OCTH 707 Advanced Anatomy: Lower Extremity, Gait, and Pelvic Mobility

Comprehensive practice flashcards covering pelvic, hip, thigh, leg, and foot osteology, muscular compartments, neurovasculature, accessory ligaments, gait biomechanics, and clinical arthroplasty precautions from OCTH 707 Advanced Anatomy.

Which three bones fuse to form each coxal (hip) bone, and where do they meet?

The ilium, ischium, and pubis fuse to form each coxal bone, meeting at the acetabulum.

What is the structural classification and specific rotational capability of the tibiofemoral joint?

It is a modified hinge joint formed between the distal femur and proximal tibia that allows flexion, extension, and medial and lateral rotation of the knee.

Which four muscles comprise the quadriceps femoris, what is their shared innervation, and what is their common insertion?

The rectus femoris, vastus medialis, vastus lateralis, and vastus intermedius; they are innervated by the femoral nerve and insert onto the tibial tuberosity via the patellar ligament and tendon.

How does the origin and action of the rectus femoris differ from the three vasti muscles?

The rectus femoris originates from the anterior inferior iliac spine (AIIS), crosses both the hip and knee joints, and flexes the hip in addition to extending the knee. The vasti originate on the femur and only extend the knee.

What are the two heads of origin for the biceps femoris muscle, and what is its insertion?

The long head originates from the ischial tuberosity, and the short head originates from the lateral lip of the linea aspera. Both insert onto the head of the fibula.

Which nerve innervates the biceps femoris, and how is the innervation split between its two heads?

It is innervated by the sciatic nerve, specifically the tibial branch to the long head and the fibular branch to the short head.

Where does the semitendinosus muscle insert, and what joint actions does it perform?

It inserts onto the proximal medial shaft of the tibia at the pes anserinus tendon. It flexes the knee, medially rotates the flexed knee, extends the hip, assists with hip medial rotation, and tilts the pelvis posteriorly.

Where is the semimembranosus muscle situated relative to the semitendinosus, and where does it insert?

It lies directly deep to the semitendinosus and inserts onto the posterior aspect of the medial condyle of the tibia.

Which three tendons converge to form the pes anserinus ('goose foot') on the proximal, medial shaft of the tibia?

The sartorius, gracilis, and semitendinosus tendons.

What are the five adductor muscles of the hip, and which one does NOT assist in hip flexion?

Gracilis, adductor brevis, adductor longus, pectineus, and adductor magnus. Gracilis does not assist with hip flexion.

Why is the adductor magnus nicknamed the '4th Hamstring,' and what dual innervation does it receive?

Part of it originates from the ischial tuberosity (like the hamstrings) and inserts at the adductor tubercle; it receives dual innervation from the obturator nerve and sciatic nerve.

Which nerves provide dual innervation to the pectineus muscle?

The femoral nerve and obturator nerve.

What are the origins, insertion, and innervation of the gluteus maximus?

Origin: Coccyx, edge of sacrum, posterior iliac crest, and sacrotuberous and sacroiliac ligaments. Insertion: Iliotibial tract and gluteal tuberosity. Innervation: Inferior gluteal nerve.

What are the functional roles of the anterior versus posterior fibers of the gluteus medius?

While the muscle as a whole abducts the hip, the anterior fibers flex and medially rotate the hip, and the posterior fibers extend and laterally rotate the hip.

According to the systematic review by Baik et al. (2021), what biomechanical role does the gluteus medius play during the stance phase of gait?

It contracts eccentrically to resist large external frontal plane forces, counteracting contralateral pelvic drop and maintaining a semineutral pelvic orientation.

What are the origins, insertion, actions, and innervation of the tensor fasciae latae (TFL)?

Origin: Iliac crest posterior to the ASIS. Insertion: Iliotibial tract. Innervation: Superior gluteal nerve. Actions: Flexes, medially rotates, and abducts the hip.

What is the longest muscle in the human body, what is its origin, and what are its actions at both joints?

The sartorius; originates at the anterior superior iliac spine (ASIS); flexes, laterally rotates, and abducts the hip, and flexes the knee.

What two muscles form the iliopsoas, where do they insert, and what are their respective innervations?

The psoas major (innervated by the lumbar plexus) and the iliacus (innervated by the femoral nerve); both insert together onto the lesser trochanter of the femur.

Which six muscles make up the 'deep 6' lateral rotators of the hip, and which one lies superficial to the sciatic nerve?

Piriformis, obturator externus, obturator internus, quadratus femoris, gemellus superior, and gemellus inferior. The piriformis lies superficial to the sciatic nerve, while the other five lie deep to it.

What are the anatomical landmarks that define the borders of the inguinal ligament?

It stretches from the anterior superior iliac spine (ASIS) to the pubic tubercle, forming the superior border of the femoral triangle.

What percentage of body weight is borne by the fibula?

The fibula bears approximately $10\%$ of the body's weight.

In this posterior view of the patella, what anatomical features distinguish its superior base from its inferior apex and its two articular facets?

