Human AnatomyFDULE2 (1).docx

Human Anatomy Fairleigh Dickinson University Spring 2024 CH 36- The thigh. This is broken up into three fascial compartments (anterior, medial, and posterior). The ANTERIOR thigh compartment muscles are collectively innervated by the femoral nerve (L2-L4). They include the following: Iliopsoas muscl...

Human Anatomy Fairleigh Dickinson University Spring 2024 CH 36- The thigh. This is broken up into three fascial compartments (anterior, medial, and posterior). The ANTERIOR thigh compartment muscles are collectively innervated by the femoral nerve (L2-L4). They include the following: Iliopsoas muscle-Made up by the psoas major muscle and the iliacus muscle. This flexes and rotates the hip. Sartorius muscle-The longest muscle in the body. Runs from the ASIS to the medial border of the tibial tuberosity. The gracilis and the semitentinosus muscles also attach at the medial tibial tuberosity. The Sartorius serves a number of actions to include flexion, abduction, and external rotation of the hip, along with flexion of the knee joint. The quadriceps femoris muscle group. These are four separate muscles but all serve to extend the knee. Their origins vary, but they all attach to the patella via the quadriceps tendon, then insert onto the tibial tuberosity. The individual muscles in this group are the rectus femoris, vastus lateralis, vastus intermedius, and the vastus medialis muscles. The MEDIAL thigh compartment muscles are collectively innervated by the obturator nerve (L2-L4), with the exception of the pectineus muscle. Given their medial location, they serve mostly to adduct the hip. The muscles in this group include the following: Pectineus muscle-Innervated by the FEMORAL nerve. This adducts and flexes the hip joint. This is superomedially located in the anterior thigh compartment. Adductor brevis muscle-The most proximal of the adductor muscles. This adducts and internally rotates the hipjoint. Adductor longus-Just distal to the above and also adducts and internally rotates the hip joint. Adductor magnus muscle-Made up of an adductor (pubofemoral) and a hamstring (ischiocondylar) division. The adductor canal runs between these two divisions and contains the femoral artery and vein. The adductor division attaches to the inferior pubic ramus and linea aspera. It adducts and internally rotates the hip joint. The hamstring division attaches to the ischiopubic ramus, ischial tuberosity and the adductor tubercle. This adducts the hip joint. This is innervated by the TIBIAL nerve. Gracilis muscle-Strap like in shape. It attaches to the inferior pubic ramus and the medial surface of the proximal shaft of the tibia. This adducts the hip and flexes the knee. Obturator externus muscle-Attaches to the external surface of the obturator membrane and the trochanteric fossa. This externally rotates the hip. The POSTERIOR thigh compartment-Are primarily extensors of the hip or flexors of the knee as a result of the posterior location. They are mostly innervated by the tibial nerve with the exception of the short head of the biceps femoris. These compartment muscles are as follows: Semitendinosus muscle-Attaches to the ischial tuberosity and the proximal tibia. This extends the hip joint and flexes and internally rotates the knee joint. Semimembranosus muscle-attaches to the ischial tuberosity and medial tibial condyle. This extends the hip joint and flexes and internally rotates the knee joint. Biceps femoris (long head) muscle-Attaches to the ischial tuberosity and fibular head. This extends the hip and flexes and externally rotates the knee joint. Along with the two posterior thigh compartment muscles listed above, the long head of the biceps femoris makes up the ”HASMTRING” muscle group. Biceps femoris (short head)-Attaches to the linea aspera and fibular head. This flexes and externally rotates the knee joint. This muscle is innervated by the COMMON FIBULAR NERVE. The vascularization of the thigh is primarily from the femoral artery and its branches along with some contributions from the obturator artery and its branches. The obturator artery branches off the internal iliac artery, exits the pelvis through the obturator foramen, and divides into anterior and posterior divisions. These serve to supply the medial compartment of the thigh and the femoral head. The femoral artery gives rise to the profunda femoris or deep femoral artery. This artery in turn forms the perforating branches that supply the posterior thigh, lateral circumflex femoral artery, and medial circumflex femoral artery, that supply the hip joint and the head of the femur. The venous system is basically matching the arteries. The femoral triangle-Located in the inguinal region and contains (from lateral to medial) the femoral nerve, artery, vein, and lymphatics (NAVL). The borders of the femoral triangle are the sartorius muscle, the adductor longus muscle, and the inguinal ligament. There is a connective tissue femoral sheath that surrounds the vessels/lymph, but not the femoral nerve. The knee joint-Rather detailed due to its great degree of movements, responses (accel/decel), along with weight bearing. The joint itself is made up of a tibiofemoral joint and a patellofemoral joint which share the same synovial capsule. This capsule is supported by the following ligaments: Patellar ligament-Transmits forces produced by the quadriceps muscles to the tibia. This is basically a continuation of the quadriceps femoris tendon that