The forearm extends from the elbow joint to the wrist joint and consists of which two bones?
Radius and Ulna
Stretched between the radius and ulna and divides the forearm into anterior and posterior compartments
Interosseous membrane
The forearm is innervated by terminal nerves from the brachial plexus. Terminal nerves comprised of ANTERIOR division nerve fibers innervate
Flexor muscles
The forearm is innervated by terminal nerves from the brachial plexus. Terminal nerves comprised of POSTERIOR division nerve fibers innervate
Extensor muscles
The primary function of the anterior forearm is
Pronation and wrist and digit flexion
The primary nerve of the anterior forearm is the
Median nerve
The primary blood supply to the anterior forearm is the
Radial and Ulnar arteries
The primary function of the posterior forearm is
Supination and wrist and digit extension
The primary nerve of the posterior forearm is the
Deep radial nerve
The primary blood supply of the posterior forearm is the
Posterior interosseous artery
The radius and ulna articulate proximlly with the humerus and with eachother and distally with
Two carpel bones
Within the forearm, the radius and ulna articulate via the
Proximal and distal radioulnar joints (synovial) and the Interosseous membrane (fibrous joint)
The movements allowed at the proximal and distal radioulnar joints are
Pronation: crossing radius over the ulna
and
Supination: placing the forearm in the anatomical position
At the distal forearm and wrist articulation, the radius articulates with scaphoid and lunate carpel bones via synovial
Radiocarpel joints (synovial)
The radiocarpel joints are supported by
Radiocarpel ligaments and collateral ligamnets
Clinically, radiocarpel joints are relevant for
Disslocation and/or fracture caused by fall on outstretched hand
Which bone is commonly fractured in radiocarpel injuries?
Scaphoid bone
Structures of the anterior forearm are located anterior to the
Interosseous membrane
Anterior forearm muscles are arranged in which three layers
- ) Superficial
- ) Intermediate
- ) Deep
What is the function of the anterior forearm muscles located in the superficial, intermediate, and deep layers?
- ) Superficial: forearm pronation and wrist felxion
- ) Intermediate: digit flexion
- ) Deep: forearm pronation and digit flexion
Deeper muscles act more
Distally
Muscles of the forearm stabilize proximal joints to enable other muscles to function more distally, i.e. they act as
Synergists
Innervate all but one and one-half of the anterior forearm muscles
Median nerve and its anterior interosseous branch
Innervates the flexor carpi ulnaris muscle and the ulnar half of the flexor digitorum profundus muscle
Ulnar nerve
Blood supply to the anterior forearm is supplied by the
Radial, ulnar, and anterior interosseous arteries
What are the 5 superficial and intermediate anterior forearm muscles?
- ) Pronator Teres
- ) Flexor carpi radialis
- ) Palmaris Longus
- ) Flexor carpi ulnaris
- ) Flexor digitorum superficialis
PROXIMALLY, the pronator teres and flexor carpi ulnaris attach to the
Medial epicondyle of the humerus and the ulna
DISTALLY, the pronator teres attaches to the
Radius
The function of the pronator teres is
Forearm pronation
PROXIMALLY, the flexor carpi radialis, palmaris longus, and flexor digitorum superficualis ALL attach to the
Medial epicondyle of the humerus
DISTALLY, the flexor carpi radialis attaches to the
Metacarpels
DISTALLY, the palmaris longus attaches to the
Palmar Aponeurosis
DISTALLY the flexor carpi ulnaris attaches to the
Pisiform
DISTALLY, the flexor digitorum superficialis attaches to the
Middle phalanges: digits 2-5
Which superficial and intermediate anterior forearm muscles are innervated by the MEDIAN nerve?
Pronator teres, Flexor carpi radialis, palmaris longus, and flexor digitorum superficialis
The function of the flexor carpi radialis is
Wrist flexion and abduction
The function of the palmaris longus is
Wrist flexion
The function of the flexor carpi ulnaris is
Wrist flexion and adduction
The function of the flexor digitorum superficialis is
Flexion at PIP
The flexor carpi ulnaris is innervated by the
Ulnar nerve
What are the three deep anterior forearm muscles?
