Human Anatomy - Lecture Notes - O. I. Savchuk 2017

Muscles of the lower limbs

Lecture outline

1. Muscles OF THE Pelvic Girdle.

2. Anterior Group of thigh muscles.

3. Posterior group of thigh muscles.

4. Medial group

5. Muscles of the Leg.

6. Muscles of the FOOT.

The cavity is filled with adipose tissue containing Lymph Nodes, major vessels, and nerves. There are two openings on the posterior wall of the axillary cavity—the triangular space and the quadrangular space—through which Vessels and nerves pass.

The cubital fossa is located in the crease of the elbow, with its floor formed by the brachialis Muscle. Beneath the Skin of this fossa lie superficial Veins used for IV injections. Deeper within, NERVES AND Arteries pass through.

MUSCLES AND FASCIAE of the Lower Limb

The Muscles of the Lower Limb are divided into the muscles of the pelvic girdle and the Muscles of the Free Lower Limb. The girdle muscles are divided into internal and external groups, while the muscles of the free limb are divided into the muscles of the thigh, leg, and foot.

Muscles of the pelvic girdle

The muscles of the pelvic girdle are divided into internal and external groups.

Internal Group of pelvic muscles:

1. The iliopsoas Muscle consists of two muscles: the psoas major (originating from the lumbar vertebrae) and the iliacus (originating from the iliac fossa of the hip bone). Both muscles merge into one, which passes through the muscular lacuna and inserts into the lesser trochanter of the Femur. Function: flexes the thigh; when the limbs are fixed, it flexes the trunk.

2. The piriformis muscle originates from the pelvic surface of the sacrum, exits the pelvic cavity through the greater sciatic foramen, dividing it into the suprapiriform and infrapiriform foramina. It inserts into the greater trochanter of the femur. Function: rotates the thigh laterally (supination).

3. The obturator internus muscle originates from the inner margin of the obturator foramen, exits through the lesser sciatic foramen, and inserts into the greater trochanter. Function: rotates the thigh laterally (supination).

External Group of pelvic muscles

1) The gluteus maximus muscle originates from the outer surface of the ilium and inserts into the gluteal tuberosity of the femur. Function: extends the thigh; when the limbs are fixed, it extends the trunk, maintaining the so-called "military posture".

2) The gluteus medius and gluteus minimus muscles lie one beneath the other. They originate from the outer surface of the ilium and insert into the greater trochanter. Function: abduct the thigh.

3) The obturator externus muscle originates from the outer margin of the obturator foramen and inserts into the greater trochanter. Function: rotates the thigh laterally.

4) The quadratus femoris muscle originates from the ischial tuberosity and inserts into the greater trochanter. Function: rotates the thigh laterally.

5) The tensor fasciae latae muscle extends from the anterior superior iliac spine and inserts into the thickened part of the fascia lata of the thigh. Function: tenses the fascia and assists in flexing the thigh.

Muscles of the free lower limb

The muscles of the thigh are divided into three groups: anterior, posterior, and medial.

Anterior group of thigh muscles

1) The quadriceps femoris muscle consists of four heads (rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius), which originate from the anterior inferior iliac spine (rectus femoris) and the linea aspera of the femur (vastus medialis, lateralis, and intermedius) and insert via a broad tendon into the tibial tuberosity. Function: extends the leg, flexes the thigh.

2) The sartorius muscle runs obliquely downward from the anterior superior iliac spine and inserts into the tibial tuberosity. Function: flexes the leg and the thigh.

Posterior group

1. The semitendinosus and semimembranosus muscles are located medially. They originate from the ischial tuberosity and insert into the Tibia. Function: they extend the thigh and flex the leg.

2. The biceps femoris muscle originates by two heads: the long HEAD from the ischial tuberosity and the short head from the femur. It inserts into the head of the Fibula. Function: extends the thigh and flexes the leg.

Medial group

The medial group includes five muscles: the pectineus, gracilis, and the adductors (magnus, longus, and brevis). They all originate from the pubis and ischium and insert into the femur (except the gracilis, which inserts into the tibia). Function: adduct the thigh.

Muscles of the lower leg

They are divided into anterior, posterior, and lateral groups. All muscles of the lower leg insert onto the foot.

The anterior group includes the following muscles: tibialis anterior, extensor hallucis longus, and extensor digitorum longus. Function: they extend the toes and dorsiflex the foot.

The posterior group includes: the triceps surae (superficial layer), tibialis posterior, flexor digitorum longus, and flexor hallucis longus (deep layer).

The triceps surae inserts into the calcaneal tuberosity via a strong tendon (the Achilles tendon) and is involved in plantar flexion of the foot. The deep muscles insert into the tarsal, metatarsal, and phalangeal bones, performing the function of flexing the foot and toes.

