Arm

Question 1

What holds the radius and ulna together (and is b/w them)?

Answer 1

Interosseous membrane

Question 2

What dermatome innervates lateral arm, lateral forearm, and thumb?

Answer 2

C6

Question 3

What dermatome innervates back of arm, back of forearm, and 2nd + 3rd digits?

Answer 3

C7

Question 4

What dermatome innervates medial arm, medial forearm, and hypothenar?

Answer 4

C8

Question 5

What dermatome innervates the nipple line?

Answer 5

T4

Question 6

What vein runs medial in the brachium and branches to form the median cubital vein?

Answer 6

Basalic v.

Question 7

The anterior compartment of the brachium is supplied by what nerve?

Answer 7

Musculocutaneous n.

Question 8

The posterior compartment of the brachium is supplied by what nerve?

Answer 8

Radial n.

Question 9

What is the most powerful flexor of the brachium?

Answer 9

Brachialis m.

Question 10

Brachialis m: innervation & action

Answer 10

• Musculocutaneous n. and radial n. (C7)

- Flexes forearm at elbow

Question 11

Biceps brachii m: innervation & action

Answer 11

• Musculocutaneous n. (C5, C6)

- Supinates and flexes forearm at elbow

Question 12

What muscle is the primary supinator of the brachium?

Answer 12

Biceps brachii m.

Question 13

Which head of the biceps brachii is lateral and which is medial?

Answer 13

Long head is lateral, short head is medial

Question 14

Coracobrachialis m: innervation & action

Answer 14

• Musculocutaneous n.

- Flexes and adducts arm at shoulder

Question 15

Triceps brachii m: innervation & action.

Answer 15

• Radial n.

- Extends arm at elbow. Long head stabilizes head of abducted humerus and extends and adducts arm at shoulder.

Question 16

What divides the posterior and anterior compartments of the brachium?

Answer 16

Medial and lateral intermuscular septa

Question 17

What three muscles are attached to the coracoid process?

Answer 17

Pectoralis minor m., coracobrachialis m., short head of the biceps brachii m.

Question 18

The musculocutaneous n. pierces through what muscle?

Answer 18

Coracobrachialis m.

Question 19

The biceps brachii tendon comes off what part of what bone?

Answer 19

Radial tuberosity of the radius bone (because it’s a supinator!)

Question 20

Where is the bicipital apneurosis? What does it overly/protect, and what does it support during venipuncture?

Answer 20

• It’s at the antecubitum
• Overlies/protects the brachial a.
• Supports the median cubital v. during venipuncture

Question 21

Which head of the triceps is least active? What does it do?

Answer 21

Long head–aids primarily in extending the arm (attached to infra-glenoid tubercle of scapula)

Question 22

Which head of the triceps is the “workhorse” of forearm extension (works during passive motions), and where is it on the arm?

Answer 22

Medial head–found deep to the long head

Question 23

Which head of the triceps generates the most force, but functions primarily against active resistance?

Answer 23

Lateral head

Question 24

The brachial a. branches into what main aa.? Where does it branch?

Answer 24

Radial a. and ulnar a. Branches at elbow.

Question 25

What are the anastomoses about the elbow?

Answer 25

M.R. Deep SIMR PAIR Superior ulnar colateral, Inferior ulnar colateral, Middle colateral, Radial colateral Posterior ulnar recurrent, Anterior ulnar recurrent, Interosseous recurrent, radial recurrent

Question 26

What muscle overlays the 2nd group of arteriole branches of the axillary a. (Screw the lawyer, save a patient)

Answer 26

Pectoralis minor m. (*Dr. I)

Question 27

What is the muscular landmark indicating transition from axillary a. --> brachial a.?

Answer 27

Lower border of teres major m.

Question 28

What 3 mm. constitute the floor on which the brachial a. runs?

Answer 28

Superior to inferior: long head of the triceps, coracobrachialis, and brachialis mm.

Question 29

What are the 3 main branches of the brachial a.?

Answer 29

Deep brachial a. (profunda brachii, runs in radial groove posteriorly), superior ulnar colateral a., inferior ulnar colateral a.

Question 30

What 3 important nerves are associated w/the brachial a.?

Answer 30

Radial, ulnar, and median nn.

Question 31

What 3 veins are associated w/the brachial a.?

Answer 31

2 venae comitantes (brachial veins), and the basilic v.

Question 32

What does injury at the musculocutaneous n. cause?

Answer 32

Flexion at the elbow (but not complete, due to brachioradialis and flexor forearm mm.)

Question 33

What does the musculocutaneous n. turn into?

Answer 33

Lateral antebrachial cutaneous n. (musculoCUTaneous, cuts, gives you a LAC (laceration).

Question 34

The radial n. passes thru the radial groove of the humerus w/what artery?

Answer 34

Deep brachial a.

Question 35

What nerves does the radial nerve branch into?

Answer 35

Posterior brachial n., inferior lateral brachial n., and posterior antebrachial cutaneous n.

Question 36

A sharp blow to the medial elbow ("funny bone") is affecting what nerve?

Answer 36

Ulnar nerve | - Has no branches in arm

Question 37

What nerve is lateral, crosses, and is then medial to the brachial a. in the arm?

Answer 37

Median n.

Question 38

What large vein is on the lateral anterior side of the arm? Which os on the medial anterior side?

Answer 38

- Lateral: cephalic v. | - Medial: basilic v.

Question 39

Explain the boundaries of the cubital fossa.

Answer 39

- Superior: imaginary line connecting medial and lateral epicondyles. - Medial: lateral border of pronator teres m. - Lateral: medial border of brachioradialis - Floor: brachialis and supinator mm. - Roof: brachial and antebrachial fascia, reinforced by the bicipital apneurosis (protects)

Question 40

What are the contents of the cubital fossa?

Answer 40

- Terminal part of the brachial a. (bifurcates into ulnar and radial aa.) - Medial n. - Radial n. (brach point into superficial and deep radial nn.) - Tendon of the biceps brachii m. - Deep veins in the area

Question 41

What area does the medial antebrachial cutaneous n. supply?

Answer 41

Some skin of bicep, but all skin of medial forearm down to the wrist

Question 42

What gives rise to the superior lateral cutaneous n of the brachium?

Answer 42

Axillary n.

Question 43

What dermatomes innervate the skin over the biceps mm.?

Answer 43

C5 and T1

Question 44

What m. inserts onto the ulnar tuberosity?

Answer 44

Brachialis m. (it's merely a flexor, not a supinator)

Question 45

The long head of the biceps originates from the _________________________.

Answer 45

Supraglenoid tubercle of the scapula

Question 46

The lateral head of the triceps originates from the _______________________.

Answer 46

Upper half of posterior humerus

Question 47

Where do the biceps insert?

Answer 47

Posterior border of bicipital tuberosity of radius (over bursa) and bicipital aponeurosis to deep fascia and subcutaneous ulna

Question 48

Where do the triceps insert?

Answer 48

Posterior part of upper surface of olecranon process of ulna and posterior capsule

Question 49

The short head of the biceps originates from the _______________________.

Answer 49

Corocoid process of the scapula

Question 50

The long head of the triceps originates from the _________________________.

Answer 50

Infraglenoid tubercle of the scapula

Question 51

The medial head of the triceps originates from the _______________________

Answer 51

Deep to lower half of posterior humerus