Lower Limb Muscles Anatomy PDF

Anatomy 09/28/2023 MOD 2C: MUSCLES OF THE LOWER LIMB Julius Caezar Reyes, MD, MHPEd, FPSA Trans Groups: 19B & 8A...

Anatomy 09/28/2023 MOD 2C: MUSCLES OF THE LOWER LIMB Julius Caezar Reyes, MD, MHPEd, FPSA Trans Groups: 19B & 8A Thickest muscle in the body CONTENT ADDITIONAL INFO RESOURCES ○ Mesomorphs possess a thick gluteus maximus ★ → muscle. Largely responsible for the prominence of the buttocks. OUTLINE Known as the “butt muscle” Gluteus maximus and tensor fascia lata form the iliotibial band that covers most of the lateral surface of the thigh. I. Muscles of the Lower Limb Portions of the fibers will blend into the tendon of Tensor A. Gluteal Muscles Fascia Lata (TFL), located at the side of the pelvis. 1. Superficial layer Has a very important role in tightening the iliotibial band 2. Deep layer to lock the knee in its standing position. B. Thigh Muscles If the gluteus maximus shortens, the femur will extend 1. Posterior Compartment the hip joint (hip extension). 2. Anterior Compartment 3. Medial Compartment C. Leg Muscles GLUTEUS MAXIMUS MUSCLE 1. Anterior Compartment 2. Lateral Compartment Origin Outer surface and crest of ilium, 3. Posterior Compartment sacrum, coccyx, and D. Foot Muscles sacrotuberous ligament 1. Dorsum 2. Plantar Insertion Iliotibial tract and gluteal 3. Layer 1 (Muscles) tuberosity of femur 4. Layer 2 (Muscles and Tendons) 5. Layer 3 (Muscles) Nerve Supply Inferior gluteal nerve 6. Layer 4 (Muscles and Tendons) II. References Nerve Roots L5; S1, 2 III. Practice Questions Action Extends, laterally rotates, and I. MUSCLES OF THE LOWER LIMB abducts hip joint Through iliotibial tract, it extends A.GLUTEAL MUSCLES and locks the knee joint Superficial layer ○ Gluteus maximus 1.2 TENSOR FASCIA LATA ○ Tensor fascia lata ○ Gluteus medius ○ Gluteus minimus Deep layer ○ Piriformis ○ Gemellus superior ○ Obturator internus ○ Gemellus inferior ○ Quadratus femoris 1. SUPERFICIAL LAYER 1.1 GLUTEUS MAXIMUS Tensor Fascia Lata.Student Copy Lower Limb Muscles. Dr. Reyes’ F2F Lecture Forms the iliotibial tract with the gluteus maximus. Assists the gluteus maximus muscle in maintaining the knee in the extended position. Gluteus Maximus. Student Copy Lower Limb Muscles. Dr. Reyes’ F2F Lecture Anatomy - Mod2C Muscles of the Lower Limb 1 of 26  TENSOR FASCIA LATA MUSCLE GLUTEUS MEDIUS MUSCLE Origin Iliac crest Origin Iliac crest; Outer surface of ilium Insertion Iliotibial tract Insertion Lateral surface of Greater trochanter of femur Nerve Supply Superior gluteal nerve Nerve Supply Superior gluteal nerve Nerve Roots L4;5 Nerve Roots L5; S1 Action Assists gluteus maximus in extending the knee joint Action Abducts thigh & medially rotates Medial rotation & abduction of hip joint hip joint Tilts pelvis when walking to permit opposite leg to clear ground ILIOTIBIAL TRACT/BAND 1.4 GLUTEUS MINIMUS Iliotibial band. Student Copy Lower Limb Muscles. Dr. Reyes’ Gluteus minimus. Student Copy Lower Limb Muscles. Dr. F2F Lecture Reyes’ F2F Lecture Formed by the gluteus maximus and tensor fascia lata. Smallest gluteal muscle Helps maintain the body in an upright position by Found under Gluteus Medius stabilizing the extended knee joint. When Gluteus Medius and Gluteus Minimus contract, Shows the extension of Tensor Fascia Lata as it inserts they will abduct the hip joint since they are found at the into the knee joint, specifically the lateral condyle of the side. tibia or iliotibial tubercle of the tibia. 1.3 GLUTEUS MEDIUS GLUTEUS MINIMUS MUSCLE Origin Outer surface of ilium, located between anterior and inferior gluteal lines Insertion Anterolateral surface of greater trochanter of femur Nerve Supply Superior gluteal nerve Nerve Roots L5; S1 Action Abducts thigh and medially rotates hip joint Tilts pelvis when walking to permit opposite leg to clear ground Gluteus medius. Student Copy Lower Limb Muscles. Dr. Reyes’ F2F Lecture Anatomy - Mod2C Muscles of the Lower Limb 2 of 26 2. DEEP LAYER 2.2 GEMELLUS SUPERIOR 2.1 PIRIFORMIS Piriformis exiting on Greater sciatic foramen. Student Copy Gemellus Superior. Student Copy Lower Limb Muscles. Dr. Lower Limb Muscles. Dr. Reyes’ F2F Lecture Reyes’ F2F Lecture They (along with Gemellus Inferior Muscle and Quadratus Femoris) are called the red carpet muscles. The sciatic nerve comes under the following muscles. It will exit the greater sciatic foramen. GEMELLUS SUPERIOR MUSCLE Origin Ischial Spine Insertion Superior border of greater trochanter of femur Nerve Supply Sacral plexus Nerve Roots L5; S1 Origin of piriformis coming from the inner surface of sacrum. Student Copy Lower Limb Muscles. Dr. Reyes’ F2F Lecture. Action External/lateral rotator of thigh It exits through the greater sciatic foramen to enter the at hip joint gluteal region. It serves as an important anatomical landmark to identify 2.3 OBTURATOR INTERNUS neurovascular structures and divides gluteal vessels and nerves into superior and inferior. Small gemelli muscles are found under the piriformis: ○ Superior gemellus ○ Inferior gemellus ○ Quadratus femoris PIRIFORMIS MUSCLE Origin Anterior surface of sacrum Inner surface of pelvis Insertion Superior border of greater trochanter of femur Nerve Supply First and second sacral nerves Nerve Roots L5; S1, S2 Obturator Internus. Student Copy Lower Limb Muscles. Dr. Reyes’ F2F Lecture Action External/lateral rotator of thigh at the hip joint The obturator internus came from the internal pelvis and covers the obturator foramen. The tendon part is seen in the gluteal region, while the