Brachial and Lumbo-Sacral Plexuses Flashcards
What does the anterior wall of the axilla consist of?
+ Pectoralis major
+ Pectoralis minor/subclavius
+ Clavipectoral fascia (deep)
What is pectoralis major palpable as?
The anterior axillary fold
What is the movement of the humerus at the GH joint?
+ Adduction
+ Medial rotation
+ Flexion
+ Extension
Where does pectoralis minor attach?
+ Ribs 3-5
+ Coracoid process of the scapula
What supplies pectoralis minor?
Medial pectoral nerves
Where does the subclavius attach?
from superior border of 1st rib to inferior surface of middle 1/3 of clavicle
What is the medial wall of the axilla composed of?
+ Ribs and intercostal spaces
+ Serratus anterior
Where does serratus anterior attach?
Ribs 1-9 to medial margin of scapula
What are the movements and functions of serratus anterior?
+ Superior external rotation of scapula
+ Draws scapula internally and forwards
+ Lowers the arm from a raised position
+ Elevation of ribs
What parts of the biceps and coracobrachialis are sometimes included in the contents of the axilla?
The proximal parts
What structures form the lateral wall of the axilla?
+ bicipital wall
+ proximal parts of biceps and coracobrachialis
What structures from the posterior wall of the axilla?
+ subscapularis
+ latissimus dorsi
+ teres major
+ scapula
where does the radial nerve pass?
posteriorly through lower triangular space with profunda brachii artery
what does the radial nerve supply?
+ all extensor muscles of arm and forearm
+ posterior skin of arm, forearm and hand
what are the roots of the radial nerve?
C5-8, T1
what are the roots of the axillary nerve?
C5-6
where does the axillary nerve pass?
through quadrilateral space and lies on surgical neck of humerus with posterior circumflex humeral artery
what does the axillary nerve supply?
+ deltoid
+ teres minor
+ skin over lower part of deltoid
what are the roots of the musculocutaneous nerve?
C5-7
where does musculocutaneous lie?
- it pierces coracobrachialis
- travels between brachialis and biceps brachii
what does musculocutaneous supply?
flexor compartment of arm (BBC)
- biceps brachii, brachialis, coracobrachialis
what does muculocutaneous become in the forearm?
lateral cutaneous nerve
what are the roots of the median nerve?
C5-8 (lateral cord)
T1 (medial cord)
where does the median nerve lie?
in the cubital fossa - travels with brachial artery
what does the median nerve supply?
+ all flexor muscles of forearm (except 1.5)
+ thumb (thenar) muscles except 1 and lateral 2 lumbricals
+ skin over lateral palm
+ latter 3 1/2 digits including nail beds
what are the roots of the ulnar nerve?
C8, T1
where does the ulnar nerve lie?
passes posterior to the elbow
what does the ulnar nerve supply?
\+ 1.5 flexors of forearm \+ majority of intrinsic muscles in hand (1 thenar muscle, all hypothenar and interosseal muscles and medial 2 luumbricals) \+ skin over palm \+ medial 1.5 digits
what is caused by a traction injury to the upper trunk (C5, C6)?
Erb-Duchenne Palsy/Erb’s Paralysis
what are symptoms of Erb-Duchenne Palsy?
+ paralysis of muscles in arm and shoulder (deltoid, biceps, brachialis)
+ loss of sensation to lateral forearm
what is the presentation of Erb-Duchenne Palsy?
+ “waiter’s tip position”
+ hanging limb
(adducted shoulder, medial rotation of arm, elbow extended)
what is caused by a traction injury to the lower trunk (C8, T1)?
Klumpke’s Palsy/Paralysis
what are the main causes of Erb-Duchenne Palsy?
+ high energy trauma (motorcycle/horse)
+ during birth (shoulder dystocia)
what are the main causes of klumpke’s palsy?
+ during birth if limb pulled excessively
+ breaking a fall from height
what are the symptoms of klumpke’s palsy?
+ paralysis of:
- intrinsic hand muscles
- flexor muscles of wrist and fingers
- forearm pronator
+ loss of sensation to medial forearm and little finger
how does klumpke’s palsy present?
claw hand (wrist and fingers flexed, forearm supinated)
what are the roots of the lumbar plexus?
L1-4
what are the roots of the sacral plexus?
L4-S4
where is the lumbar plexus located?
+ within psoas major
+ anterior to transverse process of lumbar vertebrae
which nerves supply the lower limb in the lumbar plexus?
\+ ilioingual \+ lateral cutaneous of thigh \+ genitofemoral \+ femoral \+ obturator
what are the boundaries of the femoral triangle?
BASE: inguinal ligament
APEX: sartorius
MEDIAL: adductor longus
what are the roots of the femoral nerve?
L2-4
what does the floor of the femoral triangle consist of?
pectineus and iliopsoas
what is enclosed within the femoral sheath?
femoral artery and vein
what does the femoral nerve supply?
+ some anterior thigh muscles (hip flexors, knee extensors)
+ skin of anteromedial thigh and medial leg and foot
what is the terminal branch of the femoral nerve?
saphenous nerve
where is the sacral plexus located?
+ surface of posterior pelvic wall
+ anterior to piriformis muscle
which nerves supply the lower limb in the sacral plexus?
+ superior gluteal
+ inferior gluteal
+ sciatic
+ posterior femoral cutaneous
what are the roots of the sciatic nerve?
L4-5, S1-3
what muscles does the sciatic nerve supply?
+ biceps femoris, and semitendinosus with semimembranosus
where does the sciatic nerve branch?
at the apex of the popliteal fossa, occasionally near piriformis
what are the roots of the tibial nerve?
L4-5, S1-3
which is the larger of the two branches of the sciactic nerve?
tibial
where does the tibial nerve lie?
+ descends in popliteal fossa
+ passes posteriorly and inferiorly to medial malleolus
what does the sciatic nerve supply?
+ posterior muscles in leg and knee joint: thigh extensors, leg flexors) (hamstring muscles)
+ skin of posterolateral leg, sole of foot and lateral foot
what are the roots of the common fibular/peroneal nerve?
L4-5, S1-2
where does the common fibular/peroneal nerve lie?
descends laterally in the popliteal fossa towards lateral compartment of leg
what does the common fibular/peroneal nerve supply?
+ short head of biceps
+ muscles in anterior and lateral leg
+ skin of upper lateral leg, lower posterolateral leg, anterolateral leg and dorsum
what joint movements are used to test C5 myotome?
abduction of shoulder
what joint movements are used to test C6 myotome?
flexion of the arm at elbow
what joint movements are used to test C7 myotome?
extension at the elbow
what joint movements are used to test C8 myotome?
flexion of fingers
what joint movements are used to test T1 myotome?
abduction and adduction of fingers
what is the function of the axilla?
gateway to upper limb
what is a distinguishing feature of medial pectoral nerve?
can be seen piercing pectoralis minor
what nerves are branches of the posterior cord?
- radial
- axillary
which nerve does not supply anything in the arm?
median nerve
which nerve does not supply anything in the arm?
median nerve
where does the sciatic nerve enter the gluteal region?
inferior to piriformis (infrapiriform space?greater sciatic foramen)
what is the origin of pec major?
- medial half of clavicle
- anterior surface of manubrium of sternum
- anterior surface of body of sternum
- ribs 1-6 costal cartilage
- aponeurosis of external abdominal oblique
what is the insertion of pec major?
lateral lip of intertubercular sulcus of humerus
what nerve supplies pec major?
lateral and medial pectoral nerves