elbow, forearm and wrist Flashcards
bone of arm (“upper arm”)
humerus
2 bones of forearm
radius, ulna
8 carpal bones (in supine position, lateral to medial, proximal row then distal row) - Some Lovers Try Positions That They Can’t Handle
scaphoid, lunate, triquetrum, pisiform; trapezium, trapezoid, capitate, hamate
4 regions of in this section
anterior compartment of arm, posterior compartment of arm, anterior compartment of forearm, posterior compartment of forearm
3 muscles in anterior compartment of arm
biceps brachii, brachialis, coraco-brachialis (coraco-brachialis doesn’t act over elbow)
2 muscles in posterior compartment of arm
triceps brachii, anconeus
5 superficial muscles in anterior compartment of forearm, including one which can be classified as “intermediate” (PFP[F]F when fingers put from medial epicondyle)
pronator teres, flexor carpi radialis, palmar longus, [flexor digitorum superficialis], flexor carpi ulnaris
3 deep muscles in anterior compartment of forearm
flexor digitorum profundus, flexor pollicis longus, pronator quadratus
posterior (extensor) compartment of forearm: 3 muscles that move the wrist joint
extensor carpi radialis longus, extensor carpi radialis brevis, extensor carpi ulnaris
posterior (extensor) compartment of forearm: 3 muscles that move the digits
extensor digitorum, extensor indicis, extensor digiti minimi
posterior (extensor) compartment of forearm: 3 muscles that move the thumb
abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus
2 other muscles of forearm
brachioradialis, supinator
what connects the radius and ulna, what does this separate and what does this provide
interosseous membrane of forearm (fibrous sheet, forming a fibrous joint called a syndesmosis), separating anterior and posterior compartments, providing muscles attachments and ability for forces to be transferred between bones
arterial supply of region, including location of bifurcation
brachial artery -> ulnar and radial arteries (at elbow, at level of radial neck; ulnar is medial, radial is lateral in supine position) -> ulnar descends in anterior compartment of forearm and passes into hand anteriorly (lateral to flexor carpi ulnaris), terminating to form palmar arches; radial descends laterally, lying anteriorly on radial aspect of wrist (crossing floor of anatomical snuff box), then anastomosing with ulnar branches to form palmar arches
ulnar: medial to lateral relationship of wrist joint
flexor carpi ulnaris, ulnar nerve, ulnar artery
through which branches does the ulnar artery supply medial muscles in the anterior forearm
common interosseous artery (bifurcates to form anterior and posterior interosseous arteries; posterior pierces interosseous membrane to run behind it)
what muscle does the radial artery descend the forearm under
brachioradialis
2 major superficial veins of region in supine position, and where they arise from and drain into
cephalic (lateral), basilic (medial), arising from dorsal venous arch on posterior surface of hand; basilic joins venae comitantes to form axillary vein in arm, while cephalic joins axillary vein in axilla -> subclavian vein at 1st rib
what vein connects the cephalic and basilic veins at the level of the elbow
median cubital vein (common site for venupuncture, but is variable in anatomy so blood taken from cephalic or basilic veins)
what deep veins accompany ulnar and radial arteries, and where do they flow into
venae comitantes (more than one vein), flowing into the brachial vein in arm to form axillary vein
3 main nerves of region
ulnar nerve, median nerve, radial nerve
ulnar nerve innovation
C8, T1
ulnar nerve pathway in arm and forearm to medial anterior forearm muscles
no branches in arm, proximally descending in anterior compartment -> distally descends into superficial posterior compartment -> enters forearm between heads of flexor carpi ulnaris -> descends on medial side of forearm -> supplies medial anterior forearm muscles
why is ulnar nerve at risk of damage at level of elbow
lies posterior to medial epicondyle of elbow
medial anterior forearm muscles ulnar nerve innervates
flexor carpi ulnaris, medial portion of flexor digitorum profundus (ring and little finger)
location of sensory supply of ulnar nerve
medial aspect of ventral forearm
where does ulnar nerve lie in wrist
between flexor carpi ulnaris medially and ulnar artery laterally
median nerve innervation
C6,7,8 T1
median nerve pathway in arm and forearm to become principle motor nerve of anterior compartment
no branches in arm, descending in anterior compartment (anterior to elbow lies medially to brachial artery) -> descends into forearm between heads of pronator teres, becoming principle motor nerve of anterior compartment
