MS - Anat & Phys (Knee injury, Clinical landmarks, Rotator cuff muscles, & Wrist bones)

Question 1

In general, how does knee injury present?

Answer 1

Presents with acute knee pain and signs of joint injury/instability

Question 2

What are 5 signs of joint injury/instability that are associated with knee injury? What type of injury does each indicate?

Answer 2

Presents with acute knee pain and signs of joint injury/instability: (1) Anterior drawer sign –> ACL injury (2) Posterior drawer sign –> PCL injury (3) Abnormal passive abduction (valgus stress) –> MCL injury (4) Abnormal passive adduction (varus stress) –> LCL injury (5) McMurray test: pain on external rotation –> medial meniscus; pain on internal rotation –> lateral meniscus

Question 3

What is valgus versus varus stress? What does an abnormality in each indicate?

Answer 3

Abnormal passive abduction (valgus stress) –> MCL injury; Abnormal passive adduction (varus stress) –> LCL injury

Question 4

What are 2 possible indications of the McMurray test?

Answer 4

McMurray test: (1) pain on external rotation –> medial meniscus; (2) pain on internal rotation –> lateral meniscus

Question 5

What do the Anterior versus Posterior drawer signs indicate?

Answer 5

Anterior drawer sign –> ACL injury; Posterior drawer sign –> PCL injury

Question 6

To what do “anterior” and “posterior” in ACL and PCL refer?

Answer 6

“Anterior” and “posterior” in ACL and PCL refer to sites of tibial attachment

Question 7

Draw the knee joint, including and labeling the following: (1) ACL (2) Femur (3) Fibula (4) Lateral condyle (5) Lateral meniscus (6) LCL (7) MCL (8) Medial condyle (9) Medial meniscus (10) PCL (11) Tibia.

Answer 7

See p. 411 in First Aid 2014 for visual at top right

Question 8

In what context is unhappy triad a common injury, and what causes it?

Answer 8

Unhappy triad - common injury in contact sports due to lateral force applied to a planted leg

Question 9

Of what does the Unhappy triad classically consist? What is a more common injury?

Answer 9

Classically, consists of damage to the ACL, MCL, and medial meniscus (attached to MCL); however, lateral meniscus injury is more common

Question 10

What nerve block is used to relieve pain of delivery? What is the best landmark for the pudenal nerve?

Answer 10

Pudenal nerve block (to relieve pain of delivery) - ischial spine

Question 11

What is the landmark for the appendix? Name and describe this location.

Answer 11

Appendix - 2/3 of the distance between the umbilicus and the anterior superior iliac spine (ASIS), just proximal to the ASIS (McBurney point)

Question 12

What is the best landmark for the site of lumbar puncture?

Answer 12

Lumbar puncture - iliac crest

Question 13

Name the 4 shoulder muscles that form the rotator cuff. Which of these is the most common rotator cuff injury?

Answer 13

Should muscles that form the rotator cuff: (1) Supraspinatus (most common rotator cuff injury) (2) Infraspinatus (3) Teres minor (4) Subscapularis; Think: “SITs (small t is for teres minor)”

Question 14

What nerve innervates the Supraspinatus muscle? What is this muscle’s function? How does it relate to the deltoid’s action?

Answer 14

Supraspinatus (suprascapular nerve) - abducts arm initially (before the action of the deltoid)

Question 15

What nerve innervates the Infraspinatus muscle? What is this muscle’s function? What usually causes its injury?

Answer 15

Infraspinatus (suprascapular nerve) - laterally rotates arm; pitching injury

Question 16

What nerve innervates the Teres minor muscle? What is this muscle’s function?

Answer 16

Teres minor (axillary nerve) - adducts and laterally rotates arm

Question 17

What nerve innervates the Subscapularis muscle? What is this muscle’s function?

Answer 17

Subscapularis (subscapular nerve) - medially rotates and adducts arm

Question 18

What root(s) primarily innervate(s) the rotator cuff muscles?

Answer 18

Innervated primarily by C5-C6.

Question 19

Draw a lateral view of the rotator cuff muscles, including and labeling: (1) Acromion (2) Biceps tendon (3) Coracoid (4) Infraspinatus (5) Subscapularis (6) Supraspinatus (7) Teres minor.

Answer 19

See p. 411 in First Aid 2014 for visual at bottom right

Question 20

Name the 8 wrist bones.

Answer 20

(1) Scaphoid (2) Lunate (3) Triquetrum (4) Pisiform (5) Hamate (6) Capitate (7) Trapezoid (8) Trapezium. Think: “So Long To Pinky, Here Comes The Thumb.”

Question 21

Draw and label the major 8 bones, showing their relation to one another.

Answer 21

See p. 412 in First Aid 2014 for visual

Question 22

What muscle is palpated in the anatomical snuff box?

Answer 22

Scaphoid (palpated in anatomical snuff box)

Question 23

What is the most commonly fractured carpal bone?

Answer 23

Scaphoid (palpated in anatomical snuff fox) is the most commonly fractured carpal bone

Question 24

To what condition is the scaphoid prone, and why?

Answer 24

Scaphoid (palpated in anatomical snuff box) is the most commonly fractured carpal bone and is prone to avascular necrosis owing to retrograde blood supply

Question 25

What is the lunate? What can its dislocation cause?

Answer 25

Wrist bone; Dislocation of lunate may cause acute carpal tunnel syndrome

Question 26

What wrist bone can be damaged by a fall on an outstretched hand? What type of injury can damage to the hook of this bone cause?

Answer 26

A fall on an outstretched hand that damages the hook of the hamate can cause ulnar nerve injury

Question 27

What is Carpal tunnel syndrome?

Answer 27

Carpal tunnel syndrome: Entrapment of median nerve in carpal tunnel

Question 28

What are the symptoms of Carpal tunnel syndrome, and what causes these?

Answer 28

Carpal tunnel syndrome: Entrapment of median nerve in carpal tunnel; nerve compression –> paresthesia, pain, and numbness in distribution of median nerve

Question 29

What is Guyon canal syndrome? In what patient population is it classically seen, and why?

Answer 29

Guyon canal syndrome: Compression of the ulnar nerve at the wrist or hand, classically seen in cyclists due to pressure from handlebars