Anatomy (Arm and Elbow - 11/4)

Question 1

Dermatomes
C5
C6
C7
C8

Answer 1

C5 Shoulder
C6 Thumb
C7 Middle Finger
C8 Little Finger

Question 2

Dermatomes
T4
T10

Answer 2

T4 - Nipple

T10 - Umbilicus

Question 3

Dermatomes
L1
L5
S1
S2,3,4

Answer 3

L1 - Groin
L5 - Medial Foot
S1 - Lateral Leg/Foot
S2,3,4 - Anal Area

Question 4

Myotomes
C5
C6
C7
C8/T1

Answer 4

C5 - UE Abduction
C6 - Flexion of arm/forearm
C7 - Extension of forearm
C8/T1 - Intrinsic hand muscles

Question 5

Myotomes
L2
L3,4
S1
L5
S1,2

Answer 5

L2 Flex thigh
L3,4 Extend leg
S1 Flex leg
L5 dorsiflexes foot 
S1,2 Plantar flexes foot

Question 6

What lies in intertubercular sulcus?

Answer 6

Long head of biceps

Question 7

What does capitulum articulate with?

Answer 7

Head of radius

- lateral side

Question 8

What does trochlea articulate with?

Answer 8

Trochlear notch of ulna

- medial side

Question 9

What moves into coronoid fossa with flexion of forearm?

Answer 9

Coronoid process (front of ulna)

Question 10

What moves into radial fossa with flexion of forearm?

Answer 10

Head of radius

Question 11

Medial epicondyle = origin site for

Answer 11

flexor muscles of forearm/head

Question 12

Lateral epicondyle = origin site for

Answer 12

extensor muscles of hand

Question 13

Radial groove (location and what’s there)

Answer 13

Posterior surface of humerus - radial nerve and deep brachial vessels

Question 14

Olecranon fossa

Answer 14

posterior side of distal humerus, olecranon process of ulna there on extension of forearm

Question 15

Ulnar nerve

Answer 15

Derived from medial cord –> continues through arm region –> passes posterior to medial epicondyle (“funny bone”)

Question 16

Brachial fascia

Answer 16

Surrounds muscles, blood vessels, nerves of arm

Question 17

Medial and lateral intermuscular septae

Answer 17

Extend inward from brachial fascia –> attach to humerus –> divide arm into anterior flexor compartment and posterior extensor compartment

Question 18

Triceps brachii

Answer 18

Long head: Infraglenoid tubercle (scapula) - long w/ tendon, more medial
Lateral head: Posterior surface of humerus lateral to radial groove - most lateral
Medial head: Medial to radial groove Under them (deep)

*To olecranon process of ulna
Extend forearm, extend/adduct arm
Radial nerve

Question 19

When cut lateral head of triceps diagonally near radial groove, see:

Answer 19

Medial head of triceps, radial nerve w/ deep brachial artery

Question 20

Biceps brachii

Answer 20

Long head: Supraglenoid tubercle of humerus
Short head: Coracoid process of scapula

Tendon inserts on radial tuberosity + Bicipital aponeurosis

Innervated by musculocutaneous nerve

Flex forearm, supinate

Question 21

Coracobrachialis

Answer 21

Superiorly - coracoid process, inferiorly on humerus at midpoint on medial side
Musculocutaneous nerve (also passes through to lie between biceps/brachialis muscles it also innervates)
Flex, adduct arm

Question 22

Rupture of Tendon of Long head of biceps

Answer 22

Tendon tears with forceful flexion of arm against excessive resistance –> popeye deformity

Question 23

Brachialis

Answer 23

Anterior lower half of humerus –> coronoid process/tuberosity of ulna
Musculocutaneous nerve
Flexes forearm

Question 24

Pathway of musculocutaneous nerve

Answer 24

From Lateral cord –> Passes through coracobrachialis –> distally lying on brachialis muscle, covered by biceps brachii –> exits lateral border of biceps and continues into forearm as lateral cutaneous nerve of the forearm (lateral antebrachial cutaneous nerve)

Question 25

Pathway of radial nerve

Answer 25

Passes through posterior compartment of arm through lateral intermuscular septum to lie beneath brachioradialis muscle --> superficial branch (sensory) under brachioradialis to dorsum of hand, and deep branch that pierces supinator muscle to reach posterior forearm - extensors

Question 26

Cubital fossa

Answer 26

Triangular space defined by imaginary line between medial/lateral epicondyles, brachioradialis, pronator teres muscle Cicipital aponeurosis/deep fascia = roof, brachialis + supinator muscles = floor

