5 Joints of the Lower Limb
JOINTS OF THE LOWER LIMB
Learning Objectives
- Describe the basic functions of the hip, knee, and ankle joints during locomotion
- Identify the bony, cartilaginous, ligamentous, and membranous components of these joints. List the movements permitted at each joint and the ligaments that restrict them.
- Correlate joint movements with the muscles producing these actions at each joint.
- Describe the blood and nerve supply of the joints and, in particular, the effect of interruption of blood to the head and neck of the femur.
- Identify and describe the structure and function of the knee joint and, in particular, the effects of injury to the ligaments and menisci.
- Identify the structure of the ankle and foot joints and describe how the joints and ligaments provide firm footing but flexibility of movement.
Reference: Moore, Clinically Oriented Anatomy, Chapter 5
Particularly Relevant Blue Boxes in Moore:
●Fractures of Femoral Neck, p. 659
●Dislocation of Hip Joint, p. 660-661
●Genu Valgum and Genu Varum, p. 661
●Patellar Dislocation, p. 661-662
●Knee Joint Injuries, p. 662-663
●Bursitis of the Knee Joint, p. 664-665
●Popliteal Cysts, p. 665
●Ankle Injuries, p. 665-666
●Tibial Nerve Entrapment, p. 666-667
To access the Netter Presenter Database click here
To access the Primal Pictures software click here
Check out the Primal Pictures model of the Knee Joint
Grant’s Dissector, 15th Edition, pp 198 – 203
Joints of the Lower Limb
Hip Joint (Netter 474; Moore p. 626-634)
The hip joint is a “ball and socket” synovial joint. It is modified to provide maximum stability with decreased mobility. The head of the femur fits within the acetabulum of the os coxae (hip bone). The acetabular fossa is deepened by the circular acetabular labrum, which forms a fibro-cartilaginous rim. The head of the femur is attached to the pelvis through the ligamentum teres, which has a nutrient vessel passing through its core. The joint capsule, extending from pelvis to femur, essentially covers the neck of the femur. There is an intra-articular fat pad in the joint, located near the ligamentum teres. A synovial membrane lines the capsule, but does not cover the articular surfaces of the bones.
Osteology – Proximal Femur (anterior view)
The rounded head of the femur is attached at an angle (115o to 140o) to the proximal shaft (or body) by the neck. A bony ridge known as the intertrochanteric line, interconnects the greater trochanter and the lesser trochanter. The greater trochanter serves as an attachment for the gluteus medius, minimus, and piriformis muscle, while the lesser trochanter is the attachment for the iliopsoas muscle.
Osteology – Proximal Femur – Netter 476 (posterior view)
There are many specialized bony prominences that act as attachment sites for the muscles in this region. The intertrochanteric crest provides the insertion site for the quadratus femoris muscle. The pectineal line, on the posterior aspect of the femur, is the attachment point for the pectineus muscle and the gluteal tuberosity is where the gluteus maximus muscle attaches. The linea aspera, on the posterior aspect of the femur, has a medial and lateral lip. The medial lip provides partial origin for the vastus medialis muscle, while the lateral lip provides partial origin for the vastus lateralis muscle. There is a nutrient foramen, which allows passage of a nutrient artery to supply blood to the shaft of the femur (a branch from the second perforating branch of the deep femoral artery).
Hip Joint – Capsule and Ligaments (Netter 474)
The articular capsule is made up of a very strong connective tissue that attaches to the os coxae along the bony rim of the acetabulum and the transverse ligament of the acetabulum. The capsule attaches to the femur anteriorly along the intertronchanteric line. The articular capsule covers only about 2/3 of the neck of the femur. Superficial fibers run longitudinally from pelvis to femur, while the deep fibers (zona orbicularis) run circularly, particularly in the posterior region of the capsule.
Upon extension of the hip joint, the circular fibers cause the head of the femur to closely approximate the acetabulum. In this position the hip joint reaches maximum stability.
The capsule is augmented externally by three distinct bands of very dense connective tissue:
1. Iliofemoral – the “Y” ligament of Bigelow, so-called for its inverted “Y” appearance, attaches at the inferior border of anterior inferior iliac spine and passes to the intertrochanteric line. This ligament helps to maintain posture when standing by holding the head of the femur in the acetabulum. When the ligament is tensed, it also helps to prevent the trunk from falling back and posture is maintained.
2. Pubofemoral – This ligament is located in the medial and inferior portion of the capsule. It arises from pubic portion of acetabular rim as well as the obturator crest of the superior ramus of pubis. The ligament passes to the lowermost fibers of iliofemoral ligament for attachment.
3. Ischiofemoral – This ligament covers the posterior portion of the capsule. It passes from the ischial portion of the acetabular rim upward and laterally, to attach at the anterior-superior neck region near base of greater trochanter.
