MST 2 - upper limb bones

Question 1

What are the bones of the upper limb?

Answer 1

The pectal girdle, 1 bone of the arm, 2 bones of the forearm and many bones of the hand.

Question 2

What are the joints of the upper limb?

Answer 2

The shoulder complex, the elbow joints and the joints of the wrist and hand.

Question 3

What are the features of the basic mammalian limb form?

Answer 3

The limb girdle attaches to the front of the axial skeleton, there is 1 proximal bone, 2 distal bones, one of which rotates relative to the other, and a pentadactyl hand with an opposable thumb rotated 90 degrees to the digits.
The hand has a variable number of carpal bones (8 in 2 rows of 4 in humans) with 5 digits.

Question 4

What are the 3 bones of the shoulder girdle?

Answer 4

The clavicle, scapula and the humerus.

Question 5

What type of bone is the clavicle?

Answer 5

A long bone

Question 6

What is the job of the clavicle?

Answer 6

It is fairly mobile and acts as a strut to hold the arm out.

Question 7

What other bones does the clavicle articulate with?

Answer 7

The sternum of the axial skeleton at the proximal end, and the scapula at the distal end.

Question 8

What are the main features of the scapula?

Answer 8

The spine, the supraspinous fossa, the glenoid fossa, the coracoid process and the acromion process.

Question 9

What type of bone is the scapula?

Answer 9

A flat bone.

Question 10

What is the name of the bone of the arm?

Answer 10

The humerus.

Question 11

What are the main features of the humerus?

Answer 11

The humerus has a shaft with two ends. It has a proximal articular surface, known as the head, with an anatomical and a surgical neck. There are greater, lesser and deltoid tuberosities, where muscles attach to and act upon the bone. There is a bicipital groove where the tendon of the biceps sits, between the greater and lesser tuberosities.
At the distal end of the bone there are two epcondyles, medially and laterally. The medial epicondyle is bigger as more of the muscles of the (FORE??)arm attach on this side than on the lateral side. There is also a distal articular surface, known as the trochlea - this articulates with the ulna.

Question 12

What type of bone is the humerus?

Answer 12

A long bone

Question 13

What is the difference between the anatomical and the surgical necks of the humerus?

Answer 13

The anatomical neck is the narrowest part of the humerus below the head, while the surgical neck is the part of the bone which is most likely to fracture.

Question 14

Which joint does the radius primarily articulate with?

Answer 14

The wrist. It is non-articular at the elbow (or very little articular)

Question 15

Which joint does the ulna articulate with?

Answer 15

The elbow. It is non-articular at the wrist.

Question 16

How do the radius and the ulna interact?

Answer 16

They are linked by an interosseous membrane. They have articular surfaces at the top and the bottom of the bone, where they interact with each other.

Question 17

The ________ is the medial bone of the forearm (in anatomical position)

Answer 17

Ulna

Question 18

The ____________ is the lateral bone of the forearm (in anatomical position)

Answer 18

Radius

Question 19

What features do the radius and the ulna have? What type of bone are they?

Answer 19

They are both long bones. They have have articular surfaces with each other and with the humerus and the bones of the wrist. They each have a head, and an anatomical and surgical neck. They have tuberositites for muscle attachments (eg vagial tuberosity where the biceps attach) and medial and lateral epichondyles or styloid processes, which stick out their side of the wrist.

Question 20

On which bone is the trochlea notch?

Answer 20

On the ulna. It articulates with the humerus in the elbow joint.

Question 21

What are the 3 types of bone in the wrist and hand?

Answer 21

Carpal bones, metacarpal bones and phalanges.

Question 22

How many carpal bones do humans have?

Answer 22

8 - in 2 rows of 4

Question 23

What part of the hand do the metacarpal bones form?

Answer 23

The palm and the base of the thumb

Question 24

What is the proper name for the joint of the thumb, and what kind of joint is it?

Answer 24

The first carpo-metacarpal joint. It is a saddle joint to allow more freedom of movement.

Question 25

What are the 3 types of phalanges? How many phalanges are there in each of the fingers and the thumb?

Answer 25

Proximal, middle and distal. One of each type in all of the 4 fingers, and 2 only in the thumb,

Question 26

What are the important features of the carpal bones?

Answer 26

The carpal bones form the wrist. They are found in proximal and distal rows. The radius articulates primarily with the scaphoid bone (and some with the lunate bone)

Question 27

Where is the clavicle most likely to fracture?

Answer 27

At the weak point between the lateral 1/3 and medial 2/3’s

Question 28

Where is the humerus most likely to fracture?

Answer 28

At the surgical neck. Alternative sites of fracture inlude the anatomical neck, midshaft, or supracondyla fractures.

Question 29

Where is the wrist most likely to fracture?

Answer 29

Fracture of the distal end of the radius (known as a Colles fracture) or fracture of the scaphoid bone.

Question 30

Why is fracture of the scaphoid bone clinically important to treat quickly?

Answer 30

As the radial artery of the hand provides blood distal to proximal in the hand, and is at risk from this kind of fracture, which would result in no blood getting to the scaphoid bone and consequently avascular necrosis.