Overview of the limbs Flashcards
What is the axial skeleton?
The central skeleton, consisting of the spinal column, skull and the thoracic cage
What is the appendicular skeleton?
The rest of the skeleton – all the limb skeletons are part of the appendicular skeleton
Which spinal segments are the upper limbs associated with?
C5-T1
Which spinal segments are the lower limbs associated with?
L1/2-S3
In the upper limbs are the flexors and extensors anterior or posterior?
flexors - anterior
extensors - posterior
In the lower limbs are the flexors and extensors anterior or posterior?
flexors - posterior
extensors - anterior
LIMB INTERNALLY ROTATES DURING DEVELOPMENT
Describe lower limb rotation during development
During development, as the limb buds grow out, they maintain the general arrangement of the segments
But, there is internal rotation below the hip region (in the upper to mid thigh)
Therefore, everything that should be at the front is at the back, and vice versa
What do limb compartments share?
nerve supply and blood supply
What does each compartment have?
A distinct function - e.g. extensor, flexor, both
What are the compartments of the upper limb?
Pectoral (= chest) girdle muscles
Intrinsic shoulder muscles
Anterior (upper) arm muscles – flexors
Posterior (upper) arm muscles – extensors
Anterior forearm muscles – flexors
Posterior forearm muscles – extensors
Intrinsic hand muscles
What is the forearm made of (bones)?
ulna and radius
What are the writs bones called?
carpals
What is the clavicle attached to?
manubrium
What is the only joint of the upper limb with the trunk and what kind of joint is it?
- The sternoclavicular joint is the only joint of the upper limb with the trunk (the pivot point)
What are the bones of the digit?
metacarpals and phalanges
What is the upper arm bone?
humerus
What are some muscles of the back?
trapezius
deltoid
latissimus dorsi
What does movement of the shoulder involve?
Movements of the shoulder involve both movements of the arm relative to the scapula at the shoulder joint, and movements of the scapula relative to the chest wall.
Muscles acting on the shoulder joint have attachments in the neck, anterior chest, back and arm.
What is the collective name of muscle attached to the shoulder blade?
rotator cuff muscles
What are the compartments of the lower limbs?
Hip abductors (Gluteal)
Hip extensors (Gluteal)
Hip Flexors
Anterior thigh muscles – extensors
Medial thigh muscles – adductors
Posterior thigh muscles – flexors
Anterior leg muscles – extensors (dorsiflexors)
Lateral leg muscles – foot evertors
Posterior leg muscles – flexors (plantarflexors)
Intrinsic foot muscles – variety of functions
What is the main thigh bone?
femur - very large head
What does the head of the femur fit into?
acetabulum
What does the distal end of the femur articulate with?
tibia
What is the patella?
knee cap
What are the two bones of the lower leg?
tibia and fibula
What do the distal ends of the tibia and fibula form?
ankle joint
At the ankle in standing position what is the main weight bearing bone in the lower leg?
tibia
What are the main muscles of the thigh?
quadriceps (4 heads)
What do the quadriceps attach to and what do they do?
tibia via the patella - main knee extensor
What is an anterior leg muscle?
tibialis anterior
What is the biggest gluteal muscle (buttock region)?
gluteus maximus
What are some posterior leg muscles?
hamstrings and calf muscles
Where are some muscle of the upper and lower limb attached?
- Some of the muscles of the upper limb have attachments that are low down in the back
- There’s a similar phenomenon in the lower limbs – flexors of the hip joint have attachments higher up
- The flexors of the hip joint have attachments up in the abdomen, almost to the thorax
- These muscles are the psoas and iliacus
What is the iliopsoas and where does it attach and what does it do?
- Together the iliacus and psoas form the iliopsoas, which crosses the hip joint and attaches to the iliac tuberosity
- When the muscles contract, they flex the hip
What is the thick fibrous membrane joining the tibia and fibula?
interosseous membrane - seperates the anterior and posterior compartments
(other membranes seperate the lateral and posterior compartments)
Which muscles give bulk and shape to the calf?
soleus and gastrocnemius
What is an issue regarding blood supply to the limbs?
they are far from the heart so the distance blood has to travel is long
What is the arterial supply to the upper limb?
- Aorta
- Subclavian artery (supply to both right and left upper limbs) – pulse
- When the subclavian artery enters the axilla, it becomes the axillary artery – pulse
- Continues as the brachial artery (pulse), and crosses the anterior of the elbow joint
- The brachial artery divides to form the ulnar (medial) and radial (lateral) arteries (pulses)
- Radial and ulnar arteries anastamose to form the hand arches – superficial and deep arches
- This becomes the metacarpal and digital arteries
Describe the venous drainage for the upper limb
Superficial and deep systems
- deep is same as arterial supply
- in distal parts of limbs there are not single veins usually pairs called venae comitantes
- venae comitantes -> axillary vein -> subclavian vein ->
superior vena cava
- superficially there are dorsal venous arches which give rise to the cephalic vein (radial side) and basilic vein (ulnar side)
Describe the drainage of the cephalic and basilic vein
cephalic
- into axilla region
basilic
- merges with venae comitants to from axillary vein -> subclavian -> SVC
Which veins are commonly used for insertion of a venous line?
Superficial veins in the region of the Cubital Fossa - when present the medial cubital vein (links the basilic and cephalic vein)
Describe the arterial supply to the lower limb
- The aorta bifurcates to form the common iliac arteries (right and left) – main supply to the lower limbs
- Common iliac arteries -> Internal and external iliac arteries
- The external iliac artery provides most of the supply for the lower limb
- The external iliac crosses beneath the inguinal ligament to become the femoral artery (pulse). Deep femoral artery is a branch
- The femoral artery continues down the thigh, behind the knee to form the popliteal artery (pulse)pulse)
What are the branches of the popliteal artery?