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Hip Joint – Arterial Supply (Netter 491; Moore 632) The major arterial supply to the proximal femur comes from the medial femoral circumflex artery. It passes posteriorly to the neck and supplies both the neck and head regions. The lateral femoral circumflex artery (transverse branch), also supplies the hip region. It passes anterior to the anatomic neck of the femur and supplies the neck and greater trochanter regions. The medial and lateral circumflex humeral arteries contribute to an anastamosis around the neck of the femur. Retinacular branches of the medial and lateral circumflex humeral arteries supply the head and neck of the femur. The artery that passes through the ligamentum capitus femoris (artery of the ligament of the head) is a branch of the obturator artery. This vessel is usually of minor significance in supplying the head of the femur. |
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Clinical Note: A fracture through the surgical neck of the femur (between the head and greater trochanter) is dangerous and can lead to necrosis of the tissue. The closer a fracture occurs to the head, the more likely the head will undergo necrosis due to a lack of adequate blood supply. These are called intracapsular fractures because they occur within the capsule of the joint. An extracapsular fracture (closer to the greater trochanter), will maintain a greater blood supply to the neck and head regions (Blue Box 659). Coxa valga is an alteration of the angle made by the axis of the femoral neck to the axis of the femoral shaft so that the angle exceeds 135 degrees and thus the femoral neck becomes straighter. Coxa vara is an alteration of the angle made by the axis of the femoral neck to the axis of the femoral shaft so that the angle is less than 135 degrees and thus the femoral neck becomes more horizontal. |
Hip Joint – Nerve Supply
Posteriorly, the nerve supply to the hip joint is supplied by a branch of the nerve to the quadratus femoris muscle and a branch of superior gluteal nerve. Anteriorly, branches from the femoral nerve (which supply rectus femoris) supply the hip joint
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Clinical Notes: In a diseased hip, pain may be referred to the medial side of the knee through branches of the obturator nerve, which pass through both joints. Congenital dislocation of the hip (hip dysplasia) joint is characterized by movement of the head of the femur out of the acetabulum. The head typically ruptures through the capsule onto the gluteal surface of the ileum. This occurs because of faulty development of the upper lip of the acetabulum and results in shortening, adduction, and medial rotation of the affected limb |
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Hip Fractures: Although a true hip fracture involves the hip joint, the following four proximal femur fractures are commonly referred to as hip fractures. The differences between the four fractures are important because each is treated differently.
The classic clinical presentation of a hip fracture in an elderly patient is an individual who sustains a low-energy fall, now has pain, and is unable to bear weight. On examination, the affected extremity is often shortened and externally rotated. |
Knee Joint (Netter 494, 495, 496, 497, 498; Moore 634-645)
The knee joint is a dynamic hinge joint that joins the thigh and leg. The articular capsule cannot be separated from the ligaments and aponeurosis associated with the knee joint.
Anterior View
The patella is a sesamoid bone within the strong quadriceps tendon, which attaches to the tibial tuberosity. The patellar ligament connects the inferior border of the patella to the tibial tuberosity. Aponeurotic fibers from the vastus medialis and lateralis muscles attach to the medial and lateral borders of the patellar ligament. These medial and lateral patellar retinacula help to strengthen the joint capsule as well as stabilize the patella.
Posterior View
The oblique popliteal ligament is composed mainly of fibers from the tendinous insertion of the semimembranosus muscle. This ligament passes in a lateral, superior direction in order to reinforce the posterior capsule. The arcuate popliteal ligament arises from the head of the fibula, arches supero-medially over the popliteus muscle, and spreads out over the posterior capsule. Large foramina allow for the passage of blood vessels and nerves to enter the joint cavity.
Medial and Lateral Collateral Ligaments (Netter 496)
The medial (tibial) collateral ligament arises from medial epicondyle of the femur and inserts deep to the pes anserinus on the medial condyle of the tibia. This ligament is flat, sheet-like, and can be divided into superficial and deep layers. The deep layer attaches to the medial meniscus and can be further subdivided into a menisco-femoral and menisco-tibial portion.
The lateral (fibular) collateral ligament is a rounded, pencil-like cord. It attaches to the tubercle on the lateral epicondyle of the femur above and behind the groove for the popliteus muscle. It extends down and inserts on the superior aspect of the medial head of the fibula. The tendon of the popliteus muscle passes deep to the lateral collateral ligament. The tendon of the biceps femoris muscle divides on either side of the lateral collateral ligaments lower attachment. The lateral collateral ligament does not attach to the lateral meniscus.