Pronator quadratus, flexor digitorum profundus, and flexor pollicis longus
PROXIMALLY, the pronator quadratus and flexor digitorum profundus attach at to the
Ulna
PROXIMALLY, the flexor pollicis longus attaches to the
Radius
DISTALLY, the pronator quadratus attaches to the
Radius
DISTALLY, the flexor digitorum profundus attaches to the
Distal Phalanges: digits 2-5
DISTALLY, the flexor pollicis longus attaches to the
Distal Phalanx thumb
The pronator quadratus and flexor pollicis longus are innervated by the
Anterior Interosseous nerve
The flexor digitorum profundus is innervated by the
Enterior interosseous and Ulnar nerves
The function of the pronator quadratus is
Forearm pronation
The function of the flexor digitorum profundus is
Flexion at DIP
The function of the flexor pollicis longus is
Flexion of the distal phalanx of thumb
Posterior forearm muscles cross joints of the elbow, wrist and digits. The primary functions are
Forearm supination, wrist extension, and digit extension
Posterior forearm muscles are arranged in which two layers?
- ) Superficial: wrist and digit extension
2. ) Deep
What is the function of the deep posterior forearm muscles?
Forearm supination, extension of the thumb and index finger, and thumb abduction
The brachioradialis and extensor carpi muscles are innervated by the
Radial nerve
The supinator and extensor carpi radialis brevis muscles are innervated by the
Deep radial nerve
The rest of the posterior forearm muscles, i.e. the extensor digitorum, extensor digiti minimi, extensor carpi ulnairs, abductor pollicis longus, extensor pillicis brevis, extensor pollicis longus, and the extensor indicis are ALL innervated by the
Posterior interosseous nerve
PROXIMALLY, the Brachioradialis and extensor carpi longus attach to the
Lateral Supracondylar ridge of the humerus
PROXIMALLY, the extensor carpi radialis brevis, extensor digitorum, extensor digiti minimi, and extensor carpi ulnaris ALL attach to the
Common extensor tendon (lateral epicondyle of the humerus)
PROXIMALLY, the abductor pollicis longus, extensor pollicis longus, and the extensor indicis ALL attach to the
Ulna
PROXIMALLY, the supinator attaches to the
Lateral epicondyle of the humerus and the ulna
PROXIMALLY, the extensor pollicis longus attaches to the
Interosseous membrane
What are the DISTAL attachments for the
- ) Brachioradialis
- ) Extensor carpi radialis longus
- ) Extensor carpi radialis brevis
- ) Radius
- ) Metacarpel
- ) Metacarpel
What are the DISTAL attachments for the
- ) Extensor digitorum
- ) Extensor digiti minimi
- ) Extensor carpi ulnaris
- ) Phalanges: digits 2-5
- ) Phalange: 5th digit
- ) Metacarpel
What are the 6 superficial posterior forearm muscles?
- ) Brachioradialis
- ) Extensor carpi radialis longus
- ) Extensor radialis carpi brevis
- ) Extensor digitorum
- ) Extensor digiti minimi
- ) Extensor carpi ulnaris
The function of the brachioradialis is
Flexion of forearm at elbow
The function of the extensor carpi radialis longus and extensor carpi radialis brevis is
Wrist extension and ABduction
The function of the extensor digitorum is
Extension of digits 2-5
The funtion of the extensor digiti minimi is
Extension of the 5th digit
The function of the extensor carpi ulnaris is
Wrist extension and ADduction
What are the 5 deep posterior forearm muscles?
- ) Supinator
- ) Abductor pollicis longus
- ) Extensor pollicis brevis
- ) Extensor pollicis longus
- ) Extensor indicis
What are the DISTAL attachments for the
- ) Supinator
- ) Abductor pollicis longus
- ) Extensor pollicis brevis
- ) Radius
- ) 1st metacarpel
- ) Proximal phalanx of the thumb
What are the DISTAL attachments for the
- ) Extensor pollicis longus
- ) Extensor indicis
- ) Distal phalanx of thumb
2. ) 2nd metacarpel
The function of the supinator is
Supination of the forearm
The function of the abductor pollicis longus is
ABduction of the thumb
The functions of the extensor pollicis brevis and extensor pollicis longus are
Extension of the thumb
The function of the extensor indicis is
Extension of 2nd digit
The “gateway” to the wrist and hand for muscle
tendons and important neurovascular structures
The distal forearm
Anteriorly, the median nerve passes lateral to the
Palmaris longus tendon
Posteriorly, the extensor tendons are compartmentalized by the
-serves to prevent “bowstringing” of the tendons
Extensor retinaculum