Brachial And Lumbosacral Plexuses Flashcards
What is the axilla
Important space between lateral wall of thorax and humerus
Acts as gateway to upper limb bounded by ribs, scapula and clavicle
Lines of the axilla
Anterior axillary line is in front of shoulder and down
Mid axillary line is straight through
Posterior is behind
Axillary fossa is the underarm
Anterior wall of the axilla
Pectoralis major
Underneath pectoralis minor
And underneath clavipectoral fascua (deep)
What makes up the anterior axillary fold
Pectoralis major
Function of pectoralis major
Movement of humerus at GH joint
Adduction
Medial rotation
Flexion of extended arm
Extension of flexed arm
Pectoralis minor attachments
Ribs 3-5 to coracoid process of scapula
Function of pectoralis minor
Stabilise scapula on thorax
What supplies pectoralis minor
Lateral and medial pectoral nerves
What is clavipectoral fascia continous with and where does it attach to
Neck fascia
Attaches to inferior skin of the armpit
What does clavipectoral fascia split to enclose
Pectoralis minor and subclavius
Subclavius attachments
1st rib costalcartilae to inferior surface of clavicle
Function of subclavius
To draw clavicle inferiorly
What muscles would you expect to see on chest
Deltoid at shoulder
Pectoralis major across chest with pectoralis minor underneath
Serratus anterior inferior to pectoralis major
Sternocleidomastoid muscle from sternum around neck
What is the medial wall of axilla made up of
Ribs and intercostal spaces
Serratus anterior
Where does serratus anterior attach
Ribs 1-8 to medial border of scapula
Function of serratus anterior
Protraction and lateral rotation of the scapula
Holds scapula on thoracic wall
What makes up lateral wall of axilla?
Narrow it is the bicipital groove
Proximal parts of biceps and coracobrachialis
Function of coracobrachialis
Flexes shoulder
Posterior wall of axilla
Subscapularis
Latissimus Dorsi
Teres major
Scapula
What do ventral rami of spinal nerves contain
Sensory
Motor
Sympathetic nerves
What forms the nerve plexuses
Spinal nerves with sensory motor and sympathetic nerves
What does the brachial plexus supply and via which ventral rami
Supplies upper limbs via ventral rami of c5-t1
What does the lumbar and sacra (lumbosacral) plexuses supply and via which rami
Lower limbs via ventral rami of L1 - S4
What does the dorsal ramus supply
Erector spinae muscles
What does ventral rami supply
Body wall and limb plexuses
Ventral rami come from which part of spinal cord
Cell body is in the anterior grey horn of the spinal cord
Where is axillary artery in relation to brachial plexus etc
Axillary artery goes under clavicle with brachial Lexus and is medial to T1 and branches over T1
Roots of brachial plexus
Ventral rami of spinal nerves
Lie in neck close to intervertebral foraminae
Long thoracic nerve passes inferiorly through apex f axilla on the ribs to supply serratus anterior (motor only)
Dorsal scapula passes posteriorly to the back to supply levator scapulae and rhomboids motor only
Trunks of brachial plexus
There are 3 superior middle and inferior
Lie in posterior triangle of neck posterior to scalenus anterior and subclavian artery
Branches from upper superior only
Suprascapular
Nerve to subclavius
Where is nerve to subclavius situated
Inferior to supply subclavius
Where is subscpaular nerve situated
Posterior to scapular region via suprascpaular notch to supply supraspinatus, infraspinatus
6 divisions of the brachial plexus
Each trunk gives rise to posterior and anterior
Lies posterior to clavicle and there are no branches
Anterior divisions supply muscles of anterior axilla, flexor muscles of limb and skin that overlies muscles
Posterior Division supply muscles of posterior wall of axilla, extensor muscles and skin that overlies those muscles
Cords of brachial plexus
Lie in axilla around 2nd part of axillary artery and named according to position relative to artery
Lateral medial and posterior to artery
The lateral cord has one branch the lateral pectoral nerve which passes anterior to supply pec major and minor
Posterior cord has 3 branches
Which landmark marks location subclavian artery becomes axillary artery
1st rib
Posterior cord has what branches
Radial and axillary
Which artery does radial nerve travel with and where does it supply
Profunda brachii artery
Supplies extensor muscles of arm and forearm and posterior skin of arm forearm and hand (mixed motor and sensory)
Where is axillary nerve located and what does it supply
C5 and c6
Surgical neck humerus
Posterior circumflex artery
Deltoid and teres minor and skin over lower part of deltoid
All terminal divisions of brachial plexus carry what
Both motor and sensory fibres
Musculotaneous branch is where and Carries what
C5 c6 c7
Pierces coracobrachialis and supplies flexor compartment of arm
Becomes lateral cutaneous nerve of forearm
Lateral root of median nerve
C6 c7
