The Lower Extremity BIOL 1010

FEMUR

TIBIA

FIBULA

ERROR: #7 is CUBOID #4 is LATERAL CUNEIFORM

Very similar to the upper extremity Some definitions: a. Thigh – part from the hips to knees b. Leg – part from the knee to the ankle Note that the hip joint is a ball and socket joint. It allows movement in all direction. The knee only allows flexion and extension – not circumduction. It is never normal for hyperextension of knee (genu recurvatum)

In humans, the abdominal aorta terminates into the common iliac arteries. The common iliacs divide into the external and internal iliacs. In humans, the aorta terminates as the middle sacral artery. CAT

The nerves of the lower extremity are simpler than the upper limb. There are three nerves entering the thigh. Their lateral branches serve the gluteal muscles. femoral nerve L2,3,4 anterior compartment obturator nerve L2,3,4 medial compartment sciatic nerve L4,5,S1,2,3 (sacral plexus) posterior compartment

The only one of the three that travel below the knee is the sciatic nerve. The sciatic nerve branches into two nerve: 1. tibial nerve 2. common peroneal nerve a. Superficial peroneal nerve b. Deep peroneal nerve

femurmedial lateral Anterior compartment- Extensors of the knee Femoral Nerve Medial compartment- Adductors of the knee Obturator Nerve Posterior compartment- Flexors of the knee Sciatic Nerve

The anterior compartment of the thigh is homologous to the posterior compartment of the arm. The posterior compartment of the thigh is homologous to the anterior compartment of the arm.

The leg has three compartments 1.Anterior compartment - dorsiflexors (flexors) of the foot - deep peroneal nerve 2.Posterior compartment - plantarflexors (extensors) of the foot - tibial nerve 3.Lateral compartment - extensors of the foot - superficial peroneal nerve

MuscleOriginInsertionAction Psoas major FEMORAL NERVE Transverse processes and bodies of T12-L5 femurPrime flexor of thigh and trunk. Iliacus FEMORAL NERVE Iliac fossafemurSame as psoas major Gluteus Maximus GLUTEAL NERVES for all gluteal muscels Outside of ilium, sacrum, and coccyx Iliotibial tract and femur Extends the thigh Gluteus Medius - Part exposed and part covered by maximus. Shots given here. Outside of iliumLateral surface of femur Abducts thigh. Pelvic tilt to allow opposite limb to clear ground during gait.

MuscleOriginInsertionAction Gluteus Minimus Outer surface of ilium Lateral side of femur Abductor of thigh Tensor Fascia Latae Iliac crestIliotibial tract (lateral side of femur) Extends knee, abducts, and medially rotates

The FASCIA LATA (not to be confused with the muscle of similar name) is connective tissue on the lateral side of the femur. This forms the ILIOTIBIAL BAND. This band connects the ilium and tibia and is the site of inflammation in runners – iliotibial band syndrome.

Muscles of the Medial Compartment of the Thigh Obturator Nerve MuscleOriginInsertionAction Adductor Femoris (magnus and brevis) Os coxaePosterior medial femur Adduct thigh at hip Adductor Longus Body of pubis – medial side Posterior medial femur Adduct thigh and hip GracilisMedial surface of pubis and ischium Medial surface of tibia Adduct thigh, flex leg

Muscles of the Posterior Compartment of the Thigh Tibial portion of Sciatic Nerve MuscleOriginInsertionAction Biceps Femorisischiumfibula Flex leg and extend thigh semitendinosisischiumtibia Flex leg and extend thigh semimembranosisischiumtibia Flex leg and extend thigh

MuscleOriginInsertionAction PectineuspubisLinea aspera of femur Adduct, flex, and laterally rotate thigh sartoriusASISMedial side of tibia shaft Flex, abduct, and laterally rotate hip. Flex leg Vastus lateralisFemoral shaftPatella/tibial tuberosity Extend leg Vastus medialisFemoral shaftPatella/tibial tuberosity Extend leg Vastus intermedius Femoral shaftPatella/tibial tuberosity Extend leg Rectus femorisAIISPatella/tibial tuberosity Extend leg and flex thigh Muscles of Anterior Thigh *Femoral Nerve

