Class 10 *NOT ON TEST 2 Flashcards
What is a Peripheral Nerves?
Reside outside your brain & spinal cord. Relay information between brain & rest of your body. 31 peripheral nerves that reside with the body. Generally, peripheral nerves have motor & sensory capabilities.
When a peripheral nerve has motor capabilities it….
Innervates muscles and/or group of muscles to communicate to central nervous system to move that muscle in its intended motion.
When a peripheral nerve has sensory capabilities it…..
Innervates an area of skin. As a result, when area is “activated” via sensory receptors, it conveys information via CNS about that area.
What does it mean when a nerve is said to have articular capabilities/branches?
It means it innervates parts of that associated joint capsule. Articular branches give proprioceptive feedback about that joint.
What is the Lumbosacral Plexus?
Network of nerve fibers, derived from roots of lumbar & sacral spinal nerves that branch out to form nerves supplying lower limb. In lumbar region, corresponding spinal nerves unite to form lumbosacral plexuses, from which arise nerves of lower limbs. Lumbosacral plexus includes nerves that arise from both lumbar plexus & sacral plexus.
What is the Obturator Nerve?
Mixed nerve, arises from ventral (anterior) rami of spinal nerves L2-L4. These roots unite near iliac crest, forming obturator nerve. Nerve descends through fibers of psoas major muscle & emerges from its medial border near pelvic brim to enter lesser pelvis. Here, nerve runs on lateral wall of
pelvis. Then, exits pelvis by passing through obturator canal &
to enter medial compartment of thigh.
What is the function of the Obturator Nerve?
Provide motor innervation to all medial muscles of thigh:
- adductor longus
- adductor brevis
- gracilis
- obturator externus
- ischiocondylar part of adductor magnus.
Nerve provides sensory innervation to skin over proximal part of medial thigh
Articular Innervation: Articular branch for hip & knee joints.
What is the Femoral Nerve?
largest branch of lumbar plexus. Arises from posterior cords of lumbar plexus (L2-L4) & provides motor innervation to anterior thigh muscles.
Femoral nerve emerges from lower lateral border of psoas major. Descends beneath midpoint of inguinal ligament to enter femoral triangle.
Femoral triangle is formed by lateral border of adductor longus, medial border of sartorius & inguinal ligament (pectineus & illiopsoas forming floor). Contains, femoral nerve, artery & vein.
What is the function of Femoral Nerve?
Motor Innervation:
Femoral nerve innervates:
- Illiacus
- Pectineus
- Sartorius
- Rectus femoris
- Vastus medialis
- Vastus lateralis
- Vastus intermedius
Sensory Innervation:
Anterior division of femoral nerve gives rise to nerves that supply sensation to skin over anterior & medial region of thigh.
Saphenous nerve forms terminal branch of femoral nerve & is also longest nerve in body. Descends into adductor canal. Instead, it emerges on Medial side of knee to supply sensation to skin over region of medial knee.
Articular Innervation:
In addition to providing cutaneous innervation, femoral nerve also provides articular branches that innervate capsules of hip & knee joints, & allow for proprioceptive feedback about joints
What is the Sciatic Nerve?
Terminal branch of sacral plexus. Formed from both anterior & posterior divisions of anterior (ventral) rami of spinal nerves L4 through S3. Anterior branches of these five spinal nerves meet & converge in posterior pelvic region to form single large nerve. Sciatic nerve descends posteriorly & leaves pelvis through greater sciatic foramen. Passes inferior/superior/through to piriformis.
Terminal branch of sacral plexus. Formed from both anterior & posterior divisions of anterior (ventral) rami of spinal nerves L4 through S3. Anterior branches of these five spinal nerves meet & converge in posterior pelvic region to form single large nerve. Sciatic nerve then descends posteriorly & leaves pelvis through greater sciatic foramen. Passes inferior/superior/through to piriformis muscle.
On its course through posterior thigh, sciatic nerve gives off several small motor muscular branches that innervate several muscles of thigh (muscles of posterior compartment, ischial portion of adductor magnus).
At the apex of popliteal fossa, sciatic nerve terminates by dividing into two terminal branches which are?
1) Tibial nerve
2) Common fibular (peroneal) nerve
What is the Tibial Nerve?
Continues course of sciatic nerve & descends down through posterior aspect of leg as far as heel of foot. More specifically, tibial nerve passes through center of popliteal fossa & runs below tendinous arch of soleus. Continues its course in neurovascular bundle through posterior leg compartment & passes through tarsal tunnel. When it reaches foot, tibial nerve divides into two terminal branches that innervate majority of foot muscles.
What is the common fibular (peroneal) nerve?
Courses laterally towards head of fibula. When it reaches anterior compartment of leg, nerve divides underneath fibularis longus muscle into two nerves. Superficial branch supplies lateral compartment of leg, while deep branch supplies anterior compartment of leg & medial aspect of foot.
Motor Innervation: Sciatic nerve provides direct motor supply for muscles of posterior thigh via small muscular branches. These muscles include?
- Biceps femoris
- Semimembranosus
- Semitendinosus
- Ischial portion of adductor magnus
Motor Innervation: Tibial nerve (L image) provides motor supply for muscles in posterior portion of leg & foot. These muscles include?
- Gastrocnemius
- Soleus
- Plantaris
- Popliteus
- Flexor hallucis longus
- Flexor digitorum longus
- Tibialis posterior
