Forearm Flashcards
What fascia envelopes the forearm?
Antebrachial fascia
Posterior and lateral muscles are innervated by what nerve? Anterior and Medial?
- Radial nerve
2. Median Nerve
What are the different actions of the wrist - condyloid joint?(5)
- Flexion
- Extension
- Abduction
- Adduction
- Circumduction
Supination and pronation occurs at what joint?
Radioulnar
- extension and flexion at the elbow
The metacarpals are what kind of joint?
Condyloid - circumduction occurs
interphalangeal = hinge joint –> flexion/extension
What are the two main supinators?
Biceps Brachii and Supinator muscle
What are the actions, innervations, and originate of the anterior compartment of the forearm?
Flexion and Median Nerve (all EXCEPT ulnar half of flexor digitorum profundus and flexor carpi ulnaris – ulnar N.)
Originate at medial epicondyle (via common flexor tendon)
What two muscles rotate the radius on the ulna from the anterior compartment of the forearm?
- Pronator teres (assists elbow flexion as well)
2. Pronator Quadratus
What muscles flex the hand at the wrist and insert onto palmar aponeurosis/metacarpals?
- Palmaris Longus - tense the palm, flex wrist
- Flexor Carpi Radialis - ABDuction, flex wrist
- Flexor Carpi Ulnaris - ADDuction, flex wrist
What muscles flex the hand at the wrist and DIGITS and insert onto phalanges?
- Flexor digitorum superficialis - flex MCP, PIP
- Flexor Digitorum Profundus - flex DIP*
- Flexor Pollicis Longus - flex thumb
What are the actions, innervations, and origin of the POSTERIOR compartment of the forearm?
A: Extension, rotate radius on ulna (supinator)
N: Radial Nerve*
Origin: Common extensor attachment of LATERAL epicondyle
What muscle rotates the radius on the ulna from the POSTERIOR compartment of the forearm?
Supinator
What muscles EXTEND the hand at the wrist and insert onto metacarpals 2,3, or 5?
- Extensor Carpi Radialis Longus - abduct*
- Extensor Carpi Radialis Brevis - abduct
- Extensor Carpi Ulnaris - ADDucts
*all extend
What muscles EXTEND the hand at the wrist and DIGITS and insert onto phalanges? Where do they insert?
Insert onto the extensor expansion hood
- extensor digitorum – 2 to 5
- extensor indicis - extend digit 2
- extensor digiti minimi - extends digit 5 (pinky)
What muscles EXTEND the thumb? Where do they insert?
- Abductor Pollicis Longus - base of 1st Metacarpal –> extend and abduct
- Extensor Pollicis Brevis - base of proximal phalanx (extend PIP)
- Extensor Pollicis Longus - base of distal phalanx (extends the DIP)
What muscle is also part of the posterior compartment and serves to flex the elbow and guide us to find the extensor muscles?
Brachioradialis!
- flexes the elbow when pronated
- *RADIAL NERVE**
What forms the snuff box?
- Abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus
- Contains Radial ARTERY
- Superficial Radial NERVE
- Scaphoid bone
What nerve runs between flexor digitorum superficial is and flexor digitorum profundus?
Median nerve
All the triceps insert onto_________
Olecrenon Fossa (back of arm)
What nerve lies between the medial and lateral heads of the triceps?
Radial Nerve
What nerve travels by the funny bone?
Ulnar Nerve
Once the radial nerve hits the supinator it is called:
Posterior Interosseus Nerve
Median is the Anterior Interosseus Nerve
Muscles that attach to the Radius always abduct or adduct?
Abduct
What nerve supplies the cutaneous innervations for the lateral aspect of the forearm?
Lateral Antebrachial Cutaneous (Musculocutaneous)
Medial Antebrachial Cutaneous is the Medial aspect of the arm (arises from the medial chord of the brachial plexus)
Pronator Teres Muscle
O: Medial Epicondyle
I: Radius
A: Pronation of forearm, assist with elbow flexion
N: Median Nerve
Flexor Carpi Radialis
O: Medial Epicondyle I: base of 2nd metacarpal A: flexion and ABDuction wrist N: Median N. B: Radial Artery
Flexor Carpi Ulnaris
O: medial epicondyle
I: pisiform bone, hook of hamate, 5th metacarpal
A: Flexion and ADDuction hand at wrist
N: Ulnar N.
Palmaris Longus
O: Medial Epicondyle
I: Flexor Retinaculum and Palmar Aponeurosis
A: Flexion of wrist, tenses palm*
N: Medial N.
- not everyone has this
Flexor Digitorum Superficialis
O: Medial Epicondyle
I: Bodies of middle phalanges (PIP) of medial 4 digits
A: Flexion of PIP and MCP, (assist) flex hand at wrist
N: Median N.
Flexor Digitorum Profundus
O: Medial Epicondyle
I: DIP of medial 4 digits
A: Flexion of DIP, assist flexion hand at wrist
N: Median N. , Ulnar N for the Ulnar 1/2
Pronator Quadratus
O: Distal 1/4 of anterior Ulna
I: Distal 1/4 of anterior Radius
A: Pronation of forearm
N: Median N. (anterior interosseus)
Flexor Pollicis Longus
O: Surface of radius and interosseus membrane
I: DIP of thumb
A: Flexes phalanges of thumb
N: Median N.
Extensor Carpi Radialis Longus
O: lateral supracondylar ridge of humerus
I: base of 2nd metacarpal
A: Extends and ABDucts hand at wrist
N: Radial
Extensor Carpi Radialis Brevis
O: lateral epicondyle of humerus
I: base of 3rd metacarpal
A: Extends and ABDucts hand at wrist
N: Radial N.
Brachioradialis
O: 2/3 of lateral supracondyle ridge of humerus
I: Radius
A: weak flexion of forearm when PRONATED*
N: Radial N.
Extensor Carpi Ulnaris
O: Lateral epicondyle of humerus
I: Dorsal base of 5th Metacarpal
A: Extension and ADDuction
N: Radial N. ** (posterior interosseus, not ulnar)
Extensor Digiti Minimi
O: Lateral Epicondyle
I: Extensor Expansion Hood of 5th Metacarpal*
A: Extension of 5th digit
N: Radial Nerve (posterior I = deep radial)
Extensor Digitorum
O: Lateral Epicondyle
I: extensor expansion of medial 4 digits
A: extension of medial 4 digits (assist in wrist extension)
N: Radial N. (posterior interosseus)
Abductor Pollicis Longus
O: posterior surface of ulna,radius, and interosseus membrane
I: base of 1st METACARPAL
A: abduction/ extension of the thumb and carpometacarpal joint
N: Radial N. (posterior interosseus)
Extensor Pollicis Brevis
O: Posterior surface of radius + interosseus membrane
I: base of PROXIMAL Phalanx of thumb
A: extension of PIP of thumb at carpometacarpal joint
N: Radial N. (posterior interosseus)
Extensor Pollicis Longus
O: Posterior surface of middle third of ulna, interosseus membrane
I: base of DISTAL phalanx of thumb
A: Extension of Distal phalanx
N: Radial N. (posterior interosseus)
Extensor Indicis
O: Posterior surface of ulna, interosseus membrane (close to extensor pollicis longus)
I: Extensor Expansion of 2nd digit (pointer finger)
A: Extension of 2nd digit, assist extension of hand at wrist
N: Radial Nerve (posterior interosseus)
