38 Questions
What is the location of the metacarpophalangeal (MCP) joints?
Between the metacarpal bones and the proximal phalanges
Which bone is not involved in the articulation between the forearm and the wrist?
Ulna
How many interphalangeal joints does the thumb have?
1
What is the function of the collateral ligaments in the MCP, PIP, and DIP joints?
Provide lateral stability
Which of the following is NOT a carpal bone?
Metacarpal
What is the location of the knuckles when the fist is closed?
Dorsally
Which nerve innervates the adductor pollicis muscle?
Ulnar nerve
What is the function of the adductor pollicis muscle?
Adducts the thumb and provides grip
Which of the following muscles is NOT innervated by the recurrent branch of the median nerve?
Adductor pollicis
What is the primary function of the flexor digitorum profundus and superficialis muscles?
Flexion of the fingers
Which muscle is a good landmark to locate the ulnar nerve and artery?
Flexor carpi ulnaris
Which phalanx do the muscles mentioned have short tendons that insert onto?
Proximal phalanx of the thumb
What is the name of the movement where the thumb is brought to the fifth digit?
Opposition
Which muscle is located in the HYPTHENAR region?
Adductor pollicis
What is the primary function of the muscles mentioned in the context of grip?
To provide grip by adducting the thumb
Which bone is associated with the articular disc?
Hamate
What is the percentage of the population where the palmaris longus muscle is absent?
14%
Which nerve lies between the palmaris longus and the flexor carpi radialis?
Median nerve
What is the name of the compartment where the extrinsic muscles of the hand are located?
Anterior compartment of the forearm
Which type of imaging is commonly used to visualize the soft tissues of the hand?
MRI
What is the function of the flexor carpi ulnaris and radialis when acting together?
They flex the wrist.
Where does the flexor carpi radialis insert?
Base of the 2nd metacarpal
What is the function of the extensor carpi ulnaris?
Inserts at the base of the 5th metacarpal
Which muscle is responsible for opposition of the thumb?
Opponens pollicis
What is the function of the brachioradialis?
Flexes the elbow
How many compartments are there in the hand?
5
What is the function of the lumbricals?
Extend the fingers
What is the name of the muscle that opposes the little finger?
Opponens digiti minimi
What is the name of the muscle that forms the thenar eminence?
Opponens pollicis and extensor pollicis brevis
What is the name of the fascia on the palmar surface of the hand?
Palmar aponeurosis
What is the probable cause of skier's thumb injury?
Falling onto the outstretched thumb while holding a ski pole
What is the result of a damaged ulnar collateral ligament of the metacarpophalangeal joint?
Chronic instability of the thumb
What is the common name given to a tear of the tendon that straightens the end joint of the finger?
Mallet finger
Which group of people is especially prone to triggering?
People with insulin-dependent diabetes
What is the cause of roughness of the tendon surface in trigger finger?
Thickening of the mouth of a tendon tunnel
What is the term for a painful condition in which a finger or thumb clicks or locks as it is bent towards the palm?
Trigger finger
What is the possible outcome of a mallet finger injury?
A small fragment of bone may be pulled off
What can trigger the pain of triggering in people who already have it?
Hand use at work
Study Notes
Muscles of the Hand
- The muscles that move the skeletal elements of the hand are divided into intrinsic and extrinsic groups.
- Extrinsic muscles are in the anterior and posterior compartments of the forearm and are involved in flexion and extension.
- Intrinsic muscles are located in 5 compartments: thenar, adductor, hypothenar, central, and interosseous.
Thenar Muscles
- The thenar muscles include the opponens pollicis, abductor pollicis brevis, and flexor pollicis brevis.
- The thenar eminence is formed by the extensor pollicis brevis and the 3 short thenar muscles.
Hypothenar Muscles
- The hypothenar muscles include the abductor digiti minimi, flexor digiti minimi brevis, and opponens digiti minimi.
Forearm Flexors
- The forearm flexors are extrinsic muscles of the hand that arise from the medial epicondyle of the humerus.
- They include the flexor carpi radialis, palmaris longus, flexor carpi ulnaris, flexor digitorum profundus, and flexor digitorum superficialis.
Forearm Extensors
- The forearm extensors are extrinsic muscles of the hand that include the extensor digitorum, extensor digiti minimi, extensor carpi ulnaris, extensor carpi radialis longus, and extensor carpi radialis brevis.
Skeletal Anatomy
- The wrist is composed of 8 carpal bones arranged in 2 rows of 4.
- The metacarpal bones articulate with the wrist at the carpometacarpal (CMC) joints.
- The metacarpophalangeal (MCP) joints are formed by the articulation of the metacarpal bones with the proximal phalanges.
- The heads of the metacarpals form the knuckles, which are seen dorsally with the closed fist.
Joints
- The thumb has only 1 interphalangeal (IP) joint, while the rest of the digits have proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints.
- Each of the MCP, PIP, and DIP joints has collateral ligaments, which provide lateral stability.
Movements of the Thumb
- Opposition is a trait usually associated with humans and other apes, and is defined as when the thumb is brought to the fifth digit (little finger).
- Some anatomists define opposition as contact between the thumb and other digits as apposition.
Hand Disorders
- Skier's thumb is an injury to the ulnar collateral ligament of the metacarpo-phalangeal joint.
- Mallet finger is a tear of the tendon that straightens the end joint of the finger.
- Trigger finger is a painful condition in which a finger or thumb clicks or locks as it is bent towards the palm.
This quiz covers the muscles of the hand, specifically those with short tendons that insert onto the proximal phalanx of the thumb. It also touches on their innervation by the recurrent branch of the median nerve.
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