S8) The Forearm Flashcards
Describe the structure, location and function of the ulna
![](https://s3.amazonaws.com/brainscape-prod/system/cm/280/784/647/q_image_thumb.png?1516836392)
- Structure: long bone in the forearm
- Location: lies medially, parallel to the radius
- Function: stabilising bone, pivots with the radius to produce movement
![](https://s3.amazonaws.com/brainscape-prod/system/cm/280/784/647/a_image_thumb.jpg?1516836393)
Describe the articulations of the ulna
- Proximal: articulates with trochlea of humerus at the elbow joint and head of the radius at proximal radio-ulnar joint
- Distal: radius at the distal radio-ulnar joint
![](https://s3.amazonaws.com/brainscape-prod/system/cm/280/784/649/a_image_thumb.png?1516836394)
Identify the important anatomical landmarks in the proximal region of the ulna
![](https://s3.amazonaws.com/brainscape-prod/system/cm/280/784/650/q_image_thumb.jpg?1516836394)
![](https://s3.amazonaws.com/brainscape-prod/system/cm/280/784/650/a_image_thumb.png?1516836394)
Describe the structure and purpose of the olecranon, ulna tuberosity and coronoid process
![](https://s3.amazonaws.com/brainscape-prod/system/cm/280/784/651/q_image_thumb.jpg?1516836395)
- Olecranon – a large projection of bone that extends proximally, forming part of trochlear notch
- Coronoid process – a ridge of bone projecting outwards anteriorly, forming part of the trochlear notch
- Tuberosity of ulna – a roughening immediately distal to the coronoid process
![](https://s3.amazonaws.com/brainscape-prod/system/cm/280/784/651/a_image_thumb.png?1516836395)
Describe the structure and purpose of the trochlear and radial notch
![](https://s3.amazonaws.com/brainscape-prod/system/cm/280/784/652/q_image_thumb.jpg?1516836396)
- Trochlear notch is formed by the olecranon and coronoid process and articulates with the trochlea of the humerus
- Radial notch is located on the lateral surface of the trochlear notch and articulates with the head of the radius
![](https://s3.amazonaws.com/brainscape-prod/system/cm/280/784/652/a_image_thumb.png?1516836396)
Describe the structure of shaft of the ulna
The ulnar shaft is triangular, with three borders and three surfaces and decreases in width distally
![](https://s3.amazonaws.com/brainscape-prod/system/cm/280/784/653/a_image_thumb.jpg?1516836396)
The shaft of the ulna has three surfaces.
Identify and describe them
- Anterior – site of attachment for the pronator quadratus muscle distally
- Posterior – site of attachment for many muscles
- Medial – unremarkable
![](https://s3.amazonaws.com/brainscape-prod/system/cm/280/784/654/a_image_thumb.jpg?1516836397)
The shaft of the radius has three borders.
Identify and describe them
- Posterior – palpable along the entire length of the forearm posteriorly
- Interosseous – site of attachment for the interosseous membrane
- Anterior – unremarkable
![](https://s3.amazonaws.com/brainscape-prod/system/cm/280/784/655/a_image_thumb.png?1516836398)
Identify the important anatomical landmarks in the distal region of the ulna
![](https://s3.amazonaws.com/brainscape-prod/system/cm/280/784/656/q_image_thumb.jpg?1516836398)
![](https://s3.amazonaws.com/brainscape-prod/system/cm/280/784/656/a_image_thumb.png?1516836399)
Describe the structure, location and function of the radius
![](https://s3.amazonaws.com/brainscape-prod/system/cm/280/784/657/q_image_thumb.png?1516836400)
- Structure: long bone in the forearm
- Location: lies laterally, parallel to ulna
- Function: pivots around the ulna to produce movement at the radio-ulnar joints
![](https://s3.amazonaws.com/brainscape-prod/system/cm/280/784/657/a_image_thumb.jpg?1516836401)
The radius articulates in four places.
Identify and describe them
- Elbow Joint – articulation between radial head and capitulum of humerus
- Proximal Radioulnar Joint – articulation between the radial head and radial notch of the ulna
- Distal Radioulnar Joint – articulation between ulnar notch of radius and ulnar head
- Wrist Joint – articulation between the distal radius and carpal bones
![](https://s3.amazonaws.com/brainscape-prod/system/cm/280/784/658/a_image_thumb.png?1516836401)
Identify the important anatomical landmarks in the proximal region of the radius
![](https://s3.amazonaws.com/brainscape-prod/system/cm/280/784/659/a_image_thumb.png?1516836402)
Describe the structure of the radial head, neck and radial tuberosity.
![](https://s3.amazonaws.com/brainscape-prod/system/cm/280/784/660/q_image_thumb.jpg?1516836402)
- Head of radius – disk shaped structure with a concave articulating surface and forms the proximal radioulnar joint
- Neck – narrow area of bone, which lies between the radial head and radial tuberosity
- Radial tuberosity – a bony projection
![](https://s3.amazonaws.com/brainscape-prod/system/cm/280/784/660/a_image_thumb.png?1516836402)
What holds the radial head in place during movement?