The Cruciate Ligaments
The cruciate ligaments lie within the joint capsule of the knee. These two strong rounded ligaments cross each other like the limbs of an “X”. The anterior cruciate ligament arises in front of the intercondylar eminence of the tibia and passes upward and backward to the medial aspect of the lateral femoral condyle. The posterior cruciate ligament extends from the posterior intercondylar eminence of the tibia to the lateral side of the medial condyle of the femur. The anterior cruciate prevents anterior displacement of the tibia on the femur and the posterior prevents posterior displacement of the tibia.
The meniscofemoral ligament, a subdivision of the posterior cruciate ligament, inserts into the posterior horn of the lateral meniscus and draws the meniscus posteriorly as the lateral femoralcondyle slides posteriorly on teh tibial plateau with flexion
The Menisci (Netter 495)
The menisci or semilunar cartilages of the knee joint consist of two crescent plates of fibro-cartilage. The lateral meniscus has the form of a closed “C”, while the medial meniscus has a more open “C” shape. The horns of the menisci are attached to the intercondylar area of the tibia and the peripheral portions attach to the loose coronary ligament of the capsule. The medial meniscus is also attached to the deep portion of the medial collateral ligament.
Genicular Anastomosis (Netter 499)
Within the popliteal space, the popliteal artery gives off five genicular arteries, which contribute to the anastomosis around the knee joint. Four of the arteries are paired, superior and inferior, and there is an unpaired middle artery. The middle genicular artery passes through the oblique popliteal ligament and enters the knee joint serving as the major supply to the posterior cruciate ligament.
The superior lateral genicular artery joins with a descending branch of the lateral femoral circumflex artery to form collateral circulation. The superior medial genicular forms a collateral with the supreme genicular artery. The inferior lateral genicular forms a collateral with the anterior tibial recurrent artery, while the inferior medial genicular completes the collateral circulation on the lower, medial side of the knee joint.
While there is an extensive collateral blood supply around the knee, a sudden occlusion of the popliteal artery will usually result in loss of the leg. This is due to the inability of these collaterals to open quickly and sufficiently enough to compensate for loss of flow through the popliteal artery. However, a slow occlusion within the adductor canal may allow for the collaterals to open up to some extent. In this case, the patient will usually develop a condition called “intermittent claudication” that results in leg pain during exercise from an insufficient blood supply. Note: In the lab, try to find as many of these genicular arteries as you can.
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Clinical Considerations Unhappy triad of the knee joint may occur when an athlete’s cleated shoe is planted firmly on the ground and the knee is struck from the lateral side. A knee that is markedly swollen, particularly in the suprapatellar region, is a typical indication of this condition. There is often tenderness when pressure is applied along the extent of the tibial collateral ligament. It is characterized by:
Demonstration of the Anterior Drawer Test, to examine the knee for damage to the ACL, is shown here in this Youtube video. Click here to view a video on “Clinical Evaluation of the Knee” – from the NEJM ‘s series of Videos in Clinical Medicine. Pre-patellar bursitis (housemaid’s knee) is inflammation and swelling of the pre-patellar bursa. Click here to view a video demonstrating arthrocentesis of the knee – from the New England Journal of Medicine’s series on Videos in Clinical Medicine. A Popliteal (Baker’s cyst) is a swelling behind the knee, resulting from synovial fluid that escapes posteriorly through the joint capsule. It impairs flexion and extension of the knee joint. Knock-knee (genu valgum) is a deformity in which the tibia is bent or twisted laterally. It may occur as a result of collapse of the lateral compartment of the knee and rupture of the medial collateral ligament. Bowleg (genu varum) is a deformity in which the tibia is bent medially. It may occur as a result of collapse of the medial compartment of the knee and rupture of the lateral collateral ligament. Osteoarthritis. The knee is a common site for this disease. Joggers and obese individuals are prone to its development. Osteoarthritis appears radiographically as a narrowing of the joint cavity with degenerative changes (see this image). |
The Ankle Joint (Netter 531, 514; Moore 647-650)
The important bony articulations of the foot occur in relation to the talus and to a lesser extent, the calcaneus. The ankle joint is a mortise-and-tenon type of hinge joint, formed by wedging the talus into the squared channel between the medial (tibial) and lateral (fibular) malleoli. It permits primarily flexion (plantarflexion) and extension (dorsiflexion) of the joint. The other articulations, which are necessary for the eversion and inversion of the foot, occur between the talus and calcaneus (subtalar or talocalcaneal joints) and between talus/calcaneus and the 5 small tarsals (transverse talar joint).
Medial Side of Ankle Joint (Netter 516)
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As the long flexor tendons pass distally from the deep posterior compartment, a rearrangement of the tendons occurs. They rearrange to ensure they pass posterior to the medial malleolus in the following order (anterior to posterior): |
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. Tibialis posterior
This is the mnemonic: Tom, Dick and Harry The tendons and neurovascular bundle lie superficial to the deltoid ligament. The tendon for flexor hallucis longus passes inferior to the sustentaculum tali. |
Ligaments of the Ankle Joint
Lateral Side of Ankle Joint (Netter 514, 516)
Lateral side: There are three ligaments that prevent inversion of the foot: the anterior talo-fibular, posterior talofibular, and calcaneofibular ligaments. The anterior and posterior tibiofibular ligaments interconnect the tibia and fibula.