muscle part is located on the inner surface of obturator foramen. Anatomy - Mod2C Muscles of the Lower Limb 3 of 26  Forms tendinous portion and exits via the lesser sciatic 2.5 QUADRATUS FEMORIS foramen to insert to the greater trochanter. OBTURATOR INTERNUS MUSCLE Origin Inner surface of obturator membrane Insertion Superior border of greater trochanter of femur Nerve Supply Sacral plexus Nerve Roots L5; S1 Action External/lateral rotator of thigh at hip joint 2.4 GEMELLUS INFERIOR Quadratus Femoris. Student Copy Lower Limb Muscles. Dr. Reyes’ F2F Lecture. QUADRATUS FEMORIS MUSCLE Origin Lateral border of ischial tuberosity Insertion Quadrate tubercle of femur Nerve Supply Sacral plexus Nerve Roots L5; S1 Action External/lateral rotator of thigh at hip joint Gemellus Inferior. Student Copy Lower Limb Muscles. Dr. Reyes’ F2F Lecture. GEMELLUS INFERIOR MUSCLE Origin Ischial Tuberosity Insertion Medial superior border of Greater Trochanter of Femur Nerve Supply Nerve to quadratus femoris; Sacral plexus Nerve Roots L5-S1 Action External rotator and abductor of thigh at hip joint Piriformis and the Red Carpet Muscles. Student Copy Lower Limb Muscles. Dr. Reyes’ F2F Lecture Professor’s Notes: Gemellus Superior, Gemellus Inferior, and Quadratus Femoris are collectively known as the Red Carpet Muscles, where the sciatic nerve will pass through. Piriformis and the Red Carpet Muscles are all external rotators of the hip joint. Anatomy - Mod2C Muscles of the Lower Limb 4 of 26 B. THIGH MUSCLES 1.1 BICEPS FEMORIS Posterior Compartment ○ Biceps femoris ○ Semitendinosus ○ Semimembranosus Anterior Compartment ○ Iliopsoas (Iliacus & Psoas major) ○ Sartorius ○ Quadriceps femoris Rectus femoris Vastus Lateralis Vastus Medialis Vastus Intermedius Medial Compartment ○ Gracilis ○ Pectineus ○ Obturator externus ○ Adductor longus ○ Adductor brevis ○ Adductor magnus Long head of Biceps femoris. Student Copy Lower Limb Muscles. Dr. Reyes’ F2F Lecture 1. POSTERIOR COMPARTMENT OF THE THIGH Hamstring muscles. Student Copy Lower Limb Muscles. Dr. Short head of Biceps femoris. Student Copy Lower Limb Reyes’ F2F Lecture Muscles. Dr. Reyes’ F2F Lecture All of these muscles have a common origin which is the Has 2 heads: Long and short head Ischial tuberosity. Found at the Lateral side ○ Except for the short head of the biceps femoris which originates from the linea aspera and the BICEPS FEMORIS MUSCLE lateral supracondylar ridge of the shaft of femur. They are collectively known as the Hamstring muscles Origin Long head Ischial Composed of the following (medial to lateral): tuberosity Semimembranosus, Semitendinosus, and Biceps femoris. Short head Linea aspera; Main function of the Hamstring muscles: Prime flexor of lateral the knee joint supracondylar ridge of shaft of femur Insertion Fibular head Nerve Supply Sciatic nerve (tibial portion for long head; common fibular portion for short head) Nerve Roots L5; S1, S2 Anatomy - Mod2C Muscles of the Lower Limb 5 of 26 Action Flexes and laterally rotates leg at Muscle belly is found at the most medial side (although knee joint; long head also extends the most medial tendon is that of the semitendinosus). thigh at hip joint SEMIMEMBRANOSUS MUSCLE 1.2 SEMITENDINOSUS Origin Ischial tuberosity Insertion Medial condyle of tibia Nerve Supply Tibial portion of sciatic nerve Nerve Roots L5; S1, S2 Action Flexes and medially rotates leg at knee joint; extends thigh at hip joint 2. ANTERIOR COMPARTMENT OF THE THIGH 2.1 ILIOPSOAS Semitendinosus. Student Copy Lower Limb Muscles. Dr. Reyes’ F2F Lecture Its tendon is the most medial among the three posterior muscles of the thigh (although the most medial muscle belly is that of the semimembranosus). Has a long and very prominent tendon SEMITENDINOSUS MUSCLE Origin Ischial tuberosity Insertion Upper part of medial surface of shaft of tibia Nerve Supply Tibial portion of sciatic nerve Nerve Roots L5; S1, S2 Iliopsoas. Student Copy Lower Limb Muscles. Dr. Reyes’ Action Flexes and medially rotates leg F2F Lecture at knee joint; extends thigh at hip joint 1.3 SEMIMEMBRANOSUS Iliacus and Psoas major. Student Copy Lower Limb Muscles. Semimembranosus. Student Copy Lower Limb Muscles. Dr. Dr. Reyes’ F2F Lecture Reyes’ F2F Lecture Will pass under the inguinal ligament Anatomy - Mod2C Muscles of the Lower Limb 6 of 26  Prime flexor of the hip joint ○ Will be active after or beyond 45o of hip flexion ○ Before the 45o, the abs will be responsible for hip flexion Distal combined term for the two muscles: psoas major SARTORIUS MUSCLE (medial) and iliacus (lateral). Origin Anterior superior iliac spine ILIOPSOAS MUSCLE Insertion Upper medial surface of proximal shaft of tibia Origin Psoas major Transverse processes, Nerve Supply Femoral nerve bodies, and intervertebral Nerve Roots L2, L3 discs of the 12th thoracic Action Flexes, abducts, laterally rotates and five of thigh at hip joint; lumbar Flexes and medially rotates leg at vertebrae knee joint Iliacus Iliac fossa of hip bone 2.3 QUADRICEPS FEMORIS Insertion Lesser trochanter of femur Nerve Supply Psoas major Lumbar plexus Iliacus Femoral nerve Nerve Roots Psoas major L1, L2, L3 Iliacus L2, L3 Action Flexes thigh on trunk; if thigh is fixed, it flexes the trunk on the thigh as in sitting up from lying down 2.2 SARTORIUS Rectus femoris. Student Copy Lower Limb Muscles. Dr. Reyes’ F2F Lecture Vastus lateralis, Vastus intermedius, and Vastus medialis. Sartorius. Student Copy Lower Limb Muscles. Dr. Reyes’ Student Copy Lower Limb Muscles. Dr. Reyes’ F2F Lecture F2F Lecture Has