip of coracoid
process of the scapula.
• Long head: from the sup

Question 8

Biceps brachii insertion
& intervation

Answer 8

▪ Insertion:
• Posterior part of the radial tuberosity.
• By the bicipital aponeurosis into the
deep fascia of the forearm.
• Nerve supply: Musculocutaneous nerve.

Question 9

Biceps
action

Answer 9

Flexor of the elbow.
• Powerful supinator of the flexed
forearm.
• Long head helps in stabilization of
shoulder joint.

Question 10

bicipital aponeurosis
separates

Answer 10

the brachial artery
from median cubital vein.

Question 11

The long head of biceps arises
inside the shoulder joint and
then leaves it to pass through
the bicipital groove. It is

Answer 11

intracapsular but
extrasynovial.

Question 12

Brachialis
origin Insertion

Answer 12

• Origin: lower half of anterior
surface of humerus and the two
intermuscular septa.
• Insertion: Coronoid process and
tuberosity of ulna.

Question 13

Brachialis nerve action

Answer 13

Nerve supply: Musculocutaneous
nerve. Some of the lateral part of
the brachialis is innervated by a
branch of the radial nerve.
• Action: Flexes forearm in all
positions

Question 14

Triceps brachii
origin_ insertion

Answer 14

▪ Origin: by 3 heads
• Long head: infra-glenoid tubercle of
scapula.
• Lateral head: posterior surface of
humerus above the spiral groove.
• Medial head: posterior surface of
humerus below the spiral groove.
• Insertion: Proximal end of olecranon
process of ulna

Question 15

Triceps brachii nerve
action

Answer 15

• Nerve supply: Radial nerve.
• Action:
• Main extensor of the elbow.
• Long head shares in stability of
shoulder.
• The long head helps in adduction of
abducted the arm.

Question 16

mu sculo cutaneous nerve origin , termination

Answer 16

Origin: It is a branch of the lateral
cord of brachial plexus.
• Termination: It terminates by
continuing as the lateral cutaneous
nerve of the forearm.

Question 17

muscle pierce muscu… nerve

Answer 17

• The nerve descends lateral to 3
rd
part of axillary artery. The nerve
then pierces the coracobrachialis
then it passes between biceps and
brachialis.

Question 18

Musculocutaneous branches

Answer 18

Branches: Muscular branches to:
• Two heads of biceps brachii.
• Coracobrachialis.
• The greater part of brachialis.

Question 19

Anconeus
origin _action nerve insertion

Answer 19

• Origin: Lateral epicondyle of
humerus.
• Insertion: Lateral surface of
olecranon and superior part of
posterior surface of ulna.
• Nerve supply: Radial nerve
(C7, C8, T1).
• Action: Assists triceps in
extending forearm; stabilizes
elbow joint; may abduct ulna
during pronation

Question 20

Cubital fossa
boundaries

Answer 20

• Medially: pronator teres muscle.
• Laterally: brachioradialis muscle.
• Base: directed upwards and is formed by an imaginary line
connecting the 2 humeral epicondyles.
• Apex: Directed downwards and formed by the point of
overlap of brachioradialis over pronator teres.
.roof:• Skin.
• Superficial fascia containing median cubital vein, parts of basilic
and cephalic veins, medial and lateral cutaneous nerves of
forearm.
• Deep fascia.
• Bicepital aponeurosis.
• Floor: Brachialis muscle (medially) and supinator muscle (laterally)

Question 21

Cubital fossa
contents

Answer 21

From lateral to medial:
• Biceps tendon.
• Brachial artery.
• Median nerve.

Question 22

where, stethoscope is placed in BP measuring

Answer 22

During measuring of the blood pressure the
stethoscope is placed on the brachial artery in the cubital fossa just
medial to the tendon of biceps (landmark).

Question 23

Median nerve Origin course branches

Answer 23

• Origin:
• Medial root: C. 8, T.1 (from medial cord of
brachial plexus).
• Lateral root: C.5, 6, 7 (from lateral cord of
brachial plexus).
• The two roots unite to form the median nerve
lateral to the 3
rd part of axillary artery.
• Median nerve in the axilla and arm:
• Course:
• The nerve descends lateral to the 3
rd part of
axillary artery and upper half of brachial artery.
• At the middle of arm (level of insertion of
coracobrachialis) it crosses in front of the
brachial artery from lateral to medial.
• It then descends medial to the brachial artery
down to the cubital fossa.
• It enters the forearm by passing between the 2
heads of pronator teres.
• Branches: The median nerve has no branches in
the arm.

