Anatomy of Lower Limbs

What actions do the muscles of the gluteal region produce?

Extension, medial rotation, lateral rotation, and abduction

Besides motion, what roles do gluteal muscles play?

Stability of the hip joint and locomotion

Which is the largest and most superficial gluteal muscle?

Gluteus maximus

What are the proximal attachments of gluteus maximus?

Ilium, sacrum, coccyx, sacrotuberous ligament

What are the distal attachments of gluteus maximus?

Iliotibial tract and gluteal tuberosity of the femur

What are the actions of gluteus maximus?

Powerful extensor of the flexed femur, maintains posture, lateral stabilizer of hip joint

What is the innervation of gluteus maximus?

Inferior gluteal nerve (L5-S2)

What are the attachments of gluteus medius and minimus?

Ilium and greater trochanter of the femur

What are the actions of gluteus medius and minimus?

Abduction and medial rotation of the hip joint, stabilizing the pelvis

What is the innervation of gluteus medius and minimus?

Superior gluteal nerve

What is the shape and location of tensor fascia lata?

Laterally located fusiform-shaped muscle within the fascia lata

What are the attachments of tensor fascia lata?

Lateral aspect of iliac crest → iliotibial tract of fascia and lateral condyle of tibia

What are the actions of tensor fascia lata?

Hip abduction; aids in maintaining knee extension and stabilization

What is the innervation of tensor fascia lata?

Superior gluteal nerve (L4-S1)

What characteristics do all deep hip rotators share?

Deep to gluteal muscles, arise from pelvis, attach around greater trochanter, externally rotate femur at the hip joint

Which muscles are deep hip rotators?

Piriformis, Superior gemellus, Inferior gemellus, Obturator internus, Quadratus femoris

Where does piriformis attach?

Anterior surface of sacrum → greater trochanter

What is the innervation of piriformis?

Nerve of sacral plexus (S1-S2)

Where does superior gemellus attach?

Ischial spine → greater trochanter

What is the innervation of superior gemellus?

Nerve to obturator internus and superior gemellus (L5-S2)

Where does inferior gemellus attach?

Ischial tuberosity → greater trochanter

What is the innervation of inferior gemellus?

Nerve to inferior gemellus and quadratus femoris (L4-S1)

Where does obturator internus attach?

Deep surface of obturator membrane and surrounding bone → greater trochanter

What is the innervation of obturator internus?

Nerve to obturator internus and superior gemellus (L5-S2)

Where does quadratus femoris attach?

Ischial tuberosity → quadrate tubercle of the femur

What is the innervation of quadratus femoris?

Nerve to inferior gemellus and quadratus femoris (L4-S1)

What are the proximal and distal attachments, action, and innervation of the Tensor fascia lata?

Proximal Attachment: Lateral aspect of crest of ilium between anterior superior iliac spine and tubercle of crest

Distal Attachment: Iliotibial tract of fascia lata

Action: Stabilizes knee in extension

Innervation: Superior gluteal n. (L4–S1)

What are the proximal and distal attachments, action, and innervation of the Gluteus maximus?

Proximal Attachment: Ilium behind posterior gluteal line, sacrum, coccyx, and sacrotuberous ligament

Distal Attachment: Iliotibial tract and gluteal tuberosity of femur

Action: Powerful extensor of flexed femur at hip joint; lateral stabilizer of hip and knee joints

Innervation: Inferior gluteal n. (L5–S2)

What are the proximal and distal attachments, action, and innervation of the Gluteus medius?

Proximal Attachment: Ilium between anterior and posterior gluteal lines

Distal Attachment: Greater trochanter

Action: Abducts femur at hip joint; holds pelvis secure over stance leg and prevents pelvic drop on opposite swing side during walking; hip internal rotation

Innervation: Superior gluteal n. (L4–S1)

What are the proximal and distal attachments, action, and innervation of the Gluteus minimus?

Proximal Attachment: Ilium between anterior and inferior gluteal lines

Distal Attachment: Greater trochanter

Action: Abducts femur at hip joint; holds pelvis secure over stance leg and prevents pelvic drop on opposite swing side during walking; hip internal rotation

Innervation: Superior gluteal n. (L4–S1)

What are the proximal and distal attachments, action, and innervation of the Piriformis?

Proximal Attachment: Anterior surface of sacrum

Distal Attachment: Greater trochanter

Action: Laterally rotates the hip joint

Innervation: Nerve to piriformis m. (S1–S2)

What are the proximal and distal attachments, action, and innervation of the Superior gemellus?

Proximal Attachment: Ischial spine

Distal Attachment: Greater trochanter

Action: Laterally rotates the hip joint

Innervation: Nerve to obturator internus and superior gemellus mm. (L5–S2)

What are the proximal and distal attachments, action, and innervation of the Obturator internus?

