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Leg: Anatomy

The lower leg, or just “leg” in anatomical terms, is the part of the lower limb between the knee and the ankle joint Ankle joint The ankle is a hinged synovial joint formed between the articular surfaces of the distal tibia, distal fibula, and talus. The ankle primarily allows plantar flexion and dorsiflexion of the foot. . The bony structure is composed of the tibia Tibia The second longest bone of the skeleton. It is located on the medial side of the lower leg, articulating with the fibula laterally, the talus distally, and the femur proximally. Knee Joint: Anatomy and fibula bones, which articulate with each other at the proximal and distal tibiofibular Distal tibiofibular Ankle Joint: Anatomy joints. The muscles of the leg are grouped into the anterior, lateral, and posterior compartments by extensions of fascia Fascia Layers of connective tissue of variable thickness. The superficial fascia is found immediately below the skin; the deep fascia invests muscles, nerves, and other organs. Cellulitis and exert their action on the ankle, foot Foot The foot is the terminal portion of the lower limb, whose primary function is to bear weight and facilitate locomotion. The foot comprises 26 bones, including the tarsal bones, metatarsal bones, and phalanges. The bones of the foot form longitudinal and transverse arches and are supported by various muscles, ligaments, and tendons. Foot: Anatomy, and toes.

Last updated: Mar 9, 2022

Editorial responsibility: Stanley Oiseth, Lindsay Jones, Evelin Maza

Bones and Joints

Tibia Tibia The second longest bone of the skeleton. It is located on the medial side of the lower leg, articulating with the fibula laterally, the talus distally, and the femur proximally. Knee Joint: Anatomy

  • Medial, weight-bearing bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types of the leg
  • Articulates with the femur and fibula proximally and the talus Talus The second largest of the tarsal bones. It articulates with the tibia and fibula to form the ankle joint. Ankle Joint: Anatomy and fibula distally
  • Important landmarks:
    • Tibial condyles: 
      • Horizontal proximal surfaces that articulate with the femoral condyles
      • Separated by the lateral and medial intercondylar tubercles
    • Tibial tuberosity: 
      • Triangular, superior–anterior area where condyles merge
      • Site of attachment Attachment The binding of virus particles to virus receptors on the host cell surface, facilitating virus entry into the cell. Virology for the patellar tendon
    • Shaft: anterior, lateral, and posterior surfaces
    • Medial malleolus Medial malleolus Ankle Joint: Anatomy
      • Distal projection Projection A defense mechanism, operating unconsciously, whereby that which is emotionally unacceptable in the self is rejected and attributed (projected) to others. Defense Mechanisms
      • Articulates with the talus Talus The second largest of the tarsal bones. It articulates with the tibia and fibula to form the ankle joint. Ankle Joint: Anatomy as part of the ankle

Fibula

  • Thin, lateral bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types of the leg
  • Articulates with the tibia Tibia The second longest bone of the skeleton. It is located on the medial side of the lower leg, articulating with the fibula laterally, the talus distally, and the femur proximally. Knee Joint: Anatomy proximally and distally and with the talus Talus The second largest of the tarsal bones. It articulates with the tibia and fibula to form the ankle joint. Ankle Joint: Anatomy distally
  • Important landmarks:
    • Head: 
      • Serves as the site of attachment Attachment The binding of virus particles to virus receptors on the host cell surface, facilitating virus entry into the cell. Virology for ligaments of the knee
      • Articulates with the tibia Tibia The second longest bone of the skeleton. It is located on the medial side of the lower leg, articulating with the fibula laterally, the talus distally, and the femur proximally. Knee Joint: Anatomy
    • Neck Neck The part of a human or animal body connecting the head to the rest of the body. Peritonsillar Abscess:
      • Narrow
      • The common peroneal nerve Peroneal nerve The lateral of the two terminal branches of the sciatic nerve. The peroneal (or fibular) nerve provides motor and sensory innervation to parts of the leg and foot. Popliteal Fossa: Anatomy wraps around it.
    • Shaft: medial, lateral, and posterior surfaces
    • Lateral malleolus Lateral malleolus Ankle Joint: Anatomy
      • Distal projection Projection A defense mechanism, operating unconsciously, whereby that which is emotionally unacceptable in the self is rejected and attributed (projected) to others. Defense Mechanisms
      • Articulates with the talus Talus The second largest of the tarsal bones. It articulates with the tibia and fibula to form the ankle joint. Ankle Joint: Anatomy as part of the ankle
Leg anterior and posterior view

Anterior and posterior views of the tibia Tibia The second longest bone of the skeleton. It is located on the medial side of the lower leg, articulating with the fibula laterally, the talus distally, and the femur proximally. Knee Joint: Anatomy, fibula, and tibiofibular joints