four heads Slanted muscle (sash-like), crossing the thigh anteriorly. Rectus femoris (superficial); vastus lateralis, vastus Attached to the lateral side of the inguinal ligament. intermedius, vastus medialis (deep). Action mnemonic: FABER These collectively form the quadriceps tendon into the ○ Flexion, ABbduction, External Rotation of the hip patella (then into the tubercle of tibia via the patellar joint tendon). ○ Forms the “de kwatro” position Anatomy - Mod2C Muscles of the Lower Limb 7 of 26  Quadriceps tendon inserts into the tibial tuberosity. It is the prime extensor of the knee joint. Articularis genus retracts synovial membrane RECTUS FEMORIS MUSCLE 3. MEDIAL COMPARTMENT OF THE THIGH Origin Straight Anterior inferior iliac These muscles are all adductors of the thigh head spine 3.1 GRACILIS Reflected Ilium above head acetabulum Insertion Quadriceps tendon into patella, then via ligamentum patellae into tubercle of tibia Nerve Supply Femoral nerve Nerve Roots L2, L3, L4 Action Extension of leg at knee joint VASTUS LATERALIS MUSCLE Origin Upper end and shaft of femur Insertion Quadriceps tendon into patella, then via ligamentum patellae into tubercle of tibia Nerve Supply Femoral nerve Gracilis (middle). Student Copy Lower Limb Muscles. Dr. Nerve Roots L2, L3, L4 Reyes’ F2F Lecture Action Extension of leg at knee joint Most superficial muscle on the medial side. Has a common tendon insertion with the semitendinosus (right) and sartorius muscles (left); at the anteromedial VASTUS MEDIALIS MUSCLE surface of the proximal tibia. This group is called “pes anserine muscles” Origin Upper end and shaft of femur ○ Meaning “duck’s foot” due to its configuration Mnemonic: “Sergeant”; SGT muscles (arranged anterior Insertion Quadriceps tendon into patella, to posterior) then via ligamentum patellae into ○ Sartorius, Gracilis, semiTendinosus tubercle of tibia GRACILIS MUSCLE Nerve Supply Femoral nerve Origin Inferior ramus of pubis, body of Nerve Roots L2, L3, L4 ischium Action Extension of leg at knee joint Insertion Upper part of shaft of tibia on Stabilizes patella medial surface Nerve Supply Obturator nerve VASTUS INTERMEDIUS MUSCLE Nerve Roots L2, L3 Origin Anterior and lateral surfaces of shaft of femur Action Adducts thigh at hip joint Flexes leg at knee joint Insertion Quadriceps tendon into patella, then via ligamentum patellae into tubercle of tibia Nerve Supply Femoral nerve Nerve Roots L2, L3, L4 Action Extension of leg at knee joint Anatomy - Mod2C Muscles of the Lower Limb 8 of 26 3.2 PECTINEUS However, while obturator internus will come from the inner surface of pelvis and exit via the lesser sciatic foramen, obturator externus will come from the external surface of obturator foramen. OBTURATOR EXTERNUS MUSCLE External surface of the Origin obturator foramen Medial surface of the greater Insertion trochanter Obturator nerve (posterior Nerve Supply branch) Nerve Roots L3, L4 External rotation of the Action femur/thigh at hip joint 3.4 ADDUCTOR LONGUS Pectineus. Student Copy Lower Limb Muscles. Dr. Reyes’ F2F Lecture PECTINEUS MUSCLE Origin Superior ramus of pubis Insertion Upper end of linea aspera of shaft of femur Nerve Femoral nerve and Obturator nerves Supply Nerve Roots L2, L3 Action Flexes and adducts thigh at hip joint 3.3 OBTURATOR EXTERNUS Adductor Longus. Student Copy Lower Limb Muscles. Dr. Reyes’ F2F Lecture ADDUCTOR LONGUS MUSCLE Origin Body of pubis, medial to pubic tubercle Insertion Posterior surface of middle shaft of femur (linea aspera) Nerve Supply Obturator nerve (anterior branch) Nerve Roots L2, L3, L4 Action Adducts thigh at hip joint Obturator Externus. Student Copy Lower Limb Muscles. Dr. Assists in medial rotation Reyes’ F2F Lecture Both the obturator externus and obturator internus will insert in greater trochanter. Anatomy - Mod2C Muscles of the Lower Limb 9 of 26 3.5 ADDUCTOR BREVIS Adductor Hiatus. Student Copy Lower Limb Muscles. Dr. Reyes’ F2F Lecture Adductor Hiatus – Hole/foramen created at the distal insertion of adductor magnus. ○ Where neurovascular structures pass through to Adductor Brevis. Student Copy Lower Limb Muscles. Dr. reach the posterior side of the lower limb. Reyes’ F2F Lecture ○ An anatomical landmark because the blood vessels will change their name after passing through this hiatus. ADDUCTOR BREVIS MUSCLE Origin Inferior ramus of pubis ADDUCTOR MAGNUS MUSCLE Insertion Posterior surface of proximal Origin Inferior pubic rami, ischial shaft of femur (linea aspera) tuberosity, ramus of ischium Nerve Supply Obturator nerve (anterior Insertion Posterior surface of shaft of branch) femur, adductor tubercle of femur Nerve Roots L2, L3, L4 Nerve Supply Adductor portion: obturator Action Adducts thigh at hip joint nerve Hamstring portion: sciatic nerve (tibial division) 3.6 ADDUCTOR MAGNUS Nerve Roots L2, L3, L4 Action Adducts thigh at hip joint and assists in medial rotation; Hamstring portion extends thigh at hip joint Adductor Magnus. Student Copy Lower Limb Muscles. Dr. Reyes’ F2F Lecture Anatomy - Mod2C Muscles of the Lower Limb 10 of 26 FEMORAL TRIANGLE SUBSARTORIAL CANAL Femoral Triangle. Student Copy Lower Limb Muscles. Dr. Reyes’ F2F Lecture Triangular (inverted) depression located just below the inguinal ligament. Acts like an expanded version of a funnel Subsartorial Canal. Student Copy Lower Limb Muscles. Dr. Reyes’ F2F Lecture BORDERS OF FEMORAL TRIANGLE Also called the Adductor canal Base Inguinal ligament Cylindrical structure hidden behind the sartorius Acts like the cylindrical structure in a