NERVE SUPPLY - LOWER LIMB Flashcards
WK 9 (17 cards)
Nervous System
Sensory, motor and glial cells
1. sensory:
- transmit info abt conditions inside + outside the body
2. motor:
- transmit info that controls activity of muscles and glands
3. glial/support:
- prov protection + nutrition
Divisons of the nervous system
CNS + PNS
1. Central Nervous System (CNS):
- process info and controls body functions.
- Brain and spinal cord.
- protected by axial skeleton
eg. thinking, feeling, movement coordination, breathing, HR.
2. Peripheral Nervous System (PNS):
- carries sensory info to the CNS and motor info from the CNS.
- Nerves outside the brain and spinal cord.
- not encased in bone.
eg. sensory input, muscle control, autonomic functions like heart rate and breathing.
Peripheral Nervous System
Cranial + Spinal Nerves
1. cranial nerves:
- brain -> brain stem
- 12 pairs
- support musculoskeletal head + neck
- support viscera of thorax + abdomen
2. spinal nerves:
- from SC
- 31 pairs (8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccycx)
- support structures of the trunk + limbs
Spinal Nerve Formation
Sensory + Motor Structures
Sensory Structures
1. Receptors:
- Detect external stimuli (e.g., touch, pain).
2. Sensory (Afferent) Nerve:
- Carries information toward the spinal cord and brain.
3. Dorsal Root Ganglion:
- Contains cell bodies of sensory neurons.
4. Dorsal Root:
Carries only sensory information into the spinal cord.
5. Spinal Nerve (partially):
- Mixed nerve — carries both sensory and motor fibers.
Motor Structures
1. Motor (Efferent) Nerve:
- Carries commands away from the CNS to muscles and glands.
2. Ventral Root:
- Carries only motor information out of the spinal cord.
3. Effectors:
- Muscles or glands that respond to motor commands.
4. Spinal Nerve (partially):
- Mixed nerve — carries both sensory and motor fibers.
Spinal Nerve Plexus
1. cervical plexus: (C1,2,3,4)
- neck
- diaphragm
2. brachial plexus: (C5,6,7,8,T1)
- upper limbs
3. lumbar plexus: (L1,2,3,4)
- lower limb
4. lumbosacral plexus: (L4,5,S1,2,3)
- lower limb
Sensory and Motor distriubtion
SENSORY:
to skin: (sensation)
- hot, cold, pressure, touch
to joints: (propioception)
- Hiltons law -> if a nerve supplies a muscle then the nerve will also supply that joint
MOTOR:
to muscles:
- makes it contract
to glands:
- INCR secretion of gland
- supply sweat glands to procude sweat
Lumbar and Lumbosacral plexi
Label the Nerves
Lumbar and Lumbosacral plexi
Label the Nerves
PNS - cranial nerves
Label the Nerves
PNS - spinal nerves
Label the Nerves
Lumbar Plexus
Branches of the lumbar plexus
L1,L2,L3,L4,L5
1. FEMROAL (L2,3,4)
motor distribution:
- iiliacus, pectineus, sartorius, quads
sensory distribution:
- skin of A/M thigh, knee + hip joints
course:
- lumbar plexus -> iliopsoas -> deep to inguinal lig -> thru add canal -> musc branch = quads -> articualr branch = A/M patella -> deep to VM -> splits into saphenous n.
2. SAPHENOUS
sensory distribution:
- skin of M leg -> base of great toe
course:
- branch of femoral n. -> cutaneous -> ↓ down M leg -> M malleolus -> M toe (D1)
3. OBTURATOR (L2,3,4)
motor distribution:
- pectineus, AB, AL, ant 1/2 of AM, obt ext, gracilis
sensory distribution:
- skin of M thigh + hip joint
course:
- exists pelvis via obt foramen
4. L FEMORAL CUTANEOUS
sensory distribution:
- skin of L thigh
course:
- runs across iliacus -> deep to inguinal lig
5. GENITOFEMORAL
sensory distribution:
- skin of M thigh + ext genetialia
6. MUSC BRANCHES
motor distribution:
- iliacus, psoas major
sensory distribution:
- hip joint
Lumbosacral Plexus
Branches of the lumbosacral plexus
1. SCIATIC (L4,S1,S2,S3)
motor distribution:
- hamstrings, post 1/2 AM
sensory distribution:
- hip + knee joint
course:
- exists via GSN (below piriformis), travels deep to GM, bw ischial tub + LT, travels deep to BF, splits into CP + Tib around pop fossa
2. P FEMORAL CUTANEOUS
sensory distribution:
- skin of P thigh + leg to mid calf
course:
- exists below piriformis, ↓ w sciatic
3. SUP GLUTEAL N.
motor distribution:
- glute med, glute min, TFL
sensory distribution:
- hip joint
course:
