Anatomy of Cutaneous Innervation

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Questions and Answers

Which nerve supplies the space between the 1st and 2nd toes on the dorsum of the foot?

Medial plantar nerve

Superficial fibular nerve

Deep fibular nerve (correct)

Sural nerve

What does the medial plantar nerve innervate?

Space between the 1st and 2nd toes

Medial two thirds of the sole (correct)

Lateral third of the sole

Dorsal aspect of the foot

Where does the great saphenous vein drain into?

Popliteal vein

Inferior vena cava

Great cardiac vein

Femoral vein (correct)

Which nerve supplies the medial aspect of the heel?

Medial calcaneal nerve Signup and view all the answers

What signifies a dilated and tortuous great saphenous vein?

Varicose veins Signup and view all the answers

Which vessel begins at the medial end of the dorsal venous arch?

Great saphenous vein Signup and view all the answers

Which nerve formation supplies the lateral margin of the hindfoot and midfoot?

Sural nerve Signup and view all the answers

What is the primary function of perforating veins associated with the great saphenous vein?

Connect the deep veins to superficial veins Signup and view all the answers

Which nerve is primarily responsible for supplying the skin over the anterior thigh?

Femoral nerve Signup and view all the answers

What is the role of the posterior cutaneous nerve of the thigh?

Supplies the lower medial quadrant of the gluteal region Signup and view all the answers

Which nerve provides sensation to the medial aspect of the femoral triangle?

Ilioinguinal nerve Signup and view all the answers

The saphenous nerve is a branch of which nerve?

Femoral nerve Signup and view all the answers

Which cutaneous nerve supplies the skin over the lower lateral quadrant of the gluteal region?

Lateral cutaneous nerve of thigh Signup and view all the answers

Which nerve gives rise to the sensation of the medial aspect of the thigh?

Obturator nerve Signup and view all the answers

What does the superficial fibular nerve primarily supply?

Skin over the dorsum of the foot Signup and view all the answers

Which nerve is not involved in supplying cutaneous innervation to the leg?

Lateral cutaneous nerve of thigh Signup and view all the answers

What is the starting point of the femoral artery?

At the mid inguinal point Signup and view all the answers

Which structure is NOT related to the femoral triangle?

Popliteal vein Signup and view all the answers

What is the last branch of the femoral artery?

Descending genicular artery Signup and view all the answers

Where does the popliteal artery end?

At the lower border of the popliteus muscle Signup and view all the answers

Which artery supplies the head of the femur?

Obturator artery Signup and view all the answers

What runs anteromedial in the adductor canal?

Sartorius Signup and view all the answers

Which of the following arteries is a branch of the internal iliac artery?

Obturator artery Signup and view all the answers

What is the position of the popliteal artery relative to the popliteal vein?

Deep to the vein Signup and view all the answers

What is the beginning point of the anterior tibial artery?

At the lower border of the popliteal muscle Signup and view all the answers

Which artery continues as the dorsalis pedis artery?

Anterior tibial artery Signup and view all the answers

What branches does the anterior tibial artery give off?

Muscular and nutrient arteries Signup and view all the answers

Where does the dorsalis pedis artery end?

In the sole of the foot between the 1st and 2nd toes Signup and view all the answers

What is the course of the posterior tibial artery?

Running deep to the flexor retinaculum Signup and view all the answers

What artery is the peroneal artery a branch of?

Posterior tibial artery Signup and view all the answers

Which of the following statements about the musculature supplied by the anterior tibial artery is correct?

It supplies muscles in the anterior compartment of the leg Signup and view all the answers

What is the end point of the posterior tibial artery?

Dividing into medial and lateral planter arteries Signup and view all the answers

What is the primary function of the deep fibular nerve?

Innervate the intrinsic muscles of the foot and the skin between toes Signup and view all the answers

Which muscles are innervated by the lateral branch of the deep fibular nerve?

Extensor digitorum brevis and extensor hallucis brevis Signup and view all the answers

In which compartment of the leg does the deep fibular nerve arise?

Lateral compartment Signup and view all the answers

How does the deep fibular nerve travel in relation to the anterior tibial artery during its descent?

Initially lateral, then anterior, and finally medial to the artery Signup and view all the answers

What are the nerve roots associated with the deep fibular nerve?