Image by BioDigital, edited by Lecturio

Joints

  • Proximal tibiofibular joint: 
    • Arthrodial plane joint between the lateral tibial condyle and the head of the fibula
    • Stabilized by a sturdy capsule Capsule An envelope of loose gel surrounding a bacterial cell which is associated with the virulence of pathogenic bacteria. Some capsules have a well-defined border, whereas others form a slime layer that trails off into the medium. Most capsules consist of relatively simple polysaccharides but there are some bacteria whose capsules are made of polypeptides. Bacteroides and multiple ligaments
  • Distal tibiofibular Distal tibiofibular Ankle Joint: Anatomy joint: 
    • Syndesmosis of the distal ends of the fibula and tibia Tibia The second longest bone of the skeleton. It is located on the medial side of the lower leg, articulating with the fibula laterally, the talus distally, and the femur proximally. Knee Joint: Anatomy
    • Stabilized by multiple ligaments and the interosseous membrane Interosseous Membrane A sheet of fibrous connective tissue rich in collagen often linking two parallel bony structures forming a syndesmosis type joint. It provides longitudinal stability, tensile strength, and weight distribution/transfer and may allow limited movement in syndesmoses. Forearm: Anatomy
  • Interosseous membrane Interosseous Membrane A sheet of fibrous connective tissue rich in collagen often linking two parallel bony structures forming a syndesmosis type joint. It provides longitudinal stability, tensile strength, and weight distribution/transfer and may allow limited movement in syndesmoses. Forearm: Anatomy
    • Fibrous Fibrous Fibrocystic Change tissue directed downward and laterally
    • Connects medial border of the fibula with lateral border of the tibia Tibia The second longest bone of the skeleton. It is located on the medial side of the lower leg, articulating with the fibula laterally, the talus distally, and the femur proximally. Knee Joint: Anatomy
    • Stabilizes the leg
    • Contains an opening on the proximal region that allows for the passage of the anterior tibial vessels to the anterior compartment of the leg
Posterior view of the arterial supply of the leg

Posterior view of the leg, featuring the opening on the interosseous membrane Interosseous Membrane A sheet of fibrous connective tissue rich in collagen often linking two parallel bony structures forming a syndesmosis type joint. It provides longitudinal stability, tensile strength, and weight distribution/transfer and may allow limited movement in syndesmoses. Forearm: Anatomy and the passage of the anterior tibial artery

Image by BioDigital, edited by Lecturio

Fascial Compartments

The leg is divided into 4 fascial compartments by the interosseous membrane Interosseous Membrane A sheet of fibrous connective tissue rich in collagen often linking two parallel bony structures forming a syndesmosis type joint. It provides longitudinal stability, tensile strength, and weight distribution/transfer and may allow limited movement in syndesmoses. Forearm: Anatomy and the anterior, posterior, and transverse intermuscular septa as follows:

  1. Anterior compartment:
    • Separated from the lateral compartment by the anterior intermuscular septum
    • Separated from the deep posterior compartment by the interosseous membrane Interosseous Membrane A sheet of fibrous connective tissue rich in collagen often linking two parallel bony structures forming a syndesmosis type joint. It provides longitudinal stability, tensile strength, and weight distribution/transfer and may allow limited movement in syndesmoses. Forearm: Anatomy and the tibia Tibia The second longest bone of the skeleton. It is located on the medial side of the lower leg, articulating with the fibula laterally, the talus distally, and the femur proximally. Knee Joint: Anatomy
    • Contains 4 muscles:
  2. Lateral compartment:
    • Separated from the anterior compartment by the anterior intermuscular septum
    • Separated from the superficial posterior compartment by the posterior intermuscular septum
    • Contains 2 muscles:
      • Peroneal brevis
      • Peroneal longus
  3. Superficial posterior compartment:
    • Separated from the deep posterior compartment by the transverse intermuscular septum
    • Separated from the lateral compartment by the posterior intermuscular septum
    • Contains 3 muscles:
      • Soleus
      • Gastrocnemius
      • Plantaris
  4. Deep posterior compartment:
    • Separated from the anterior compartment by the interosseous membrane Interosseous Membrane A sheet of fibrous connective tissue rich in collagen often linking two parallel bony structures forming a syndesmosis type joint. It provides longitudinal stability, tensile strength, and weight distribution/transfer and may allow limited movement in syndesmoses. Forearm: Anatomy and the tibia Tibia The second longest bone of the skeleton. It is located on the medial side of the lower leg, articulating with the fibula laterally, the talus distally, and the femur proximally. Knee Joint: Anatomy
    • Separated from the superficial posterior compartment by the transverse intermuscular septum
    • Contains 4 muscles:
Cross section of the leg

Cross section of the leg, featuring the fascial compartments and the location of the major vessels

Image by Lecturio.