Proximal Attachment: Deep surface of obturator membrane and surrounding bone

Distal Attachment: Greater trochanter

Action: Laterally rotates the hip joint

Innervation: Nerve to obturator internus and superior gemellus mm. (L5–S2)

What are the proximal and distal attachments, action, and innervation of the Inferior gemellus?

Proximal Attachment: Ischial tuberosity

Distal Attachment: Greater trochanter

Action: Laterally rotates the hip joint

Innervation: Nerve to inferior gemellus and quadratus femoris mm. (L4–S1)

What are the proximal and distal attachments, action, and innervation of the Quadratus femoris?

Proximal Attachment: Lateral aspect of ischium just anterior to ischial tuberosity

Distal Attachment: Intertrochanteric crest

Action: Laterally rotates the hip joint

Innervation: Nerve to inferior gemellus and quadratus femoris mm. (L4–S1 for parallel construction)

From which spinal levels does the lower limb receive sensory and motor innervation?

The lower limb receives sensory and motor innervation from L1-S4 ventral rami via the lumbar plexus (L1-L4) and sacral plexuses (L4-S4).

What spinal levels make up the anterior division of the sacral plexus?

The anterior division of the sacral plexus consists of ventral rami from L4 to S4, which form a network and give rise to the following five nerves.

What is the course and function of the Pudendal nerve (S2–S4)?

Exits the pelvis via the greater sciatic foramen, enters the gluteal region, and courses to the perineum through the lesser sciatic foramen.

The pudendal nerve provides motor innervation to the muscles of the pelvic floor and sensory innervation to the skin of the perineum.

What is the course and function of the Posterior femoral cutaneous nerve (S1–S3)?

Exits the pelvis via the greater sciatic foramen, inferior to the piriformis muscle.

The nerve remains deep to the gluteal maximus muscle and emerges at the inferior border, providing sensory innervation to the posterior region of the thigh.

Also called the Posterior cutaneous nerve of the thigh.

What is the function of the Tibial nerve (L4–S3)?

The tibial nerve provides motor innervation to the hamstring muscles (excluding the short head of the biceps femoris muscle) and a hamstring head of the adductor Magnus muscle in the medial compartment of the thigh.

It provides motor innervation to the posterior compartment of the leg as well as to the plantar muscles of the foot.

Sensory branches provide cutaneous innervation to the posterolateral region of the leg and the lateral region of the foot.

Where is the preferred site for intermuscular injections in the gluteal region, and why?

The gluteal region is a common site for intermuscular injections. Specifically, the superior lateral portion of the gluteal region is the preferred site to avoid injuring structures such as the sciatic nerve.

What is the sacroiliac joint?

Synovial joint between sacrum and ilium

What does the sacroiliac joint transfer?

Weight from vertebral column to lower limb

What is the hip joint type?

Ball-and-socket synovial joint

What does the hip joint allow?

Flexion, extension, abduction, adduction, medial and lateral rotation, circumduction

What are the roles of the hip joint?

Support for the weight of the head, arms, and trunk during static postures (Standing)

Dynamic Movements (walking and running)

What is the term for the articulating surface of the pelvic bone of the hip joint?

the Acetabulum

What structures form the hip joint articulation?

Acetabulum of hip bone + head of femur

What is the acetabular labrum?

A wedge-shaped fibrocartilaginous ring around the periphery of the acetabulum, which increases stability by deepening the socket and increasing the concavity of the articulating surface.

Besides deepening the socket, what is another function of the acetabular labrum?

The acetabular labrum also assists in maintaining contact of the acetabulum with the femoral head.

What artery provides the principal blood supply to the hip?

The medial circumflex femoral artery provides the principal blood supply to the hip.

What provides ligamentous support to the hip joint?

The following structures provide ligamentous support to the hip joint: The capsule contains three capsular ligaments: two anterior ligaments and one posterior ligament.

When do the ligaments of the hip primarily become taut, and what do they permit?

The ligaments of the hip primarily become taut with extension of the hip and permit little, if any, distraction between the articulating surfaces.

How does the joint capsule of the hip extend?

The joint capsule is strong and extends like a sleeve from the acetabulum to the base of the neck of the femur.

What circular fibers form a ring around the neck of the femur in the hip joint capsule?

The joint capsule possesses circular fibers, which form a ring around the neck of the femur, called the zona orbicularis.

What is the attachment, function, and importance of the Iliofemoral ligament?

Iliofemoral ligament. Extends from the anterior iliac spine and bifurcates to attach to the intertrochanteric line of the femur. The strongest ligament and the one that limits hip extension.

What is the attachment of the Pubofemoral ligament?

Pubofemoral ligament. Attaches from the anterior aspect of the pubic ramus and extends posteriorly to attach to the anterior surface of the intertrochanteric fossa.