- Posterior tibial artery (pulse)
- Anterior tibial artery (pulse)
- Peroneal artery
- The anterior tibial artery rise rise to the dorsalis pedis
What is the use of pulse in the foot?
efficiency of blood supply to the distal parts of the limb
Describe venous drainage of the lower limb
Deep System of Venous Drainage – venous return follows arterial supply
- Anterior & Posterior tibial venae Comitantes
- Popliteal Vein -> femoral Vein -> external iliac vein
Superficial system of Venous Drainage
- Venous arches
- The venous arches give rise to the long saphenous vein
- Short saphenous vein
Where do the great and small saphenous veins arise from?
venous network of dorsum of foot
Where does the long and short saphenous veins drain?
long - blood drains into the femoral vein in groin
short - blood drains into the popliteal vein behind the knee -> femoral vein
What is the importance of the femoral triangle?
Is the region of the groin where the femoral artery is accessed e.g. access to the cardiac vessels to carry out angiograms and angioplasty. A pulse can be felt in this area. Catheters can be put into the big vessels of the femoral triangle, to access the heart chambers.
What can cause varicose veins?
Perforating veins connecting superficial and deep veins contain a valve that will allow flow only from superficial to deep. If such a valve is compromised, blood is pushed from deep to superficial veins leading to varicose veins.
Why do patients on surgical wards wear special socks?
Prevent DVT
Compression stockings compress the superficial veins, and push venous return deeply to produce vigorous venous return.
What is the calf pump?
In the leg, the deep vessels are sandwiched between layers of calf muscles. During walking and running, contractions of these muscles squeeze the thin-walled veins and push blood up the veins: the calf pump. Immobility (e.g. a long plane journey) means less efficient venous return from the foot and leg.
Describe the distribution of spinal nerves to the neck, upper limbs, trunk, lower limb and perineum
C1-4: neck C5-T1: upper limb T2-L1: trunk L2-S3: lower limb S2-C2: perineum
What is a plexus?
A plexus is a region where spinal nerves merge, swap fibres and form new branches. The nerves from different spinal roots merge.
Which plexus supplies the upper limb?
brachial
Which nerve supplies the anterior compartment of the thigh and what plexus does it come from?
- femoral nerve
- from the lumbosacral plexus
- comes under the inguinal ligament
Which nerve supplies the medial compartment of the thigh?
the obturator nerve (enters through obturator of pelvis)
What are the two kinds of innervation?
segmental of peripheral
Describe the segmental motor supply to the limbs
Groups of motor nerve cell bodies in the spinal cord supply particular muscles
C5-T1 = upper limb, L2-S3 = lower limb
There are plexi for each limb
- Anterior divisions of spinal nerves give rise to the flexor muscles
- Posterior divisions of spinal nerves give rise to the extensor muscles
Describe the principles of segmental motor supply to the limbs
- Muscles are often supplied by two adjacent segments
- Muscles with the same action on joint will have the same nerve supply
- Opposing muscles are usually 1-2 segments above or below
- The more distal in limb (the further away from the trunk) = the more caudal in spine the nerve is
List the segmental motor supply to the upper limb - shoulder, elbow, forearm, wrist, long tendons to hand and intrinsic hand
Shoulder:
- Abduction C5, adduction C6-C8
- External rotation C5, internal rotation C6-C8
Elbow:
- Flexion C5 and C6
- Extension C7 and C8
Forearm:
- Supination (outward rotation) C6
- Pronation C7 and C8
Wrist:
- Flexion C6 and C7
- Extension C6 and C7
Long tendons to hand: - Flexion C7 and C8
- Extension C7 and C8
Intrinsic hand: T1
List the segmental motor supply to the lower limb - hip,knee and ankle
Hip: Flexion L2 and L3, extension L4 and L5
Knee: Extension L3 and L4, flexion L5 and S1
Ankle: Dorsiflex L4 and L5, plantarflex S1 and S2
Describe the dermatomes of the upper and lower limbs
In the upper limb, dermatomes are relatively well organised in relation to the spinal origins
In the lower limbs, there are oblique fields (due to twisting during development)
What is cutaneous sensory innervation?
Refers to the nerves that take fibres from the spinal root to the skin. Due to swapping over at plexi, they may have fibres from other roots as well
Where is segmental innervation from?
a single spinal root
List the sensory segmental supply to the upper limb (dermatomes)
C4: infraclavicular region
C5: lateral arm
C6: lateral forearm and thumb
C7: middle finger
C8: little finger and medial forearm
T1: medial arm
T2: axilla and trunk
T4: nipple
T10: umbilicus
T12: lower abdomen
What is compartment syndrome?
Muscle groups in confined compartments are separated by thick, fibrous septa. If you got swelling in one of these compartments, you would get compression -> COMPARTMENT SYNDROM
Where does compartment syndrome commonly occur?
anterior, posterior and lateral compartments of the leg
What pressure is needed to collapse vessels?
50-60 mmHg
What can cause compartment syndrome?
Acute compartment syndrome (trauma associated)
Chronic compartment syndrome (exercise-induced)
What does acute compartment syndrome require and why?
emergency fasciotomy to prevent death of muscles and other tissues - skin opened and muscle compartment to relieve pressure
