Lecture 11

Question 1

What is the common origin of the anterior compartment muscles of the antebrachium?

Answer 1

Medial epicondyle of the humerus

Question 2

What is the common function of the muscles of the anterior compartment of the antebrachium?

Answer 2

Wrist and digit flexion

Question 3

What is the anterior compartment of the antebrachium innervated by?

Answer 3

Median and ulnar nerves

Question 4

Superficial muscles coming off the medial epicondyle

Answer 4

Pronator teres
Flexor carpi radialis
Palmaris longus (not everyone has this)
Flexor carpi ulnaris

Question 5

Flexor digitorum superficialis

1. Proximal Attachment
2. Where it travels
3. Function
4. Innervation

Answer 5

1. Humero-ulnar head and radial head
2. To shafts of middle phalanges of digits 2-5
3. Flexes middle phalanges of medial four fingers, proximal phalanges at MP joints; can flex each finger independently
4. Median nerve

Question 6

Flexor digitorum profundus

1. Proximal Attachment
2. Where it travels
3. Function
4. Innervation
5. Vascularization

Answer 6

1. Proximal two-thirds of anterior surface of ulna and interosseous membrane
2. To distal phalanges 2-5
3. Only muscle that can flex distal IP joints of fingers; can flex index finger independently
4. Median nerve via anterior interosseous nerve and ulnar nerve
5. Anterior interosseous artery

Question 7

Flexor pollicis longus

1. Proximal Attachment
2. Where it travels
3. Function
4. Innervation

Answer 7

1. Mid-anterior surface of radius and interosseous membrane
2. To distal phalanx of thumb
3. Flexes distal phalanx of thumb
4. Median nerve

Question 8

What is the common function of the muscles of the posterior antebrachium?

Answer 8

Primarily wrist and hand extensors

Question 9

What is the common origin of the muscles of the posterior antebrachium?

Answer 9

Lateral epicondyle of humerus

Question 10

What are the muscles of the posterior forearm innervated by?

Answer 10

Radial nerve via the deep branch of the radial nerve or the posterior interosseous nerve

Question 11

Superficial muscles originating from the lateral epicondyle

Answer 11

Brachioradialis
Extensor carpi radialis longus
Extensor carpi radialis brevis
Extensor digitorum
Extensor digiti minimi
Extensor carpi ulnaris

Question 12

Deep extensor muscles of posterior antebrachium

Answer 12

Supinator
Extensor indicis
Abductor pollicis longus
Extensor pollicis longus
Extensor pollicis brevis

Question 13

Outcropping Muscles

Answer 13

Abductor pollicis longus
Extensor pollicis longus
Extensor pollicis brevis

Question 14

Brachioradialis

1. Proximal Attachment
2. Distal Attachment
3. Function
4. Blood Supply
5. Innervation

Answer 14

1. Proximal 2/3 of supraepicondylar ridge of humerus
2. Distal radius, proximal to styloid process
3. Flexes forearm when it is pronated
4. Radial collateral artery, radial recurrent artery, radial artery
5. Radial nerve

Question 15

Extensor Carpi Radialis Longus

1. Proximal Attachment
2. Distal Attachment
3. Function
4. Blood Supply
5. Innervation

Answer 15

1. Lateral supracondylar ridge of humerus
2. Dorsal aspect of base of 2nd metacarpal
3. Extends and abducts hand at wrist
4. Radial collateral artery, radial recurrent artery, recurrent interosseous artery, and posterior interosseous artery
5. Radial nerve

Question 16

Extensor Carpi Radialis Brevis

1. Proximal Attachment
2. Distal Attachment
3. Function
4. Blood Supply
5. Innervation

Answer 16

1. Lateral epicondyle of humerus (common extensor origin)
2. Dorsal aspect of base of 3rd metacarpal
3. Extends and abducts hand at wrist
4. Radial collateral artery, radial recurrent artery, recurrent interosseous artery, and posterior interosseous artery
5. Deep branch of radial nerve

Question 17

Extensor Digitorum

1. Proximal Attachment
2. Distal Attachment
3. Function
4. Blood Supply
5. Innervation

Answer 17

1. Lateral epicondyle of humerus
2. Extensor expansions of medial four fingers
3. Extends medial 4 fingers at metacarpophalangeal joints and somewhat at interphalangeal joints
4. Posterior interosseous artery, recurrent interosseous, and perforating branch of anterior interosseous arteries
5. Posterior interosseous nerve

Question 18

Extensor Digiti Minimi

1. Proximal Attachment
2. Distal Attachment
3. Function
4. Blood Supply
5. Innervation

Answer 18

1. Lateral epicondyle of humerus
2. Extensor expansion of fifth finger
3. Extends 5th finger at metacarpophalangeal joint and somewhat at interphalangeal joint
4. Posterior interosseous artery, recurrent interosseous, and perforating branch of the anterior interosseous arteries
5. Posterior interosseous nerve

