L8: Musculo-neuro-vascular systems of the arm and anterior compartment of the forearm Flashcards
compartments of forearm
similar to arm, forearm is surrounded by a layer of fascia called antebrachial fascia
> is continuous with brachial fascia proximally and fascia of the hand distally
forearm us divided into 2 compartments by:
-medial intermuscular septum
-ulna
-interosseous membrane
-radius
-lateral intermuscular septum
compartment syndrome
excessive swelling or bleeding within a compartment
usually after an injury
exerts pressure on anything within that compartment - nerves, muscles, arteries and veins
can cause irreversible damage to all tissues in compartment
treated with emergency fasciotomy
anterior compartment (8) of forearm;
> superficial muscles (5)
pronator teres
flexor carpi radialis
palmaris longus
flexor carpi ulnaris
flexor digitorum superficialis
anterior compartment (8) of forearm
> deep muscles (3)
flexor pollicis longus
flexor digitorum profundus
pronator quadratus
general rule
anterior forearm supplied by
anterior forearm muscles supplied by the median nerve:
-either directly
- or by anterior interosseous nerve (a branch of median nerve)
EXCEPT:
- flexor carpi ulnaris > ulnar nerve
- ulnar 1/2 of flexor digitorum profundus > ulnar nerve
pronator teres; origin + insertion
origin:
-medial epicondyle of humerus
-coronoid process of ulna
insertion:
- anterior surface of radial mid-shaft
pronator teres; innervation + actions
innervation: median nerve
actions: pronates forearm at radioulnar joint, weak flexor of elbow joint
Flexor carpi radialis; origin + insertion
origin:
- medial epicondyle of humerus
insertion:
- palmar surface of base of metacarpals 2 and 3
Flexor carpi radialis; innervation + actions
innervation: median nerve
actions: flexes wrist (radiocarpal) joint, weak radial deviation of wrist
palmaris longus; origin + insertion
origin:
- median epicondyle of humerus
insertion:
- flexor retinaculum
- palmar aponeurosis
palmaris longus; innervation + actions
innervation: median nerve
actions: flexes hand at wrist (radiocarpal) joint, tightens palmar aponeurosis when gripping
flexor carpi ulnaris; origin + insertion
origin: 2 heads
- humeral head: medial epicondyle
- ulnar head: medial + posterior surface of olecranon
flexor carpi ulnaris; innervation + actions
innervation: ulnar nerve
actions: flexes wrist at radiocarpal joint, flexes 5th CMC joint, adducts hand
flexor digitorum superficialis; origin + insertion
origin:
- medial epicondyle of humerus
- coronoid process of ulna
- anterior surface of radial shaft (distal to tuberosity)
insertion:
- middle phalanges 2-5 (palmar surface, either side of base
flexor digitorum superficialis; innervation + actions
innervation: median nerve
actions: flexes proximal and middle phalanges of digits 2-5 [i.e. at MCP/PIP joints]
'’superficialis divides in two, to allow profundus to pass through’’