Thigh Flashcards
Describe the proximal end of the femur
Head – Has a smooth surface with a depression on the medial surface – this is for the attachment of the ligament of the head. At the hip joint, it articulates with the acetabulum of the pelvis.
Neck – Connects the head of the femur with the shaft. It is cylindrical, projecting in a superior and medial direction – this angle of projection allows for an increased range of movement at the hip joint
Greater trochanter – this is a projection of bone that originates from the anterior shaft, just lateral to where the neck joins. It is angled superiorly and posteriorly, and can be found on both the anterior and posterior sides of the femur. It is the site of attachment of the abductor and lateral rotator muscles of the leg
Lesser trochanter – much smaller than the greater trochanter. It projects from the posteromedial side of the side, just inferior to the neck-shaft junction. The psoas major and iliacus muscles attach here.
Intertrochanteric line – a ridge of bone that runs in a inferomedial direction on the anterior surface of the femur, connecting the two trochanters together. The iliofemoral ligament attaches here – a very strong ligament of the hip joint. After it passes the lesser trochanter on the posterior surface, it is known as the pectineal line.
Intertrochanteric crest – similar to the intertrochanteric line, this is a ridge of bone that connects the two trochanters together. It is located on the posterior surface of the femur. There is a rounded tubercle on its superior half, this is called the quadrate tubercle, which is where the quadratus femoris attaches.
Describe the posterior view of the proximal head of the femur
Describe the shaft of the femur
The shaft descends in a slight medial direction. This brings the knees closer to the body’s center of gravity, increasing stability.
On the posterior surface of the femoral shaft, there are roughened ridges of bone, these are called the linea aspera (Latin for rough line)
Proximally, the medial border of the linea aspera becomes the pectineal line. The lateral border becomes the gluteal tuberosity, where the gluteus maximus attaches.
Distally, the linea aspera widens and forms the floor of the popliteal fossa, the medial and lateral borders form the the medial and lateral supracondylar lines. The medial supracondyle line stops at the adductor tubercle, where the adductor magnus attaches.
Describe the distal end of the femur
Medial and lateral condyles – rounded areas at the end of the femur. The posterior and inferior surfaces articulate with the tibia and menisci of the knee, while the anterior surface articulates with the patella.
Medial and lateral epicondyles – bony elevations on the non articular areas of the condyles. They are the area of attachment of some muscles and the collateral ligaments of the knee joint.
Intercondylar fossa – A depression found on the posterior surface of the femur, it lies in between the two condyles. It contains two facets for attachment of internal knee ligaments.
Facet for attachment of the posterior cruciate ligament – found on the medial wall of the intercondylar fossa, it is a large rounded flat face, where the posterior crucitate ligament of the knee attaches.
Facet for attachment of anterior cruciate ligament – found on the lateral wall of the intercondylar fossa, it is smaller than the facet on the medial wall, and is where the anterior cruciate ligament of the knee attaches.
What are the muscles in the anterior compartment of the thigh?
There are three major muscles in the anterior thigh – the pectineus, sartorius and quadriceps femoris. In addition to these, the end of the iliopsoas muscle passes into the anterior compartment.
Give the attachments, innervation and action of the illiopsoas
The iliopsoas is actually two muscles, the psoas major and the iliacus. They originate in different areas, but come together to form a tendon, hence why they are commonly referred to as one muscle.
Unlike many of the anterior thigh muscles, the iliopsoas does not extend the leg at the knee joint.
Attachments: The psoas major originates from the lumbar vertebrae, and the iliacus originates from the iliac fossa of the pelvis. They insert together onto the lesser trochanter of the femur.
Actions: The iliopsoas flexes the lower limb at the hip joint and assists in lateral rotation at the hip joint.
Innervation: The psoas major is innervated by anterior rami of L1-3, while the iliacus is innervated by the femoral nerve.
Give the attachments, innervation and action of the Quadriceps Femoris
The quadriceps femoris consists of four individual muscles; three vastus muscles and the rectus femoris. They form the main bulk of the thigh, and collectively are one of the most powerful muscles in the body.
The quadriceps femoris attaches to the patella via a tendon. The patella attaches to the tibia by the patella ligament. The quadriceps femoris is the main extensor of the knee.
Vastus Muscles
There are three vastus muscles – vastus medialis, vastus intermedius and vastus lateralis.
They are located exactly where their names suggest; the medialis lies on the medial side of the anterior thigh, and the lateralis lies on the lateral side. The intermedius is found deep to the other muscles.
Collectively, the vastus muscles extend at the knee joint, and are innervated by the femoral nerve.
Rectus Femoris:
Attachments: Originates from the ilium, just superior to the acetabulum. It runs straight down the leg (the latin for straight is rectus), and attaches to the patella by the quadriceps femoris tendon.