Joins with medial root to form median nerve
Medial root of median nerve
C8 T1
Joins with lateral root to form median nerve
Median nerve
C6 7 8 T1
Travels with brachial artery
Most medial structure in cubital fossa
Supplies flexor muscles of forearm except 1half LOAF
Hand thumb muscles and lateral 2 Lumbricals
Skin over lateral palm and lateral 31/2 digits and nail beds
Ulnar nerve
Posterior to elbow
Supplies 11/2 flexors of forearm
Supplies intrinsic muscles in hand and skin over palm and medial 11/2 digits
Traction injury to upper trunk (c5c6)
Erb-Duchenne Palsy or Erbs paralysis
High energy trauma motorcylcle/birth
Paralysis in muscles of arm and shoulder such as deltoid biceps and brachialis
Loss of sensation to lateral forearm
Presents as waiters tip position hanging limb (addicted shoulder, medial rotation of arm, elbow extended)
Traction injury to lower trunk (c8t1)
Klumpke’s palsy / paralysis
Occur birth if limb pulled
Paralysis of intrinsic hand muscles, flexor muscles of wrist and fingers, forearm pronator
Loss of sensation to medial forearm and little finger
Claw hand (wrist and fingers flexed and forearm supinated)
Lumbar and sacral plexus is made up on nerves
Lumbar plexus L1-4
Sacral L4-S4
Where does lumbrar and sacral plexuses innverate
Lower limb
Pelvis and perineum
What are the largest nerves from the plexuses entering the thigh
Femoral nerve L2-4
Sciatic nerve L4-S3
Where is lumbar plexus located
Within psoas major muscle anterior to transverse processes of lumbar vertebrae
Which nerves supply the lower Limb
Ilioinguinal Lateral cutaneous of the thigh Genitofemoral Femoral (s and m) Obturator (s and m)
What are the base apex and medial aspects of the femoral triangle
Inguinal ligament base
Sartorial muscle laterally apex
Adductor longus muscle medial
Muscular floor of triangle is pectineus medially and iliopsoas laterally
Roof is fascia lata
Within the femoral triangle
Lateral - femoral nerve (l2-4)
Middle - femoral artery
Medial - femoral vein
What does the femoral sheath enclose
Femoral artery and vein NOT the nerve
The femoral nerve
Supplied by l2,3,4
Latest branch descending in abdomen through pelvis to mid point of inguinal ligament
Behind inguinal ligament to thigh
Passes through femoral triangle
Articular branches to hip and knee joints
Terminal cutaneous branch is the saohenous nerve which continues with artery and vein through adductor canal to leg
What does femoral nerve supply
Anterior thigh muscles (hip flexors, knee extensor) and skin of anteromedial thigh and medial leg and foot
Sacral plexus
Surface of posterior pelvic wall anterior to piriformis muscle
Superior gluteal, inferior gluteal and sciatic(ms) and posterior femoral cutaneous nerves supply lower limb
Also has smal branches such as nerve to piriformis, obturator internus and quadratus femoris
Sciatic nerve
L4,5,S1,2,3
Greater sciatic foramen
Supplies no structures in gluteal region however
Runs ndeep to gluteus maximus midway between ischial tuberosity and greater trochanter behind hip joint
What does sciatic nerve supply
Posterior thigh muscles
All of leg and foot muscles
Skin to most of leg and foot via two branches tibial and common fibulae
Where does sciatic nerve branch (bifurcation)
Apex of popliteal fossa
Can branch near piriformis too
Tibial branch
From sciatic
Descends in politest fosssa and posterior to leg to foot passing posteriorly and inferiorly to medial mallelous
What does tibial nerve supply
Posterior muscles in leg and knee joint skin of posterlateral leg
Sole of foot
Lateral foot
Common fibulae (perineal)
L4,5,S1,2
Smaller branch
Descends laterally in popliteal fossa towards lateral compartment of leg before branching
What does common fibulae nerve supply
Short of biceps and muscles in anterior and lateral leg
Skin of upper lateral leg
Lower poser player all leg, anterolateral leg and dosrum of foot
Myotomes - Proximal and distal muscles are supplied
Proximal muscles supplied by neurones from superior roots deltoid c5c6
Distal muscles supplied by neurones from inferior roots intrnic muscles of hand T1
Muscles that share action in joint are supplied by neurones originating form same spinal segment
Deltoid c5c6
Supraspinatus c5c6
Antagonistic muscles supplied by two segments usually run in numerical sequence
Flexion elbow c5c6
Extension elbow c7c8
Abduction of shoulder controlled by
C5
Flexion of elbow controlled
C6
Extension elbow controlled
C7
Flexion of fingers controlled
C8
Abduction and adduction of fingers
T1
Biceps tendon tap tests
C6
Triceps tendon tap tests
C7
How are sensory neurones delivers
By peripheral cutaneous nerves
C5 dermatomes test
Upper lateral side of arm
C6 dermatomes test
Pad of thumb
C7 dermatomes test
Pad of index finger
C8 dermatomes test
Pad of little finger
T1 dermatomes test
Skin on medial side of elbow
What are dermatomes used for
Test for spinal cord damage and can help to determine level of damage
