Lower Extremity Muscles PDF

Dr Mojtaba Karimipour Department of Anatomical Sciences Urmia University of Medical Sciences Urmia, Iran  The fascia of the lower limb The fascia of the lower limb is made up of the superficial and deep fascia. The superficial fascia lies deep to skin and is made up of loose connective...

Dr Mojtaba Karimipour Department of Anatomical Sciences Urmia University of Medical Sciences Urmia, Iran  The fascia of the lower limb The fascia of the lower limb is made up of the superficial and deep fascia. The superficial fascia lies deep to skin and is made up of loose connective tissue. This layer is continuous with the superficial fascia at the lower margin of the anterior abdominal wall and gluteal region. The deep fascia of the thigh (fascia lata) is a tough fibrous sheath that envelops the whole of the thigh like a sleeve( like a strong, extensible, and elasticated stocking. It begins proximally around the iliac crest and inguinal ligament and ends distal to the bony prominences of the tibia. It is continuous with what is renamed the deep fascia of the leg (also known as the crural fascia). An ovoid hiatus known as the saphenous opening is present in the fascia lata just inferior to the inguinal ligament. The great saphenous vein passes through the saphenous opening and finally empty into the femoral vein. The iliotibial band (ITB) or tract is a lateral thickening of the fascia lata in the thigh and serves as an important structure involved in lower extremity motion Proximally it splits into superficial and deep layers, and receives most of the tendon of gluteus maximus and tensor fasciae latae muscles. It’s primary action is to stabilize the hip and knee The IT band stabilizes the knee both in extension and in partial flexion, and is therefore used constantly during walking and running.. Intermuscular septum of thigh The intermuscular septum of thigh is a fold of deep fascia in the thigh, which divided the thigh into 3 compartments including:  Anterior compartment  Medial compartment  Posterior compartment Intermuscular septum of thigh attach to linea aspera of the femur  Muscle compartments of the Thigh  Anterior compartment  Medial compartment  Posterior compartment These compartments are separated by intermuscular septum (a dense fold of deep fascia) Each compartment contains a number of muscles Muscles in anterior compartment of the Thigh The sartorius muscle is the longest muscle in the human body. Together with the quadriceps femoris, it belongs to the anterior muscles of the thigh. The sartorius muscle has an oblique course throughout the thigh; it arises from the anterior superior iliac spine, crosses to the medial side of the thigh, and finally inserts to the medial side of the proximal tibia. Due to its oblique course, the sartorius muscle flexes, abducts and externally rotates the thigh, and flexes and internally rotates the leg. The quadriceps femoris muscle, commonly known as the quad muscle, is the strongest muscle of the human body. It is located in the anterior compartment of the thigh, together with the sartorius. The quadriceps femoris muscle translates to “four- headed muscle” from Latin. It consists of four individual muscles;  rectus femoris, arises from hip bone  vastus medialis, arises from femur  vastus lateralis, arises from femur Nerve: Femoral nerve Out of all four muscles, only the rectus femoris crosses both the hip and knee joints. The others cross only the knee joint. These muscles differ in their origin, but share a common quadriceps femoris tendon which inserts into the patella. The function of the quadriceps femoris muscle is to extend the leg at the knee joint and to flex the thigh at the hip joint The tendons of the four muscles that collectively form the quadriceps femoris muscle (i.e. the rectus femoris, vastus lateralis, vastus medialis and vastus intermedius muscles) converge to form a single tendon of quadriceps femoris. The fibers of this tendon travel superficial to the patella, where they become continuous with the patellar ligament, which inserts onto the tibial tuberosity. The iliopsoas is a muscle in the anterior compartment of the thigh. It is comprised of two separate muscles; the psoas major and iliacus. These muscles arise in the pelvis and pass under the inguinal ligament into the anterior compartment of the thigh – where they form a common tendon. Attachments: Psoas major – originates from the lumbar vertebrae Iliacus – originates from the iliac fossa of the pelvis. They insert together onto the lesser trochanter of the femur. Actions: Flexion of the the thigh at the hip joint. Innervation: Psoas major – anterior rami of L1-3 Iliacus – femoral nerve.  