funnel, Medial Border Adductor longus neurovascular structures from the femoral triangle will continue to descend through this canal. Contains the femoral vessels and nerve, and the Lateral Border Sartorius saphenous nerve. Roof Gutter shaped and fomed from lateral to medial by the C. LEG MUSCLES iliopsoas, pectineus, and Anterior Compartment adductor longus ○ Extensor Retinaculum (ligament) ○ Tibialis Anterior Floor Iliopsoas and Pectineus ○ Extensor Hallucis Longus ○ Extensor Digitorum Longus Neurovascular Femoral nerve and its ○ Peroneus/Fibularis Tertius structures that branches occupy this Femoral artery and its Lateral Compartment structure branches ○ Peroneus/Fibularis longus Femoral vein and its ○ Peroneus/Fibularis brevis (arranged from tributaries lateral to medial) Femoral canal (deep Posterior Compartment inguinal/Cloquet’s lymph ○ Gastrocnemius nodes) ○ Soleus Great saphenous vein ○ Plantaris ○ Popliteus ○ Flexor Retinaculum ○ Tibialis posterior ○ Flexor digitorum longus ○ Flexor hallucis longus ANTERIOR COMPARTMENT OF THE LEG Anatomy - Mod2C Muscles of the Lower Limb 11 of 26  EXTENSOR RETINACULUM OF THE LEG EXTENSOR HALLUCIS LONGUS Extensor Retinaculum. Student Copy Lower Limb Muscles Extensor Hallucis Longus. Student Copy Lower Limb pptx from Doc Reyes. Muscles pptx from Doc Reyes. Counterpart of the Extensor Retinaculum of the Inserts at the big toe Hand Extends the hallux Bands of connective tissue which holds tendons in place and prevent bowstringing of tendons EXTENSOR HALLUCIS LONGUS TIBIALIS ANTERIOR Origin Anterior surface of fibula Insertion Base of distal phalanx of great toe Nerve Deep fibular nerve Supply Nerve Roots L4. L5 Action Extends toes Extends foot at ankle joint EXTENSOR DIGITORUM LONGUS Tibialis Anterior. Student Copy Lower Limb Muscles pptx from Doc Reyes. Inserts to the base of the first metatarsal or sometimes at the navicular bone Action: dorsiflexion; prime dorsiflexor of the foot TIBIALIS ANTERIOR Origin Lateral surface of shaft of tibia and interosseous membrane Insertion Base of first metatarsal bone; medial Extensor Digitorum Longus. Student Copy Lower Limb cuneiform or sometimes at the Muscles pptx from Doc Reyes. navicular bone Extends small toes Nerve Deep fibular nerve Four tendons that would supply the rest of the toes Supply Nerve Roots L4, L5 EXTENSOR DIGITORUM LONGUS Action Extends food at ankle joint Origin Anterior surface of shaft of fibula Inverts foot at subtalar and transverse tarsal joints Insertion Extensor expansion of lateral four Holds up medial longitudinal arch of toes foot Nerve Deep fibular nerve Supply Nerve Roots L5; S1 Anatomy - Mod2C Muscles of the Lower Limb 12 of 26 Action Extends toes Ends on the tubercle of the 5th metatarsal (travels Extends foot at ankle joint below) Action: plantarflexion, mainly eversion PERONEUS/FIBULARIS TERTIUS Insert at the medial surface of the foot Evert the foot PERONEUS/FIBULARIS LONGUS Origin Lateral surface of shaft of fibula Insertion Base of first metatarsal and the medial cuneiform Nerve Superficial fibular nerve Supply Nerve Roots L5; S1, S2 Peroneus/Fibularis Tertius. Student Copy Lower Limb Muscles pptx from Doc Reyes. Action Plantarflexes foot at ankle joint Everts foot at subtalar and Attaches at the tubercle of the 5th metatarsal transverse tarsal joints Action: foot evertor muscle (lateral side would Supports lateral longitudinal and elevate) transverse arches of foot ○ all muscles at the lateral side are foot evertors; at medial side are foot invertors PERONEUS/FIBULARIS BREVIS PERONEUS/FIBULARIS TERTIUS Origin Anterior surface of shaft of fibula Insertion Base of fifth metatarsal bone Nerve Deep fibular nerve Supply Nerve Roots L5; S1 Action Extends foot at ankle joint Everts foot at subtalar and Peroneus/Fibularis Brevis. Student Copy Lower Limb transverse tarsal joints Muscles pptx from Doc Reyes. LATERAL COMPARTMENT OF THE LEG Attaches at the tubercle of 5th metatarsal Lateral muscles of the leg are all evertors of the Action: eversion foot “Fibularis/Peroneus/Tertius” = evertors PERONEUS/FIBULARIS BREVIS Fibularis longus and fibularis brevis ○ Same insertion: tubercle of the fifth Origin Lateral surface of shaft of fibula metatarsal ○ Difference is in the tendon, these are at Insertion Base of fifth metatarsal bone the lateral side PERONEUS/FIBULARIS LONGUS Nerve Superficial fibular nerve Supply Nerve Roots L5; S1, S2 Action Plantarflexes foot at ankle joint Everts foot at subtalar and transverse tarsal joints Supports lateral longitudinal and transverse arches of foot Extensor/Fibularis Longus. Student Copy Lower Limb Muscles pptx from Doc Reyes. Anatomy - Mod2C Muscles of the Lower Limb 13 of 26  POSTERIOR COMPARTMENT OF THE LEG Tiptoe - testing strength of soleus ○ While bending the knee - remove action of GASTROCNEMIUS gastrocnemius Soleus is seen coming from the soleal line Action: Plantar Flexion only SOLEUS Origin Shafts of tibia and fibula Insertion Via “tendo calcaneus” into posterior surface of calcaneum Nerve Tibial nerve Supply Gastrocnemius. Student Copy Lower Limb Muscles pptx Nerve Roots S1, S2 from Doc Reyes. Two heads: Action Together with gastrocnemius and ○ Medial plantaris is powerful plantar flexor of ○ Lateral ankle joint Role: knee flexion (crosses the knee joint) and Provides main propulsive force in mainly plantarflex (Inserts at the calcaneus) walking and running ○ Tiptoeing TRICEPS SURAE GASTROCNEMIUS Origin Lateral head Lateral condyle of femur Medial head Above medial condyle of femur Insertion Via “tendo