15 - Anterior arm and Forearm Cubital Fossa

Question 1

elbow joint

Answer 1

A synovial hinge joint (allows flexion and extension) with articulations between:

1) the trochlea of the humerus and the trochlear notch of the ulna.
2) the capitulum of the humerus and the superior aspect of the radial head
- Primarily supported by the ulnar and radial collateral ligaments

Question 2

proximal radioulnar joint

Answer 2

Pivot type of synovial joint allowing for pronation and supination Contained within the same joint capsule as the elbow joint Articulation is between the head of radius and radial notch of the ulna
- Primarily supported by the annular ligament

Question 3

intermediate radioulnar joint

Answer 3

• a syndesmosis (fibrous joint) consisting of an interosseous membrane connecting the interosseous margins of the radius and ulna.
• The interosseous membrane does not hinder movements of pronation & supination.
• It provides a site for muscle attachment and helps to transfer forces from the radius to the ulna

Question 4

nursemaid’s elbow

Answer 4

• subluxation and dislocation of the radial head
• sudden pulling of the upper limb may tear the anular ligament and cause an inferior displacement of the radial head.
• the superior portion of the anular ligament may become trapped between the capitulum and radial head, causing pain.
• Pain is least with a flexed and pronated forearm

Question 5

distal radioulnar joint

Answer 5

pivot type of synovial joint allowing for pronation and supination. The articulating sufaces are the ulnar notch of the radius and the head of the ulna. The articulating surfaces are separated by an L-shaped articular disc that continues under the distal end of the ulna and also serves to separate the joint cavities of the distal radio-ulnar and wrist joints.

Question 6

radiocarpal joint (wrist joint)

Answer 6

condyloid type of synovial joint allowing for flexion-extension and adduction-abduction. The articulating surfaces are the distal end of the radius and the proximal surfaces of the lunate and scaphoid bones (the triquetrum will articulate with the distal radius during adduction of the wrist)

Question 7

1st carpometacarpal joint

Answer 7

Saddle synovial joint; flex-ext; abd-add; some axial rotation (circumduction)

Question 8

1st metacarpophalangeal joint

Answer 8

Hinge synovial; flex-ext

Question 9

metacarpophalangeal joint

Answer 9

Condyloid synovial; flex-ext; abd-add

Question 10

proximal interphalangeal joint

Answer 10

Hinge synovial; flex-ext

Question 11

distal interphalangeal joint

Answer 11

Hinge synovial; flex-ext

Question 12

planes of movement for thumb and four digits

Answer 12

*movements of the thumb occur in a plane that is perpendicular to the plane of movements of the medial four digits.

Question 13

biceps brachii O, I, (long head a short head) Innervation, A

Answer 13

Origin:
-Long head - supraglenoid tubercle
-Short head - coracoid process
Insertion: radial tuberosity Innervation: musculocutaneous Action: supinates & flexes forearm Some shoulder flexion

Question 14

coracobrachialis is pierced by what nerve

Answer 14

musculocutaneous n.

Question 15

brachialis Innervation, A

Answer 15

Innervation - musculocutaneous n.

Action – primary forearm flexor

Question 16

common flexor attachment

Answer 16

• located on medial epicondyle of humerus

- gives rise to superficial flexor and pronator muscles in the forearm

Question 17

superficial muscles that cross both elbow and wrist of anterior forearm

Answer 17

-Pronator teres
-Flexor carpi radialis
Palmaris longus (often absent, when present it fans out distally to form the palmar aponeurosis)
-Flexor carpi ulnaris

Question 18

innervation of muscles in anterior compartment of forearm

Answer 18

median nerve

EXCEPT flexor carpi ulnaris which is innervated by ulnar nerve

Question 19

brachioradialis

Answer 19

functionally a flexor muscle and is best seen in anterior view, but is physically located in the extensor compartment, so receives innervation by the nerve of the extensor compartment, the radial nerve.

Question 20

flexor digitorum superficialis

Answer 20

• only muscle in the intermediate muscle group of the anterior compartment of the forearm.
• takes origin, at least in part, from the common flexor tendon on the medial epicondyle of the humerus.
• divides into four tendons which insert on either side of each of the medial four intermediate phalanges

Question 21

3 muscles in deep group of anterior compartment of forearm

Answer 21

• Flexor digitorum profundus (divides into four tendons which insert on the distal phalanges of the medial four digits. It is the only muscle capable of flexing the distal interphalangeal joints (DIP))
• Flexor pollicis longus
• Pronator quadratus

Question 22

flexor retinaculum

Answer 22

• transverse carpal ligament
• thickening of antebrachial fascia at the wrist
• serves to hold down the long flexor tendons to help maintain mechanical advantage during wrist flexion. It also forms the roof of the carpal tunnel

Question 23

carpal tunnel

Answer 23

-the median nerve
-tendon of flexor pollicis longus (in it’s own synovial
sheath)
-the tendons of flexor digitorum superficialis (FDS) and profundus (FDP) muscles (sharing a common synovial sheath).