Anterior Compartment — Dorsiflexor Muscles

  • There are 4 muscles in the anterior compartment responsible for dorsiflexion or extension Extension Examination of the Upper Limbs of the foot Foot The foot is the terminal portion of the lower limb, whose primary function is to bear weight and facilitate locomotion. The foot comprises 26 bones, including the tarsal bones, metatarsal bones, and phalanges. The bones of the foot form longitudinal and transverse arches and are supported by various muscles, ligaments, and tendons. Foot: Anatomy and/or toes:
    • Tibialis anterior: powerful dorsiflexor of the foot Foot The foot is the terminal portion of the lower limb, whose primary function is to bear weight and facilitate locomotion. The foot comprises 26 bones, including the tarsal bones, metatarsal bones, and phalanges. The bones of the foot form longitudinal and transverse arches and are supported by various muscles, ligaments, and tendons. Foot: Anatomy
    • Extensor digitorum Extensor digitorum Forearm: Anatomy longus: extends the 4 lateral toes and the foot Foot The foot is the terminal portion of the lower limb, whose primary function is to bear weight and facilitate locomotion. The foot comprises 26 bones, including the tarsal bones, metatarsal bones, and phalanges. The bones of the foot form longitudinal and transverse arches and are supported by various muscles, ligaments, and tendons. Foot: Anatomy
    • Extensor hallucis longus: extends the big toe (hallux) and the foot Foot The foot is the terminal portion of the lower limb, whose primary function is to bear weight and facilitate locomotion. The foot comprises 26 bones, including the tarsal bones, metatarsal bones, and phalanges. The bones of the foot form longitudinal and transverse arches and are supported by various muscles, ligaments, and tendons. Foot: Anatomy
    • Peroneus tertius: everts and dorsiflexes the foot Foot The foot is the terminal portion of the lower limb, whose primary function is to bear weight and facilitate locomotion. The foot comprises 26 bones, including the tarsal bones, metatarsal bones, and phalanges. The bones of the foot form longitudinal and transverse arches and are supported by various muscles, ligaments, and tendons. Foot: Anatomy
  • Common nerve supply: deep fibular nerve Deep fibular Nerve Foot: Anatomy (ventral rami of L4– S2 S2 Heart Sounds)
  • Common blood supply: anterior tibial artery, branch of the popliteal artery Popliteal Artery The continuation of the femoral artery coursing through the popliteal fossa; it divides into the anterior and posterior tibial arteries. Popliteal Fossa: Anatomy
Table: Anterior compartment — dorsiflexor muscles
Muscle Origin Insertion Innervation Function
Tibialis anterior Lateral condyle, lateral surface of proximal tibia Tibia The second longest bone of the skeleton. It is located on the medial side of the lower leg, articulating with the fibula laterally, the talus distally, and the femur proximally. Knee Joint: Anatomy, and interosseous membrane Interosseous Membrane A sheet of fibrous connective tissue rich in collagen often linking two parallel bony structures forming a syndesmosis type joint. It provides longitudinal stability, tensile strength, and weight distribution/transfer and may allow limited movement in syndesmoses. Forearm: Anatomy (IO) Medial cuneiform and base of 1st metatarsal Deep fibular nerves (L4, L5, S1 S1 Heart Sounds)
  • Dorsiflexion of ankle
  • Inversion of foot Foot The foot is the terminal portion of the lower limb, whose primary function is to bear weight and facilitate locomotion. The foot comprises 26 bones, including the tarsal bones, metatarsal bones, and phalanges. The bones of the foot form longitudinal and transverse arches and are supported by various muscles, ligaments, and tendons. Foot: Anatomy
Extensor digitorum Extensor digitorum Forearm: Anatomy longus Lateral condyle of tibia Tibia The second longest bone of the skeleton. It is located on the medial side of the lower leg, articulating with the fibula laterally, the talus distally, and the femur proximally. Knee Joint: Anatomy, anterior surface of fibula, and IO Middle and distal phalanges Phalanges Bones that make up the skeleton of the fingers, consisting of two for the thumb, and three for each of the other fingers. Hand: Anatomy of digits 2–5
  • Extends digits 2–5
  • Dorsiflexes ankle
Extensor hallucis longus Anterior surface of midfibula and IO Distal phalanx of hallux (digit 1)
  • Extends hallux
  • Dorsiflexes ankle
Fibularis tertius Anterior surface of lower fibula and IO Base of 5th metatarsal

Lateral Compartment Evertor Muscles

  • Also called the peroneal compartment of the leg
  • The muscles listed here are are primarily responsible for foot Foot The foot is the terminal portion of the lower limb, whose primary function is to bear weight and facilitate locomotion. The foot comprises 26 bones, including the tarsal bones, metatarsal bones, and phalanges. The bones of the foot form longitudinal and transverse arches and are supported by various muscles, ligaments, and tendons. Foot: Anatomy eversion Eversion Chronic Apophyseal Injury; they also contribute to plantar flexion Flexion Examination of the Upper Limbs and dorsiflexion.
    • Fibularis, or peroneus, longus
    • Fibularis, or peroneus, brevis
  • Both muscular tendons pass posterior to the lateral malleolus Lateral malleolus Ankle Joint: Anatomy to enter the foot Foot The foot is the terminal portion of the lower limb, whose primary function is to bear weight and facilitate locomotion. The foot comprises 26 bones, including the tarsal bones, metatarsal bones, and phalanges. The bones of the foot form longitudinal and transverse arches and are supported by various muscles, ligaments, and tendons. Foot: Anatomy deep in relation to the fibular (or peroneal) retinaculum.
  • Common nerve supply: primarily by the superficial fibular nerve Superficial Fibular Nerve Foot: Anatomy
  • Common blood supply: perforating branches from the anterior tibial artery
Table: Lateral compartment — evertor muscles
Muscle Origin Insertion Innervation Function
Fibularis longus Head and proximal ⅔ of lateral fibula 1st metatarsal and medial cuneiform Superficial fibular nerves (L5, S1 S1 Heart Sounds)
Fibularis brevis Midportion of lateral fibula Base of 5th metatarsal Everts foot Foot The foot is the terminal portion of the lower limb, whose primary function is to bear weight and facilitate locomotion. The foot comprises 26 bones, including the tarsal bones, metatarsal bones, and phalanges. The bones of the foot form longitudinal and transverse arches and are supported by various muscles, ligaments, and tendons. Foot: Anatomy; weak plantar flexion Flexion Examination of the Upper Limbs

Posterior Compartment Flexor Muscles

  • Muscles of the posterior compartment are primarily responsible for plantar flexion Flexion Examination of the Upper Limbs.
  • The flexor muscles are divided into superficial and deep layers by the transverse intermuscular septum.
  • Common nerve supply: tibial nerve Tibial Nerve The medial terminal branch of the sciatic nerve. The tibial nerve fibers originate in lumbar and sacral spinal segments (L4 to S2). They supply motor and sensory innervation to parts of the calf and foot. Popliteal Fossa: Anatomy
  • Common blood supply: posterior tibial artery and fibular vessels (deep layer)