The tensor fasciae latae muscle belongs to the group of gluteal muscles and it can be easily palpated.  The tensor fasciae latae (TFL) is a muscle located in the proximal anterolateral thigh, situated between the superficial and deep fibres of the iliotibial tract.  The Tensor fasciae latae arises from the anterior part of the iliac crest and the anterior superior iliac spine  It is inserted between the two layers of the iliotibial band of the fascia lata  Nerve: Superior gluteal nerve  Action: Assists in medial rotation, abduction, and flexion of thigh at hip joint. Furthermore, the TFL works with the IT band to stabilize the knee in full extension Muscles in medial compartment of the Thigh The muscles of the medial compartment (adductor compartment) are one of three subgroups of the thigh muscles. Overall, these muscles mainly act to adduct the thigh at the hip joint. The muscles of the medial compartment of thigh consist of the: - pectineus; - adductor magnus; - adductor longus; - adductor brevis; - gracilis; - obturator externus. These muscles arise from hip bone and insert to femur All muscles in this compartment, except a part of the adductor magnus are innervated by the obturator nerve. Adductor magnus is innervated by the obturator and sciatic nerves  Muscles in posterior compartment of the Thigh (Hamstring) These muscles are:  Biceps femoris  Semimembranosus  Semitendinosus muscles. The actions of the hamstrings include hip extension, knee flexion. Collectively the hamstrings are innervated by the sciatic nerve They mainly arise from ischial tuberosity and inserted to tibia and fibula The femoral triangle (Scarpa’s triangle) is a triangular space located in the upper thigh beneath the inguinal ligament. The femoral triangle is bordered by: Adductor longus muscle medially Sartorius muscle laterally Inguinal ligament forming the base of the triangle The floor of the femoral triangle consists of several muscles from lateral to medial, including iliacus and psoas major (collectively known as iliopsoas), pectineus, and adductor longus muscles. Contents: From lateral to medial, the femoral triangle contains the femoral nerve, femoral artery, femoral vein, and femoral canal The gluteal muscles are a group of muscles that make up the buttock area The gluteal muscles consists of the superficial and deep gluteal muscles The superficial gluteal muscles: Gluteus maximus Gluteus medius Gluteus minimus The gluteus maximus is the most superficial gluteal muscle that forms the prominence of the gluteal region The gluteus maximus is the main extensor muscle of the hip in humans The Gluteus Maximus (GM) muscle is the largest and most powerful in the human body Gluteus maximus Origin: Ilium, iliac crest, posterior inferior aspect of sacrum and coccyx, and sacrotuberous ligament Insertion: Primarily in fascia lata at the iliotibial band; also into the gluteal tuberosity on posterior femoral surface Action: Major extensor of hip joint, assists in laterally rotating the thigh Innervation: Inferior gluteal nerve  Gluteus medius The gluteus medius is located directly under the gluteus maximus. It originates from outer surface of ilium Its insertion is greater trochanter of the femur ACTION: Abduction of the hip joint NERVE: Superior gluteal nerve Gluteus medius is an important muscle in walking, running, and single-leg weight-bearing because it prevents the opposite side of the pelvis from dropping during these activities. When a limb is taken off the ground, the pelvis on that side will tend to drop through a loss of support from below. Gluteus medius works to maintain the side of the pelvis that drops, therefore allowing the other limb to swing forward for the next step Gluteus minimus Gluteus minimus muscle is the smallest one of the three gluteal muscles, it lies deep to the gluteus medius muscle. The gluteus minimus is similar to the gluteus medius in function, structure, nerve and blood supply Gluteus minimus acts in synergy with the gluteus medius to produce the movements on the hip joint; the internal rotation and abduction of the thigh. Moreover, this muscle is an important stabilizer of the pelvis in the gait cycle. Waddling gait In waddling gait weakness in the gluteus medius muscles leads the hip on the swinging side to drop during gait, in an attempt to counteract, the patient bends the trunk towards the other side, resulting in the gait to appear waddling.  