- Explanation: What Does the Term “Scope” Mean?
- Where Can the Scope Bone Be Found in the Arm?
- Facts About the Radial Bone
- Functions of the Scope
- Scope Bone Anatomy
- Parts of the Scope
- 1. Upper End (Proximal Scope)
- 2. Body/Shaft
- 3. Lower End (Distal Scope)
- Scope Bone Muscle Attachments
- Muscle Name
- Attachment to Scope
- Muscle Name
- Origin at Scope
- Scope Bone Side Determination
- FAQ
- References
Explanation: What Does the Term “Scope” Mean?
Scope, also referred to as the radial bone, represents one of the two forearm bones in the human body, the other being the ulna. It plays a vital role in the formation and utilization of hands [1].
Where Can the Scope Bone Be Found in the Arm?
Situated on the thumb side of the hand, the scope bone lies laterally in the lower arm, running parallel to the ulna [1, 2].
Scope Bone Placement
Facts About the Radial Bone |
|
| Number in the human body | Two ― one in each arm |
| Type | Long bone [2] |
| Primary ossification centers | One ― at the middle of the shaft (emerging around the 8th week of fetal life) [3] |
| Secondary ossification centers | Two ― one for the distal end (appearing around 2 years) and another for the proximal end (emerging around 5 years) (all the centers fuse together by 20 years) [4] |
| Forms articulations with | Humerus, ulna, scaphoid, lunate |
Scope X-ray Image
Functions of the Scope
Efficient operation of the scope is crucial for engaging in everyday activities involving the hands, such as grasping objects, supporting the arm, throwing, writing, typing, using a phone, and so on.
- It creates a hinge joint with the humerus bone, allowing flexion and extension of the elbow [7].
- The scope rotates around the ulna at the wrist, enabling pronation and supination of the hand [8].
- The bone also forms an ellipsoidal joint with the proximal carpal row, facilitating wrist movement, rotation, bending, and flexing [7].
Scope Bone Anatomy
The radial bone is somewhat longitudinally triangular [2], divided into the upper end, body/shaft, and the lower end.
Labeled Diagram of Scope Bone Anatomy
Parts of the Scope |
|
1. Upper End (Proximal Scope) |
|
| Landmarks:
1. A disk-shaped head (caput radii) 2. A neck, continuing from the head, narrowing towards the shaft [2] 3. The radial tuberosity, a bony projection below the neck [3] |
Surfaces and Articulations:
1. A concave articular surface on top of the head for the capitulum of the humerus (elbow humeroradial joint) [5] 2. A smooth circumference of the head articulating with the radial notch of the ulna (proximal radio-ulnar joint) [3] |
2. Body/Shaft |
|
| Landmarks:
There are several landmarks on the radial shaft for the origin and insertion of various tendons [6] |
Borders
1. Anterior; 2. Posterior; 3. Medial (or interosseous, the sharpest border where the interosseous membrane connects) Surfaces 1. Anterior; 2. Posterior; 3. Lateral [3] |
3. Lower End (Distal Scope) |
|
| Landmarks:
1.A styloid process projecting distally on the lateral side 2. A prominent dorsal tubercle (or Lister’s tubercle) on the dorsal surface [3] 3. The ulnar notch on the medial side [1] |
Surfaces and Articulations:
1. The concave surface of the ulnar notch articulating with the ulnar head (distal radio-ulnar joint) [2] 2. A lateral triangular area on the distal or inferior surface forming joints with the carpal bones, scaphoid, and lunate (wrist joint) [2] |
Scope Bone Muscle Attachments |
|
Muscle Name |
Attachment to Scope |
| Biceps brachii | The rough posterior surface of the radial tuberosity [3] |
| Pronator teres | Lateral surface of the shaft |
| Pronator quadratus | Medial surface of the shaft |
| Supinator | Laterally on the shaft, covering one-third of the proximal radius (both origin and insertion) |
Muscle Name |
Origin at Scope |
| Flexor digitorum superficialis | Medial surface of the shaft |
| Flexor pollicis longus | Medial surface of the shaft |
| Abductor pollicis longus | Anterior surface of the shaft [5] |
A layer of hyaline cartilage covers both the proximal and distal ends of the scope, smoothing the articular surfaces to reduce friction during arm movements. It also acts as a shock absorber, lessening stress on the elbow and wrist joints from any impact [1].
The anterior part of the radial tuberosity is enveloped in a synovial bursa, known as the radial bursa, to keep it separated from the biceps tendons (of the biceps brachii muscle) during movements [3].
Scope Bone Side Determination
By facing the radial tuberosity anteriorly (or towards oneself), the thumb should be on the same side as the styloid process of the scope. Holding the bone in this manner helps in determining if it is the left or right scope.
FAQ
What are the most common injuries and conditions linked to the scope?
The scope is the most frequently fractured bone in the human body, with distal radius fractures being the most prevalent form of radial fracture [9]. Radial head dislocation is another common injury associated with the bone [10]. The bone may also be affected by arthritis of the wrist or elbow joints.
Ulna or scope ― which bone is longer and larger?
Although the ulna is longer than the scope, the latter is relatively thicker along its entire length, particularly in the shaft area [8].
References
- http://www.innerbody.com/image_skel14/skel20.html
- http://teachmeanatomy.info/upper-limb/bones/radius/
- https://www.earthslab.com/anatomy/radius-bone/
- https://www.bartleby.com/107/53.html
- https://www.kenhub.com/en/library/anatomy/the-radius-and-the-ulna
- https://courses.lumenlearning.com/boundless-ap/chapter/the-upper-limb/
- https://www.getbodysmart.com/upper-limb-bones/radius-ulna
- https://radiopaedia.org/articles/radius
- https://orthoinfo.aaos.org/en/diseases–conditions/distal-radius-fractures-broken-wrist/
- https://www.healthline.com/human-body-maps/radius-bone