The lateral group consists of the fibularis (peroneus) longus and brevis muscles, which plantarflex and pronate the foot (lowering its medial margin and raising its lateral margin).

Muscles of the foot

They are divided into dorsal and plantar groups. The plantar group consists of the muscles of the great toe eminence, the muscles of the little toe eminence, and the muscles of the middle group.

The muscles of the great toe eminence are the abductor hallucis, adductor hallucis, and flexor hallucis brevis.

The muscles of the little toe eminence are the abductor digiti minimi, flexor digiti minimi brevis, and opponens digiti minimi.

The middle group consists of the flexor digitorum brevis, quadratus plantae, and four lumbrical muscles. They flex the toes.

Interosseous muscles: three plantar muscles adduct the toes, while four dorsal muscles abduct them.

Fasciae of the lower limb

They are a continuation of the fascia lata and cover the muscles of the leg, forming sheaths for them. In and above the ankle joint region, the fascia thickens, forming the extensor, flexor, and peroneal retinacula. Just like in the hand, synovial sheaths are formed here. Anteriorly, there are three synovial sheaths for the extensor tendons; behind the medial malleolus, There are also three synovial sheaths for the flexor tendons; and behind the lateral malleolus, there are initially two, and then one common sheath for the fibularis brevis and longus muscles.

The Fascia of the dorsum of the foot is thin and transparent, while on the sole, it forms the plantar aponeurosis.

Topography of the lower limb

On the anteromedial surface of the thigh, the femoral triangle is distinguished, within which important Blood Vessels and nerves are located: the femoral artery, vein, and nerve. It is bounded superiorly by the inguinal ligament, laterally by the sartorius muscle, and medially by the adductor longus muscle.

The femoral canal is normally absent; it is formed only during The Development of femoral hernias.

The space behind the inguinal ligament is divided by the iliopectineal arch (a band of the iliac fascia extending from the inguinal ligament to the iliopubic eminence) into two compartments (lacunae): 1) the muscular lacuna, located laterally (through which the iliopsoas muscle and the femoral nerve pass); and 2) the vascular lacuna, located medially (through which the femoral artery and vein pass).

It is through the vascular lacuna that Internal Organs herniate from the pelvic or Abdominal cavity beneath the fascia lata of the thigh. In such cases, the femoral canal is formed. Its walls are defined laterally by the femoral vein, posteriorly by the Deep Layer of the fascia lata, and anteriorly by the inguinal ligament. In the medial corner of the vascular lacuna lies the femoral ring (the internal ring of the femoral canal, or its inlet). It is bounded laterally by the femoral vein, anteriorly and superiorly by the inguinal ligament, medially by the lacunar ligament, and posteriorly by the pectineal ligament. The external (outlet) ring is the saphenous opening described above.

Adductor canal

It connects the anterior region of the thigh with the popliteal fossa. The medial wall of this canal is formed by the adductor magnus muscle, the lateral wall by the vastus medialis muscle, and the anterior wall by the vastoadductor membrane (a fibrous lamina spanning between these muscles). This canal connects the anterior region of the thigh with the popliteal fossa, and contains the femoral artery, femoral vein, and saphenous nerve.

The popliteal fossa is diamond-shaped. Beneath the fascia, it contains adipose tissue, lymph nodes, and the popliteal artery, vein, and nerves.

References:

1. Hayda, S.P. Human Anatomy and Physiology. Kyiv: Vyshcha Shkola, 1980.

2. Dybenko, K.A. Anatomical Ukrainian-Latin-English Dictionary-Reference Book. Kyiv: Dovira, 1997. - 344 p.

3. Kravchuk, S.Yu. Human Anatomy. Chernivtsi: Podillia, 1998. - Vol. 1. - 291 p.

4. Kravchuk, S.Yu. Human Anatomy. Chernivtsi: Podillia, 1998. - Vol. 2. - 339 p.

5. Mateshchuk-Vatseba, L.R. Normal Anatomy: A Textbook. Lviv: Poklyk Sumlinnia, 1997. - 267 p.

6. Ivanitsky, M.F. Human Anatomy. Moscow: Fizkultura i Sport, 1985. - 480 p.

7. Sapin, M.R., Bilich, G.L. Guide to Practical Exercises in Human Anatomy. Moscow: Vysshaya Shkola, 1989. - 543 p.

8. Sinelnikov, R.D. Atlas of Human Anatomy (Multi-volume edition "Meditsina". By body systems).

9. Great Medical Encyclopedia. Sections: Human Anatomy, by body systems.

10. Anatomy and Physiology with Pathology // Ed. by Fedoniuk, Ya.I., Bilyk, L.S., Mykula, N.Kh. Ternopil: Ukrmedknyha, 2001.