- The radial head is held in place by the annular radial ligament, which forms a collar around the joint
- The is lined with a synovial membrane, reducing friction during movement
![](https://s3.amazonaws.com/brainscape-prod/system/cm/280/784/661/a_image_thumb.jpg?1516836403)
Describe the structure of the shaft of the radius
- It is triangular in shape, with three borders and three surfaces and expands in diameter distally
- The lateral surface has a small roughening for the attachment of the pronator teres muscle
![](https://s3.amazonaws.com/brainscape-prod/system/cm/280/784/662/a_image_thumb.jpg?1516836403)
Identify the important anatomical landmarks in the distal region of the radius
![](https://s3.amazonaws.com/brainscape-prod/system/cm/280/784/663/a_image_thumb.png?1516836404)
Describe the structure and purpose of the styloid process, ulnar notch and scaphoid and lunate facets
- Styloid process – distal projection of lateral side of radial shaft
- Ulnar notch – concavity on medial surface which articulates with the head of ulna, forming the distal radioulnar joint
- Scaphoid and lunate facets – articulate with the scaphoid and lunate carpal bones to form the wrist joint
![](https://s3.amazonaws.com/brainscape-prod/system/cm/280/784/664/a_image_thumb.png?1516836404)
The radioulnar joints are two locations in which the radius and ulna articulate in the forearm.
Describe their anatomical position and articulation
- Proximal radioulnar joint is an articulation between the head of the radius, and the radial notch of the ulna (located near the elbow)
- Distal radioulnar joint is an articulation between the head of the ulna and the ulnar notch of the radius (located proximal to wrist joint)
![](https://s3.amazonaws.com/brainscape-prod/system/cm/280/784/665/a_image_thumb.png?1516836404)
What type of joint are the radioulnar joints?
The radioulnar joint is a pivot type synovial joint
Identify the movements possible at the radioulnar joints and the muscles responsible
- Pronation produced by the pronator quadratus and pronator teres
- Supination produced by the supinator and biceps brachii
The articular disk is a fibrocartilaginous ligament present in the distal radioulnar joint.
What are its functions?
![](https://s3.amazonaws.com/brainscape-prod/system/cm/280/784/668/q_image_thumb.png?1516836405)
- Binds the radius and ulna together, and holds them together during movement at the joint
- Separates the distal radioulnar joint from the wrist joint
![](https://s3.amazonaws.com/brainscape-prod/system/cm/280/784/668/a_image_thumb.jpg?1516836405)
What are three major functions of the interosseous membrane?
![](https://s3.amazonaws.com/brainscape-prod/system/cm/280/784/669/q_image_thumb.png?1516836406)
- Holds the radius and ulna together during pronation and supination
- Acts as a site of attachment for muscles of the forearm
- Transfers forces from the radius to the ulna
![](https://s3.amazonaws.com/brainscape-prod/system/cm/280/784/669/a_image_thumb.png?1516836406)
Identify the 3 types of muscles in the anterior compartment of the forearm
- Superficial muscles
- Intermediate muscles
- Deep muscles
Identify the superficial muscles in the anterior compartment of the forearm
- Flexor carpi ulnaris
- Flexor carpi radialis
- Palmaris longus
- Pronator teres
What is a common characteristic of all superficial muscles in the anterior compartment of the forearm?
They all originate from a common flexor tendon, which arises from the medial epicondyle of the humerus
![](https://s3.amazonaws.com/brainscape-prod/system/cm/280/784/672/a_image_thumb.jpg?1516836407)
State the function and innervation of the flexor carpi ulnaris muscle
![](https://s3.amazonaws.com/brainscape-prod/system/cm/280/784/673/q_image_thumb.jpg?1516836407)
- Function: wrist flexion and adduction
- Innervation: ulnar nerve
![](https://s3.amazonaws.com/brainscape-prod/system/cm/280/784/673/a_image_thumb.jpg?1516836407)
State the origin and attachment of the flexor carpi ulnaris muscle
![](https://s3.amazonaws.com/brainscape-prod/system/cm/280/784/674/q_image_thumb.jpg?1516836408)
- Origin: medial epicondyle
- Attachment: pisiform carpal bone
![](https://s3.amazonaws.com/brainscape-prod/system/cm/280/784/674/a_image_thumb.jpg?1516836408)
State the function and innervation of the palmaris longus muscle
![](https://s3.amazonaws.com/brainscape-prod/system/cm/280/784/675/q_image_thumb.jpg?1516836408)
- Function: wrist flexion
- Innervation: median nerve
![](https://s3.amazonaws.com/brainscape-prod/system/cm/280/784/675/a_image_thumb.jpg?1516836408)
State the origin and attachment of the palmaris longus muscle
![](https://s3.amazonaws.com/brainscape-prod/system/cm/280/784/677/q_image_thumb.jpg?1516836409)
- Origin: medial epicondyle
- Attachment: flexor retinaculum of the wrist
![](https://s3.amazonaws.com/brainscape-prod/system/cm/280/784/677/a_image_thumb.jpg?1516836410)
State the function and innervation of the flexor carpi radialis muscle
![](https://s3.amazonaws.com/brainscape-prod/system/cm/280/784/679/q_image_thumb.jpg?1516836410)
- Function: wrist flexion and abduction
- Innervation: median nerve
![](https://s3.amazonaws.com/brainscape-prod/system/cm/280/784/679/a_image_thumb.jpg?1516836411)