CH 10: The Wrist & Hand

Question 1

Main Thenar & Hypothenar muscles

Answer 1

Thenar:
- Abductor Pollicis Brevis
- Flexor Pollicis Brevis
- Opponens Pollicis

Hypothenar:
- Abductor Digiti Minimi
- Flexor Digiti Minimi
- Opponens Digiti Minimi

Question 2

What is an extensor hood and what is its purpose? Which fingers have dual tendons?

Answer 2

The extensor, or Dorsal Hoods, are flattened, curved & sheath-like tendons of the extensor digitorum. By inserting into the Hoods, the intrinsic muscles of the hand can perform precise and delicate movements that would otherwise be impossible with just the muscles and extensor tendons alone.

Digits 2 + 5 have dual tendons that insert into their respective hoods, for even greater control.

Question 3

Characteristics & MOI of Bennett’s and Boxer’s fractures

Answer 3

Both are fractures within the hand as a result of trauma due to striking or being struck by an object.

Boxer’s: Break in the distal end of the 5th metacarpal
Bennett’s: Break in the proximal end of the 1st metacarpal (thumb)

S/S: Pain, deformity, crepitus, swelling & abnormal mobility

Question 4

What is a wrist ganglion?

Answer 4

Considered to be benign synovial masses filled with gelatinous mucoid material. Typically a chronic condition seen on the dorsal aspect of the wrist.

Direct cause is unknown but is usually a result of repetitive microtrauma sustained by the wrist capsule and supporting ligamentous structures.

Question 5

Describe the MCP, PIP & DIP joints and how they differ from the thumb

Answer 5

MCP: Metacarpo-phalangeal joints (knuckles)
All digits have this joint

PIP: Proximal interphalangeal joints
DIP: Distal interphalangeal joints
These joints apply to to digits 2-5

IP: Interphalangeal joint - only applies to thumb as it has one less joint than other fingers.