Question 24

fibrous digital sheath

Answer 24

• Once these tendons reach the palmar surface of the proximal phalanges of the medial four digits
• extend between the MP joints and the distal phalanges and function to hold the tendons against the phalanges to prevent them from ‘bowing’ during finger flexion

Question 25

long flexor tendons

Answer 25

FDP and FDS are surrounded by synovial sheaths as they pass through the fibrous digital sheaths. The synovial sheath of the fifth digit is continuous with the synovial sheath in the carpal tunnel (the others are not).

Question 26

tendon of FPL

Answer 26

has its own synovial sheath that continues from the carpal tunnel into the fibrous digital sheath of the pollex.

Question 27

carpal tunnel syndrome

Answer 27

Swelling of the synovial sheaths is the major cause

Question 28

brachial artery

Answer 28

-supplies all of the blood to structures in the anterior compartment of the arm
-Begins at the inferior border of the teres major muscle as a distal continuation of the axillary artery.
-It travels through the anterior arm with the median nerve and gives off:
–Branches to the humerus and structures in the anterior arm
–Deep artery of the arm (Profunda brachii artery) that
travels to the posterior compartment of the arm with the radial nerve.
–Collateral branches to the anastomosis around the elbow

Question 29

radial artery and ulnar artery

Answer 29

The brachial artery continues distally, it travels through the cubital fossa and terminates at the level of the radial head by bifurcating

Question 30

cubital fossa

Answer 30

triangular depression on anterior aspect of the elbow

Question 31

borders of cubital fossa

Answer 31

• Base: (superior) imaginary line connecting medial and lateral humeral epicondyles
• Medial border: pronator teres
• Lateral border: brachioradialis

Question 32

contents of cubital fossa

Answer 32

• Tendon of Biceps brachii (with bicipital aponeurosis)
• Brachial artery and its terminal branches (radial and ulnar arteries) (with their accompanying veins)
• Median nerve

Question 33

ulnar artery

Answer 33

• travels with the median nerve between the two heads of the flexor digitorum superficialis muscle then moves medially to travel with the ulnar nerve.
• Travels with the ulnar nerve lateral to the tendon of the flexor carpi ulnaris (where pulse can be felt)
• Runs superficial to the flexor retinaculum to reach the palmar surface of the hand
• Major branches:
• -Common interosseous artery divides into:
• –anterior interosseous artery
• –posterior interosseous artery

Question 34

radial artery

Answer 34

• Travels the length of the forearm just medial to
  the brachioradialis muscle.
• At the wrist it comes to lie on the anterior surface of the radius (take pulse here) before coursing onto the dorsum of the hand. -Major Branches:
  -Superficial palmar branch (to superficial palmar arterial arch)
  -Deep palmar branch (to deep palmar arterial arch)

Question 35

musculocutaneous nerve

Answer 35

• Innervates all of the muscles in the anterior compartment of the arm.
• one of two terminal branches of the lateral cord of the brachial plexus.
• Pierces coracobrachialis muscles
• Continues distally in the plane between biceps brachii and brachialis muscles
• Emerges lateral to the biceps brachii muscle as the lateral cutaneous nerve of the forearm (a.k.a. lateral antebrachial cutaneous n.)

Question 36

median nerve

Answer 36

• arises from the brachial plexus by contributions from both the lateral and medial cords. It travels through the arm with the brachial artery and enters the cubital fossa on its medial side. It exits the cubital fossa by passing between the two heads of the pronator teres muscle and travels in the forearm between intermediate and deep muscle layers.
• All superficial and intermediate muscles of the anterior compartment of the forearm except for flexor carpi ulnaris

Question 37

anterior interosseous n

Answer 37

• branch of median nerve

- supplies all the deep muscles of the forearm except for the ulnar half of the flexor digitorum profundus muscle.

Question 38

palmar cutanous nerve

Answer 38

• branch of median nerve
• (to skin of the central palm) before travelling through the carpal tunnel on its way to innervate more muscles in the hand

Question 39

ulnar nerve

Answer 39

• terminal branch of the medial cord of the brachial plexus. It enters the forearm by passing through the cubital tunnel between the two heads of the flexor carpi ulnaris muscle (which it supplies).
• travels through forearm between FCU and FDP with ulnar artery
• While in the forearm it gives off:
• branches to FCU and ulnar half of FDP -Palmar cutaneous n. (to the hand) -Dorsal cutaneous n. (to the hand)
• It enters the hand, with the ulnar vessels, by passing superficial to the flexor retinaculum in the ulnar canal (a.k.a., guyon’s canal - between the pisiform and hook of the hamate).