calcaneus” into posterior surface of calcaneum Triceps Surae. Student Copy Lower Limb Muscles pptx from Doc Reyes. Nerve Tibial nerve Supply Two heads of the Gastrocnemius and the Soleus make up the Triceps Surae Nerve Roots S1, S2 PLANTARIS Action Plantar flexes foot at ankle joint Flexes knee joint SOLEUS Plantaris. Student Copy Lower Limb Muscles pptx from Doc Reyes. Long tendon (Fisherman’s nerve) Soleus. Student Copy Lower Limb Muscles pptx from Doc ○ Olden civilizations thought it was a nerve Reyes. due to its length Pressed between the gastrocnemius and soleus Cut through the Gastrocnemius to appreciate the Soleus Does not cross the knee joint Anatomy - Mod2C Muscles of the Lower Limb 14 of 26  PLANTARIS Nerve Roots L4, L5, S1 Origin Lateral supracondylar ridge of femur Action Flexes leg at knee joint Unlocks knee joint by lateral rotation Insertion Posterior surface of calcaneus via of femur on tibia and slackens calcaneal tendon ligament of joint Nerve Tibial Nerve POPLITEAL FOSSA Supply Nerve Roots S1, S2 Action Plantar flexes foot at ankle joint Flexes knee joint ACHILLES/CALCANEUS TENDON Popliteal Fossa. Student Copy Lower Limb Muscles pptx from Doc Reyes. Behind the knee Diamond-shaped muscular compartment Superior border: ○ Upper Medial: Semitendinosus, Semimembranosus ○ Upper Lateral: Biceps Femoris Achilles/Calcaneal tendon. Student Copy Lower Limb Lower border: Muscles pptx from Doc Reyes. ○ Medial: Medial Head of Gastrocnemius ○ Lateral: Lateral Head of Gastrocnemius Tendon of the plantaris, gastrocnemius, and soleus All plantar flexors FLEXOR RETINACULUM POPLITEUS Flexor Retinaculum. Student Copy Lower Limb Muscles pptx from Doc Reyes. Popliteus. Student Copy Lower Limb Muscles pptx from Doc Reyes. Medial side of the ankle Connected to the medial malleolus Deepest structure of the popliteal area Responsible for unlocking the knee joint TIBIALIS POSTERIOR ★ Hard/Impossible to assume sitting from standing if knee cannot be unlocked POPLITEUS Origin Lateral surface of lateral condyle of femur and lateral meniscus Insertion Posterior surface of tibia, superior to soleal line Nerve Tibial nerve Supply Anatomy - Mod2C Muscles of the Lower Limb 15 of 26  Tibialis Posterior. Student Copy Lower Limb Muscles pptx FLEXOR HALLUCIS LONGUS from Doc Reyes. Attach at the base of the navicular bone Action: plantar flexor Most of the muscles on the posterior fascial compartment are plantar flexors TIBIALIS POSTERIOR Origin Posterior surface of shafts of tibia and fibula and interosseus membrane Insertion Tuberosity of navicular bone and Flexor Hallucis Longus. Student Copy Lower Limb Muscles other neighboring bones pptx from Doc Reyes. Nerve Tibial nerve Specific for the hallux Supply Flexes the big toe Nerve Roots L4, L5 FLEXOR HALLUCIS LONGUS Action Plantar flexes foot at ankle joint Origin Posterior surface of shaft of fibula Inverts foot at subtalar and transverse tarsal joints Insertion Base of distal phalanx of big toe Supports medial longitudinal archs of foot Nerve Tibial nerve Supply FLEXOR DIGITORUM LONGUS Nerve Roots S2, S3 Action Flexes distal phalanx of big toe Plantar flexes foot at ankle joint Supports medial longitudinal arch of foot FOOT MUSCLES Dorsum Extensor Digitorum Brevis Extensor Hallucis Brevis Plantar Flexor Digitorum Longus. Student Copy Lower Limb Muscles Plantar fascia pptx from Doc Reyes. Layer 1: (Muscles) Four tendons and would supply the four toes Abductor hallucis Flexes the toes Flexor digitorum brevis Abductor digiti minimi FLEXOR DIGITORUM LONGUS Layer 2: (Muscles and tendons) Flexor hallucis longus tendon Origin Posterior surface of shaft of tibia Flexor digitorum longus tendon Quadratus plantae Insertion Bases of distal phalanges of lateral Lumbricals 1-4 four digits Layer 3: (Muscles) Nerve Tibial nerve Flexor hallucis brevis Supply Flexor digiti minimi Adductor hallucis Nerve Roots S2, S3 Layer 4: (Muscles and tendons) Action Flexes distal phalanges of lateral Dorsal and Plantar Interossei four toes Tibialis posterior tendon Plantar flexes foot at ankle joint Peroneus/ Fibularis longus tendon Supports medial and lateral Tibialis posterior tendon longitudinal arches of foot Anatomy - Mod2C Muscles of the Lower Limb 16 of 26  DORSUM Nerve Deep fibular nerve EXTENSOR DIGITORUM BREVIS Supply Nerve Roots L5 or S1, or both Action Aids in the extensor hallucis longus in extending the great toe at the metatarsophalangeal joint PLANTAR Plantar muscles with four layers: ○ Requires a great cushion that would bear the weight of the entire body Plantar surface Extensor Digitorum Brevis. Student Copy Lower Limb Muscles pptx from Doc Reyes. ○ thick skin, lots of subcutaneous fascia, connective tissue Short muscle for the little toes ○ foot absorbs most of our weight, must have the most cushion EXTENSOR DIGITORUM BREVIS PLANTAR FASCIA Origin Anterior part of upper surface of the calcaneum and from the inferior extensor retinaculum Insertion By four tendons into the proximal phalanx of big toe and long extensor tendons to second, third, and fourth toes Nerve Deep peroneal nerve Supply Nerve Roots S1, S2 Plantar Fascia. Student Copy Lower Limb Muscles pptx from Action Extends toes Doc Reyes. White connective tissue structure: covers entire EXTENSOR HALLUCIS BREVIS surface of plantar region ○ Start from the tubercle of the ankle up until the toes Thick subcutaneous tissue. Once skin is removed, there is a white structure that will cover the entire surface of the plantar region called plantar fascia. Once removed, you can see the layers. LAYER 1 