- exists pelvis above piriformis
4. INF GLUTEAL N.
motor distribution:
- glute max
sensory distribution:
- hip joint
course:
- exists pelvis below piriformis
5. MUSC BRANCHES
motor distribution:
- lat rotators ( X obt ext)
sensory distribution:
- hip joint
Sciatic nerve
Branches of the sciatic nerve
L4, S1, S2, S3
1. SCIATIC (L4,S1,S2,S3)
motor distribution:
- hamstrings, post 1/2 AM
sensory distribution:
- hip + knee joint
course:
- exists via GSN (below piriformis), travels deep to GM, bw ischial tub + LT, travels deep to BF, splits into CP + Tib around pop fossa
2. TIBIAL N.
motor distribution:
- P compartment
sensory distribution:
- knee + ankle joint
course:
- branch of sciatic nerve around pop fossa, travels thru pop fossa P to pop vessel, ↓ deep to gastrocs and soleus, ↓ P to M malleolus, in TT split into MPN + LPN
3. MPN
motor distribution:
- abd hall, FDB, FHB, 1st lumbrical
sensory distribution:
- skin of medial 3 + 1/2 digits, corresponding sole and joints in the foot
4. LPN
motor distribution:
- FDMB, add hall, 2-4th lumbricals, interossei, abDM, FA
sensory distribution:
- skin of the lateral 1 + 1/2 digits, corresponding sole and joints in the foot
5. SURAL N
sensory distribution:
- skin of the P/L leg, heel and L skin of the sole
course:
- branch of the tibial and CP nerve -> cutaneous -> travels superficially down P/L leg -> pass P to L malleolus + L foot
6. CP
motor distribution:
- BF (SH)
sensory distribution:
- knee joint, skin of A/P/L leg
course:
- branch of sciatic nerve around pop fossa -> travels L w BF tendon -> wraps around fib neck (A) -> divides into sup and deep peroneal nerves.
7. SUP PERONEAL N.
motor distribution:
- FL, FB
sensory distribution:
- skin of L leg, dorsum of foot (X skin bw D1+2, or ankle joint)
course:
- branch of CP nerve -> ↓ bw FL + FB -> cutaneous in Distal A/L leg -> dorsum of foot
8. DEEP PERONEAL N.
motor distribution:
- ant comp
sensory distribution:
- skin bw digits 1&2, ankle and foot joints
course:
- branch of CP nerve -> ↓ bw TA + EHL-> dorsum of foot bw D1-2
Damage to Peripheral Nerves
Most vulnerable sites
Effects
Most vulnerable sites:
- close to skin
- bw skin + bony projection
- bw retinacula + bone
- on bone
Effects:
- paralysis / paresis
- loss of sensation
- seen ditsal to lesion
Describing Peripheral Nerve Lesions
EG of lesion of the femoral nerve at the ingiunal ligament:
Motor loss, sensory loss, functional motor loss and deformity
Motor loss:
- list of all muscles
eg. quad fem, sartoius, pectinues, (X iliacus = bc above inguinal lig)
Sensory loss:
- description of an area of skin
eg. LOS to med (+ A) thigh, leg, foot
Fucntional motor loss:
- list of motor tasks = effected and how = effected
eg. DCR knee ext, DCR hip flex during gait
Deformity:
- abnormal postures -> imabalnce in muscle activity
Myotomes and Dermatomes
Myotomes
what:
- group of muscles supplied by x1 spinal nerve (both dorsal and ventral rami)
HIP flexion - L2, L3
HIP extension - L4, L5
KNEE extension - extension L3, L4
KNEE flexion - L5, S1
ANKLE dorsiflexion - L4, L5
ANKLE plantarflexion - S1, S2
TOE extension - L5, S1
TOE flexion - S1, S2
Myotomes and Dermatomes
Dermatomes
what:
- area of skin supported by x1 spinal nerve
L1: ↑ A/L thigh -> M prox inguinal region
iliopsoas -> HF
L2: Middle A/L thigh -> M distal inguinal region
iliopsoas, RF, sart -> HF
L3: ↓ A/L thigh -> Distal 1/3 of M knee
VM, VL -> KE
L4: L Distal thigh -> M calf / M malleolus
TA, VL -> Dorsi/Inv + KE
L5: P/L superior gluteal region + A/L lower leg -> dorsum of foot
EHL, glute med/min, TP, FL/B/T -> D1 ext, hip abd, in/ev
S1: P/L 1/2 of glute, thigh, leg, foot, sole
glute max, gastr, soleus, FB/L/T -> PF, HE, ev
S2: P/M 1/2 thigh, leg, foot, sole
hammys, FDL, intrinsic foot -> KF, Dflex
S3+S4: perinuem, skin of ext genitalia, anus
levator ani, coccygeus, ext anal spincter
