Forearm and Wrist Flashcards
Muscles of the anterior compartment of the forearm are
arranged in two layers, with the muscles of the superficial layer
largely arising from ________.
Medial epicondyle
What is the function of the muscles from the anterior compartment of the forearm?
Primarily flexors of the hand at the wrist and/or
finger flexors
Which arteries supply the anterior forearm?
Radial + Ulnar arteries
Innervates all muscles of the anterior forearm except the flexor carpi ulnaris and flexor digitrorum profundus
Median Nerve
Which two muscles of the anterior forearm are not innervated by the median nerve?
Which nerve supplies them?
Flexor carpi ulnaris + Flexor digitorum profundus
Ulnar nerve
Attachment and function of Pronator Teres
Origin: medial epicondyle of humerus
Insertion: Medial lateral surface of radius
Function: pronates forearm and flexes elbow
Attachment and function of Flexor carpi radialis
Origin: medial epicondyle of humerus
Insertion: base of 2nd metacarpal bone
Function: flexes hand at wrist and abduct it
Attachment and function of Palmaris longus
Origin: medial epicondyle of humerus
Insertion: distal half of flexor reticunaculum
Function: flexes hand at wrist and tightens palmar aponeurosis
Attachment and function of Flexor carpi ulnaris
Origin
- Humeral head: medial epicondyle of humerus
- Ulnar head: olecranon and posterior ulna
Insertion: pisiform bone, hook of hamate bone, and 5th metacarpal bone
Function: flexes hand at wrist and ADDucts it
Attachment and function of Flexor digitorum superficialis
Origin
- Humero-ulnar head: medial epicondyle of humerus, ulnar collateral ligament, and coronoid process of ulna
- Radial head: superior half of anterior radius
Insertion: body of middle phalanges of medial four digits
Function: flexes distal phalanges of medial four digits, weakly flexes proximal phalanges, forearm and wrist.
Flexor digitorum profundus (FDP)
Origin: Proximal three quarters of medial and anterior surfaces of ulna and interosseous membrane
Insertion: Bases of distal phalanges of 2nd, 3rd, 4th, and 5th digits
Fx: Flexes distal phalanges of medial four digits; assists with wrist flexion
Flexor pollicis longus
Origin: Anterior surface of radius and adjacent interosseous membrane
Insertion: Base of distal phalanx of thumb
Fx: Flexes phalanges of 1st digit
Pronator quadratus
Origin: Distal quarter of anterior surface of ulna
Insertion: Distal quarter of anterior surface of radius
Fx: Pronates arm and forearm
Muscles from posterior compartment of forearm (10)
Brachioradialis Extensor carpi radialis longus Extensor carpi radialis brevis Extensor digitorum minimi Extensor carpi ulnaris Supinator Abductor pollicis longus Extensor pollicis brevis Extensor pollicis longus Extensor indicis
Primarily extensors of the hand at the wrist and/or finger extensors; arise mostly from lateral epicondyle of humerus and are innervated by radial nerve
Brachioradialis
Origin: Proximal two thirds of lateral supraepicondylar ridge of humerus
Insertion: Lateral surface of distal end of radius proximal to styloid process
Fx: Flexes mid-pronated forearm at elbow
Extensor carpi radialis longus
Origin: Lateral supra-epicondylar ridge of humerus
Insertion: Base of 2nd metacarpal bone
Fx: Extends and abducts hand at wrist
Extensor carpi radialis brevis
Origin: Lateral epicondyle of humerus
Insertion: Base of 3rd metacarpal
Fx: Extends and abducts hand at wrist
Extensor digitorum
Origin: Lateral epicondyle of humerus
Insertion: Extensor expansions of medial four fingers
Fx: Extends medial four digits at MCP joints; extends hand at wrist joint
Extensor digiti minimi
Origin: Lateral epicondyle of humerus
Insertion: Extensor expansion of 5th finger
Fx: Extends 5th digit at MCP and IP joints
Extensor carpi ulnaris
Origin: Lateral epicondyle of humerus and posterior border of ulna
Insertion: Base of 5th metacarpal bone
Fx: Extends and addcuts hand at wrist
Supinator
Origin: Lateral epicondyle of humerus, radial collateral and anular ligaments, supinator fossa, crest of ulna
Insertion: Lateral, posterior, and anterior surfaces of proximal third of radius
Fx: Supinates forearm and rotates radius to turn palm anteriorly
Abductor pollicis longus
Origin: Posterior surface of ulna, radius, and interosseous membrane
Insertion: Base of 1st metacarpal
Fx: Abducts the thumb and extends it at CMC joint
Extensor pollicis longus
Origin: Posterior surface of middle third of ulna and interosseous membrane
Insertion: Base of distal phalanx of thumb
Fx: extends distal phalanx of thumb at MCP and IP joints
Extensor pollicis brevis
Origin: Posterior surface of distal third of radius and interosseous membrane
Insertion: Base of proximal phalanx of the thumb
Fx: Extends proximal phalanx of thumb at CMC joint
Extensor indicis
Origin: Posterior surface of distal third of ulna and interosseous membrane
Insertion: Extensor expansion of 2nd finger
Fx: Extends 2nd digit and helps to extend hand at wrist
Monteggia fracture
Fracture of the ulna with dislocation of the proximal radio-ulnar joint
Galeazzi fracture
Fracture of distal radius with distal radio-ulnar joint dislocation
Carpal tunnel
Formed by the arching alignment of the carpal bones and the thick flexor retinaculum (transverse carpal ligament), which covers the tunnel on its anterior surface.
Structures passing through the carpal tunnel
- Four flexor digitorum superficialis tendons
- Four flexor digitorum profundus tendons
- One flexor pollicis longus tendo
- Median nerve
Extensor retinaculum
Segregates tendons into 6 compartment
Median Nerve Compression and Carpal Tunnel Syndrome
Most common compression neuropathy, is often linked to occupational repetitive movements related to wrist flexion and extension, holding the wrist in an awkward position, or strong gripping of objects.
Long-term compression often leads to thenar atrophy and weakness of the thumb and index fingers.