Superficial layer of the posterior compartment of the leg

Muscle Origin Insertion Innervation Function
Gastrocnemius
  • Lateral head: lateral condyle of femur
  • Medial head: medial condyle of femur
Posterior aspect of calcaneus Calcaneus The largest of the tarsal bones which is situated at the lower and back part of the foot, forming the heel. Foot: Anatomy via calcaneal tendon Tibial nerves ( S1 S1 Heart Sounds, S2 S2 Heart Sounds)
  • Plantar flexes ankle
  • Flexes knee
Soleus Posterior surface of fibula and soleal line of tibia Tibia The second longest bone of the skeleton. It is located on the medial side of the lower leg, articulating with the fibula laterally, the talus distally, and the femur proximally. Knee Joint: Anatomy Plantar flexes ankle
Plantaris Inferior lateral supracondylar ridge of femur Weak plantar flexion Flexion Examination of the Upper Limbs

Deep layer of the posterior compartment of the leg

Muscle Origin Insertion Nerve supply Function
Popliteus Popliteus Popliteal Fossa: Anatomy Lateral aspect of lateral condyle of femur and lateral meniscus Posterior tibia Tibia The second longest bone of the skeleton. It is located on the medial side of the lower leg, articulating with the fibula laterally, the talus distally, and the femur proximally. Knee Joint: Anatomy above soleal line Tibial nerves (L4, L5, S1 S1 Heart Sounds, S2 S2 Heart Sounds, S3 S3 Heart Sounds)
  • Weak knee flexion Flexion Examination of the Upper Limbs
  • Unlocks knee by lateral rotation Rotation Motion of an object in which either one or more points on a line are fixed. It is also the motion of a particle about a fixed point. X-rays of femur on stable tibia Tibia The second longest bone of the skeleton. It is located on the medial side of the lower leg, articulating with the fibula laterally, the talus distally, and the femur proximally. Knee Joint: Anatomy
Flexor digitorum longus Posterior surface of tibia Tibia The second longest bone of the skeleton. It is located on the medial side of the lower leg, articulating with the fibula laterally, the talus distally, and the femur proximally. Knee Joint: Anatomy below soleal line Distal phalanges Phalanges Bones that make up the skeleton of the fingers, consisting of two for the thumb, and three for each of the other fingers. Hand: Anatomy of digits 2–5
  • Flexes digits 2–5
  • Plantar flexes ankle
Flexor hallucis longus Lower ⅔ of posterior fibula and interosseous membrane Interosseous Membrane A sheet of fibrous connective tissue rich in collagen often linking two parallel bony structures forming a syndesmosis type joint. It provides longitudinal stability, tensile strength, and weight distribution/transfer and may allow limited movement in syndesmoses. Forearm: Anatomy Distal phalanx of hallux
Tibialis posterior Interosseous membrane Interosseous Membrane A sheet of fibrous connective tissue rich in collagen often linking two parallel bony structures forming a syndesmosis type joint. It provides longitudinal stability, tensile strength, and weight distribution/transfer and may allow limited movement in syndesmoses. Forearm: Anatomy and posterior borders of tibia Tibia The second longest bone of the skeleton. It is located on the medial side of the lower leg, articulating with the fibula laterally, the talus distally, and the femur proximally. Knee Joint: Anatomy and fibula Tuberosity of the navicular Navicular Foot: Anatomy bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types, 1st–3rd cuneiform bones, and 2nd–4th metatarsal bones Metatarsal Bones The five long bones of the metatarsus, articulating with the tarsal bones proximally and the phalanges of toes distally. Foot: Anatomy

Blood Supply

Arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology of the lower leg

A continuation of the popliteal artery Popliteal Artery The continuation of the femoral artery coursing through the popliteal fossa; it divides into the anterior and posterior tibial arteries. Popliteal Fossa: Anatomy supplies blood to the lower leg. The artery bifurcates at the lower margin of the popliteal fossa Popliteal fossa The popliteal fossa or the “knee pit” is a diamond-shaped, fat-filled, shallow depression on the posterior aspect of the knee joint. The popliteal fossa is located at the dorsal aspect of the knee and contains an increased number of lymph nodes as well as structures of the neurovascular system that travel from the thigh to the lower leg. Popliteal Fossa: Anatomy and sends branches to the anterior compartment, the anterior tibial artery, and the posterior and lateral compartments, forming the tibioperoneal trunk.

