Muscles - Anterior Forearm Flashcards
What are the muscles of the superficial compartment?
1) Flexor carpi ulnaris
2) Palmaris longus
3) Flexor carpi radialis
4) Pronator teres
They all originate from a common tendon, which arises from the medial condyle of the humerus.
Flexor carpi ulnaris
Origin - medial condyle and ulna
Insertion - pisiform carpal bone
Actions - flexion and adduction of wrist
Innervation - ulnar nerve
Palmaris longus
This is absent in about 15% of the population.
Dissection tip - when reflecting back the palmaris longus, you will find the median nerve immediately beneath it.
Origin - medial condyle
Insertion - flexor retinaculum of the wrist
Actions - flexion of the wrist
Innervation - median nerve
Flexor carpi radialis
Origin - medial condyle
Insertion - base of metacarpals II and III
Actions - flexion and abduction of the wrist
Innervation - median nerve
Pronator teres
The lateral border of the pronator teres forms the medial border of the cubital fossa, an anatomical triangle over the elbow.
Origin - medial condyle and coronoid process of ulna
Insertions - mid-shaft of the radius
Actions - pronation of the forearm
Innervation - median nerve
What are the muscles of the intermediate compartment?
1) Flexor digitorum superficialis
It is a good anatomical landmark in the forearm - the median nerve and ulnar artery passes between its two heads, and then travels posteriorly.
Flexor digitorum superficialis
Origin - medial epicondyle and radius
Insertion - splits into four tendons which then travel through the carpal tunnel, and attach to the middle phalanges of the four fingers.
Action - Flexes the metacarpophalangeal joints and proximal interphalangeal joints at the four fingers, and flexes the wrist.
Innervation - median nerve
What are the muscles of the deep compartment?
1) Flexor digitorum profundus
2) Flexor pollicis longus
3) Pronator quadratus
Flexor digitorum profundus
Origin - ulna and associated interroseous membrane
Insertion - at the wrist, it splits into four tendons, that pass through the carpal tunnel and attach to the distal phalanges of the four fingers.
Action - it is the only muscle that flexes the distal interphalangeal joints of the fingers. It also flexes at the metacarpophalangeal joints at the wrist.
Innervation - medial half (ring and pinky) is innervated by the ulnar nerve. the lateral half is innervated by the anterior interroseous branch of the median nerve.
Flexor pollicis longus
It lies lateral to the FDP.
Origin - anterior surface of radius and surrounding interroseous membrane.
Insertion - inserts to the base of the distal phalanx of the thumb.
Action - flexes the interphalangeal joint and metacarpophalangeal joint of the thumb.
Innervation - median nerve (anterior interosseous branch).
Pronator Quadratus
A square shaped muscle found deep the tendons of the FDP and the FPL.
Origin - anterior surface of the ulna.
Insertion - anterior surface of the radius.
Action - pronates the forearm.
Innervation - median nerve (anterior interosseous branch).
