Anatomy of Limbs 1.2 - Introduction Flashcards
Describe the development of the upper limb
- Flexors are anterior (forwards movement)
- Extensors are posterior (backwards movement)
Describe the development of the lower limb
- Limb rotates internally (undergoes a permanent pronation resulting in twisting of the dermatome fields)
- Extensors are anterior (forwards movement)
- Flexors are posterior (backwards movement - eg. bend the knee)
Which nerves supply the upper limbs?
C5-T1
Which nerves supply the lower limbs?
L2-S3
What are compartments in limb anatomy?
- Limbs are divided into compartments
- Compartments have distinct functions
- Tend to have the same nerve supply
- Tend to have the same blood supply
List the compartments of the upper limb
- Pectoral girdle muscles
- Intrinsic shoulder muscles
- Anterior arm muscles (flexors)
- Posterior arm muscles (extensors)
- Anterior forearm muscles (flexors)
- Posterior forearm muscles (extensors)
- Intrinsic hand muscles
What do movements of the shoulder involve?
- Movement of the arm relative to the shoulder, and the scapula relative to the chest wall
- Attachments in the neck, anterior chest, back and arm
List the compartments of the lower limb
- Hip abductors (gluteal)
- Hip extensors (gluteal)
- Hip flexors
- Anterior thigh muscles (extensors)
- Medial thigh muscles (adductors)
- Posterior thigh msucles (flexors)
- Anterior leg muscles (extensors)
- Lateral leg muscles (foot evertors)
- Posterior leg muscles (flexors)
- Intrinsic foot muscles
Where do muscles (flexors of the hip) and nerves of the lower limb arise?
- Muscles with attatchments in the abdomen and pelvis are hip flexors
- Nerves supplying the lower limb are from the lumbosacral plexus (L2-S3)
Describe the arterial supply to the upper limb
- Aorta
- Subclavian
- Axillary
- Brachial
- Ulnar and radial
- Hand palmar branches
- Metacarpal and digital arteries
Describe the venous drainage of the upper limb
- Superficial and deep systems
- Dorsal venous arch
- Cephalic (radial side) and basilic (ulnar side) vein, joined by median cubital vein
- Venae comitantes (deep - pair of veins running with the arteries)
- Axillary vein
- Subclavian vein
- SVC
Which vein is not always present?
Median cubital vein - though this vein is often used for venupuncture
Which arteries supply the lower limb?
- Aorta
- Common iliac (external/internal)
- Femoral artery (external iliac becomes this when it passes under the inguinal ligament)
- Popliteal artery (posterior tibial, anterior tibial, peroneal artery, dorsalis pedis)
Describe the venous drainage of the lower limb
Deep
- Anterior and posterior tibial venae comitantes
- Popliteal vein
- Femoral vein
- External iliac vein
Superficial
- Venous arches
- Long saphenous vein (drains into femoral vein at the groin)
- Short saphenous vein (drains into popliteal vein at the popliteal fossa)
What is the femoral triangle?
- Region of the groin where the femoral artery is accessed
- Access for angiograms and angioplasty
- A pulse can be felt
List the important clinical points for lower limb veins
- Perforating veins connecting superficial and deep veins contain a valve that will allow flow only from superficial to deep
- If compromised, blood is pushed to superficial veins causing varicose veins
What are elastic surgical socks for?
- Compress the superficial veins, promoting more vigorous deep venous return
- Immobility of the calf pump can result in deep vein thrombosis due to reduced venous return
What are the nerves of the lower limb?
- Arise from lumbosacral plexus
- Femoral nerve (anterior compartment of thigh)
- Obturator nerve (medial compartment of thigh)
- Sciatic nerve (remaining compartments)
What are the types of innervation?
- Segmental
- Peripheral
Describe segmental supply to the limbs
- C5-T1 upper
- L2-S3 lower
- Plexi for each limb (brachial and lumbosacral)
- Anterior divisions = flexor muscles
- Posterior divisions = extensor muscles
- Anterior and posterior divisions from the anterior ramus
List the prinicples of segmental supplies
- Muscles supplied by two adjacent segments
- Same action on joint = same nerve supply
- Opposing muscles 1-2 segments above or below
- More distal in limb = more caudal in spine
Describe the segmental motor supply to the upper limb
Shoulder
- Abduction C5, adduction C678
- External rotation C5, internal rotation C678
Elbow
- Flexion C56, extension C78
Forearm
-Supination C6, pronation C78
Wrist
- Flexion C67, extension C67
Long tendons to hand
- Flexion C78, extension C78
Intrinsic hand
T1
What is compartment syndrome?
- Muscle compartments are separated by fibrous walls
- Ischaemia caused by trauma-induced increased pressure in a confined limb compartment
- Commonly the anterior, posterior and lateral compartments of the leg
- 50-60mmHg collapses small vessels (Normal 25mmHg) and reduced blood flow
- Acute is trauma, chronic is exercise induced. If surgery not performed, all of the muscles can be destroyed
Describe segmental motor supply to the lower limb
Hip
- Flex L23
- Extend L45
Knee
- Extend L34
- Flex L5, S1
Ankle
- Dorsiflex L45
- Plantarflex S12
Where is the arm anatomically?
Between the shoulder and the elbow
Where is the leg anatomically?
Between the knee and the ankle - above this is this thigh
Compare segmental supply with cutaneous sensory
Different peripheral nerves from the same segment supply different areas of the skin. Spinal root supply is the addition of all of those peripheral nerves together
How are nerves assessed in the limbs?
- Motor function
- Sensory function
- Reflex function
- Autonomic function
What is inversion and eversion?
- Eversion movement of the foot outward
- Inversion movement of the foot inward