Actions: This is the only muscle of the quadriceps to cross both the hip and knee joints. It flexes the leg at the hip joint, and extends at the knee joint.
Innervation: Femoral nerve.
Give the attachments, innervation and actions of Sartorius
The sartorius is the longest muscle in the body. It is long and thin, running across the thigh in a inferomedial direction. The sartorius is positioned more superficially than the other muscles in the leg.
Attachments: Originates from the anterior superior iliac spine, and attaches to the superior, medial surface of the tibia.
Actions: At the hip joint, it is a flexor, abductor and lateral rotator. At the knee joint, it is also a flexor.
Innervation: Femoral nerve.
Give the attachments, innervation and action of pectineus
The pectineus muscle is a flat muscle that forms the base of the femoral triangle. It has a dual innervation, and thus can be considered an transitional muscle between the anterior thigh and medial thigh compartments.
Attachments: It originates from the pectineal line on the anterior surface of the pelvis, and attaches to the pectineal line on the posterior side of the femur, just inferior to the lesser trochanter.
Actions: Adduction and flexion at the hip joint.
Innervation: Femoral nerve. May also receive a branch from the obturator nerve.
Label a cross section of the medial thigh
What are the muscles in the medial compartment of the thigh?
The muscles in the medial compartment of the thigh are collectively known as the hip adductors. There are five muscles in this group; gracilis, obturator externus, adductor brevis, adductor longus and adductor magnus.
Give the attachments, innervation and action of the adductor magnus
The adductor magnus is the largest muscle in the medial compartment. It lies posteriorly to the other muscles.
Functionally, the muscle can be divided into two parts; the adductor part, and the hamstring part.
Attachments: The adductor part originates from the inferior rami of pubis and the rami of ischium, attaching to the linea aspera of the femur. The hamstring portion originates from the ischial tuberosity and attaches to the adductor tubercle on the distal and medial side of the femur.
Actions: They both adduct the thigh. The adductor component also flexes the thigh, with the hamstring portion extending the thigh.
Innervation: Adductor part is innervated by the obturator nerve (L2-L4), the hamstring part is innervated by the tibial nerve (L4-S3).
Give the attachments, innervation and actions of adductor longus
The adductor longus is a large, flat muscle. It partially covers the adductor brevis and magnus. The muscle forms the medial border of the femoral triangle.
Attachments: Originates from the pubis, and expands into a fan shape, attaching broadly to the linea aspera of the femur
Actions: Adduction and medial rotation of the thigh.
Innervation: Obturator nerve (L2-L4)
Give the attachments, innervation and actions of adductor brevis
The adductor brevis is a short muscle, lying underneath the adductor longus.
It lies in between the anterior and posterior divisions of the obturator nerve. Therefore, it can be used as an anatomical landmark to identify the aforementioned branches.
Attachments: Originates from the body of pubis and inferior pubic rami. It attaches to the linea aspera on the posterior surface of the femur, proximal to the adductor longus.
Actions: Adduction of the thigh.
Innervation: Obturator nerve (L2-L4).
Give the attachments, innervation and actions of obturator externus
This is one of the smaller muscles of the medial thigh, and it is located most superiorly.
Attachments: It originates from the membrane of the obturator foramen, and adjacent bone. It passes under the neck of femur, attaching to the posterior aspect of the greater trochanter.
Actions: Laterally rotates the thigh.
Innervation: Obturator nerve (L2-L4).
Label the muscles in the anterior compartment
Give the attachments, innervation and actions of Semimembranosus
Attachments: It originates from the ischial tuberosity, but does so more superiorly than the semitendinosus and biceps femoris. It attaches to the medial tibial condyle.
Actions: Flexion of the leg at the knee joint. Extension of thigh at the hip. Medially rotates the thigh at the hip joint and the leg at the knee joint.
Innervation: Tibial part of the sciatic nerve.
What are the borders of the femoral canal?
Medial border – Lacunar ligament.
Lateral border – Femoral vein.
Anterior border – Inguinal ligament.
Posterior border – Pectineal ligament, superior rami of the pubi and the pectineus muscle
The opening to the femoral canal is located at its superior border, known as the femoral ring. The femoral ring is closed by a connective tissue layer – the femoral septum. This septum is pierced by the lymphatic vessels exiting the canal.
What are the contents of the femoral canal?
The femoral canal contains:
Lymphatic vessels – draining the deep inguinal lymph nodes.
Deep lymph node – the lacunar node.
Empty space.
Loose connective tissue.
The empty space allows distension of the adjacent femoral vein, so it can cope with increased venous return, or increased intra-abdominal pressure.
