NERVE SUPPLY - LOWER LIMB Flashcards
WK 9
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
- 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. - 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: (C1,2,3,4)
- 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
1. femoral (L2,3,4)
motor distribution:
- iiliacus, pectineus, sartorius, quads
sensory distribution:
- skin of A and med thigh, knee + hip joints
2. saphenous
motor distribution:
- X
sensory distribution:
- skin of med leg to base of great toe
3. obturator (L2,3,4)
motor distribution:
- pectineus, AB, AL, ant 1/2 of AM, obt ext, gracilis
sensory distribution:
- skin of med thigh + hip joint
4. lateral femoral cutaneous
motor distribution:
- X
sensory distribution:
- skin of lat thigh
5. gentiofemoral
motor distribution:
- X
sensory distribution:
- skin of med thigh + ext genetialia
6. muscular branches
motor distribution:
- iliacus, psoas major
sensory distribution:
- hip joint
Lumbosacral Plexus
Branches of the lumbosacral plexus
1. posterior femoral cutaneous
motor distribution:
- X
sensory distribution:
- skin of P thigh + leg to mid calf
2. superior gluetal nerve
motor distribution:
- glute med, glute min, TFL
sensory distribution:
- hip joint
3. inferior gluteal nerve
motor distribution:
- glute max
sensory distribution:
- hip joint
4. muscular branches
motor distribution:
- lat rotators ( X obt ext)
sensory distribution:
- hip joint
5. sciatic (L4,S1,S2,S3
motor distribution:
- hamstrings, post 1/2 AM
sensory distribution:
- hip + knee joint
Sciatic nerve
Branches of the sciatic nerve
1. Tibial
motor distribution:
- gastrocs, soleus, plantaris, popliteus, TP, FHL, FDL
sensory distribution:
- knee + ankle joint
2. medial plantar
motor distribution:
- abd hall, FDB, FHB, 1st lumbrical
sensory distribution:
- skin of medial 3 + 1/2v digits, corresponding sole and joints in the foot
3. lateral plantar
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
4. sural
motor distribution:
- X
sensory distribution:
- skin of the L + post leg, heel and L skin of the sole
5. common peroneal
motor distribution:
- X (but see branches)
sensory distribution:
- knee joint, skin of A P and lat leg (adj to knee joint)
6. superficial peroneal
motor distribution:
- peroneous L + B
sensory distribution:
- skin of L leg, dorsum of foot (X skin bw digits 1 and 2, or ankle joint)
7. deep peroneal
motor distribution:
- TA, EHL, EDL, PT, EDB
sensory distribution:
- skin bw digits 1&2, ankle and foot joints
8. sural
motor distribution:
- X
sensory distribution:
- skin of the L & P leg, heel + L skin of the sole
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
