The Lower Limb

Pelvis, Thigh, Leg

and Foot

Innervation

Plexuses of the Lower Limb “Lumbosacral plexus” Lumbar Plexus

Arises from L1-L4 Lies within the psoas major

muscle Mostly anterior structures

Sacral Plexus Arises from spinal nerve

L4-S4 Lies caudal to the lumbar

plexus Mostly posterior structures

Diaphragm and posterior abdominal wall:The psoas major and minor muscles, the quadratus lumborum

muscle. The lumbar plexus and its related nerves.

Lumbosacral plexus

Lumbar plexus (T12- L4):

1- Obturator nerve (L2-L3-L4) 2- Femoral nerve (L2-L3-L4)3- Lumbosacral trunk (L4-L5)7- subcostal nerve (T12)8- iliohypogastric N. (T12-L1)9- ilioinguinal N. (L1)10- genitofamoral N. (L1-L2) 11- lateral cutaneous N. of the thigh (L2-L3)

Lumbar Plexus Femoral nerve

Cutaneous branches Thigh, leg, foot (e.g. saphenous nerve)

Motor branches Anterior thigh muscles (e.g. quadriceps,

sartorius, iliopsoas) Obturator nerve

Sensory Skin medial thigh; hip, knee joints

Motor Adductor muscles

Lateral femoral cutaneous Sensory

Skin lateral thigh Genitofemoral

Sensory Skin scrotum, labia major, anterior thigh

Motor Cremaster muscle

Lumbosacral plexusSacral plexus:Sciatic nerve (roots):L4L5S1S2S3

*Sciatic nerve is the thickest nerve of body.*It is composed of Common Peroneal andTibial nerves.*Com. Peroneal: composed of dorsal rami Tibial: composed of ventral rami

*L4+L5= Lumbosacral trunk

3- Lumbosacral trunk4- Sciatic nerve5- common peroneal N.6- tibial N.12- posterior femoral cutaneous nerve13- pudendal nerve14- superior gluteal nerve

Sacral Plexus Sciatic

Motor: Hamstring

Branches into: Tibial nerve

Cutaneous Posterior leg and sole of foot

Motor Posterior leg, foot

Common fibular (peroneal) nerve Cutaneous

Anterior and lateral leg, dorsum foot Motor

Lateral compartment, tibialis anterior, toe extensors

Superior gluteal nerve Motor

Gluteus medius and minimus, tensor fasciae latae

Sacral Plexus (continued)

Inferior gluteal nerve Motor

Gluteus maximus

Posterior femoral cutaneous nerve Sensory

Inferior buttocks, posterior thigh, popliteal fossa

Pudendal nerve Sensory

External genitalia, anus Motor

Muscles of perineum

Vasculature

Arteries

Common iliac (from aorta) branches into: Internal iliac

Supplies pelvic organs

External iliac Supplies lower limb

Arteries

Internal iliac branches into: Cranial and Caudal Gluteals (Superior and Inferior)

Gluteals Internal Pudendal

Perineum, external genitalia Obturator

Adductor muscles Other branches supply rectum,

bladder, uterus, vagina, male reproductive glands

Arteries

External iliac becomes……. Femoral

Once passes the inguinal ligament Lower limb Branches into Deep femoral

Adductors, hamstrings, quadriceps Branches into Medial/lateral femoral

circumflex Head and neck of femur

Femoral becomes…… Popliteal (continuation of femoral)

Branches into: Geniculars

Knee Splits into:

Anterior Tibial Anterior leg muscles, further branches to

feet Posterior Tibial

Flexor muscles, plantar arch, branches to toes

Veins Deep Veins: Mostly share names of arteries Ultimately empty into Inferior Vena

Cava Plantar Tibial Fibular Popliteal Femoral External/internal iliac Common iliac

Superficial Veins Dorsal venous arch (foot) Great saphenous (empties into femoral) Small saphenous (empties into

popliteal)

Lower limb: Muscles, Nerves and Vessels

Arteries to the pelvis

The internal iliac artery and it’s branches

Arteries of the pelvis and the thigh

5- abdominal aorta4- common iliac artery1- internal iliac artery15- external iliac artery19- femoral artery24- deep femoral artery25- medial circumflex femoral artery27- lateral circumflex femoral artery30- terminal branches of deep femoral artery, the perforating arteries.33- descending genicular artery

Arteries of the leg

4-5: lateral and medial superior genicular aa.6-7:lateral and medial inferior genicular aa.8- medial (middle) genicular artery (piercing the oblique popliteal ligament to reach inside the knee joint).1- Anterior tibial artery2- posterior tibial artery20- fibular artery 12- Dorsalis pedis artery

Arteries of the foot

*When the Anterior tibial artery (1) passesBeneath the superior extensor retinaculum,It is called dorsal artery of the foot orDorsalis Pedis artery (11).12- shows where its pulsation can be felt.Ant. Tibial artery or Dorsalis pedis may giveThe lateral tarsal artery (13).