Extensor Hallucis Brevis. Student Copy Lower Limb Muscles pptx from Doc Reyes. Short muscle for the big toe EXTENSOR HALLUCIS BREVIS Origin In common with extensor digitorum brevis (above) Abductor Hallucis, Flexor Digitorum Brevis, and Abductor Digiti Minimi. Student Copy Lower Limb Muscles pptx from Insertion Dorsal aspect of the base of Doc Reyes. proximal phalanx of the great toe (digit 1 or hallux) Layer 1 (2 abductors, 1 flexor) ○ Toe and pinky toe Abductor hallucis Anatomy - Mod2C Muscles of the Lower Limb 17 of 26  Abductor digiti minimi LAYER 2 ○ Rest of the toes Flexor digitorum brevis ABDUCTOR HALLUCIS ABDUCTOR HALLUCIS Origin Medial tuberosity of calcaneum and flexor retinaculum Insertion Base of proximal phalanx of big toe Nerve Medial plantar nerve Flexor Hallucis Longus Tendon and Flexor Digitorum Longus Supply Tendon. Student Copy Lower Limb Muscles pptx from Doc Reyes. Nerve Roots S2, S3 Layer 2 (combination of long tendons and muscles) Action Flexes and abducts big toe ○ Tendon of flexor digitorum longus (little Braces medial longitudinal arch toes) and tendon of flexor hallucis longus (big toe) FLEXOR DIGITORUM BREVIS ○ Posterior side: Quadratus plantae Four lumbricals FLEXOR DIGITORUM BREVIS originates from tendons of the Origin Medial tubercle of calcaneum flexor digitorum longus (similar to hand) Insertion Four tendons to four lateral toes - flex metatarsophalangeal joints of inserted into borders of middle the foot phalanx; tendons perforated by those of flexor digitorum longus Nerve Medial plantar nerve Supply Nerve Roots S2, S3 Action Flexes lateral four toes Braces medial and lateral longitudinal arches ABDUCTOR DIGITI MINIMI Quadratus Plantae and Lumbricals. Student Copy Lower Limb ABDUCTOR DIGITI MINIMI Muscles pptx from Doc Reyes. Origin Medial and lateral tubercles of the QUADRATUS PLANTAE calcaneum Insertion Base of proximal phalanx of fifth toe QUADRATUS PLANTAE Nerve Lateral plantar nerve Origin Medial and lateral sides of Supply calcaneum Nerve Roots S2, S3 Insertion Tendon of flexor digitorum longus Action Flexes and abducts fifth toe Nerve Lateral plantar nerve Braces lateral longitudinal arch Supply Nerve Roots S2, S3 Action Assists flexor digitorum longus in flexing lateral four digits Anatomy - Mod2C Muscles of the Lower Limb 18 of 26 LUMBRICALS 1-4 FLEXOR DIGITI MINIMI LUMBRICALS 1-4 FLEXOR DIGITI MINIMI Origin Tendons of flexor digitorum longus Origin Base of 5th metatarsal Insertion Dorsal extensor expansion; bases of Insertion Lateral side of base of proximal proximal phalanges of lateral four phalanx of little toe toes Nerve Lateral plantar nerve Nerve First lumbrical: medial plantar nerve Supply Supply Remainder: lateral plantar nerve Nerve Roots S2, S3 Nerve Roots S2, S3 Action Flexes metatarsophalangeal joint of little toe Action Extends toes at interphalangeal ADDUCTOR HALLUCIS joints ADDUCTOR HALLUCIS LAYER 3 Origin Oblique head: bases of the second, third, and fourth metatarsal bones Transverse head: plantar ligaments Insertion Lateral side of the base of the proximal phalanx of big toe Nerve Deep branch of lateral plantar nerve Supply Nerve Roots S2,S3 Flexor Hallucis Brevis, Flexor Digiti Minimi, and Adductor Hallucis. Student Copy Lower Limb Muscles pptx from Doc Action Flexes metatarsophalangeal joint of Reyes. big toe Holds together metatarsal bones Layer 3 (pure muscles) ○ Adductor hallucis LAYER 4 ○ Flexor digiti minimi ○ Flexor hallucis brevis Layer 4 (Tendons and muscles) ○ Interosseous muscles (DAB, PAD - replace FLEXOR HALLUCIS BREVIS palmar to plantar) and the reference: 2nd toe Dorsal interosseus - abduct FLEXOR HALLUCIS BREVIS Second toe equipped with two Origin Cuboid, lateral cuneiform, tibialis Third and fourth has its own posterior insertion dorsal interosseous None for the little toe since it has Insertion Medial tendon into medial side of its own abductor digiti minimi base of proximal phalanx of big toe; None for the big toe since it has lateral tendon into lateral side of its own abductor hallucis base of proximal phalanx of big toe Plantar interossei - adduct (move Nerve Medial plantar nerve closer to the second toe) Supply None for big toe since it has its own adductor hallucis Nerve Roots S2, S3 ○ Tendon that crosses the plantar surface of the foot → peroneus longus tendon and Action Flexes metatarsophalangeal joint of tibialis posterior big toe Supports medial longitudinal arch Anatomy - Mod2C Muscles of the Lower Limb 19 of 26 PLANTAR INTEROSSEUS MUSCLE DORSAL INTEROSSEI (FOUR MUSCLES) Origin Adjacent sides of shafts of metatarsals Insertion 1st: medial side of second toe Remainder: lateral sides of 2nd-4th digits - also dorsal extensor expansion Plantar Interosseous Muscle. Student Copy Lower Limb Muscles Nerve Lateral plantar nerve pptx from Doc Reyes. Supply PLANTAR INTEROSSEI (THREE MUSCLES) Nerve Roots S2, S3 Origin Inferior surfaces of third, fourth, and Action abduction of toes; flexes fifth metatarsal bones metatarsophalangeal joints and extends interphalangeal joints Insertion Medial side of bases of proximal phalanges of lateral three toes TIBIALIS POSTERIOR TENDON AND PERONEUS/FIBULARIS LONGUS TENDON Nerve Lateral plantar nerve Supply Nerve Roots S2, S3 Action Abduction of toes, flexes metatarsophalangeal joints and extends interphalangeal joints DORSAL INTEROSSEUS MUSCLE Tibialis Posterior Tendon and Peroneus Longus Tendon. Student Copy Lower Limb Muscles pptx from Doc Reyes. II. REFERENCES Dr. Reyes Face-to-Face Lecture on Muscles of the Lower Limb Wineski L. E. & Snell