Deep gluteal muscles The deep gluteal muscles are a set of smaller muscles, located underneath the gluteus minimus. The general action of these muscles is to laterally rotate the lower limb. They also stabilise the hip joint by ‘pulling’ the femoral head into the acetabulum of the pelvis. Piriformis The piriformis muscle is a key landmark in the gluteal region. It is the most superior of the deep muscles. Obturator Internus The Gemelli – Superior and Inferior Quadratus Femoris Landmark of the Gluteal Region The piriformis is an important anatomical landmark in the gluteal region. As the muscle travels through the greater sciatic foramen, it effectively divides the gluteal region into an inferior and superior part. This division determines the name of the vessels and nerves that supply the area. In addition, the piriformis can be used to locate the sciatic nerve (a major peripheral nerve of the lower limb). The sciatic nerve enters the gluteal region directly inferior to the piriformis, and is visible as a flat band, approximately 2cm wide. By Anatomically, the leg is defined as the region of the lower limb below the knee. It consists of a posterior, anterior and lateral compartment. In accordance, the muscles of the leg are organized into three groups: Anterior (dorsiflexor) group or compartment, which contains: Tibialis anterior Extensor digitorum longus Fibularis tertius Eextensor hallucis longus Muscles in this group act to dorsiflex and invert the foot These muscles are collectively innervated by the deep fibular nerve  The posterior group of muscles primarily produce plantar flexion of the foot at the ankle joint Nerve: tibial Posterior (plantar flexor) group or compartment, which consists of A superficial layer comprised of: Gastrocnemius Plantaris Soleus, And a deep layer comprised of: Tibialis posterior Flexor hallucis longus Popliteus Flexor digitorum longus  Gastrocnemius The gastrocnemius muscle is a superficial two-headed muscle that is in the back part of the lower leg of humans AND is responsible for normal walking and running actions. The lateral and medial heads of the gastrocnemius muscle arise from the lateral and medial epicondyle of the femur, respectively The gastrocnemius muscle and the soleus (another muscle of the calf), join together at the Achilles tendon and insert on the back side of heel bone, called the calcaneus Action: Plantar flexes foot and flexes knee ; the muscle provides the propelling force in running and jumping.  Plantaris The Plantaris muscle is a small muscle with a short belly is one of the superficial muscles of the superficial posterior compartment of the leg The Plantaris is placed between the Gastrocnemius and Soleus It arises from the femur It forms a long slender tendon which crosses obliquely between the two muscles of the calf, and runs along the medial border of the tendo calcaneus, It blends with the calcaneal tendon ( Achilles tendon) and inserts onto the calcaneus Action: Plantar flexes foot and flexes knee Soleus The soleus is a large muscle on the back of lower leg It lays immediately deep to the gastrocnemius This powerful muscle arises from the back of tibia and attaches to heel (calcaneous) bone as part of the Achilles tendon The soleus muscle is active during activities like walking, running, and jumping The word soleus comes from the Latin term "solea," which means sandal Its major action is plantarflexion of the ankle joint The soleus muscle also functions to help pump blood from lower leg back to the heart Deep layer of the posterior group of leg muscles Deep layer comprised of Tibialis posterior Flexor hallucis longus Popliteus Flexor digitorum longus Muscles within this compartment primarily produce ankle plantarflexion and toe flexion, with exception of the popliteus which acts on the knee. Tendons of tibialis posterior, flexor hallucis longus and flexor digitorum longus muscles pass through the tarsal tunnel beneath the flexor retinaculum and insert into the sole, enabling plantar flexion at the ankle joint The tarsal tunnel is a passage found along the inner leg underneath the medial malleolus of the ankle The roof of the tarsal tunnel is formed by the flexor retinaculum of the foot The floor of the tarsal tunnel is formed by the medial malleolus and the calcaneus Contents of the tarsal tunnel Tibialis posterior tendon Flexor digitorum longus tendon Posterior tibial artery Posterior tibial vein Tibial nerve Flexor hallucis longus tendon  Tarsal tunnel syndrome (TTS) The tarsal tunnel syndrome is caused by a compression of the tibial nerve and causes pain, tingling or numbness in the foot.  Popliteus The popliteus is a muscle within the deep compartment of the posterior leg. It lies behind the knee joint Attachments: Originates from the lateral condyle of the femur and the lateral meniscus of the knee joint. It inserts onto the proximal tibia Actions: - stabilizes knee joint -unlocks knee joint so that flexion can occur (laterally rotates femur on fixed tibia)  Lateral (fibular) group or compartment , which consists of: Fibularis longus ibularis brevis