attaches between the patella and tibial tuberosity. Medial (tibial) collateral ligament-Attaches to the medial epicondyle of the femur, medial meniscus, and tibial condyle. This resists valgus forces on the knee. Lateral (fibular) collateral ligament-Attaches to the lateral femoral epicondyle and fibular head. This resists varus forces on the knee. There are also ligaments within the capsule. These include the anterior cruciate ligament, which resists anterior translation of the tibia on the femur OR posterior translation of the femur on the tibia. The posterior cruciate ligament is stronger than the ACL. It connects the tibia to the femur and resists posterior translation of the tibia on the femur OR anterior translation of the femur on the tibia. The ligaments of the knee are supported by medial and lateral menisci. Menisci are similar to ligaments in that they connect bone to bone, but they are made of a smooth, elastic fibrocartilaginous CT rather than dense CT. They provide overall support to ligaments and also serve to reduce friction. There are also a number of bursa present around the knee joint to reduce friction as well. The popliteal fossa-Diamond shaped area posterior to the knee joint. This area is covered by a layer of fat that serves to protect the underlying neurovascular structures. These include the popliteal artery and vein, the termination of the small saphenous vein, the common fibular and tibial nerves (branches of the sciatic nerve), and popliteal lymph nodes and vessels. Please note that in this popliteal fossa, the popliteal artery gives off a number of “Genicular” branches which supply the capsule of the knee joint. Moving inferiorly, at the distal border of the popliteal fossa, the popliteal artery branches into an anterior and posterior tibial artery. The LEG-Runs from the knee to the ankle and is made up of three fascial compartments, anterior, lateral and posterior. Please note that the posterior compartment of the LEG is broken down further into a superficial and deep section. The main actions of these muscles include dorsiflexion, plantar flexion, eversion, and inversion of the foot. Anterior compartment-These muscles serve to dorsiflex the foot and are innervated by the deep fibular nerve. This group includes tibialis anterior, the extensor digitorum longus, extensor hallicus longus, and fibularis tertius muscles. All have at least one attachment to the fibula with the exception of tibialis anterior. Also, fibularis tertius is not present in all individuals. Lateral compartment-These muscles serve to plantarflex and evert the foot. They are innervated by the superficial fibular nerve. This group includes the fibularis longus and fibularis brevis muscles. Posterior compartment-These muscles serve to plantarflex and invert the foot. Both superficial and deep group muscles are innervated by the tibial nerve. The superficial group contains the following muscles: Gastrocnemius, soleus, and plantaris muscles. The gastrocnemius and soleus muscles attach to the calcaneus bone via a common calcaneal (achillies) tendon. Damage to this tendon is a relatively severe injury as both motion and weight bearing are greatly impaired. The deep posterior leg group contains the following muscles: Popliteus muscle-This unlocks the knee joint (laterally rotates the femur on a fixed tibia) Flexor hallicus longus muscle-Flexes the great toe Flexor digitorum longus muscle-Flexes digits 2-5 Tibialis posterior muscle-Inverts and plantarflexes the foot. The blood supply to the leg comes from the anterior and posterior tibial arteries. The anterior tibial artery supplies blood to the anterior leg compartment primarily, and some of the lateral leg compartment. It will travel distally, run anterior to the ankle and form the dorsalis pedis artery. This will give rise to the lateral tarsal artery and will supply the toes dorsally. The posterior tibial artery supplies the posterior compartment of the leg. It travels distally and will give rise to the lateral and medial plantar arteries which supply the plantar aspect of the foot. Before it does this however, the posterior tibial artery gives off a fibular artery that supplies the posterior and lateral compartments of the leg. The leg is drained via the small saphenous vein laterally, and the great saphenous vein medially. Both these veins emerge from the dorsal venous arch. The FOOT-We have mentioned foot bones last week. We have briefly mentioned blood supply to the foot above. Please note that the plantar surface of the foot has a plantar aponeurosis (similar to the hand). The medial and lateral planter nerves supply most of the foot muscles as well as sensation to the plantar surface of the foot. Most sensation to the dorsum of the foot is provided by the dorsal lateral cutaneous nerve of the foot. The foot has an incredibly detailed arrangement of muscular layers and compartments. At this point in the semester, I will mercifully spare us from much of this detail and mention but two muscles the Big Pic Anatomy mentioned with the anterior compartment of the leg, but classified them as being located on the dorsum of the foot. These are: Extensor digitorum brevis muscle-attaching to the calcaneus and dorsal surface of digits 2-4. This extends digits 2-4 and is innervated by the deep fibular nerve. Extensor hallicus brevis muscle-Attaches to the calcaneus and dorsal surface of the great toe. This extends the great toe and is innervated by the deep fibular nerve.