R. S. (2018). Snell's Clinical Anatomy by Regions (Tenth ed.). Wolters Kl Dorsal Interosseus Muscle. Student Copy Lower Limb Muscles pptx from Doc Reyes. Anatomy - Mod2C Muscles of the Lower Limb 20 of 26  PRACTICE QUESTIONS Reminder: each individual is assigned to make two (2) practice questions each, with respective rationales. DISCLAIMER: Practice questions WERE NOT fact-checked and DID NOT undergo proofreading. Please be advised. You may comment on the specific question if you have any corrections. MUSCLES OF THE LOWER LIMB QUESTIONS ANSWER RATIONALE 1. What happens when the hamstring muscles A A. Flexion of the knee contract? B. Dorsiflexion of the ankle a. flexion of the knee b. dorsiflexion of the ankle C. Extension of the knee joint c. extension of the knee joint d. extension of the thigh D. Extension of the thigh The hamstring muscles are the prime flexors of the knee joint. Hence, when the hamstring muscles contract, the angle between the thigh and calf decreases which allows the bending of the knee. Source: Dr. Reyes’ F2F Lecture on Muscles of the Lower Limb 2. Which muscle, known as the "fisherman's nerve" in C A. Flexor hallucis longus ancient civilizations because of its length, is often considered vestigial in humans? B. Extensor digitorum longus a. Flexor hallucis longus C. Plantaris b. Extensor digitorum longus c. Plantaris D. Peroneus brevis d. Peroneus brevis Plantaris is commonly regarded as vestigial in humans due to its relatively minor role in lower limb function when compared to other leg muscles. Its function is a weak assistant to the gastrocnemius muscle in the plantarflexion of the ankle. Source: Dr. Reyes’ F2F Lecture on Muscles of the Lower Limb 3. What muscles make up the triceps surae in the calf? C A. Soleus and Tibialis Anterior a. Soleus and Tibialis Anterior B. Gastrocnemius and Hamstrings b. Gastrocnemius and Hamstrings c. Gastrocnemius (two heads) and Soleus C. Gastrocnemius (two heads) and Soleus d. Quadriceps and Adductors D. Quadriceps and Adductors The triceps surae consists of the two heads of the gastrocnemius muscle and the soleus muscle, collectively responsible for movements involving the calf and ankle. This combination of muscles enables functions like walking, running, and maintaining ankle stability. Source: Dr. Reyes’ F2F Lecture on Muscles of the Lower Limb 4. What muscles insert into the Achilles tendon? B A. Quadriceps and Gluteus Maximus a. Quadriceps and Gluteus Maximus B. Gastrocnemius, Soleus, and Plantaris b. Gastrocnemius, Soleus, and Plantaris c. Biceps Brachii and Deltoid C. Biceps Brachii and Deltoid d. Pectoralis Major and Latissimus Dorsi Anatomy - Mod2C Muscles of the Lower Limb 21 of 26  D. Pectoralis Major and Latissimus Dorsi These three muscles converge at the Achilles tendon, which attaches to the heel bone (calcaneus), and collectively they play a vital role in plantar flexion, providing power for activities like walking and running. Source: Dr. Reyes’ F2F Lecture on Muscles of the Lower Limb 5. What small muscle of the knee acts to medially rotate D A. Gastrocnemius muscle the Tibia on the Femur? B. Peroneus longus muscle a. Gastrocnemius muscle b. Peroneus longus muscle C. Biceps femoris muscle c. Biceps femoris muscle d. Popliteus muscle D. Popliteus muscle laterally rotates the femur on the tibia (which means that this muscle rotates the tibia medially (internal rotation) on the femur. Source: Snell’s Clinical Anatomy by Regions (9th edition - Chapter 10), page 502 6. What muscle causes the Hallux deformity of the big B A. Abductor Hallucis Muscle toe as it exerts persistent deforming pressure on its insertion? B. Adductor Hallucis Muscle a. Abductor Hallucis Muscle C. Flexor Hallucis Brevis Muscle b. Adductor Hallucis Muscle c. Flexor Hallucis Brevis Muscle D. Extensor Hallucis Brevis Muscle d. Extensor Hallucis Brevis Muscle An over-adduction of the hallux causes bunion, also termed as hallux valgus deformity. Moreover, the muscle responsible for the adduction of the hallux is the adductor hallucis muscle. It adducts the base of the proximal phalanx medially towards the 2nd and 3rd digits. Source: MOD2C-Ankle and Foot 7. All of the following muscles have the same nerve B A. Tibialis Anterior innervation except for: B. Flexor Digitorum Brevis a. Tibialis Anterior b. Flexor Digitorum Brevis C. Extensor Hallucis Longus c. Extensor Hallucis Longus d. Extensor Digitorum Longus D. Extensor Digitorum Longus All of the following muscles mentioned except for Flexor Digitorum Brevis are innervated by the Deep Fibular Nerve. Flexor Digitorum Brevis is innervated by the Medial Plantar Nerve. Source: MOD2C-Ankle and Foot 8. What are the bundle of muscles for Gemellus B a. Triangle Quad Superior/Inferior and Quadratus Femoris called? b. Red Carpet c. Linear Vessel a. Triangle Quad d. Musculocutaneous Quad b. Red Carpet c. Linear Vessel All muscles mentioned are called red carpet because d. Musculocutaneous Quad the sciatic nerve is under the following muscles. Source: Dr. JC’s F2F Lecture about the Anatomy of the Lower Limb Anatomy - Mod2C Muscles of the Lower Limb 22 of 26 9. This muscle which inserts at the posterior surface of C A. Gastrocnemius plantarflexes ankle when knee calcaneus via calcaneal tendon, weakly assists is extended gastrocnemius in plantarflexing the ankle: B. Soleus plantar Flexes ankle; independent of a. Gastrocnemius position of knee; steadies leg on foot b. Soleus c. Plantaris C. Plantaris weakly assists gastrocnemius in d. NOTA plantarflexing the ankle. D. NOTA Source: