Posterior Forearm Flashcards
The muscles in the posterior compartment of the forearm tend to be of what function
Extensor muscles which produce extension at the wrist and the fingers
Extensor Muscles are supplied by what nerve
Radial nerve
Brachioradialis
Origin and innervation are characteristic of an extensor muscle but its actually a flexor at the elbow.
Attachments of Brachioradialis
Proximal aspect of the lateral supracondylar ridge of the humerus, and attaches to the distal end of the radius
Action of Brachioradialis
Flexion at the elbow
Innervation of brachioradialis
Radial nerve
Extensor Carpi Radialis Longus and Brevis
Located on the lateral aspect of the posterior forerm
Attachements of Extensor Carpi Radialis Longus and Brevis
The ECRL originates from the supracondylar ridge, while the ECRB originates from the lateral epicondyle. Their tendons attach to metacarpal bones II and III.
Action of Extensor Carpi Radialis Longus and Brevis
Extends and abducts the wrist
Attachments of Extensor Digitorum
Originates from the lateral epicondyle. The tendon continues into in the distal part of the forearm, where it splits into four, and inserts into the extensor hood of each finger.
Actions of Extensor Digitorum
Extends medial four fingers at the MCP and IP joint
Extensor Digiti Minimi in relation to extensor digitorum
Lies medially to extensor digitorum
Attachements of Extensor Digiti Minumi
Originates from the lateral epicondyle of the humerus. It attaches, with the extensor digitorum tendon, into the extensor hood of the little finger
Actions of Extensor Digiti Minimi
Extends the little finger, and contributes to extension at the wrist
Attachments of Extensor Carpi Ulnaris
Originates from the lateral epicondyle of the humerus, and attaches to the base of metacarpal V.
Actions of Extensor Carpi Ulnaris
Extension and adduction of the wrist
Attachments of Aconeus
Originates from the lateral epicondyle, and attaches to the posterior and lateral part of the olecranon.
Actions of aconeus
Extends and stabilises the elbow joint. Abducts the ulnar during pronation of the forearm.
Supinator
Lies in the floor of the cubital fossa. It has two heads, which the deep branch of the radial nerve passes between.
Attachements of supinator
It has two heads of origin. One originates from the lateral epicondyle of the humerus, the other from the posterior surface of the ulna. They insert together into the posterior surface of the radius
Actions of supinator
Supinates the forearm
Abductor Pollicus Longus
Immediately distal to the supinator muscle. The tendon contributes to the lateral border of the anatomical snuffbox
Attachments of Abductor Pollicus Longus
Originates from the interosseous membrane and the adjacent posterior surfaces of the radius and ulna. It attaches to the lateral side of the base of metacarpal
Actions of Abductor Pollicus Longus
Abducts the thumb
Innervation of Abductor Pollicus Longus
Posterior interosseous branch of the radial nerve
Exstenor Pollicus Brevis attachments
Originates from the posterior surface of the radius and interosseous membrane. It attaches to the base of the proximal phalanx of the thumb.
Actions of Extensor Pollicus Brevis
Extends at the MCP and CM joints of the thumb
Innervation of Extensor Pollicus Brevis
Posterior interosseus branch of the radial nerve
Extensor Pollicus Longus
Tendon forms the medial border of the anatomical snuffbox in the hand
Attachments of Extensor Pollicis Longus
Originates from the posterior surface of the ulna and interosseous membrane. It attaches to the distal phalanx of the thumb.
Actions of Extensor Pollicus Lobgus
Extends all joints of the thumb
Innervation of the extensor pollicus longus muscle
Posterior interosseous branch of the radial nerev