what is median nerve at risk from as it lies medially to brachial artery, anterior to elbow
damage by supracondylar fractures of humerus
6 forearm muscles median nerve supplies
pronator teres, flexor digitorum superficialis, lateral portion of flexor digitorum profundus (index and middle finger), flexor carpi radialis, pronator quadratus, palmaris longus
where does median nerve lie in wrist
superficially in anterior wrist, between tendons of flexor digitorum superficialis and flexor digitorum profundus, and deep to palmaris longus (if present), before entering hand through carpal tunnel; can be damaged here also
radial nerve innervation
C5,6,7,8 T1
radial nerve pathway in arm and forearm to posterior muscles
lies on humerus in radial groove -> superior to elbow divides into superficial radial nerve (cutaneous sensory) and deep branch of radial nerve -> deep branch of radial nerve descends into forearm between heads of supinator -> becomes posterior interosseous nerve -> ends as pseduoganglion below extensor retinaculum
what is radial nerve at risk from as it lies in radial (spiral) groove of humerus
humeral shaft fractures (can be damaged by injuries to gleno-humeral joint and wrist)
2 muscles supplied by radial nerve in forearm
brachioradialis, extensor carpi radialis longus
2 muscles supplied by deep radial nerve
extensor carpi radialis brevis
6 muscles supplies by posterior interosseous nerve
extensor digitorum, extensor digiti minimi (little finger), extensor carpi ulnaris, abductor pollicis longus, extensor pollicis brevis, extensor indicis
where are superficial forearm muscles attached proximally
common flexor tendon at medial epicondyle (condyles are trochlea (ulna) and capitulum (radius))
what process is present at distal ends of ulna and radius, and why is it important
styloid process, important for muscle attachment and shape of wrist joint
which carpal bone doesn’t articulate with the distal end of either the radius orulna
pisiform (medial so nearest ulna; sesamoid bone - embedded in muscle tendon)
nerve supply of anterior muscles of arm and sensory innervation of lateral forearm, and spinal nerves
supplied by musculocutaneous nerve (C5,6,7); becomes lateral cutaneous nerve of forearm
biceps brachii attachments
proximal attachments of 2 heads to supraglenoid tubule of scapula and coracoid process, merging to form central tendon, with distal attachments to radial tuberosity and aponeurosis which merges with fascia
brachialis attachments
proximal attachment to humerus and distal attachment to coronoid process of ulna
nerve supply of posterior compartment of arm
radial nerve (C7,8)
triceps brachii attachments
proximal attachments of 3 heads to infraglenoid tubercle and posterior humeral shaft, with distal attachment to olecranon process of ulna
general location of flexors (and pronators)
anterior
general location of flexors (and supinators)
posterior
what other “superficial” muscle has a proximal attachment at the common flexor tendon at the medial epicondyle
flexor digitorium superficialis
2 locations where deep or posterior muscles have attachments to
proximal attachments on shafts of ulna and radius, interosseous membrane
location and function of palmar aponeurosis
under skin in palmar region, protecing contents of tendons and vessels beneath it (even if palmaris longus if absent, palmar aponeurosis still present)
what is the flexor retinaculum
band of connective tissue binding tendons, bony features and other contents of wrist to prevent bowing and protecting them
what does the flexor retinaculum form
roof of carpal tunnel
name of muscles moving wrist
carpi muscles
name of muscles moving groups of digits
digitorum
name of muscles moving thumb
pollicis
name of muscle moving index finger
indicis
name of muscle moving little finger
digiti minimi
what muscle must exist if there is a longus
brevis
what muscle must exist if there is a superficialis
profundus
where is the anatomical snuff box and what tendons define it
lateral posterior distal aspect of forearm and wrist when supine; extensor pollicis longus, extensor pollicis brevis, abductor pollicis longus
why is the anatomical snuff box important
radial artery and scaphoid bone present (scaphoid bone frequently damaged, with recurrent blood supply so if fractured can have problems moving wrist)
contents of cubital fossa (anterior to elbow joint)
brachial artery, median nerve, median cubital vein, bicep tendon, fascia, pronator teres, brachioradialis, lymph nodes
where else are lymph nodes located and where do they drain
axillary nodes for draining distal parts of upper limb
what do larger lymphatic vessels run alongside
veins
