Hand and Wrist

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Questions and Answers

Which carpal bone articulates proximally with the radius?

Pisiform

Lunate (correct)

Triquetrum

Scaphoid

What forms the ulnar border of the carpal tunnel?

Triquetrum

Pisiform (correct)

Capitate

Hamate

Which metacarpal is distinctively separated from the others?

First metacarpal (correct)

Fifth metacarpal

Third metacarpal

Second metacarpal

What is the largest carpal bone?

Capitate Signup and view all the answers

Pain from a scaphoid fracture is typically felt in which area?

Around the anatomical snuffbox Signup and view all the answers

Each metacarpal articulates distally with which bones?

Phalanges Signup and view all the answers

What anatomical feature is formed by the heads of the metacarpals?

Knuckles Signup and view all the answers

What type of joint is the radiocarpal joint?

Ellipsoid joint Signup and view all the answers

What is the primary function of the palmar aponeurosis?

To protect underlying structures Signup and view all the answers

Which finger is primarily affected by Dupuytren’s contracture?

Little finger and ring finger Signup and view all the answers

What movements are possible at the metacarpophalangeal joint for digits 2-5?

Flexion, extension, adduction, and abduction Signup and view all the answers

Which condition is characterized by pressure on the median nerve within the carpal tunnel?

Carpal Tunnel Syndrome Signup and view all the answers

What type of movements does the thumb perform at its joint?

Flexion, extension, adduction, abduction, and axial rotation Signup and view all the answers

What anatomical structure forms a tunnel over the carpal bones?

Flexor retinaculum Signup and view all the answers

Which of the following is NOT a movement allowed by the radiocarpal joint?

Rotation Signup and view all the answers

In which condition does collagen proliferation occur within the palmar fascia?

Dupuytren’s contracture Signup and view all the answers

What is the primary function of the dorsal interossei muscles?

Abduction of the index, middle, and ring fingers at the metacarpophalangeal joints Signup and view all the answers

Which lumbrical muscle arises from the radial side of the tendon of the index finger?

Lumbrical 1 Signup and view all the answers

Which of the following muscles arises from the radial side of metacarpal bone 4?

Palmar interossei muscle 2 Signup and view all the answers

Which nerve innervates all the dorsal interossei muscles?

Ulnar nerve Signup and view all the answers

How are Lumbricals 3 and 4 differentiated from Lumbricals 1 and 2 in terms of fiber arrangement?

They are bipennate. Signup and view all the answers

What is the primary blood supply to the hand?

Radial and ulnar arteries Signup and view all the answers

What nerve supplies the 1st and 2nd lumbricals?

Median nerve Signup and view all the answers

Which of the following best describes the palmar interossei?

They are responsible for adduction of the fingers. Signup and view all the answers

Which statement is correct regarding the attachment of the lumbrical muscles?

They attach to the lateral margin of the proximal phalanges. Signup and view all the answers

Which lumbrical muscle arises from the ulnar side of the middle finger tendon?

Lumbrical 3 Signup and view all the answers

What is the primary function of the lumbrical muscles?

Gripping actions of the hand Signup and view all the answers

Which of the following statements about the dorsal interossei is true?

They occupy the space between the metacarpal bones. Signup and view all the answers

Which nerve supplies the 3rd and 4th lumbricals?

Ulnar nerve Signup and view all the answers

Which type of muscle arrangement characterizes the interossei muscles?

Bipennate Signup and view all the answers

From which metacarpals do the first dorsal interossei arise?

Metacarpals 1 & 2 Signup and view all the answers

Where do the fibers of the second dorsal interossei insert?

Radial side of 3rd digit Signup and view all the answers

Which dorsal interossei arises from metacarpals 3 & 4?

Third dorsal interossei Signup and view all the answers

What is the insertion point for the fourth dorsal interossei?

Base of the 4th digit proximal phalanx Signup and view all the answers

Which of the following statements about interossei muscles is correct?

They have a bipennate structure. Signup and view all the answers

Which dorsal interossei muscle inserts onto the radial side of the base of the 2nd digit proximal phalanx?

First dorsal interossei Signup and view all the answers

What is the primary function of the interossei muscles?

Adduction and abduction of the fingers Signup and view all the answers

Which dorsal interossei originate from metacarpals 4 & 5?

Fourth dorsal interossei Signup and view all the answers

What is a unique trait of the fibers of the interossei muscles at their insertion points?

They converge distally. Signup and view all the answers

Study Notes

Hand and Wrist Anatomy

The hand is the distal part of the upper limb, divided into wrist (carpus), palm (metacarpus), and digits (fingers).
In the resting position, fingers form a flexed arcade, with the little finger most flexed and the index finger least.
The hand has 27 bones.
The wrist (carpus) has 8 carpal bones.