Question 27

Brachial artery

Answer 27

``` Begins at lateral border of teres major muscle (continues from axillary artery) Accompanies median nerve in arm 3 major branches--> 1. Deep brachial artery 2. Superior ulnar collateral artery 3. Inferior ulnar collateral artery ```

Question 28

Deep brachial artery

Answer 28

1st branch of brachial artery | Passes posteriorly and accompanies radial nerve in radial groove

Question 29

Superior ulnar collateral artery

Answer 29

2nd brach of brachial artery | Accompanies ulnar nerve and passes behind medial epicondyle

Question 30

Inferior ulnar collateral artery

Answer 30

3rd (smallest) brach of brachial artery | Supplies area of elbow joint and anastomoses with recurrent branches of ulnar/radial arteries

Question 31

Anterior flexor compartment

Answer 31

biceps brachii, coracobrachialis, brachialis | Innervated by musculocutaneous nerve

Question 32

Posterior extensor compartment

Answer 32

Triceps brachii | Innervated by radial nerve

Question 33

What muscle supinates the forearm?

Answer 33

Biceps brachii (also flexes)

Question 34

Quandrangular space

Answer 34

Formed by teres minor, long head triceps, humerus, teres major Transmits posterior circumflex humeral artery and axillary nerve

Question 35

Triangular interval

Answer 35

Formed by teres major, long and lateral heads of triceps | Location of deep brachial artery and radial nerve, which both go into radial groove

Question 36

Where is tendon of long head of biceps?

Answer 36

Runs over head of humerus, ensheathed by layer of synovial membrane that follows the tendon as far as the surgical neck of the humerus. Held in intertubercular groove by transverse humeral ligament and tendon of pec major.

Question 37

Bicipital aponeurosis

Answer 37

Overlies/protects brachial artery in cubital fossa | Extension of biceps tendon

Question 38

Where does long head of biceps have origin?

Answer 38

Supraglenoid tubercle of scapula

Question 39

Where do most ruptures of long head of biceps occur?

Answer 39

From attachment at supraglenoid tubercle of scapula

Question 40

What tendon is most associated with tendonitis of biceps?

Answer 40

Long head attachment that goes through intertubercular groove (back and forth under synovial sheath)

Question 41

Ulnar nerve injury

Answer 41

Common in fracture of medial epicondyle - funny bone Denervates most intrinsic hand muscles. Power of wrist adduction is impaired When try to flex the wrist joint --> hand drawn to the lateral side by the FCR (supplied by the median nerve) in the absence of the “balance” provided by the FCU. Difficulty making a fist because, in the absence of opposition, the metacarpophalangeal joints become hyperextended, and he or she cannot flex the 4th and 5th digits at the distal interphalangeal joints when trying to make a fist. Person cannot extend the interphalangeal joints when trying to straighten the fingers. Claw hand The deformity results from atrophy of the interosseous muscles of the hand supplied by the ulnar nerve.

Question 42

Median nerve injury

Answer 42

Cannot make fist - hand of benediction (2,3 fingers remain extended) Cannot abduct/adduct thumb Sensory loss

Question 43

Radial nerve injury

Answer 43

Common with humerus fractures at surgical neck, incorrect use of crutches with axillary pressure (posterior cord) If happens higher up - may denerve triceps (cannot extend elbow) If lower - just brachioradialis, supinator, extensor muscles of forearm/wrist Wrist drop

Question 44

Musculocutaneous nerve injury

Answer 44

Usually protected - maybe stabbing Denerve biceps brachii, coracobrachialis --> weak flexion of arm, supination of forearm Also brachialis - weak flexion of elbow

Question 45

Branches of brachial artery

Answer 45

Profunda brachii artery (deep artery of the arm) superior and inferior ulnar collateral arteries

Question 46

Profunda brachii artery

Answer 46

Follows radial nerve -- anastomose around elbow

Question 47

Superior ulnar collateral artery

Answer 47

Follows ulnar nerve -- anastomose around elbow

Question 48

Median nerve location

Answer 48

First located lateral to, then crosses, and is finally medial to brachial artery No branches/innervation in arm (goes to hand)

Question 49

Musculocutaneous nerve location

Answer 49

Pierces coracobrachialis muscle (sending branches to it), the biceps and brachialis muscles Continues as lateral antebrachial cutaneous nerve

Question 50

Radial nerve location

Answer 50

Passes in radial groove on back of humerus with deep brachial artery, pierces lateral intermuscular septum and divides into superficial and deep branches in front of lateral epicondyle In arm - branches to triceps and skin

Question 51

Ulnar nerve location

Answer 51

Located medial to axillary and brachial arteries until middle of arm where it pierces the medial intermuscular septum to enter posterior compartment and run with superior ulnar collateral artery in groove behind medial epicondyle of humerus No branches/innervation in arm (goes to hand)

Question 52

Boundaries of cubital fossa

Answer 52

2 humeral epicondyles, brachioradialis, Pronator teres, deep fascia/bicipital aponeurosis, brachialis/supinator

Question 53

Deep structures in antecubital fossa

Answer 53

Median nerve, brachial artery, biceps tendon, radial nerve