Muscles of the Anterior Forearm Flashcards
This part of the forearm serves as an attachment site for many muscles
Interosseous membrane
The anterior compartment of the forearm performs what actions?
Flexion
Pronation
Nerves that innervate the anterior compartment of the forearm
Median and Ulnar Nerve
The posterior compartment of the forearm performs what actions?
Extension and supination
All of the muscles of the posterior compartment are innervated by
The Radial Nerve
Because many of the muscles of the forearm originate from the humerus, which causes the muscles in to be located where in the forearm?
What does this accomplish?
The muscles are located proximally. This allows the wrist and hand to be less bulky.
The 5 superficial muscles of the anterior forearm are…
- Pronator Teres
- Flexor Carpi Radialis
- Palmaris Longus
- Flexor Carpi Ulnaris
- Flexor Digitorum Superficialis
All of the muscles of the anterior compartment of the forearm attach to the common flexor tendon which originates off of….
the medial epicondyle of the humerus
Most of the muscles of the forearm are innervated by
The median nerve
Round, tubular shaped muscle that extends from common flexor to halfway down the radius
Pronator Teres
Origin of the pronator teres
Medial epicondyle of the humerus and somewhat off the coronoid process of the ulna
What passes through the small opening on the pronator teres where the muscle originates?
Median nerve
Where does pronator teres insert?
Radius, lateral side midway down
What nerve innervates the pronator teres
Median nerve
What action is the pronator teres responsible for?
What other action can it assist with?
Pronation
Flexion at the elbow
Anterior muscle of the forearm that acts with the flexor carpi ulnaris to help flex the wrist
It cannot also help flex the elbow
Flexor Carpi Radialis
When acting alone or with extensors, what movement does the flexor carpi radialis perform?
Abducts the wrist
What structure is located laterally to the flexor carpi radialis?
Radial Artery
Where does the flexor carpi radialis insert?
The base of the 2nd and 3rd metacarpals
What is the sheet that carpi muscles must pass through when crossing wrist?
Flexor Retinaculum
What innervates the flexor carpi radialis?
Median nerve
This muscle lies superficial to flexor digitorrum and is fairly small, has little affect on wrist strength
Palmaris Longus (Absent in 15% of ppl)
What is the insertion of the palmaris longus?
Origin?
Palmar Aponeurosis
Medial epicondyle of the humerus
Fascia covering the palm of the hand
Palmar Aponeurosis
Action of the palmaris longus
Flex the wrist
What lies just lateral to the palmaris longus, between the palmaris longus and flexor carpi radialis?
The median nerve
The most medial muscle of the superficial flexors
Flexor Carpi Ulnaris
What action does the flexor carpi ulnaris have when working with other flexors?
What about when it acts with extensors?
Has some ability to do this because it crosses the elbow joint
Flexion
Adduct the wrist
Flex the elbow
What innervates the flexor carpi ulnaris?
Ulnar nerve
What two structures lie just laterally to flexor carpi ulnaris tendon?
Ulnar nerve and artery
Flexor carpi ulnaris originates off of
Medial epicondyle and some off the olecranon process
Where does flexor carpi ulnaris insert into?
Pisiform bone and the base of the 5th metacarpal
The anterior forearm muscle that divides at the wrist into 4 tendons to each finger, and is the largest of the superficial muscles
Flexor Digitorum Superficialis
The tendons of this muscle split as they attach into the middle phalanx, which allows the tendons of the FDP to pass through
Flexor Digitorum Superficialis
Origins of the flexor digitorum superficialis
Insertion of the flexor digitorum superficialis
the medial epicondyle of the humerus, the coronoid process of the ulna, the upper half of the radius
Middle phalanx of each of the four fingers
Flexor Digitorum Superficialis is innervated by
The median nerve (lies deep to it)
Flexor Digitorum Superficialis performs what actions?
Flexes the middle phalanges and
Flexes the the metacarpal phalangeal joint
Flexes the wrist
The three deep muscles of the anterior forearm
Flexor Pollicis Longus
Flexor Digitorum Profundus
Pronator Quadratus
Do the deep muscles of the forearm cross the elbow joint and therefore originate on the common flexor tendon?
No!
Deep muscle of the forearm that lies along the radius and flexes the distal phalanx of the thumb and the proximal phalanx, and first metacarpal
Flexor Pollicis Longus
The only muscle that flexes the interphalengeal joint of the thumb
Flexor Pollicis Longus
What is the origin of the flexor pollicis longus?
The anterior surface of the radius and the interossesous membrane
What is insertion of the flexor pollicis longus?
Distal Phalanx of the thumb
What is it innervated by?
Median nerve
What is the main action of the flexor pollicis longus?
Flexes the distal phalanx of the thumb
The large deep muscle of the forearm located medial to the flexor pollicis longus
Flexor Digitorum Profundus
Origin of the flexor digitorum profundus
The ulna and the interosseus membrane
Action of the flexor digitorum profundus
Flexes the distal phalanges of the four medial digits
Helps to curl fingers and flex the hand in making fist
What two nerves innervate the flexor digitorum profundus?
Median nerve and ulnar nerve
The integrity of which nerve can be tested by flexing the first finger?
The little finger?
Median nerve (lateral)
Ulnar nerve (medial)
A square shaped muscle that pronates the forearm, looks like a small bandage covering the lower anterior three inches of forearm
Pronator Quadrates
The prime mover in pronation that initiates it
Pronator Quadratus
What muscles assists the pronator quadratus when more speed and power is needed?
Pronator Teres
Origin of the pronator quadratus
Distal portion of the anterior surface of the ulna
Insertion of the ulna
Distal portion of the anterior surface of the radius
Innervates the pronator quadratus
Median nerve
Do the median and ulnar nerve do anything in the arm?
No. Just pass through it.
Anterior forearm nerve that passes anterior to the Anterior forearm nerve that passes posterior to the elbow joint (funny bone)
Median Nerve
Ulnar Nerve
Nerve that passes deep to the flexor retinaculum
Nerve that does not pass deep to the flexor retinaculum
Median Nerve
Ulnar Nerve
The passage formed by the carpal bones and the flexor retinaculum where all long flexor tendons to the digits and thumb, and where median nerve passes through
Carpal Tunnel
Flexor retinaculum is attached laterally to…
Medially to…
Scaphoid and trapezium
Pisiform and Hamate
Irritation and swelling in the synovial sheet of carpal tunnel puts pressure on the____ which can cause symptoms of carpal tunnel
Median Nerve