Podcast
Questions and Answers
What structure does the head of the radius articulate with?
What structure does the head of the radius articulate with?
Which structure holds the neck of the radius to the ulna?
Which structure holds the neck of the radius to the ulna?
Which part of the radius is rough and below the neck?
Which part of the radius is rough and below the neck?
Which carpal bones are most commonly fractured?
Which carpal bones are most commonly fractured?
Signup and view all the answers
What does the ulnar notch of the radius receive?
What does the ulnar notch of the radius receive?
Signup and view all the answers
Where is the carpal articular surface located on the radius?
Where is the carpal articular surface located on the radius?
Signup and view all the answers
Which bone is considered the medial bone of the forearm when positioned correctly?
Which bone is considered the medial bone of the forearm when positioned correctly?
Signup and view all the answers
Which structure is the most prominent end distally on the radius?
Which structure is the most prominent end distally on the radius?
Signup and view all the answers
Which bone is excluded from the articulation in the wrist joint?
Which bone is excluded from the articulation in the wrist joint?
Signup and view all the answers
What type of joint is the humeroulnar joint classified as?
What type of joint is the humeroulnar joint classified as?
Signup and view all the answers
Which movement primarily occurs at the proximal radioulnar joint?
Which movement primarily occurs at the proximal radioulnar joint?
Signup and view all the answers
How many phalanges does digit one (the thumb) have?
How many phalanges does digit one (the thumb) have?
Signup and view all the answers
What type of joint is the radiocarpal joint classified as?
What type of joint is the radiocarpal joint classified as?
Signup and view all the answers
What is the main function of the interosseous membrane in the radioulnar joints?
What is the main function of the interosseous membrane in the radioulnar joints?
Signup and view all the answers
Which joint allows the radius to cross over the ulna during pronation?
Which joint allows the radius to cross over the ulna during pronation?
Signup and view all the answers
Which type of joint is formed between the capitulum of the humerus and the head of the radius?
Which type of joint is formed between the capitulum of the humerus and the head of the radius?
Signup and view all the answers
What type of joint is the first metacarpal-carpal joint?
What type of joint is the first metacarpal-carpal joint?
Signup and view all the answers
Which muscle is considered the 'true' flexor of the forearm?
Which muscle is considered the 'true' flexor of the forearm?
Signup and view all the answers
What action is primarily allowed by interphalangeal joints?
What action is primarily allowed by interphalangeal joints?
Signup and view all the answers
Which of the following muscles is NOT part of the superficial group in the flexor aspect of the forearm?
Which of the following muscles is NOT part of the superficial group in the flexor aspect of the forearm?
Signup and view all the answers
Which muscle occupies the posterior compartment of the forearm?
Which muscle occupies the posterior compartment of the forearm?
Signup and view all the answers
What is the structural difference between the second and superficial layers of flexor muscles in the forearm?
What is the structural difference between the second and superficial layers of flexor muscles in the forearm?
Signup and view all the answers
Which carpal joints are classified as gliding joints?
Which carpal joints are classified as gliding joints?
Signup and view all the answers
The contraction of an extensor and a flexor on the same side results in which type of movement at the wrist?
The contraction of an extensor and a flexor on the same side results in which type of movement at the wrist?
Signup and view all the answers
Which muscle is located in the fourth layer of the forearm muscles?
Which muscle is located in the fourth layer of the forearm muscles?
Signup and view all the answers
The extensor digitorum (communis) splits into how many tendons?
The extensor digitorum (communis) splits into how many tendons?
Signup and view all the answers
Which muscle is part of the superficial group of the extensor forearm?
Which muscle is part of the superficial group of the extensor forearm?
Signup and view all the answers
Where are the proximal attachments of the 'outcropping muscles' located?
Where are the proximal attachments of the 'outcropping muscles' located?
Signup and view all the answers
Which muscle acts on the thumb and is part of the second layer of the extensor forearm?
Which muscle acts on the thumb and is part of the second layer of the extensor forearm?
Signup and view all the answers
What is the anatomical snuff box?
What is the anatomical snuff box?
Signup and view all the answers
What is the primary action of the muscles in the superficial group of the extensor forearm?
What is the primary action of the muscles in the superficial group of the extensor forearm?
Signup and view all the answers
In anatomical terms, which side is the extensor carpi ulnaris located?
In anatomical terms, which side is the extensor carpi ulnaris located?
Signup and view all the answers
Which muscle is responsible for flexing the middle phalanges?
Which muscle is responsible for flexing the middle phalanges?
Signup and view all the answers
What function does the Flexor pollicis longus serve?
What function does the Flexor pollicis longus serve?
Signup and view all the answers
Which muscle is primarily involved in the pronation of the forearm?
Which muscle is primarily involved in the pronation of the forearm?
Signup and view all the answers
Which of the following muscles is known to extend the thumb?
Which of the following muscles is known to extend the thumb?
Signup and view all the answers
Which muscle is involved in extending and abducting the wrist?
Which muscle is involved in extending and abducting the wrist?
Signup and view all the answers
Study Notes
Ulna
- Distal end contains the olecranon process and radial notch
- Head of the ulna is distal
- Grasp proximal end with the trochlear notch facing anterior
- Hold as the medial bone in the forearm with the radial notch facing lateral towards the radial bone (lateral)
Radius
- Head articulates with capitulum of humerus and ulna
- Neck held to ulna by annular ligament
- Radial tuberosity - biceps brachii inserts here
- Ulnar notch - receives head of ulna
- Styloid process - surface landmark, most prominent end distally
- Carpal articular surface - articular surface located at the distal most aspect of the radius and located between the ulnar notch and the styloid process.