Question 24

Ulnar nerve

Answer 24

• Origin:
- It is a branch of medial cord of brachial plexus.
- Fibres of C7 come from lateral root of median
nerve.
• Ulnar nerve in the axilla and arm:
• Course:
• The nerve descends close to the medial side
of 3
rd part of axillary artery and upper half
of brachial artery.
• At the middle of the arm (level of insertion
of coracobrachialis) it pierces the medial
intermuscular septum to reach the posterior
compartment.
• It descends down to the back of medial
epicondyle.
• It enters the forearm by passing between
the 2 heads of flexor carpi ulnaris muscle.
• Branches: The ulnar nerve has no branches
in the arm.

Question 25

Radial nerve

Answer 25

• Origin: From the posterior cord of
brachial plexus.
• Radial nerve in the axilla and arm:
• Course:
• The nerve descends posterior to 3
rd
part of axillary artery and upper part
of brachial artery.
• Then it passes through the lower
triangular space to reach the spiral
groove with the profunda brachii
artery; here it lies between the
medial and lateral heads of triceps.
Thereafter, it pierces the lateral
intermuscular septum to reach the
front of arm where it descends
between the brachialis and
brachioradialis muscles.

▪ Branches in the axilla:
• Muscular branches to long and medial heads of triceps
• Posterior cutaneous nerve of the arm •
▪ Branches in the spiral groove:
• Muscular branches to the lateral and medial heads of triceps.
• Muscular branch to the anconeus muscle.
• Lower lateral cutaneous nerve of the arm
• Posterior cutaneous nerve of the forearm.
•
▪ Branches in the groove between brachialis and
brachioradialis:
• Muscular branch to the lateral part of brachialis.
• Muscular branch to brachioradialis.
• Muscular branch to extensor carpi radialis longus.

• Termination : the radial nerve terminates in front of the
lateral epicondyle where it divides into:
– Superficial terminal branch (continuation of radial nerve).
– Deep terminal branch called posterior interosseosus nerve.

Question 26

Brachial artery origin termination

Answer 26

• Origin: as a continuation of the axillary
artery at the lower border of teres major
muscle.
• Termination: opposite the neck of radius by
dividing into two terminal branches.

Question 27

Brachial artery course

Answer 27

• The artery descends in the anterior
compartment of the arm accompanied with
its 2 venae commitants. Along its whole
course, the artery is relatively superficial.
• In the upper part of the arm, the median
nerve lies on the lateral side of the artery
while the ulnar nerve and basilic vein lie on
its medial side.
• At the middle of the arm, the median nerve
crosses in front of the artery, from the
lateral to the medial side and continues
along the medial side of the brachial artery
down to the cubital fossa.

Question 28

Brachial artery branches

Answer 28

1-Profunda brachii artery, the largest
branch that accompanies the radial
nerve in the spiral groove. It gives an
ascending branch. The profunda brachii
ends by giving anterior and posterior
descending arteries that share in
anastomosis around elbow.
2-Muscular branches.
3-Nutrient artery to the humerus.
4-Superior ulnar collateral artery.
5-Inferior ulnar collateral artery: which
divide into anterior and posterior
branches.
6- Terminal branches:
• Radial artery.
• Ulnar artery

Question 29

❖Changes that occur at the level of insertion of
coracobrachialis:

Answer 29

• The median nerve: crosses in front of brachial artery from
lateral to medial.
• The ulnar nerve: pierces the medial intermuscular septum to
reach the posterior compartment.
• The radial nerve & profunda brachii artery: descend on the
back of humerus through the spiral groove.
• The basilic vein: pierces the deep fascia to ascend medial to
brachial artery.
• The medial cutaneous nerve of the arm and forearm: pierces
the deep fascia to pass through the superficial fascia.
• The nutrient artery of the humerus: enters into the bone.