1.Semitendinosus 2.Biceps Femoris 3.Caudofemoralis 4.Gluteus Maximus 5.Gluteus Medius 6.Tensor Fascia Lata 7.Sartorius

The rectus femoris cross two joints, therefore it has actions on the two joints involved. The patella is articulates with the FEMUR, not the tibia. The patella is attached to the femur and tibia by the PATELLAR LIGAMENT. When this ligament is pulled, the patella is lifted superiorly and brings the leg into an extended position. In the posterior leg, the GASTROCNEMIUS muscle is responsible for plantarflexion. It originates at the femur and inserts on the posterior surface of the calcaneus. It crosses two joints so it can flex the knee and plantarflex (extend) the foot. It is innervated by the tibial nerve.

L2 L3 L4 iliopsoas Rectus femoris pectineus Vastus medialis Vastus intermedius sartorius Vastus lateralis Motor Branches of the Femoral Nerve

Adductus magnus gracilis Adductor longus Adductor brevis Motor Branches of the Obturator Nerve

L4 L5 S1 S2 S3 Semitendinosis Biceps femoris semimembranosus Hamstrings Gastrocnemius and posterior compartment of the leg and foot Tibial nerve Common peroneal nerve Deep peroneal nerve Anterior compartment of leg Lateral compartment of leg Superficial peroneal nerve Motor Branches of the Sciatic Nerve

calcaneus talus cuboid navicular Medial, intermediate, and lateral cuneiforms metatarsals phalanges The Foot

Anterior Leg Structures - Superficial Identify the Following: Tibialis Anterior Peroneus Longs Peroneus Brevis Extensor Digitorum Longus Patellar Tendon Patella Tibia Peroneus Tertius Extensor Hallucis Longus Popliteus Tendon Sartorius Tendon

Posterior Leg Structures - Superficial Identify the Following: Femur Tibia Fibula Soleus Achilles Tendon Plantaris Popliteus Calcaneus

Posterior Leg Structures - Deep Identify the Following: Achilles Tendon Flexor Hallucis Longus Flexor Digitorum Longus Calcaneus Talus Tibia Fibula Femur

Intrinsic Muscles of the Foot These muscles all originate and insert on foot bones. They help to flex, extend, abduct, or adduct the toes. All the intrinsic muscles of the foot are found on the plantar surface (except the one on the dorsal aspect). The plantar muscles are arranged in 4 layers, from superficial to deep.

Intrinsic Muscles of the Foot MuscleOriginInsertionActionLayer Extensor Digitorum Brevis (deep fibular nerve) Anterior part of calcaneus Base of proximal phalanx 1, extensor expansions of toes 2-4 Extend the MPJOnly one on dorsum of foot Flexor Digitorum Brevis (medial plantar nerve) Calcaneal tuberMiddle phalanx of toes 2-4 Flex toes1 Abductor Hallucis (medial plantar nerve) Tuber calcanei and flexor retinaculum Proximal phalanx of hallux Abducts hallux1 Abductor digiti minimi (lateral plantar nerve) Tuber calcaneiLateral side base of little toe proximal phalanx Abducts little toe1

MuscleOriginInsertionActionLayer Quadratus Plantae (lateral plantar nerve) calcaneusTendon on FDLStraightens the pull of FDL 2 Lumbricales (medial and lateral plantar nerve) Tendons of FDLExtensor expansion of proximal phalanx of toes 2-5 on medial side Flex at MPJ and extend at IPJ 2 Flexor Hallucis Brevis (medial plantar nerve) Lateral cuneiform and cuboid bones Base of proximal phalanx of hallux. Each tendon of this muscle has an associated sesamoid bone Flex hallux at MPJ3 Adductor Hallucis (lateral plantar nerve) Bases of metatarsals 2-4, Base of proximal phalanx of great toe Weak adductor of great toe 3 Flexor Digiti Minimi Brevis (lateral plantar nerve) Base of 5 th metatarsal Base of 5 th toe proximal phalanx Flexes little toe3 Plantar and Dorsal Interossei (lateral plantar nerve) Same as interossei of hand 4