Skip to Main Content

++

Big Picture

++

The forearm (antebrachium) consists of the radius and ulna. Proximally, the forearm articulates with the humerus through the elbow complex (humeroulnar and humeroradial joints). Distally, the forearm articulates with the carpal bones through the wrist complex, enabling a wide array of actions. The muscles of the forearm that act upon the elbow, wrist complex, and the digital joints are organized into two fascial compartments, similar to those of the arm muscles. The anterior compartment contains flexor muscles and the posterior compartment contains extensor muscles.

++

Actions of the Wrist

++

The configuration of the wrist complex allows for motion in two planes (Figure 32-1A):

++

  • Flexion
  • Extension
  • Radial deviation (abduction)
  • Ulnar deviation (adduction)

++
Figure 32-1
Graphic Jump Location

A. Actions of the wrist joint. Superficial (B) intermediate (C) and deep (D) muscles of the anterior forearm.

++

Forearm Muscles of the Anterior Compartment

++

The actions produced by the muscles in the anterior compartment of the forearm depend upon which joints the muscles cross. Some muscles cross the elbow, wrist, digits, and perhaps a combination of each. The muscles in the anterior compartment of the forearm have the following similar features:

++

  • Common attachment. Medial epicondyle of the humerus.
  • Common innervation. Median nerve with minimal contribution from the ulnar nerve.
  • Common action. Flexion.

++

The vascular supply to the anterior forearm muscles is from branches of the ulnar and radial arteries.

++

The muscles in the anterior compartment of the forearm are divided into three groups: superficial, intermediate, and deep.

++

  • Superficial group (Figure 32-1B)
    • Pronator teres muscle. Possesses two heads and crosses the elbow complex. The humeral head of the pronator teres muscle attaches to the medial epicondyle and the supraepicondylar ridge of the humerus, and the ulnar head attaches to the coronoid process. Distally, the pronator teres muscle attaches to the midshaft of the radius. The pronator teres muscle primarily produces pronation at the forearm. The median nerve provides innervation (C6–C7) to the pronator teres muscle.
    • Flexor carpi radialis muscle. Attaches to the medial epicondyle and the base of metacarpals 2 and 3. The primary action of the flexor carpi radialis muscle is wrist flexion and radial deviation. The median nerve (C6–C7) supplies innervation to this muscle.
    • Palmaris longus muscle. Attaches to the medial epicondyle of the humerus and courses superficially over the flexor retinaculum to the palmar aponeurosis in the hand. The primary action of the palmaris longus muscle is to resist shearing forces of the palmar aponeurosis; it is also considered a wrist flexor. Innervation is provided by the median nerve (C7–C8). It is important to note that the palmaris longus muscle may be absent on one or both sides in some individuals....

Want remote access to your institution's subscription?

Sign in to your MyAccess profile while you are actively authenticated on this site via your institution (you will be able to verify this by looking at the top right corner of the screen - if you see your institution's name, you are authenticated). Once logged in to your MyAccess profile, you will be able to access your institution's subscription for 90 days from any location. You must be logged in while authenticated at least once every 90 days to maintain this remote access.

Ok

About MyAccess

If your institution subscribes to this resource, and you don't have a MyAccess profile, please contact your library's reference desk for information on how to gain access to this resource from off-campus.

Subscription Options

AccessPharmacy Full Site: One-Year Subscription

Connect to the full suite of AccessPharmacy content and resources including 30+ textbooks such as Pharmacotherapy: A Pathophysiologic Approach and Goodman & Gilman's The Pharmacological Basis of Therapeutics, high-quality videos, images, and animations, interactive board review, drug and herb/supplements databases, and more.

$595 USD
Buy Now

Pay Per View: Timed Access to all of AccessPharmacy

24 Hour Subscription $34.95

Buy Now

48 Hour Subscription $54.95

Buy Now

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.