Brachium and Cubital Fossa: Ch 12

Question 1

Biceps Brachii

Answer 1

• flexes the forearm and supinates the hand; most powerful supinator of hand above 90 degrees of flexion; long heal also assists in flexion of arm
• musculocutaneous N.

Question 2

fascia of brachium

Answer 2

• brachial fascia = outer layer- circle around muscles
• intermuscular septum (lateral and medial) - divides muscles into flexor and extensor compartments. this also has two lamina that enclose a neurovascular compartment (brachial a, vv, median n. and musculocutaneous and ulnar nn.)

Question 3

Brachialis

Answer 3

A: flexion of forearm (most powerful of primary flexors)
N: musculocutaneous n.

Question 4

Brachioradialis

Answer 4

A: flexion of the forearm (best mechanical advantage when hand is midway between supination and pronation i.e. handshake)
N: Radial N.

Question 5

Coracobrachialis

Answer 5

A: flexion and adduction of humerus
N: musculocutaneous n.

Question 6

Triceps Brachii

Answer 6

A: all heads act to extend the forearm; long head also acts at the shoulder joint to extend and adduct arm
N: radial N

Question 7

Radial n.

Answer 7

innervates posterior surface muscles: extensors
C5-T7
(also innervates brachioradialis - although this is a flexor for the forearm)

Question 8

Musculocutaneous n.

Answer 8

innervates anterior surface muscles: flexors

C5,6,7

Question 9

Anconeus

Answer 9

A: assists triceps in extension of forearm
N: radial n.

Question 10

Brachial a.

Answer 10

• continuation of axillary a. distal to inferior border of teres minor
• goes through medial brachium
• ends within cubital fossa where it divides into radial and ulnar aa.
  three branches: profunda (deep) brachial, superior ulnar collateral, inferior ulnar collateral

Question 11

Profunda Brachial

Answer 11

• (deep brachial) largest branch of brachial artery
• arises posteromedially and accompanies the radial nerve around the humerus and divides into middle and radial collateral arteries

Question 12

Superior ulnar collateral

Answer 12

• branch of brachial artery that arises medially and courses inferiorly to medial epicondyle

Question 13

inferior ulnar collateral

Answer 13

• branch of brachial artery that arises medial, at distal portion of brachial and courses anterior to medial epicondyle

Question 14

Where does median nerve go?

Answer 14

• comes from axilla anterior to brachial artery.
• moves medial of artery.
• goes through cubital fossa deep to bicipital aponeurosis where it passes into the forearm between two heads of pronator teres muscle.
  DOES NOT provide any branches to the brachium

Question 15

which nerves provide articular branches to the elbow joint before they exit brachium?

Answer 15

• median, ulnar, musculocutaneous, radial

Question 16

Boundaries of cubital fossa

Answer 16

Lateral : brachioradialis muscle 
Medial: pronator teres muscle
Superior: line drawn through both humeral epicondyles
Roof: deep fascia
Floor: brachialis and supinator muscles

Question 17

Contents of cubital fossa

Answer 17

from lateral –> medial
T: tendon of the biceps
A: Brachail artery dividing into radial and ulnar arteries
N: median nerve

Question 18

Structures associated with the cubital fossa

Answer 18

1. superficial: median cubital vein, lateral antebrachial cutaneous n. (from musculocutaneous n.)
2. deep: bifurcation of the radial nerve into superificial and deep branches

Question 19

when does axillary a. turn into brachial a?

Answer 19

distal to inferior border of teres major