Together, the lateral tarsal and dorsalis pedisMake the arcuate artery (14) giving rise toMetatarsal (15) and dorsal digital (16) arteries.*Dorsalis pedis gives a deep branch to joinThe plantar arch.

Arteries of the foot

Posterior tibial artery(2) in the plantar regiongives the medial (21) and lateral (23) Plantar arteries.

Lateral plantar artery makes most part of theplantar arch (22) which give rise to plantarmetatarsal arteries (24) and proper plantardigital arteries (25).The dorsal and plantar arches are connected via perforating branches.

Pulsation of dorsalis pedis artery may be lost in some peripharal vascular diseases such asBurger’s disease or also in diabetes mellitus. Occlusion of blood vessels lead to gangrene.And even autoamputation of the first toe.Scars on the skin may develop.

                                                 

                                                                 

                                                        

       

Femoral hernia:

Subinguinal region

9- external pudendal vessels10- superficial epigastric vessels11- superficial circumflex iliac vessels

Anterior thigh region (deep)The femoral triangle

Borders: Sartorius laterallyAdductor longus, medially and also the floorIlioinguinal ligament superiorly.

Floor: iliopsoas m., pectineus m., and adductor longus.

Content: A- lateral femoral cutaneous nerveB- Femoral nerveC- Structures inside the femoral sheath

*Content of Femoral Ring:Femoral artery and genitofemoral N. (fem)Femoral veinLymph nodes and areolar tissue (femoralCanal), the Rosenmuller node (they drain theGlans penis and clitoris)

*Femoral hernia: painful, more in female, below and lateral to pubic tubercle.

Anterior thigh region (deep)Subsartorius (adductor, Hunter’s) canal:

*Starts distal to femoral triangle.

Content: Femoral artery and vein, saphenous nerve,nerve to Vastus medialis, small branches of Obturator nerve and great saphenous vein

Deep gluteal region:

Greater sciatic foramenis divided by Piriformis muscle (2).

Suprapiriformis hiatus: sup. Gluteal vessels (3, 4, 5)

Infrapiriformis hiatus: Inferior Gluteal vessels (8,9)Internal pudendal artery and vein (10)Pudendal nerve (11)Posterior Cutaneous N. of the thigh (14) Sciatic nerve (15)Nerve to obturator internus (not shown) [18- inf. Clunial N., and 19- perineal N. are branches of posterior cutaneous N. of the thigh.]

Int. pudendal artery, pudendal nerve and nerve toObturator int. reenter the pelvis through lesser Sciatic foramen.Lesser Sciatic Foramen:Int. pudendal vessels. Pudendal nerve. Nerve toObturator int. and tendon of Obturator internus.

Posterior femoral region

Division of sciatic nervePerforating vessels (artery and vein)

Popliteal region (superficial)

1- Greater saphenous vein (medially)2- Saphenous nerve (medially)3- Small saphenous vein4- Medial sural cutaneous nerve5- Branches of post. femoral cutaneous N.

Popliteal fossa:

Diamond shape.Walls:Inferiorly:Gastrocnemius (medial and lateral heads) M.Superiorly: Semitendinosus and semimembranosus (medial) Biceps femoris (lateral)

Its floor is composed of:Popliteal surface of femur, knee joint and upperTibial bone, oblique popliteal ligament andPopliteal muscle with its covering fascia.