L4-S1 Signup and view all the answers

Study Notes

Buttock Cutaneous Innervation

Upper medial quadrant: Supplied by posterior rami of upper three lumbar and upper three sacral nerves (L1,2,3 & S1,2,3)
Upper lateral quadrant: Supplied by lateral branches of subcostal (T12) and iliohypogastric nerves (L1)
Lower medial quadrant: Supplied by branches of posterior cutaneous nerve of thigh (S1,2,3)
Lower lateral quadrant: Supplied by branches of lateral cutaneous nerve of thigh (L2,3)
Skin over coccyx (in natal cleft): Supplied by branches of lower sacral and coccygeal nerves

Thigh Cutaneous Innervation

Superomedial aspect: Supplied by smaller branches of the lumbar plexus
Anterior and most of the thigh: Supplied by femoral nerve, which arise from the lumbar plexus
Lower medial, posterior thigh and knee: Supplied by posterior cutaneous nerve of thigh
Lower lateral, lateral thigh and knee: Supplied by lateral cutaneous nerve of thigh
Lateral aspect of femoral triangle: Supplied by femoral branch of the genitofemoral nerve, which arises from the lumbar plexus
Medial aspect of femoral triangle: Supplied by ilioinguinal nerve, which arises from the lumbar plexus
Medial aspect of thigh: Supplied by branches from the anterior branch of the obturator nerve, which arises from the lumbar plexus

Leg Cutaneous Innervation

Central superior and posterior leg: Supplied by posterior cutaneous nerve of thigh
Anteromedial leg and medial aspect of foot: Supplied by saphenous nerve, a sensory branch of the femoral nerve
Anterolateral leg and dorsum of foot: Supplied by superficial fibular nerve, a branch of the common fibular nerve
Posterolateral leg and lateral margin of foot: Supplied by sural nerve, formed by contributions from the tibial and common fibular nerves

Foot & Ankle Cutaneous Innervation

Space between 1st and 2nd toes on dorsum of foot: Supplied by deep fibular nerve
Dorsum of foot (except space between 1st and 2nd toes): Supplied by superficial fibular nerve
Medial two thirds of the sole of the foot: Supplied by medial plantar nerve, a terminal branch of the tibial nerve
Lateral third of the sole of foot: Supplied by lateral plantar nerve, a terminal branch of the tibial nerve
Medial aspect of the heel: Supplied by medial calcaneal nerve, a branch of the tibial nerve
Lateral margin of hindfoot and midfoot: Supplied by sural nerve, formed by contributions from the tibial and common fibular nerves
Medial margin of hindfoot and midfoot: Supplied by saphenous nerve, a branch of the femoral nerve

Superficial Veins of Lower Limb

Dorsal Venous Arch:
- Location: Over head of metatarsal bones
- Tributaries: Receives digital veins & veins from the sole
- Ending: Forms great & small saphenous veins
Great Saphenous Vein (Long Saphenous Vein):
- Beginning: From medial end of dorsal venous arch
- Ending: Draining into femoral vein about 4cm (1.5 inch) below & lateral to pubic tubercle (passing through saphenous opening)
- Course: Passes in front of medial malleolus, ascends in superficial fascia over medial aspect of leg (accompanied by saphenous nerve). Passes behind the knee (joining small saphenous). Curves forward around medial aspect of thigh, passes through saphenous opening piercing cribriform fascia. Contains numerous valves and connected with deep veins of lower limb by perforating veins
- Tributaries:
  - Superficial circumflex iliac vein
  - Superficial epigastric vein - joins lateral thoracic vein to form thoracoepigastric vein (connecting SVC & IVC)
  - Superficial external pudendal vein
  - Accessory vein
  - Unnamed veins
- Applied Anatomy:
  - Intravenous infusion (venous cutdown)
  - Used as graft for diseased coronary association.
  - If dilated, tortuous - called varicose veins
Small Saphenous Vein (Short Saph):
- Beginning: From lateral end of dorsal venous arch
- Ending: Draining into popliteal vein
- Course: Ascends behind lateral malleolus (accompanied by sural nerve). Follows lateral border of tendo-calcaneus. Runs up to middle of back of leg, pierces deep fascia and passes between the 2 heads of gastrocnemius in the lower part of popliteal fossa.
- Tributaries:
  - Small veins from back of leg
  - Anastomosing vein with great saphenous vein
  - Communicating vein with foot deep veins

