C - Forearm Muscles & Hand (unit 3) Concept C
Outcropping muscles (deep, posterior compartment)
abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus all act on thumb!
palmaris longus
absent in 15-20% of people slender tendon blends in with palmar aponeurosis flexion at wrist
carpi - forearm
action is limited to the wrist. tendons of these muscles do NOT attach to phalanges
forearm muscles anterior compartment proximal attachment (superficial)
all 4 attach to medial epicondyle (PT, FCR, PL, FCU)
What is the most lateral muscle of the forearm?
brachioradialis
muscles of superficial layer of posterior forearm (6)
brachioradialis extensor carpi radialis longus (ECRL) extensor carpi radialis brevis (ECRB) extensor digitorum (ED) extensor digiti minimi (EDM) extensor carpi ulnaris (ECU)
How are the forearm muscles compartmentalized?
dense regular CT surrounds groups of anterior forearm muscles and posterior forearm muscles. called antebrachial fascia.
where do you find muscles name carpi?
either side of the exposed ulna or the brachioradialis. carpis course with wrist but not phalanges
what is the common action of the posterior compartment of forearm muscles?
extension
extensor - forearm
extension of digits and/or wrist, NOT elbow
muscles of the deep layer of the posterior forearm (4)
extensor indicis (EI) extensor pollicis longus (EPL) extensor pollicis brevis (EPB) abductor pollicis longus (APL)
flexor - forearm
flexion of digits and/or wrist, NOT elbow
muscles of deep layer of anterior forearm (2)
flexor digitorum profundus, flexor pollicis longus
muscles of the intermediate layer of the anterior forearm (1)
flexor digitorum superficialis
brachioradialis
most lateral forearm muscle, good landmark! attaches highest up (most proximally) on humerus does not cross/work on wrist weak flexor of forearm at elbow
pollicis - forearm
muscle acts upon digit 1 (thumb/pollux)
digitorum - forearm naming
muscle acts upon digits 2-5
pronator teres
pronates forearm - pulls radius over ulna does not cross wrist
what is the only muscle on the anterior forearm (that we study) that does not cross the wrist and therefore can have no affect on the wrist?
pronator teres
muscles of superficial layer of anterior forearm (4)
pronator teres flexor carpi radialis palmaris longus flexor carpi ulnaris
how are posterior forearm muscles grouped/named
superficial layer deep layer *extensor
If a muscle acts upon a digit(s), does it also act at the wrist?
yes, it can.
forearm muscles posterior compartment proximal attachment (superficial)
ECRB, ED, EDM, ECU all attach to the Lateral Epicondyle of humerus
how are anterior forearm muscles grouped
Superficial layer Intermediate layer Deep layer *flexor