Content of popliteal fossa:Popliteal arteryPopliteal veinTibial N.Common peroneal N.Genicular arteries and veins

Posterior region of the leg

1- triceps surae m.2- gastrocnemius3- soleus4- calcaneal tendon5- saphenous nerve6- great saphenous vein7- small saphenous vein9- medial sural nerve10- communicating branch (lateral sural N.)11- sural nerve12- lateral dorsal cutaneous nerve15- common peroneal nerve16- posterior tibial artery17- peroneal (fibular artery18- popliteal artery19- anterior tibial artery20- perforating branch of fibular artery

Medial retromalleolar region:

1-2, the Flexor retinaculum3- greater saphenous vein5- saphenous nerve

Structures passing beneath theFlexor retinaculum (from medial to lateral):

Tibialis posterior tendon (7)Flexor digitorum longus (8)Posterior tibial artery and veins (10, 11)Tibial nerve (12)Flexor Hallucis longus (9)

Muscles of the dorsum of the foot:Tendon of the long extensors of the foot, lie superficial to these muscles and they form a dorsal aponeurosis into which the short Extensors of the digits, plantar and dorsal Interosseous muscles radiate.

Extensor digitorum brevis (6):Origin: Calcaneus (7)Insertion: with 3 tendons to dorsal aponeurosis (8).Function: dorsiflexion of these digitsInnervation: Deep peroneal nerve (S1-S2).

Extensor Hallucis brevis (9):Origin: CalcaneusInsertion: Dorsal aponeurosis of 1st digitFunction: Dorsiflexion of 1st digitInnervation: Deep peroneal nerve (S1-S2).

10- tibialis anterior tendon11- Peroneus tertius

Muscles of the sole of the foot:

1- Plantar AponeurosisConsist of longitudinal and transverse fibers.It maintains the longitudinal arch of the footand protects the vessels and nerves there.

5- Abductor Hallucis:Origin: Tuber Calcanei (6), plantar aponeurosis (7).Insertion: medial sesomoid bone (8) and base of proximal phalanx of 1st toe (9).Innervation: Medial plantar Nerve (L5-S1).

10- Fexor Hallucis Brevis: Origin: medial cuneiform bone (11)It has 2 heads. A medial head (12) which extends to medial sesamoid bone (13) andIts lateral head (15) extend to lateral sesamoidbone (16) and inserted on proximal phalanxof 1st toe. Innervation: Medial Plantar Nerve (L5-S1).

Muscles of the sole of the foot:

11- Flexor digitorum Brevis:Origin: tuber calcaneiInsertion: middle phalax of 2nd-4th digitsInnervation: Medial Plantar N (L5-S1).

1- Lumbriclas (4 ones)Tiny muscles originating from tendon (2)of the flexor digitorum longus (medial side).Insertion: Dorsal aponeurosis of 2nd-5th digit. Function: plantar flexion of these digitsInnervation: Medial Plantar N to 1, and Lat Plantar N to 2, 3 and 4 (S2 and S3)

3- Quadratus Plantae:Origin: by 2 heads from calcaneusInsertion: lateral border of the tendon of theFlexor digitorum longus. Innervation: Lateral Plantar N. (S1-S2).

Muscles of the sole of the foot:

Plantar interossei MM (3), BlueThey have single head, Number 7Originate from medial side of 3rd-5th metatarsals bones.Insertion: medial side of 3rd-5th digits.Function: Adductors of the digitsInnervation: Lateral Plantar N (S2-S3).

Dorsal interossei MM (4), RedThey have 2 heads Number 9Originate from opposing surface of allmetatarsals Insertion: to base of 2nd-4th digitsFunction: Abductors of the digits Innervation: Lateral Plantar N (S2-S3).

Muscles of the sole of the foot:

1- Adductor Hallucis: Has 2 heads:oblique head (3) and the transverse head (9).Innervation: Lateral Plantar N (S1-S2)

7- Long Plantar Ligament

12-Opponens digiti minimi,Innervation: Lat Plantar N (S1-S2)

15-16: Flexor Digiti Minimi:Innervation: Lateral Plantar N (S1-S2)

18- Abductor Digiti MinimiOrigin: calcaneus(20) and 5th metatarsal (21)Insertion: Base of proximal phalanx of the 5th digit (22).Innervation: Lateral Plantar N (S1-S2).

23- Quadratus Plantae

Plantar region superficial:

Plantar aponeurosis (1)

Plantar region deep:

Lateral plantar nerve (13) and Medial plantar nerve (4), innervate themuscles and skin of the plantar side.

Plantar arteries and veins (15,16, 3, 4) are involved in blood supply and venous drainage of the plantar region of the foot.