Forearm Flashcards
forearm
from elbow to wrist
functionally includes distal humerus
bones in forearm
radius - lateral
ulna- medial
interosseus m
unites the two bones
radio-ulnar joints
synovial joint
radius moves over ulna
supination and pronation
posterior thickening of antebrachial fascia
extensor retinaculum
forms 6 extensive tunnels for extensors of forearm
anterior thickening of antebrachial fascia
palmar l.
continuous with extensor retinaculum
flexor retinaculum
AKA transverse carpal l.
distal and deep to palmar carpal l.
muscles of anterior compartment of forearm
flexors and pronators
median n. and branches
(exception 1.5 muscls via ulnar n.)
posterior compartment muscles of forearm
extensors and supinators
radial n. and branches
forearm anterior compartment superficial layer
pronator teres, flexor carpi radialis, palmaris longus, flexor carpi ulnaris
forearm anterior compartment intermediate layer
flexor digitorum superficialis
forearm anterior compartment deep layer
pronator quadratus, flexor digitorum profundus, flexor policis longus
forearm anterior compartment joints crossed by layers
superficial and intermediate layers - elbow and wrist
deep layer- wrist only
pronator teres heads
superficial and deep
median n. passes between heads (impingement possible)
actions of pronator teres
pronation forearm
flexion of forearm
innervation of pronator teres
median n.
flexor carpi radialis
medial to pronator teres
tendon doesn’t pass through carpal tunnel
radial a. lie lateral to tendon
actions of flexor carpi radialis
flexion of forearm
radial deviation of wrist
innervation of flexor carpi radialis
median n.
palmaris longus
absent in one or both sides in 14%
passes superficial to flexor retinaculum to attach on palmar aponeurosis
closely related to median n at wrist
actions of palmaris longus
flexion of wrist
tenses palmar aponeurosis
palmaris longus innervation
median n.
flexor carpi ulnaris
most medial of superficial flexors
ulnar n. and a. lie lateral to tendon at wrist
heads of flexor carpi ulnaris
humeral and ulnar
ulnar nerve enters forearm between two heads of?
flexor carpi ulnaris
“cubital tunnel” (impingement)
actions of flexor carpi ulnaris
flexion of wrist
ulnar deviation of wrist
innervation of flexor carpi ulnaris
ulnar n.
flexor digitorum superficialis
median n. enters forearm by passing between its two heads
heads of flexor digitorum superficialis
humeroulnar
radial
flexor digitorum superficialis tendons
all pass through carpal tunnel
split distally
actions of flexor digitorum superficialis
flexion of proximal and middle phalanges and wrist
flexor digitorum superficialis innervation
median n .
flexor digitorum profundus
only muscle that can flex distal and interphalangeal joints
flexor digitorum profundus tendons
all 4 pass through carpal tunnel
pass through splits of FDS distally
actions of flexor digitorum profundus
medial 1/2 - flexion of distal phalanges of digits 4/5
lateral 1/2 - flexion of distal phalanges 2/3
all flexion of wrist
innervation of flexor digitorum profundus
medial 1/2 - ulnar nerve
lateral 1/2 - anterior interosseus nerve (branch of median nerve)
flexor pollicis longus
lies lateral to FDP
tendon passes through carpal tunnel
action of flexor pollicis longus
flexion of thumb
flexion of wrist
innervation
AIN
pronator quadratus
deepest muscle of ant. forearm
covers distal radius and interosseous membrane
AIN and AIA pass deep to muscle
pronator quadratus actions
prime mover for forearm pronation
deep fibers bind radius and ulna
innervation of pronator quadratus
AIN
pronator syndrome
nerve impingement syndrome - median n is compressed between heads of pronator teres
causes of pronator syndrome
activities that involve repeated pronation
pregnancy
idiopathic
symptoms of pronator syndrome
pain/tenderness in proximal forearm
Hypoestesia (decrease in sensation) of central palm and palmar aspects of radial 3 1⁄2 digits
Weakness with flexion and pronation of forearm
injury to median nerve at elbow caused by
supracondylar fracture
laceration to supracondylar area
symptoms of injury to median n at elbow
digits 1-3 : weakness/loss of flexion (FDS, FDP, FPL)
proximal interphalangeal joints 4/5 - weakened flexion (FDS)
injury to median nerve at elbow characteristics
hand of benidiction
themar mm. function is lost - thumb ADD and extends, thenar eminence flattens
sensory loss - central and lateral 2/3 of palm, palmar side of radial 3.5 digits
injury to ulnar n at elbow
27% of nerve lesions
majority of intrinisic mm. hand affected
ulnar deviation impaired
wrist flexion also impaired (hand drawn laterally)
sites of injury for ulnar n. injury at elbow
posterior to medial epicondyle
cubital tunnel
in hand
injury to ulnar n at elbow characteristics
difficulty making fist
claw hand
injury to ulnar n at elbow sensory loss
medial aspect of palm
dorsum of hand
medial 1.5 digits
what flexor compartment mm have more than one head or origin
flexor carpi ulnaris, FDS, pronator teres
what nerve might be impinged in the cubital tunnel? by pronator teres?
ulnar n. / median n.
which flexor compartment tt pass through carpal tunnel
FDS, FPL, FDP
what digits affected by an injury to ulnar nerve at elbow
ABD and ADD of digits 2-5 (loss of dorsal, palmar, interosseous mm)
sensory loss medial half of digits 4/5
extensor compartment superficial layer
brachioradialis
extensor carpi radialis longus
extensor carpi radialis brevis
extensor digitorum
extensor digiti minimi
extensor carpi ulnaris