What is the attachment of the Ischiofemoral ligament?

Ischiofemoral ligament. Attaches from the superior acetabular rim and labrum to the inner surface of the greater trochanter.

Where does the ligament of the head of the femur (ligamentum teres) attach?

Attaches to the head of the femur (fovea). The ligament courses deep to the transverse acetabular ligament to attach to the acetabular notch.

What role does the ligament of the head of the femur play in hip joint stability and blood supply?

The ligament of the head of the femur does not appear to play a major role in the stability of the hip joint, but rather serves as a conduit for the secondary arterial supply to the head of the femur from the obturator artery.

What is the function of the Transverse acetabular ligament?

Transverse acetabular ligament. Completes the circle of the acetabular labrum by spanning the acetabular notch and forming a foramen for the passage of the ligament of the head of the femur.

What are bursae?

Bursae are synovial sacs filled with synovial fluid.

Where are bursae found?

They are found at areas in the tissue at which friction would otherwise develop.

What function do bursae serve?

Bursae serve as small cushions because they decrease the friction between two moving structures, such as tendon and bone.

What are the two most important bursae in the gluteal region?

The two most important bursae in the gluteal region are as follows:

Subtendinous iliac bursa. Separates the iliacus and psoas major muscles from the anterior joint capsule.

Trochanteric bursa. Separates the gluteus maximus muscle from the greater trochanter.

What is the longest and strongest bone in the body and the primary bone of the thigh?

The femur is the longest and strongest bone in the body and primary bone of the thigh.

What is the most common site of hip fracture?

Neck of the femur is the most common site of the hip fracture.

With which structures does the femur articulate?

The femur articulates with the acetabulum (hip joint) and tibia and patella (knee joint).

What movements does the knee joint enable, and what is its function?

The knee joint enables flexion, extension, and minimal rotation and supports the weight of the body during static positions and dynamic movement during gait.

Which bones articulate to form the knee joint, and what actions does it enable?

The articulations between the femur, tibia, and patella form the knee joint and enable the following actions.

What is flexion at the knee joint?

Flexion. Bending the knee joint.

What is extension at the knee joint?

Extension. Straightening the knee joint.

What rotational movements occur at the knee joint?

Internal and external rotation. Small rotational movements in the vertical axis.

Into what compartments is the thigh divided?

Anterior, medial, posterior

What divides the thigh compartments?

Fascial intermuscular septa

What is the innervation of the anterior thigh?

Femoral nerve

What is the innervation of the medial thigh?

Obturator nerve

What is the innervation of the posterior thigh?

Sciatic nerve

What is the common innervation of anterior thigh muscles?

Femoral nerve

What are the general actions of anterior thigh muscles?

Flex hip and extend knee

What is the primary blood supply of the anterior thigh?

Femoral artery

What is the longest muscle in the body?

Sartorius muscle. The longest muscle in the body.

What are the attachments of the sartorius muscle?

Attachments. Anterior superior iliac spine and pes anserinus ("goose's foot") along the medial border of the tibial tuberosity.

What are the actions of the sartorius muscle?

Actions. Flex, abduct, and externally rotate the hip joint; flex the knee joint.

What is the innervation of the sartorius muscle?

Innervation. Femoral nerve (L2-L3).

What muscles are in the anterior compartment of the thigh?

Sartorius muscle and Quadriceps femoris muscle group

What actions do anterior thigh muscles perform?

Flexion of the hip and extension of the knee

What nerve innervates the anterior thigh muscles?

Femoral nerve (L2-L4)

What's the longest muscle in the body?

Sartorius muscle

Where does the sartorius muscle attach?

Anterior superior iliac spine and pes anserinus along the medial border of the tibial tuberosity

What muscle group is a strong knee extensor?

Quadriceps femoris

How many muscles are in the quadriceps femoris group?

Four

Where do all quadriceps muscles attach distally?

Patella via quadriceps tendon and tibial tuberosity

What nerve innervates quadriceps femoris?

Femoral nerve (L2-L4)

Where does the rectus femoris attach and what are its actions?

Anterior inferior iliac spine to quadriceps tendon; flexes the hip joint and extends the knee joint

Where does the vastus lateralis attach and what does it do?

Linea aspera to quadriceps tendon; extends the knee joint

Where does the vastus medialis attach and what does it do?

Linea aspera to quadriceps tendon; extends the knee joint

Where does the vastus intermedius attach and what does it do?

Upper two-thirds of femoral shaft to quadriceps tendon; extends the knee joint

What muscles make up the medial compartment of the thigh?

Pectineus, Adductor brevis, Adductor longus, Adductor magnus, Gracilis, Obturator externus

What is the main action of medial thigh muscles?

Adduction of the hip