Arm elbow and cubital fossa

Question 1

Describe muscle of the anterior arm- corachobrachialis

Answer 1

Origin – corocoid process
* Insertion – medial aspect
of humerus
* Innervation –
musculocutaneous nerve
(C5-C7)
* Action – flexes and
adducts arm at shoulder

Question 2

Describe biceps brachii

Answer 2

Biceps brachii = “two headed arm
muscle”
* Origin – supraglenoid tubercle of
scapula (long head) and coracoid
process (short head)
* Insertion – radial tuberosity
* Innervation – musculocutaneous
nerve (C5-C7)
* Action – flexion of arm and
forearm, and powerful supination

Question 3

Describe brachialis

Answer 3

Brachialis
* Origin – anterior aspect of
humerus
* Insertion – ulnar tuberosity
and anterior surface of
coronoid process of ulna
* Innervation –
musculocutaneous nerve (C5-
C6) and radial nerve (C7)
* Action – powerful flexor of
forearm

Question 4

Describe muscles of posterior arm- triceps brachii

Answer 4

Triceps brachii = “three-headed arm
muscle”
* Origin –
– infraglenoid tubercle of the scapula
(long head)
– posterior surface of humerus,
superior to radial groove (lateral
head)
– inferior to the radial groove (medial
head)
* Insertion – olecranon of ulna
* Innervation – radial nerve (C6, C7,
C8)
* Action – extension of arm and
forearm

Question 5

What myotomes are elbow flexion and extension used to test

Answer 5

Elbow flexion –
test of C6
myotome (with
some C5)

Elbow
extension –
test of C7
myotome

Question 6

What are the arteries of the arm

Answer 6

Brachial artery –
– Profunda brachii a.
– 2 ulnar collateral aa.
– Radial a.
– Ulnar a.
* Profunda brachii
– Divides into radial and middle
collateral aa.

Question 7

What are the veins of the arm

Answer 7

Paired (deep) brachial veins
* Basilic vein – medial aspect of
the arm, becomes axillary vein
at teres major
* Cephalic vein – anterolateral
aspect of the arm, joins
axillary vein

Question 8

Describe the peripheral nerves of the arm

Answer 8

Musculocutaneous (C5-C7)
– Passes thru coracobrachialis
and between biceps and
brachialis
– Lateral cutaneous nerve of
forearm
* Median (C5-T1)
– Travels in anterior
compartment, related to
brachial artery
* Ulnar (C7-T1)
– Follows brachial artery, passes
to posterior compartment,
around medial epicondyle
* Radial (C5-T1)
– Accompanies deep artery
– Passes to anterior
compartment anterior to elbow
– Muscular and cutaneous
branches

Question 9

What are the boundaries and gateways of the cubital fossa

Answer 9

Boundaries
– Lateral – Brachioradialis
– Medial – Pronator teres
– Base – line between
epicondyles
– Floor – Brachialis
– Roof – skin, fascia
* Contents
– Tendon of biceps brachii
– Brachial artery
– Median nerve
* Arranged lateral to medial,
T-A-N
* Artery and nerve protected by
aponeurosis

Question 10

What are the veins in the cubital fossa

Answer 10

Boundaries
– Lateral – Brachioradialis
– Medial – Pronator teres
– Base – line between
epicondyles
– Floor – Brachialis
– Roof – skin, fascia
* Contents
– Tendon of biceps brachii
– Brachial artery
– Median nerve
* Arranged lateral to medial,
T-A-N
* Artery and nerve protected by
aponeurosis

Question 11

What is the significance of the brachial artery

Answer 11

Used to measure blood pressure
– Cuff placed around arm proximally and compresses brachial artery
against humerus
– Stethoscope over artery (medial to biceps tendon) in cubital fossa