Carpal Bones

Scaphoid, Lunate, Triquetrum, Pisiform, Hamate, Capitate, Trapezoid, Trapezium
They work together for wrist movement, the sequence is thumb to little finger in an anticlockwise direction.
Proximal row of carpal bones:
Scaphoid - articulates with the radius to form the radial border of the carpal tunnel.
Lunate - articulates with the radius.
Triquetrum - lies on the medial side of the proximal row of carpal bones.
Pisiform - forms the ulnar border of the carpal tunnel.
Distal row of carpal bones:
Hamate - articulates with 4 carpal bones and the 4th and 5th metacarpals.
Capitate - the largest carpal bone, articulates with 4 carpal bones and the 3rd metacarpal.
Trapezoid - articulates with 3 carpal bones and the 2nd metacarpal and with the scaphoid and trapezoid.
Trapezium - articulates with the scaphoid and the trapezoid as well as the 1st and 2nd metacarpal. It has a tubercle on the palmar surface, which projects anteriorly.

Metacarpal Bones

Each palm has 5 metacarpal bones.
Each metacarpal has a head, body, and base
The first metacarpal is separated from the other metacarpals, allowing independent movement.
Knuckles are formed by the heads of each metacarpal bone.

Phalanges

There are 14 phalanges in total (including thumb).
Fingers, excluding the thumb, have 3 phalanges: proximal, intermediate, and distal.
The thumb (pollux) has 2 phalanges.
Distal phalanges run from intermediate phalanges to the end of the hand (thumb is an exception).
Intermediate phalanges run from proximal phalanges until the second joint.
Proximal phalanges run from the metacarpals to the first joint.

Joints

Joints exist between each phalanx.
Interphalangeal joints (IP):
Distal Interphalangeal Joints (DIP.)
Proximal Interphalangeal Joints (PIP).
Interphalangeal joint of the thumb
Metacarpophalangeal (MCP) joints: between metacarpals and phalanges.
Carpometacarpal (CMC) joints: between carpals and metacarpals,
radiocarpal joint (main wrist joint). It is an ellipsoid joint that lies between the radius and the three proximal carpal bones (scaphoid, lunate, triquetrum) allowing movement along two planes- back and front, and side to side.
radiocarpal joint movements include flexion, extension, adduction/ulnar flexion, and abduction/radial flexion.

Palmar Aponeurosis (Palmar Fascia)

A triangular sheet of connective tissue beneath the skin, converging near the wrist and radiating to the Finger bases.
Its apex is connected to the palmaris longus tendon.
It protects underlying structures like tendons, vessels, and nerves. (e.g. Dupuytren’s contracture).

Clinical Relevance

Scaphoid bone fracture - the most common fracture in the wrist, typically caused by falling on an outstretched hand. Pain is often felt in and around the anatomical snuffbox.
Carpal Tunnel Syndrome - pressure on the median nerve causes pain, numbness, and tingling symptoms.
Allens test- a clinical test used to check for adequate anastomoses (connections) between the radial and ulnar arteries.

Muscles

Extrinsic: long muscles originating in the forearm, responsible for forceful gripping.
Intrinsic: short muscles located within the hand, responsible for precision movements.

Intrinsic Muscle Groups

Thenar Muscles (thumb side):
Flexor pollicis brevis
Abductor pollicis brevis
Opponens pollicis
Hypothenar Muscles (little finger side):
Flexor digiti minimi brevis
Abductor digiti minimi
Opponens digiti minimi
Mid-hand Muscles:
Lumbricals: essential for finger movement (flexion at MCP joints and extension at PIP/DIP joints) (1st and 2nd supplied by median nerve, 3rd and 4th by ulnar nerve).
Dorsal interossei: abduct index, middle, and ring finger. (innervated by ulnar nerve).
Palmar interossei: adduct fingers (innervated by ulnar nerve).
Adductor pollicis (also in the thenar region)

Blood Supply

Ulnar and Radial arteries are the two main blood suppliers to the hand, originating from the brachial artery
Both form a vascular network in the hand, and separated into palmar and dorsal.

Venous Drainage

Superficial and deep veins drain blood from the hand and follow the path of the arteries.
Dorsal digital veins (dorsal view) - drain into dorsal metacarpal veins, which drain into the dorsal venous network at the back of the hand.
Cephalic and Basilic veins - originate from lateral and medial sides of the dorsal venous network, respectively.
Palmar digital veins (palmar view) - drain into both Superficial and Deep venous palmar arch.
Palmar metacarpal veins drain into dorsal metacarpal veins and deep palmar arch

Innervation

Three main nerves from brachial plexus innervate the hand and wrist:
Median nerve
Ulnar nerve
Radial nerve (supplies sensation in the dorsal aspect of the hand, also sensation in radial 2-3.5 fingers.)

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Description

Test your knowledge on the anatomy of the hand and wrist, including the classification and function of the carpal bones. This quiz covers essential details about the bones and structure of the hand, providing insights into how they work together. Perfect for students studying anatomy or healthcare professionals.