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The tendons for the peroneus longus and brevis muscles, pass posterior to the lateral malleolus. The peroneus brevis tendon inserts on the base of the 5th metatarsal, while the tendon for the peroneus longus passes deep within the sole of the foot to insert on the 1st metatarsal and the
medial cuneiform. These tendons are held in place by the superior and inferior peroneal retinacula (Netter 517) |
Medial Side of the Ankle Joint (Netter 514)
The deltoid ligament is a triangular ligament that attaches the medial malleolus to the talus and calcaneus bones. The superficial fibers attach along the sustentaculum tali and the deep fibers attach the medial malleolus to the talus.
This ligament prevents eversion of the foot. Weakness of this ligament, allows eversion and places greater weight on the medial side of the arch; this may be a pre-disposing factor in flatfoot. Ligaments on both the medial and lateral sides of the ankle prevent the posterior displacement of the calcaneus with regard to the tibia, fibula, and talus.
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Clinical Note: “Twisting” an ankle, or forced eversion or inversion of the foot, may produce a painful sprain. A sprain results in torn or stretched ligaments with marked swelling and disability. Forced eversion would affect the deltoid ligament and forced inversion affects the lateral ligaments (including the anterior talofibular ligament). |
Joints of the Lower Limb quiz click here
Structure List For the Lower Limb
Bony and CT Landmarks
Pelvis
Anterior/posterior superio/inferior iliac spines
ilium, ischium, pubis
Pubic tubercle
Inguinal ligament
ischial tuberosity, ischial spine
Obturator foramen, iliac fossa
iliac crest
Femur:
Greater trochanter
Lesser trochanter
Linea aspera
Adductor tubercle
Fascia lata
Iliotibial tract (band)
Tibial tuberosity
Muscles
Anterior Thigh
Sartorius
Iliopsoas
Pectineus
Quadiceps femoris:
Rectus femoris
Vastus medialis, lateralis, intermedius
Medial thigh
Adductor longus
Adductor brevis
Adductor magnus
Gracilis
Obturator externus
Pectineus
Blood Vessels and Lymphatics
Great saphenous vein
Inguinal and femoral lymph nodes
Fenoral artery and vein
Profunda femoris
Lateral femoral circumflex artery
Medial femoral circumflex artery
Nerves
Cutaneous and motor branches of femoral nerve, especially saphenous nerve
Obturator nerve: anterior and posterior divisions
Gluteal Region and Posterior Thigh
Bony landmarks
Ischial tuberosity/spine
Sacrotuberous/sacrospinous ligaments
Greater/lesser sciatic foramina
Muscles
Gluteus maximus, medius, minimus
Tensor fascia lata
Piriformis
Obturator internus
Superior/inferior gemelli
Quadratus femoris
Nerves/arteries
Inferior gluteal nerve and artery
Superior gluteal nerve and artery
Sciatic nerve
Pudendal/internal pudendal nerve and artery
Popliteal Area and Knee
Medial/lateral condyles of femur/tibia
Head and neck of fibula
Patella
Tibial tuberosity
“Pes anserinus” (insertions of sartorius,gracilis and semitendinosus)
Medial/lateral collateral ligaments
Medial/lateral menisci
Anterior/posterior cruciate ligaments
Muscles
Popliteus
Gastrocnemius
Blood Vessels
Popliteal artery and vein
Geniculate arterial anastomoses
Tibial nerve
Common peroneal nerve
Leg and Foot
Medial/lateral malleolus
Bones of foot
Tuberosity of 5th metatarsal
Sustentaculum tali
Deltoid ligament (medial)
Lateral ligaments
Anterior talofibular ligament
Calcaneofibular ligament
Anterior inferior tibiofibular ligament
Posterior Leg
Muscles
Gastrocnemius
Soleus
Plantaris
Flexor digitorum longus
Flexor Hallucis longus
Tibialis posterior
Blood Vessels
Posterior tibial artery
Peroneal (Fibular) artery
Tibial nerve
Lateral leg
Muscles
Peroneus longus/brevis
Superficial peroneal nerve
Anterior Leg, Dorsum of Foot
Muscles
Tibialis Anterior
Extensor Hallucis longus
Peroneus tertius
Extensor hallucis brevis
Extensor digitorum brevis
Blood Vessels
Anterior tibial artery
Dorsalis pedis artery
Deep peroneal nerve
Terminal cutaneous branches of deep/superficial nerve