Origin Trajectory Branches Supply
Anterior tibial artery (accompanied by the deep peroneal nerve Deep peroneal nerve Foot: Anatomy) Division of popliteal artery Popliteal Artery The continuation of the femoral artery coursing through the popliteal fossa; it divides into the anterior and posterior tibial arteries. Popliteal Fossa: Anatomy into anterior tibial artery and tibiofibular trunk
  • Begins in popliteal fossa Popliteal fossa The popliteal fossa or the “knee pit” is a diamond-shaped, fat-filled, shallow depression on the posterior aspect of the knee joint. The popliteal fossa is located at the dorsal aspect of the knee and contains an increased number of lymph nodes as well as structures of the neurovascular system that travel from the thigh to the lower leg. Popliteal Fossa: Anatomy
  • Enters anterior compartment through upper opening of interosseous membrane Interosseous Membrane A sheet of fibrous connective tissue rich in collagen often linking two parallel bony structures forming a syndesmosis type joint. It provides longitudinal stability, tensile strength, and weight distribution/transfer and may allow limited movement in syndesmoses. Forearm: Anatomy
  • Continues as the dorsalis pedis
  • Recurrent branches to knee joint Knee joint The knee joint is made up of the articulations between the femur, tibia, and patella bones, and is one of the largest and most complex joints of the human body. The knee is classified as a synovial hinge joint, which primarily allows for flexion and extension with a more limited degree of translation and rotation. Knee Joint: Anatomy anastomosis
  • Muscular branches
  • Medial and lateral malleolar branches
Anterior compartment of leg
Posterior tibial artery (accompanied by tibial nerve Tibial Nerve The medial terminal branch of the sciatic nerve. The tibial nerve fibers originate in lumbar and sacral spinal segments (L4 to S2). They supply motor and sensory innervation to parts of the calf and foot. Popliteal Fossa: Anatomy) Terminal branch of tibioperoneal trunk
  • Begins at lower border of popliteal fossa Popliteal fossa The popliteal fossa or the “knee pit” is a diamond-shaped, fat-filled, shallow depression on the posterior aspect of the knee joint. The popliteal fossa is located at the dorsal aspect of the knee and contains an increased number of lymph nodes as well as structures of the neurovascular system that travel from the thigh to the lower leg. Popliteal Fossa: Anatomy
  • Lies deep to soleus muscle
  • Passes under medial malleolus Medial malleolus Ankle Joint: Anatomy
  • Divides into medial and lateral plantar arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology
  • Circumflex branch to knee
  • Muscular branches
  • Medial malleolar and calcaneal branches
  • Posterior compartment of leg
  • Plantar aspect of foot Foot The foot is the terminal portion of the lower limb, whose primary function is to bear weight and facilitate locomotion. The foot comprises 26 bones, including the tarsal bones, metatarsal bones, and phalanges. The bones of the foot form longitudinal and transverse arches and are supported by various muscles, ligaments, and tendons. Foot: Anatomy
Peroneal artery Peroneal Artery Ankle Joint: Anatomy Terminal branch of tibioperoneal trunk
  • Begins at lower border of popliteal fossa Popliteal fossa The popliteal fossa or the “knee pit” is a diamond-shaped, fat-filled, shallow depression on the posterior aspect of the knee joint. The popliteal fossa is located at the dorsal aspect of the knee and contains an increased number of lymph nodes as well as structures of the neurovascular system that travel from the thigh to the lower leg. Popliteal Fossa: Anatomy
  • Travels along medial border of fibula
  • Divides into calcaneal branches
Muscular branches Lateral compartment and deep layer of posterior compartment of leg

Veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins: Histology of the lower leg

There are 2 venous drainage networks in the leg: 

  • The deep venous branches unite to form the popliteal vein Popliteal Vein The vein formed by the union of the anterior and posterior tibial veins; it courses through the popliteal space and becomes the femoral vein. Popliteal Fossa: Anatomy.
  • The superficial or saphenous veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins: Histology are located in the subcutaneous tissue Subcutaneous tissue Loose connective tissue lying under the dermis, which binds skin loosely to subjacent tissues. It may contain a pad of adipocytes, which vary in number according to the area of the body and vary in size according to the nutritional state. Soft Tissue Abscess.
Origin Trajectory Tributaries Drainage
Great saphenous vein (accompanied by saphenous nerve Saphenous nerve Foot: Anatomy) Continuation of medial end of dorsal venous arch Dorsal venous arch Foot: Anatomy of the foot Foot The foot is the terminal portion of the lower limb, whose primary function is to bear weight and facilitate locomotion. The foot comprises 26 bones, including the tarsal bones, metatarsal bones, and phalanges. The bones of the foot form longitudinal and transverse arches and are supported by various muscles, ligaments, and tendons. Foot: Anatomy
  • At ankle, passes anterior to medial malleolus Medial malleolus Ankle Joint: Anatomy
  • Ascends leg medially
  • Passes behind medial condyles of femur and tibia Tibia The second longest bone of the skeleton. It is located on the medial side of the lower leg, articulating with the fibula laterally, the talus distally, and the femur proximally. Knee Joint: Anatomy
  • Drains into saphenofemoral junction
  • Short saphenous vein
  • Superficial external pudendal vein
  • Superficial epigastric veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins: Histology
  • Superficial circumflex iliac vein
  • Lateral femoral cutaneous vein
Anteromedial aspect of leg and plantar aspect of foot Foot The foot is the terminal portion of the lower limb, whose primary function is to bear weight and facilitate locomotion. The foot comprises 26 bones, including the tarsal bones, metatarsal bones, and phalanges. The bones of the foot form longitudinal and transverse arches and are supported by various muscles, ligaments, and tendons. Foot: Anatomy
Small saphenous vein (accompanied by sural nerve) Continuation of lateral end of dorsal venous arch Dorsal venous arch Foot: Anatomy of foot Foot The foot is the terminal portion of the lower limb, whose primary function is to bear weight and facilitate locomotion. The foot comprises 26 bones, including the tarsal bones, metatarsal bones, and phalanges. The bones of the foot form longitudinal and transverse arches and are supported by various muscles, ligaments, and tendons. Foot: Anatomy
  • At ankle, passes posterior to lateral malleolus Lateral malleolus Ankle Joint: Anatomy
  • Ascends in midline of posterior leg
  • Drains into saphenopopliteal junction ( variable Variable Variables represent information about something that can change. The design of the measurement scales, or of the methods for obtaining information, will determine the data gathered and the characteristics of that data. As a result, a variable can be qualitative or quantitative, and may be further classified into subgroups. Types of Variables)
Posterior aspect of leg
Medial and posterior view of the leg featuring the venous drainage of the leg

