PAS407 (Class 10) - The Hand UPDATED ACTUAL and Correct Answers

PAS407 (Class 10) - The Hand UPDATED ACTUAL and Correct
Answers
Question: Overview
Answer:
Intricate dexterity = precision allows for a varying degree of manipulation and control
- opposition due to 90 degrees rotation of 1st digit
Note: the amount of the motor cortex dedicated to the hand is actually greater than the amount
dedicated to all the
other compartments of the upper limb combined

Question: Bones of the hand
Carpal Bones
Answer:
Articulate with the radius proximally
Articulate with the metacarpal bones distally
Arranged in 2 rows with 4 bones a piece

Question: Carpal Bones (Proximal Row)
Scaphoid Bone
Answer:
- Boat shaped appearance (meaning of scaphoid)
- concave distal surface
- convex proximal surface
- Bone is separated by a neck into proximal and distal regions
- prominent tubercle on the palmar surface for attachment of the transverse carpal ligament (where red
dot is on
pic)
- Smooth proximal surface articulates with the distal surface of radius
- Convex surface articulates with 4 of the other carpal bones

Question: Carpal Bones (Proximal Row)
Lunate Bone
Answer:
Lunate = moon shaped
- lies medial to scaphoid
- articulates with scaphoid through the concave surface

,Articulates with triangular disc in a neutral hand position

Question: Carpal Bones (Proximal Row)
Triquetrium Bone
Answer:
Named for Pyramidal appearance
- Doesn't actually contribute to the wrist joint in a neutral wrist position
- only when wrist is in ULNAR DEVIATION, the triquetrium articulates with the articular disc
covering the ulna
Articulates with:
- Lunate laterally
- Hamate distally
- Pisiform anteriorly

Question: Carpal Bones (Proximal Row)
Pisiform Bone
Answer:
Named after its pea shaped appearance
- Considered part of the first row of carpal bones, but sits on a separate plane anterior to other bones
- only articulation is with the triquetrium posteriorly
- serves as a sesamoid bone, floating in the tendon of the flexor carpi ulnaris
- Pisiform + Hook of Hamate forms a lateral elevation providing protection to the ulnar n.
- these 2 also form a lateral anchor for the transverse carpal ligament (roof of carpal tunnel)

Question: Carpal Bones (Distal Row)
Trapezium Bone
Answer:
In latin = "little table"
- named so since it serves role in supporting the first metacarpal on the scaphoid
Distal articular surface is saddle-shaped, forming a saddle joint with the complimentary surfaces on
the first
metacarpal bone
Carpal / Metacarapl articulation is critical in thumb opposition and versatility of hand function

Question: Carpal Bones (Distal Row)
Trapezoid Bone
Answer:

, Articulating with the medial surface of the trapezium is the TRAPEZOID
- name reflects its geometric shape
- articulates with the scaphoid proximally and the 2nd metacarpal distally

Question: Carpal Bones (Distal Row)
Capitate Bone
Answer:
Capitate means head bone
- named so since the proximal projection articulates with the scaphoid bone (like head of humerus)
Largest of all the carpal bones
Forms keystone of the carpal bones
- articulating with trapezoid and hamate laterally and medially
- and with 3rd metacarpal distally

Question: Carpal Bones (Distal Row)
Hamate (Hook) Bone
Answer:
Most prominent feature is the "hamulus" or hook that projects from the palmar
surface
- along with pisiform, this forms the superior portion of the medial wall of the carpal tunnel
- serves as an attachment point for the transverse carpal ligament

Question: Order of Bones Mnemonic
Answer:
Scared = Scaphoid
Lovers = Lunate
Try = Triquetrium
Positions = Pisiform
That = Trapezium
They = Trapezoid
Can't = Capitate
Handle = Hamate

Question: Metacarpals
Answer:
Characteristics of long bones
- base of each bone is situated proximally
- forms gliding joints with carpal bones