4.1.3. Extensor and Abductor Muscles of the Thumb Flashcards
What are the Muscles of the Posterior Forearm commonly known as?
Extensor Muscles
What is the General Function of these Muscles?
To Produce Extension at the Wrists and Fingers
Which Nerve innervates the Muscles of the Posterior Forearm?
The Radial Nerve
- How many groups can the Muscles of the Posterior Forearm be Divided into, Anatomically?
- What are they?
- 2
- a) Superficial Muscles of the Posterior Forearm
- b) Deep Muscles of the Posterior Forearm
- How many groups can the Muscles of the Posterior Forearm be Divided into, Functionally?
- What are they?
- 3
- a) Muscles which Extend and Abduct / Adduct the Hand at the Wrist Joint
- b) Muscles which Extend the Medial 4 Digits
- c) Muscles which Extend or Abduct the Thumb
What are the 3 Muscles which Extend of Abduct the Thumb?
- Abductor Pollicis Longus
- Extensor Pollicis Brevis
- Extensor Pollicis Longus
Is the Abductor Pollicis Longus an Anatomically Superficial or Deep Muscle of the Posterior Forearm?
Deep
Where is the Abductor Pollicis Longus located, in relation to the Supinator Muscle?
Immediately Distal to the Supinator Muscle
What does the Tendon of the Abductor Pollicis Longus contribute to in the Hand?
Lateral Border of the Anatomical Snuffbox
Where does the Abductor Pollicis Longus Originate from?
- Interosseous Membrane
- Adjacent Posterior Surface of the Radius
- Adjacent Posterior Surface of the Ulna
Where does the Abductor Pollicis Longus attach distally?
Lateral Part of the Base of Metacarpal I
What is the function of the Abductor Pollicis Longus?
Abduction of the Thumb
What is the innervation of the Abductor Pollicis Longus?
Posterior Interosseous Branch of the Radial Nerve
Is the Extensor Pollicis Brevis an Anatomically Superficial or Deep Muscle of the Posterior Forearm?
Deep
Where is the Extensor Pollicis Brevis located, in relation to the Abductor Pollicis Longus?
- Medially
2. Deep
What does the Tendon of the Extensor Pollicis Brevis contribute to in the Hand?
Lateral Border of the Anatomical Snuffbox
Where does the Extensor Pollicis Brevis Originate from?
- Posterior Surface of the Radius
2. Interosseous Membrane
Where does the Extensor Pollicis Brevis attach distally?
Base of the Proximal Phalanx of the Thumb
What is the function of the Extensor Pollicis Brevis?
- Extension of the Metacarpopharangeal Joint of the Thumb
2. Extension of the Carpometacarpal Joints of the Thumb
What is the innervation of the Extensor Pollicis Brevis?
Posterior Interosseous Branch of the Radial Nerve
Is the Extensor Pollicis Longus an Anatomically Superficial or Deep Muscle of the Posterior Forearm?
Deep
Does the Extensor Pollicis Longus have a Larger or Smaller Belly than the Extensor Pollicis Brevis?
Larger
Where does the Tendon of the Extensor Pollicis Longus travel in the Wrist?
Medially to the Dorsal Tubercle
How does the Tendon of the Extensor Pollicis Longus use the Dorsal Tubercle?
The Dorsal Tubercle is used as a “Pulley” to increase the Force Exerted
What does the Tendon of the Extensor Pollicis Longus contribute to in the Hand?
Medial Border of the Anatomical Snuffbox
Where does the Extensor Pollicis Longus Originate from?
- Posterior Surface of the Ulna
2. Interosseous Membrane
Where does the Extensor Pollicis Longus attach distally?
Distal Phalanx of the Thumb
What is the function of the Extensor Pollicis Longus?
Extension of all Joints of the Thumb:
- Extension of the Carpometacarpal Joint
- Extension of the Metacarpophalangeal Joint
- Extension of the Interphalangeal Joint
What is the innervation of the Extensor Pollicis Longus?
Posterior Interosseous Branch of the Radial Nerve