MOD2C-Ankle and Foot 10. The iliotibial band consists of which muscle(s)? B A. Gluteus maximus and gluteus minimus are part of the muscles that make up the buttocks A. Gluteus maximus and gluteus minimus B. Gluteus maximus and tensor fascia lata B. Gluteus maximus and tensor fascia lata C. Gluteus minimus and gluteus medius make up the iliotibial band that runs down the D. Iliac and tibia thigh. C. Gluteus minimus and gluteus medius are part of the muscles that make up the buttocks D. Iliac and tibia do not make up anything 11. To where will the Obturator Internus attach to after it C A. Lesser trochanter is not found in any insertion becomes tendinous? site for the gluteus muscles. a. Lesser trochanter B. Sciatic notch is not found in any insertion site b. Sciatic notch for the gluteus muscles. c. Greater Trochanter d. Sciatic Foramen C. Greater Trochanter since the Obturator Internus will approach the sciatic notch and thus will become tendinous as it attaches to the greater trochanter. D. Sciatic Foramen is not found in any insertion site for the gluteus muscles. 12. What is the thickest muscle in the body? C A. Gluteus medius is just under the maximus. a. Gluteus medius B. Biceps femoris is only on the posterior thigh. b. Biceps femoris c. Gluteus maximus C. Gluteus maximus is the thickest muscle in d. semitendinosus our body which is also responsible for the prominence of the buttocks. D. Semitendinosus is only on the posterior thigh. 13. Which anatomical landmark divides the gluteal A vessels and nerves into superior and inferior. A. Piriformis emerges through the greater sciatic foramen to enter the gluteal region a. Piriformis and divides gluteal vessels and nerves into b. Gemellus superior superior and inferior. c. Gemellus inferior d. Iliotibial band B. Gemellus superior does not divide any vessels or nerves. C. Gemellus inferior does not divide any vessels or nerves. D. Iliotibial band does not divide any vessels or nerves. Anatomy - Mod2C Muscles of the Lower Limb 23 of 26 14. What is the smallest gluteal muscle? B A. Gluteus maximus is the largest and most superficial muscle. a. Gluteus maximus b. Gluteus minimus B. Gluteus minimus is the smallest and c. Gluteus medius deepest muscle out of the 3 gluteal d. None of the above muscles. C. Gluteus medius is in between gluteus maximus and gluteus minimus. D. None of the above 15. The following foot muscles are found in the third D E. Abductor hallucis & Abductor digiti minimi layer. belong to the first layer; while only Flexor hallucis brevis belongs to the third layer. a. Abductor hallucis, Flexor digitorum brevis, Abductor digiti minimi F. Adductor hallucis & Flexor digitorum brevis b. Adductor hallucis, Flexor digitorum brevis, belong to the first layer; while only Abductor Abductor digiti minimi digiti minimi belongs to the third layer. c. Abductor hallucis, Flexor digitorum brevis, Flexor digiti minimi G. Abductor hallucis & Flexor digitorum brevis d. Adductor hallucis, Flexor hallucis brevis, brevis belong to the first layer; while only Flexor digiti minimi Flexor digiti minimi belongs to the third layer. H. Third layer foot muscles include the Adductor hallucis, Flexor hallucis brevis, Flexor digiti minimi. 16. What forms the base of the femoral triangle? C A. Sartorius borders the femoral triangle on the lateral side. a. Sartorius b. Iliopsoas B. Iliopsoas does not border any side of the c. Inguinal ligament femoral triangle. d. Adductor longus C. Inguinal ligament forms the base of the femoral triangle. D. Adductor longus borders the femoral triangle on the medial side. 17. Which muscle borders the medial side of the D E. Sartorius borders the femoral triangle on the Femoral triangle respectively? lateral side. a. Sartorius F. Iliopsoas does not border any side of the b. Iliopsoas femoral triangle. c. Inguinal ligament d. Adductor longus G. Inguinal ligament forms the base of the femoral triangle. H. Adductor longus borders the femoral triangle on the medial side. 18. The Plantaris muscle weakly assists which muscle B While all the four muscles mentioned contribute to in plantarflexing the ankle? the plantarflexion of the ankle, the Plantaris muscle specifically (weakly) assists the a. Tibialis posterior Gastrocnemius muscle. b. Gastrocnemius c. Peroneus longus d. Flexor hallucis longus 19. Which muscle is responsible for hip flexion of more A A. The Iliopsoas is the prime flexor of the hip than 45 degrees? joint of more than 45 degrees. Before 45 degrees, the abs are responsible for it. a. Iliopsoas b. Gluteus maximus B. Gluteus maximus extends the knee joint c. Sartorius d. Piriformis C. Sartorius flexes, abducts, laterally rotates Anatomy - Mod2C Muscles of the Lower Limb 24 of 26  thigh at hip joint; Flexes and medially rotates leg at knee joint D. Piriformis is the lateral rotator of thigh at hip joint 20. What muscle forms the lateral border of the femoral C A. Inguinal ligament forms the base of the triangle? femoral triangle. a. Inguinal ligament B. Adductor longus forms the medial border of b. Adductor longus the femoral triangle. c. Sartorius d. pectineus C. Sartorius forms the lateral border of the femoral triangle. D. Pectineus forms the floor of the femoral triangle. 21. The foramen where neurovascular structures pass B A. Adductor Brevis does not have any foramen. through to reach the posterior side of the lower limb is found in which muscle? B. Adductor Magnus a. Adductor Brevis C. Adductor Longus does not have any foramen. b. Adductor Magnus c. Adductor Longus It contains the Adduct