Medial and posterior views of the leg, featuring the superficial venous drainage

Image by BioDigital, edited by Lecturio

Deep veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins: Histology of the leg:

  • Located deep to the deep fascia Fascia Layers of connective tissue of variable thickness. The superficial fascia is found immediately below the skin; the deep fascia invests muscles, nerves, and other organs. Cellulitis of the leg
  • Accompany the arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology of the leg of the same name:
    • Anterior tibial veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins: Histology
    • Posterior tibial veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins: Histology
    • Peroneal veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins: Histology
  • Converge at the inferior border of popliteus Popliteus Popliteal Fossa: Anatomy muscle to form the popliteal vein Popliteal Vein The vein formed by the union of the anterior and posterior tibial veins; it courses through the popliteal space and becomes the femoral vein. Popliteal Fossa: Anatomy
Deep veins of the leg

Posterior view of the leg, featuring the deep venous drainage

Image by BioDigital, edited by Lecturio

Innervation

The sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology and motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology innervation to the lower limb is supplied by the lumbosacral plexus (L1– S4 S4 Heart Sounds).

  • Sciatic nerve Sciatic Nerve A nerve which originates in the lumbar and sacral spinal cord (l4 to s3) and supplies motor and sensory innervation to the lower extremity. The sciatic nerve, which is the main continuation of the sacral plexus, is the largest nerve in the body. It has two major branches, the tibial nerve and the peroneal nerve. Gluteal Region: Anatomy: biggest and longest nerve from the lumbosacral plexus; gives off many branches and divides into the tibial nerve Tibial Nerve The medial terminal branch of the sciatic nerve. The tibial nerve fibers originate in lumbar and sacral spinal segments (L4 to S2). They supply motor and sensory innervation to parts of the calf and foot. Popliteal Fossa: Anatomy and the common peroneal nerve Peroneal nerve The lateral of the two terminal branches of the sciatic nerve. The peroneal (or fibular) nerve provides motor and sensory innervation to parts of the leg and foot. Popliteal Fossa: Anatomy
    • Tibial nerve Tibial Nerve The medial terminal branch of the sciatic nerve. The tibial nerve fibers originate in lumbar and sacral spinal segments (L4 to S2). They supply motor and sensory innervation to parts of the calf and foot. Popliteal Fossa: Anatomy: provides motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology function to the posterior compartment in the leg and multiple sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology branches to the entire leg (sural, medial calcaneal, and medial and lateral plantar nerves); passes inferior and posterior to the medial malleolus Medial malleolus Ankle Joint: Anatomy in the ankle, through the tarsal tunnel.
      • Sural nerve: sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology supply to the skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions over the posterolateral aspect of the distal third of the leg and lateral border of the foot Foot The foot is the terminal portion of the lower limb, whose primary function is to bear weight and facilitate locomotion. The foot comprises 26 bones, including the tarsal bones, metatarsal bones, and phalanges. The bones of the foot form longitudinal and transverse arches and are supported by various muscles, ligaments, and tendons. Foot: Anatomy
    • Common peroneal nerve Peroneal nerve The lateral of the two terminal branches of the sciatic nerve. The peroneal (or fibular) nerve provides motor and sensory innervation to parts of the leg and foot. Popliteal Fossa: Anatomy ( common fibular nerve Common Fibular Nerve The lateral of the two terminal branches of the sciatic nerve. The peroneal (or fibular) nerve provides motor and sensory innervation to parts of the leg and foot. Popliteal Fossa: Anatomy): provides motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology function to the short head of the biceps femoris Biceps femoris Thigh: Anatomy, then bifurcates into two branches:
      • Deep peroneal (fibular) nerve: terminal branch of the common peroneal nerve Peroneal nerve The lateral of the two terminal branches of the sciatic nerve. The peroneal (or fibular) nerve provides motor and sensory innervation to parts of the leg and foot. Popliteal Fossa: Anatomy, provides motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology function to the anterior compartment and sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology supply to the 1st interdigital space of the foot Foot The foot is the terminal portion of the lower limb, whose primary function is to bear weight and facilitate locomotion. The foot comprises 26 bones, including the tarsal bones, metatarsal bones, and phalanges. The bones of the foot form longitudinal and transverse arches and are supported by various muscles, ligaments, and tendons. Foot: Anatomy
      • Superficial peroneal (fibular) nerve: terminal branch of the common peroneal nerve Peroneal nerve The lateral of the two terminal branches of the sciatic nerve. The peroneal (or fibular) nerve provides motor and sensory innervation to parts of the leg and foot. Popliteal Fossa: Anatomy, provides motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology function to the lateral compartment and sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology supply to the lower anterior aspect of the leg and dorsum of the foot Foot The foot is the terminal portion of the lower limb, whose primary function is to bear weight and facilitate locomotion. The foot comprises 26 bones, including the tarsal bones, metatarsal bones, and phalanges. The bones of the foot form longitudinal and transverse arches and are supported by various muscles, ligaments, and tendons. Foot: Anatomy
  • Saphenous nerve Saphenous nerve Foot: Anatomy: branch of the femoral nerve Femoral Nerve A nerve originating in the lumbar spinal cord (usually L2 to L4) and traveling through the lumbar plexus to provide motor innervation to extensors of the thigh and sensory innervation to parts of the thigh, lower leg, and foot, and to the hip and knee joints. Femoral Region and Hernias: Anatomy, arises from the femoral triangle Femoral triangle Femoral Region and Hernias: Anatomy, pure sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology function to the skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions over the medial half of the leg