Carpal Bones
- There are 8 carpal bones in the wrist
- The scaphoid and the lunate articulate with the radius in the wrist joint and are therefore the most commonly fractured carpals
Proximal Row
- Scaphoid (navicular)
- Lunate
- Triquetrum (triquetral, triangular)
- Pisiform
Distal Row
- Trapezium
- Trapezoid
- Capitate
- Hamate (Hook)
Metacarpals
- Numbered 1-5 from radial side to ulnar side (lateral to medial in anatomical position)
- Each has a base (proximal), body, and head (distal).
Phalanges
- Numbered as are the metacarpals
- Digit one (1) has only two phalanx (proximal and distal)
- The other four digits (2-5) have proximal, middle, and distal phalanges
Elbow Joint
- There are two synovial joints sharing a common joint cavity and surrounded by an articular capsule:
- Humeroulnar: a hinge joint, trochlea of humerus fits into trochlear (semilunar) notch.
- Humeroradial: a gliding joint, capitulum of humerus articulates with superior surface of the head of the radius.
Radioulnar Joint
- 3 joints:
- Proximal radioulnar: a pivot synovial joint, the head of the radius rotates within the annular ligament which holds the radial head tightly against the radial notch of the ulna, allowing pronation and supination of the palm of the hand.
- Middle radioulnar: a type of fibrous joint called a syndesmosis, the sheet of fibers is called an interosseous membrane.
- Distal radioulnar: a synovial, pivot joint, distal end of the ulna pivots against the ulnar notch of the radius, allowing the radius to cross over the ulna in pronation.
Wrist Joint
- Radiocarpal joints: The ulna is excluded from articulation by an articular disc, so the only active joint is that between the radius and the two carpals, the scaphoid and lunate bones. A condyloid joint reinforced by several ligaments. Allows flexion/extension, adduction/abduction, and circumduction.
- Intercarpal joints: between all the carpal bones, gliding joints.
Joints of the hand
- 1st Metacarpal-carpal: Saddle type of synovial joint
- #2-5, Metacarpal-carpal: Gliding type of synovial
- #2-5, Metacarpophalangeal: Condyloid synovial joints
- 1st Metacarpophalangeal: Hinge synovial joint
- Interphalangeal: Hinge synovial joints, so allow only flexion/extension
Muscles of the Forearm and hand
- The arm is the region between the shoulder and elbow. The muscles of the arm function at either/both the shoulder and/or the elbow.
- Extensors occupy the posterior compartment of the forearm; flexors occupy the anterior compartment; contraction of an extensor and a flexor on the same side results in abduction/adduction of the wrist.
Flexor Aspect of the Forearm
- Muscles are neatly arranged in four layers. In general, as you proceed from superficial to deep, the muscles of each layer act more distally in the limb; this is not so for the deepest (fourth) layer.
Superficial group
- All of these muscles have complete or partial attachment off the medial epicondyle of the humerus.
- Pronator teres
- Flexor carpi radialis
- Palmaris longus
- Flexor carpi ulnaris
Second Layer
- Flexor digitorum superficialis
Third Layer
- Flexor digitorum profundus
- Flexor pollicis longus
Fourth Layer
- Pronator quadratus
Extensor Aspect of the Forearm
- Muscles are also arranged in layers, although this arrangement is complicated somewhat by a group of "outcropping muscles" that act on the thumb.
- All of these muscles have complete or partial attachment off the lateral epicondyle of the humerus. Again, as with the flexor forearm, the muscles lying deeper have their action on more distal portions of the limb.
Superficial group
- Extensor carpi radialis longus
- Extensor carpi radialis brevis
- Extensor digitorum (communis)
- Extensor carpi ulnaris
- Extensor digiti minimi
Second Layer
- This layer includes the "outcropping muscles" which form a bulge on the posterolateral surface of the inferior forearm. These muscles have their proximal attachments on the radius and interosseous membrane and distal attachments, via prominent tendons, onto the thumb. These tendons form the boundaries of an area at the base of the thumb called the "anatomical snuff box", where the radial artery passes through and the pulse can be felt here by pressing the artery against the deeper lying trapezium and scaphoid.
- Extensor Pollicis Longus
- Abductor Pollicis Longus
- Extensor Pollicis Brevis
Matching
- Extensor carpi radialis longus and brevis - 8. Extends and abducts the wrist
- Extensor carpi ulnaris - 8. Extends and abducts the wrist
- Extensor digitorum - 10. Extends the fingers
- Extensor pollicis longus and brevis - 4. Extends the thumb
- Flexor carpi radialis - 6 Powerful wrist flexors that also stabilize the wrist during finger extension
- Flexor carpi ulnaris - 6 Powerful wrist flexors that also stabilize the wrist during finger extension
- Flexor digitorum profundus - 3. Flexes the distal Interphalangeal joints
- Flexor digitorum superficialis - 1. Flexes the wrist and middle phalanges
- Flexor pollicis longus - 7. Flexes the distal phalanx of the thumb
- Pronators teres and quadratus - 2. Pronates the forearm
- Palmaris longus - 5. May not be present in some of us
- Abdcutor pollicis longus - 9. These muscles form the anatomical snuff box
- Supinator - 11. Supinates the forearm
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
This quiz explores the anatomy of the ulna, radius, and carpal bones in the forearm and wrist. It covers key features, such as articulations and locations, to enhance your understanding of human skeletal anatomy. Perfect for anatomy students and enthusiasts!