Arteries of Lower Limb

Femoral Artery:
- Beginning: At inguinal ligament, continuation of external iliac artery at mid inguinal point
- Ending: At adductor hiatus, becoming popliteal artery
- Course: Enters thigh behind inguinal ligament. Inside the femoral sheath (at mid inguinal point). Enters femoral triangle and leaves apex of triangle, entering adductor hiatus to become popliteal artery (descends vertically to adductor tubercle of femur)
- Relations:
  - Femoral Triangle:
    - Lateral: Femoral nerve
    - Medial: Femoral vein
    - Anterior: Skin & fascia
    - Posterior: Psoas & Pectineus
  - Adductor Canal:
    - Anteromedial: Sartorius
    - Anterolateral: Vastus medialis
    - Posterior: Adductor longus & magnus
- Branches:
  - Superficial circumflex iliac artery (runs toward ASIS)
  - Superficial epigastric artery (runs toward umbilicus)
  - Superficial external pudendal artery (supplies scrotum, labia majora)
  - Deep external pudendal artery (supplies scrotum, labia majora)
  - Profundus femoris artery
  - Descending genicular artery (the last branch) supplies knee joint
Obturator Artery:
- Beginning: Branch of internal iliac artery (anterior division)
- Ending: By division into anterior and posterior divisions
- Course: Enters thigh with obturator nerve through obturator canal to medial compartment of thigh
- Branches:
  - Visceral: To urinary bladder
  - Muscular: To neighboring muscles
  - Articular: To hip joint, anter into ligament of head of femur (ligamentum teres) to supply head of femur
  - Pubic branch
Popliteal Artery:
- Beginning: At adductor hiatus, as continuation of femoral artery
- Ending: At lower border of Popliteus muscle, dividing into anterior and posterior tibial arteries
- Descends in popliteal fossa: First medial to popliteal vein, then deep to it, and finally lateral to the vein
- Relations:
  - Anterior (from above downward)
    - Popliteal surface of femur
    - Knee joint
    - Popliteal muscle
  - Posterior (from superficial to deep)
    - Skin & fascia
    - Tibial nerve
    - Popliteal vein
- Branches:
  - Muscular: To muscles beside
  - Anterior & Posterior tibial arteries (terminal branches)
  - Middle genicular artery
  - Superior medial genicular artery
  - Superior lateral genicular artery
  - Inferior medial genicular artery
  - Inferior lateral genicular artery
Anterior Tibial Artery:
- Beginning: Smaller terminal branch of popliteal artery, at lower border of Popliteus muscle
- Ending: Continues as dorsalis pedis artery in front of ankle
- Course: Enters anterior compartment of leg through opening in upper part of interosseous membrane, running down with deep peroneal nerve. Leaves leg by passing deep to superior extensor retinaculum (between extensor hallucis longus - medially and deep peroneal nerve and extensor digitorum longus - laterally). Here the artery is superficial and can be palpable.
- Branches:
  - Muscular: To muscles beside
  - Nutrient: To bones
  - Anterior & posterior tibial recurrent arteries
  - Medial & lateral malleolar arteries
Dorsalis Pedis Artery:
- Beginning: Continuation of anterior tibial artery in front of ankle
- Ending: In sole of foot between 1st and 2nd toes, joining the plantar arch
- Course: Descends in dorsum of foot, just lateral and parallel to tendon of extensor hallucis longus, between big and second toe
- Branches:
  - Medial & lateral tarsal arteries
  - First plantar and dorsal metatarsal artery - gives digital branches to big toe and medial side of second toe
  - Arcuate artery - gives 4 metatarsal arteries - gives digital branches to lateral 3 and 1/2 fingers
Posterior Tibial Artery:
- Beginning: Larger terminal branch of popliteal artery at lower border of Popliteus muscles
- Ending: By dividing into medial & lateral plantar arteries, behind medial malleolus (deep to flexor retinaculum)
- Course: Enters posterior compartment of leg between soleus and gastrocnemius above it, and (tibia and tibialis posterior muscles) below it. Runs with tibial nerve (the nerve is first medial, then superficial, and finally lateral to the artery). In the lower part of the leg, it is superficial, covered only by skin and fascia (in front of medial border of tendo-calcaneus)
- Branches:
  - Muscular: To muscles beside
  - Nutrient: To tibia
  - Peroneal artery and communicating branch to peroneal artery
  - Medial malleolar
  - Medial calcaneal
  - Medial and lateral plantar (terminal)
  - Circumflex fibular
Peroneal Artery:
- Beginning: From posterior tibial artery
- Ending: Behind inferior tibiofibular joint, dividing into calcaneal branches
- Course: Runs in lateral compartment.
Deep Fibular Nerve (Deep Peroneal Nerve):
- Nerve roots: L4-S1
- Anatomical Course:
  - Terminal division of common fibular nerve (branch of sciatic nerve)
  - Arises within the lateral compartment of the leg, between fibularis longus muscle and the neck of the fibula
  - Travels medially, pierces intermuscular septum, and enters anterior compartment of the leg
  - Accompanied by anterior tibial artery, descents in a plane initially between tibialis anterior and extensor digitorum longus, and then distally between tibialis anterior and extensor hallucis longus
  - During its descent, the deep fibular nerve is initially lateral, then anterior, and finally medial to anterior tibial artery
  - At the ankle, the deep fibular nerve travels underneath the extensor retinaculum
  - Divides within the dorsum of the foot into two branches:
    - Lateral branch: Innervates two intrinsic muscles of the foot (extensor digitorum brevis and extensor hallucis brevis)
    - Medial branch: Innervates the skin of the webbed space between the 1st and 2nd toes

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Description

This quiz covers the cutaneous innervation of the buttocks and thighs, detailing the specific nerves that supply different areas of the skin. Test your knowledge on the origins and distributions of these nerves based on anatomical regions. A great resource for students of anatomy and medical professionals alike.