Clinical Relevance

The following are common conditions associated with the lower leg:

  • Tibial fracture Fracture A fracture is a disruption of the cortex of any bone and periosteum and is commonly due to mechanical stress after an injury or accident. Open fractures due to trauma can be a medical emergency. Fractures are frequently associated with automobile accidents, workplace injuries, and trauma. Overview of Bone Fractures: most common type of long bone fracture Long Bone Fracture Buckle or Torus Fracture, usually caused by direct trauma Direct Trauma Toddler’s Fractures: Tibial fractures may occur at any point of the tibia Tibia The second longest bone of the skeleton. It is located on the medial side of the lower leg, articulating with the fibula laterally, the talus distally, and the femur proximally. Knee Joint: Anatomy and often are associated with a concomitant fracture Fracture A fracture is a disruption of the cortex of any bone and periosteum and is commonly due to mechanical stress after an injury or accident. Open fractures due to trauma can be a medical emergency. Fractures are frequently associated with automobile accidents, workplace injuries, and trauma. Overview of Bone Fractures of the fibula. There is a high risk of open fracture Fracture A fracture is a disruption of the cortex of any bone and periosteum and is commonly due to mechanical stress after an injury or accident. Open fractures due to trauma can be a medical emergency. Fractures are frequently associated with automobile accidents, workplace injuries, and trauma. Overview of Bone Fractures, neurovascular injury, compartment syndrome Compartment Syndrome Compartment syndrome is a surgical emergency usually occurring secondary to trauma. The condition is marked by increased pressure within a compartment that compromises the circulation and function of the tissues within that space. Compartment Syndrome, poor healing of the fracture Fracture A fracture is a disruption of the cortex of any bone and periosteum and is commonly due to mechanical stress after an injury or accident. Open fractures due to trauma can be a medical emergency. Fractures are frequently associated with automobile accidents, workplace injuries, and trauma. Overview of Bone Fractures, and wound infection.
  • Peripheral artery disease Peripheral artery disease Peripheral artery disease (PAD) is obstruction of the arterial lumen resulting in decreased blood flow to the distal limbs. The disease can be a result of atherosclerosis or thrombosis. Patients may be asymptomatic or have progressive claudication, skin discoloration, ischemic ulcers, or gangrene. Peripheral Artery Disease: condition due to atherosclerosis Atherosclerosis Atherosclerosis is a common form of arterial disease in which lipid deposition forms a plaque in the blood vessel walls. Atherosclerosis is an incurable disease, for which there are clearly defined risk factors that often can be reduced through a change in lifestyle and behavior of the patient. Atherosclerosis. Peripheral artery disease Peripheral artery disease Peripheral artery disease (PAD) is obstruction of the arterial lumen resulting in decreased blood flow to the distal limbs. The disease can be a result of atherosclerosis or thrombosis. Patients may be asymptomatic or have progressive claudication, skin discoloration, ischemic ulcers, or gangrene. Peripheral Artery Disease presents initially as intermittent claudication Intermittent claudication A symptom complex characterized by pain and weakness in skeletal muscle group associated with exercise, such as leg pain and weakness brought on by walking. Such muscle limpness disappears after a brief rest and is often relates to arterial stenosis; muscle ischemia; and accumulation of lactate. Thromboangiitis Obliterans (Buerger’s Disease) and may progress to ischemic pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways at rest and very commonly presents in the calves Calves Erythema Nodosum. The underlying atherosclerosis Atherosclerosis Atherosclerosis is a common form of arterial disease in which lipid deposition forms a plaque in the blood vessel walls. Atherosclerosis is an incurable disease, for which there are clearly defined risk factors that often can be reduced through a change in lifestyle and behavior of the patient. Atherosclerosis produces arterial stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS) and/or occlusion of the arterial vessels in the extremities, causing poor tissue perfusion. Clinically, as the disease progresses, hypoperfusion causes the affected extremity to become pale, cold, and paresthetic.
  • Deep vein thrombosis Deep vein thrombosis Deep vein thrombosis (DVT) usually occurs in the deep veins of the lower extremities. The affected veins include the femoral, popliteal, iliofemoral, and pelvic veins. Proximal DVT is more likely to cause a pulmonary embolism (PE) and is generally considered more serious. Deep Vein Thrombosis: Phlebothrombosis occurs when a blood clot forms in a vein in the absence of an inflammatory reaction. The most common sites of venous thrombosis Thrombosis Formation and development of a thrombus or blood clot in the blood vessel. Epidemic Typhus are the deep veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins: Histology of the leg. The most dangerous complication is when part of the clot travels to the lungs Lungs Lungs are the main organs of the respiratory system. Lungs are paired viscera located in the thoracic cavity and are composed of spongy tissue. The primary function of the lungs is to oxygenate blood and eliminate CO2. Lungs: Anatomy, causing a pulmonary embolism Pulmonary Embolism Pulmonary embolism (PE) is a potentially fatal condition that occurs as a result of intraluminal obstruction of the main pulmonary artery or its branches. The causative factors include thrombi, air, amniotic fluid, and fat. In PE, gas exchange is impaired due to the decreased return of deoxygenated blood to the lungs. Pulmonary Embolism. The thrombus can be visualized on ultrasonography. Anticoagulation Anticoagulation Pulmonary Hypertension Drugs is the main form of treatment.