The broad, blunt superior border is the base, the pointed inferior border is the apex, and the articular surface is divided into a smaller medial facet and a larger lateral facet.

What are the seven tarsal bones of the foot?

Talus, calcaneus, cuboid, navicular, medial (1st) cuneiform, intermediate/middle (2nd) cuneiform, and lateral (3rd) cuneiform.

What distinct joint actions occur at the talocrural (tibiotalar) joint versus the subtalar joint?

The talocrural joint permits dorsiflexion and plantarflexion; the subtalar joint permits inversion and eversion.

Which two muscles comprise the triceps surae, and why is the soleus clinically referred to as the 'second heart'?

The gastrocnemius and soleus; the soleus is called the 'second heart' because its strong contractions pump deoxygenated blood from the leg back to the heart.

What muscle has a short muscle belly but the longest tendon in the human body?

The plantaris muscle.

Why is the popliteus muscle nicknamed 'the key which unlocks the knee'?

It medially rotates the tibia (or laterally rotates the femur) on a flexed knee, unlocking the knee joint from terminal extension so that flexion can begin.

What are the distal insertion points of the fibularis (peroneus) longus versus fibularis (peroneus) brevis?

Fibularis longus inserts onto the 1st metatarsal base and medial cuneiform; fibularis brevis inserts onto the tuberosity of the 5th metatarsal.

Which muscles occupy the anterior compartment of the leg, and what is their common innervation?

Tibialis anterior, extensor digitorum longus, and extensor hallucis longus; all are innervated by the deep fibular nerve.

In the mnemonic 'Tom, Dick, AN' Harry,' what anatomical structures pass behind the medial malleolus from anterior to posterior?

Tibialis posterior tendon, Flexor Digitorum longus tendon, posterior tibial Artery, tibial Nerve, and Flexor Hallucis longus tendon.

Which muscle is located on the dorsum of the foot, what is its innervation, and what is its action?

Extensor digitorum brevis; innervated by the deep fibular nerve; extends the 2nd through 4th toes at the metatarsophalangeal and interphalangeal joints.

Which three muscles compose the first (most superficial) layer of the plantar foot directly deep to the plantar aponeurosis?

Flexor digitorum brevis, abductor hallucis, and abductor digiti minimi.

Which muscles are found in the second and third layers of the plantar foot?

Layer 2: Quadratus plantae and lumbricals. Layer 3: Flexor hallucis brevis, adductor hallucis, and flexor digiti minimi brevis.

What are the respective actions and arrangements of the plantar versus dorsal interossei of the foot?

Plantar interossei (3 muscles) adduct toes 3-5 toward the 2nd toe (PAD) and flex MTP joints; dorsal interossei (4 muscles) abduct toes 2-4 away from the 2nd toe (DAB) and flex MTP joints.

What are the primary stabilizing functions of the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL)?

The ACL prevents anterior displacement of the tibia relative to the femur; the PCL prevents posterior displacement of the tibia relative to the femur.

What anatomical course is taken by the common fibular nerve around the knee?

It branches from the sciatic nerve and courses superficially along the posterior/lateral side of the knee, wrapping directly around the posterior neck/head of the fibula.

Which three ligaments comprise the lateral collateral ligament complex of the ankle, and which is most commonly injured in ankle sprains?

Anterior talofibular ligament (ATFL), calcaneofibular ligament (CFL), and posterior talofibular ligament (PTFL). The ATFL is most commonly injured.

What is the difference between an arthroplasty and an arthrodesis?

An arthroplasty is joint reconstruction or replacement, whereas an arthrodesis is surgical joint fusion.

What are the three specific movement precautions following a posterolateral hip arthroplasty?

1. No hip flexion greater than $90^\circ$. 2. No internal rotation. 3. No adduction (such as crossing legs or feet).

What are the three specific movement precautions following an anterolateral hip arthroplasty?

1. No external rotation. 2. No adduction (crossing legs or feet). 3. No hip extension.

What percentage of the normal gait cycle is spent in the stance phase versus the swing phase?

The stance phase accounts for $60\%$ of the gait cycle, and the swing phase accounts for $40\%$.

What are the five sub-phases of the stance phase in new gait terminology, and what classic terms correspond to each?

1. Initial contact (Heel strike), 2. Loading response (Foot flat), 3. Mid-stance (Midstance), 4. Terminal stance (Heel off), and 5. Pre-swing (Toe-off).

What defines an antalgic gait pattern?

A painful limp adopted to avoid weight-bearing pain on an injured limb, characterized by a noticeably shorter stance phase on the affected side.

What gait abnormality is characterized by a contralateral pelvic drop during stance, and what muscle weakness causes it?

Trendelenburg gait, caused by weakness of the gluteus medius on the weight-bearing (stance) side.

What kinematic compensations characterize a hemiplegic gait?

Excessive hip flexion and circumduction of the lower extremity to compensate for decreased ankle dorsiflexion and foot drop.

What assistive device is depicted here, and what primary functional deficit does it address?

An ankle-foot orthosis (AFO) or foot drop splint, which provides joint stability and assists with ankle dorsiflexion during the swing phase of gait.