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Thursday, October 09, 2008

The skin overlying the region where a “cut-down” is made to access the Great saphenous vein is supplied by

Question 10
The skin overlying the region where a “cut-down” is made to access the Great saphenous vein is supplied by
a.       Femoral Nerve
b.      Sural Nerve
c.       Tibial Nerve
d.      Superf. Peroneal Nerve
a)      Femoral Nerve
Gray’s Anatomy 38th Edition Page 1281, 1564
All Book
New Stem
Ä     The posterior division of the femoral nerve supplies the saphenous nerve and branches to the quadriceps femoris and the knee joint
Ä     Saphenous Nerve is the largest femoral cutaneous branch and this descends lateral to the femoral artery into the adductor canal, where it crosses anteriorly to become medial to the artery. At the distal end of the canal it leaves the artery, emerging through the aponeurotic covering with the saphenous branch of the descending genicular artery. It proceeds vertically along the medial side of the knee behind the sartorius, pierces the fascia lata between the tendons of the sartorius and gracilis and becomes subcutaneous. Thence it descends the medial side of the leg with the long saphenous vein along the medial tibial border and divides distally into a branch continuing along the tibia to the ankle and into another passing anterior to the ankle to supply the skin on the medial side of the foot, often as far as the hallucial metatarsophalangeal joint; it connects with the medial branch of the superficial peroneal nerve.
The nerve which supplies the medial malleolar region is Saphenous Nerve. But it is not given as one of the choices. However Femoral nerve is given. So we opt for that
Near midthigh the saphenous nerve gives a branch to the subsartorial plexus. As it leaves the adductor canal an infrapatellar branch pierces the sartorius and fascia lata to supply the prepatellar skin; proximal to the knee it connects with medial and intermediate femoral cutaneous nerves; distal to it, it connects with other branches of the saphenous nerve; laterally it connects with the lateral cutaneous femoral nerve, forming a patellar plexus.
Ä     Saphenous Nerve is also called as the long or internal saphenous nerve.
Ä     It is the largest cutaneous branch of the femoral nerve.
n-j :.0h4indent:-.25in;mso-list:l0 level2 lfo1; tab-stops:list 1.0in'>o       to the internal jugular via the inferior petrosal sinus and a plexus of veins on the internal carotid,
o       to the pterygoid plexus by veins traversing the emissary sphenoidal foramen, foramen ovale and foramen lacerum and
o       to the facial vein via the superior ophthalmic.
Ä     The two sinuses are connected by anterior and posterior intercavernous sinuses and the basilar plexus. All connections are valveless; the direction of flow in them is reversible.
Ä     If the question had been “Which is a tributary” then the answer is superficial middle cerebral vein
Ä     If the question had been “Which is not a connection” the answer is Deep Middle Cerebral Vein
Inferior Petrosal Sinuses drain the cavernous sinuses to the internal jugular veins. Each begins postero-inferiorly at its cavernous sinus and runs back in a groove between the petrous temporal and basilar occipital bones. Traversing the anterior part of the jugular foramen it ends in the superior jugular bulb. It receives labyrinthine veins via the cochlear canaliculus and the vestibular aqueduct and tributaries from the medulla oblongata, pons and inferior cerebellar surface. According to Browder and Kaplan the sinus is more often a plexus and sometimes drains by a vein in the hypoglossal canal to the suboccipital vertebral plexus.
Propulsion of blood in the sinus is partly due to pulsation of the internal carotid artery. It is also influenced by gravity and hence by the position of the head.

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