  • Chronic venous insufficiency Chronic venous insufficiency Chronic venous disease is a spectrum of disorders characterized by venous dilation and/or abnormal vein function in the lower extremities resulting from venous hypertension. “Chronic venous insufficiency” refers to the more severe forms of chronic venous disease. Skin changes typically distinguish chronic venous insufficiency from milder forms of venous disease. Chronic Venous Insufficiency: When venous blood is unable to follow the normal antegrade path of return to the heart, it refluxes distally into the leg, causing venous congestion. This insufficiency presents as lower extremity edema Edema Edema is a condition in which excess serous fluid accumulates in the body cavity or interstitial space of connective tissues. Edema is a symptom observed in several medical conditions. It can be categorized into 2 types, namely, peripheral (in the extremities) and internal (in an organ or body cavity). Edema, trophic skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions changes, and discomfort.
  • Peripheral nerve injuries: A common peroneal (or fibular) nerve injury Nerve Injury Surgical Complications can present as foot Foot The foot is the terminal portion of the lower limb, whose primary function is to bear weight and facilitate locomotion. The foot comprises 26 bones, including the tarsal bones, metatarsal bones, and phalanges. The bones of the foot form longitudinal and transverse arches and are supported by various muscles, ligaments, and tendons. Foot: Anatomy drop (weakness with dorsiflexion) and numbness of the lateral leg/dorsum of the foot Foot The foot is the terminal portion of the lower limb, whose primary function is to bear weight and facilitate locomotion. The foot comprises 26 bones, including the tarsal bones, metatarsal bones, and phalanges. The bones of the foot form longitudinal and transverse arches and are supported by various muscles, ligaments, and tendons. Foot: Anatomy. Injury to the common peroneal nerve Peroneal nerve The lateral of the two terminal branches of the sciatic nerve. The peroneal (or fibular) nerve provides motor and sensory innervation to parts of the leg and foot. Popliteal Fossa: Anatomy can occur at the proximal fibula secondary to a fracture Fracture A fracture is a disruption of the cortex of any bone and periosteum and is commonly due to mechanical stress after an injury or accident. Open fractures due to trauma can be a medical emergency. Fractures are frequently associated with automobile accidents, workplace injuries, and trauma. Overview of Bone Fractures of the fibula or pressure from a cast.
  • Tarsal tunnel syndrome Tarsal tunnel syndrome Entrapment of the distal branches of the posterior tibial nerve (which divides into the medial plantar, lateral plantar, and calcaneal nerves) in the tarsal tunnel, which lies posterior to the internal malleolus and beneath the retinaculum of the flexor muscles of the foot. Symptoms include ankle pain radiating into the foot which tends to be aggravated by walking. Examination may reveal tinel’s sign (radiating pain following nerve percussion) over the tibial nerve at the ankle, weakness and atrophy of the small foot muscles, or loss of sensation in the foot. Ankle and Foot Pain: a compressive neuropathy Neuropathy Leprosy caused by compression Compression Blunt Chest Trauma of the tibial nerve Tibial Nerve The medial terminal branch of the sciatic nerve. The tibial nerve fibers originate in lumbar and sacral spinal segments (L4 to S2). They supply motor and sensory innervation to parts of the calf and foot. Popliteal Fossa: Anatomy under the flexor retinaculum Flexor Retinaculum Ankle Joint: Anatomy at the posterior–medial aspect of the ankle. Tarsal tunnel syndrome Tarsal tunnel syndrome Entrapment of the distal branches of the posterior tibial nerve (which divides into the medial plantar, lateral plantar, and calcaneal nerves) in the tarsal tunnel, which lies posterior to the internal malleolus and beneath the retinaculum of the flexor muscles of the foot. Symptoms include ankle pain radiating into the foot which tends to be aggravated by walking. Examination may reveal tinel’s sign (radiating pain following nerve percussion) over the tibial nerve at the ankle, weakness and atrophy of the small foot muscles, or loss of sensation in the foot. Ankle and Foot Pain is often secondary to trauma, rheumatoid arthritis Rheumatoid arthritis Rheumatoid arthritis (RA) is a symmetric, inflammatory polyarthritis and chronic, progressive, autoimmune disorder. Presentation occurs most commonly in middle-aged women with joint swelling, pain, and morning stiffness (often in the hands). Rheumatoid Arthritis, postsurgical changes, ganglionic cysts Cysts Any fluid-filled closed cavity or sac that is lined by an epithelium. Cysts can be of normal, abnormal, non-neoplastic, or neoplastic tissues. Fibrocystic Change, and wearing tight shoes and presents as pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways and paresthesia in the medial–plantar surface of the foot Foot The foot is the terminal portion of the lower limb, whose primary function is to bear weight and facilitate locomotion. The foot comprises 26 bones, including the tarsal bones, metatarsal bones, and phalanges. The bones of the foot form longitudinal and transverse arches and are supported by various muscles, ligaments, and tendons. Foot: Anatomy, particularly while walking and standing.

References

  1. Drake, R. L., Vogl, A. W., Mitchell, A. W. M. (2014). Gray’s Anatomy for Students (3rd ed.). Philadelphia, PA: Churchill Livingstone.
  2. Moore, K. L., Dalley, A. F., & Agur, A. M. R. (2014). Clinically Oriented Anatomy (7th ed.). Philadelphia, PA: Lippincott Williams & Wilkins.
  3. Netter, F. (2019). Atlas of Human Anatomy (7th ed.). Philadelphia, PA: Saunders.

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