Question 19

Extensor Carpi Ulnaris

1. Proximal Attachment
2. Distal Attachment
3. Function
4. Blood Supply
5. Innervation

Answer 19

1. Lateral epicondyle of humerus and posterior border of ulna
2. Dorsal aspect of base of fifth metacarpal
3. Extends and adducts hand at wrist
4. Radial collateral artery, recurrent interosseous, and posterior interosseous artery
5. Posterior interosseous nerve

Question 20

Pronator Quadratus

1. Proximal Attachment
2. Distal Attachment
3. Function
4. Innervation

Answer 20

1. Distal third of ulna
2. Distal third of radius
3. Pronates forearm, helps interosseous membrane to hold radius and ulna together
4. Anterior interosseous branch of median nerve

Question 21

Pronator Teres

1. Proximal Attachment
2. Distal Attachment
3. Function
4. Innervation

Answer 21

1. Ulnar head; coronoid process of ulna; humeral head; medial epicondyle and supracondylar ridge
2. Middle third of lateral surface of radius
3. Pronates forearm, flexes antebrachium
4. Median nerve

Question 22

Supinator

1. Proximal Attachment
2. Distal Attachment
3. Function
4. Innervation

Answer 22

1. Lateral epicondyle of humerus, radial collateral and annular ligaments; ulnar crest
2. Proximal 1/3 of radius (nearly all surfaces as it wraps around the bone)
3. Supinates forearm; brings radius back to anatomical position
4. Deep branch of radial nerve

Question 23

Median Nerve

Answer 23

Supplies all other muscles in the anterior compartment not supplied by ulnar nerve; gives off anterior interosseous nerve

Crosses anterior cubital fossa medial to brachial artery; passes between the two heads of the pronator teres; travels between the flexor digitorum superficialis and flexor digitorum profundus

Question 24

Ulnar Nerve

Answer 24

Supplies flexor carpi ulnaris, half of flexor digitorum profundus

From posterior compartment of brachium; through sulcus in medial epicondyle; into antebrachium between two heads of flexor carpi ulnaris; extends between flexor carpi ulnaris and flexor digitorum profundus

Question 25

Radial Nerve

Answer 25

Runs in the arm in the radial groove and extends down the lateral side of the humerus, pierces lateral intermuscular septum in lower arm and enters antebrachium between brachioradialis and brachialis muscles; passes in front of lateral epicondyle and enters cubital fossa; divides into superficial and deep branches

Question 26

Deep Branch of Radial Nerve

Answer 26

Wraps laterally around the neck of the radius between superficial and deep layers of supinatus; renamed posterior interosseous nerve and runs with posterior interosseous artery; motor to all extensor muscles of forearm except extensor carpi radialis longus and anconeus (latter 2 are supplied by radial nerve before it becomes branches)

Question 27

Superficial Branch of Radial Nerve

Answer 27

Cutaneous (primarily sensory), accompanies radial artery proximally; emerges from beneath brachioradialis in distal forearm; supplies lateral half of dorsum of hand and dorsum of thumb and index finger

Question 28

Elbow Complex 1. Type of Joint 2. Function 3. Joints in the Elbow Complex

Answer 28

1. Hinge joint (uniaxial) 2. Antebrachium extension and flexion; antebrachium supination and pronation 3. Humeroulnar joint, humeroradial joint, radioulnar joints (superior, inferior, intermediate)

Question 29

Humeroulnar Joint

Answer 29

Trochlear notch to trochlea; flexion and extension`

Question 30

Humeroradial Joint

Answer 30

Fovea of head of radius to capitulum; flexion, extension, pronation, supination

Question 31

Superior Radioulnar Joint

Answer 31

Radial notch of ulna and annular ligament

Question 32

Inferior Radioulnar Joint

Answer 32

Ulnar notch of radius, articular disc, head of ulna

Question 33

Intermediate Radioulnar Joint

Answer 33

Interosseous membrane; syndesmosis joint

Question 34

Medial (Ulnar) Collateral Ligament

Answer 34

Medial epicondyle to coronoid process and olecranon process; slack ligament results in valgus deformity

Question 35

Lateral (Radial) Collateral Ligament

Answer 35

Lateral epicondyle to annular ligament and olecranon process; slack ligament results in varus deformity

Question 36

Annular Ligament

Answer 36

Attached to ulna; forms sling around neck of radius

Question 37

Carrying Angle

Answer 37

Axes: Longitudinal axis of humerus and long axis through trochlea Angle in Men: 5 degrees Angle in Women: 10-15 degrees

Question 38

Cubitus Valgus

Answer 38

Increase in carrying angle of elbow

Question 39

Cubitus Varus

Answer 39

Decrease in carrying angle of elbow