Chapter 12 Part 2 Appendicular Muscles Legs and

Chapter 12, Part 2 Appendicular Muscles Legs and Hips

Fig. 12. 15 a Psoas minor Iliac crest Psoas major Gluteus medius Iliacus Gluteus maximus Tensor fasciae latae Sartorius Iliopsoas Pectineus Adductor brevis Adductor longus Gracilis Rectus femoris Vastus lateralis Iliotibial tract Adductor magnus Biceps femoris, long head Semimembranosus Patella Biceps femoris, short head Gastrocnemius (a) Right thigh, anterior view (b) Right thigh, lateral view

Fig. 12. 15 b Iliac crest Sacrum Gluteus maximus (cut) Piriformis Superior gemellus Obturator internus Sacrotuberous ligament Inferior gemellus Ischial tuberosity Gluteus medius (cut) Gluteus minimus Gluteus medius (cut) Gluteus maximus (cut) Quadratus femoris Gracilis Biceps femoris, long head Adductor magnus Semitendinosus Iliotibial tract

Fig. 12. 16 View of cross section Lateral thigh and some gluteal muscles abduct the thigh. Anterior Femur Lateral Posterior thigh muscles extend the thigh and/or flex the leg/knee. Anterior thigh muscles flex the hip and/or Medial extend the leg/knee. Medial thigh muscles adduct the thigh. Posterior

Fig. 12. 17 (a) Right thigh, anterior view • Most muscles that move thigh originate on the os coxae and insert on the femur • Hip flexors insert on anterior femur and flex thigh • Psoas major originates on vertebrae, iliacus originates on iliac fossa; both fuse into iliopsoas that inserts on femur • Sartorius originates on ASIS, inserts on tibial tuberosity; crosses thigh, assists with hip flexion; medially rotates leg Iliacus Psoas major Iliopsoas Sartorius

Fig. 12. 15 a • Hip adductors are medial on thigh • Adductor longus, adductor brevis, gracilis, and pectineus also flex thigh • Adductor magnus also extends and laterally rotates thigh (a) Right thigh, anterior view Pectineus Adductor brevis Adductor longus Gracilis Adductor magnus • originates on pubis and ischial tuberosity, inserts on medial femur

Fig. 12. 15 a (b) Right thigh, lateral view • Tensor fasciae latae is small muscle that attaches to lateral thickening of fascia lata called iliotibial tract Iliac crest Tensor fasciae latae Gluteus maximus Iliotibial tract Sartorius

• Gluteus muscles extend thigh • Gluteus medius and minimus also abduct and medially rotate thigh Iliac crest Sacrum Gluteus maximus (cut) Iliac crest Gluteus medius Gluteus maximus Fig. 12. 15 b Gluteus medius (cut) Gluteus minimus Gluteus medius (cut) Gluteus maximus (cut)

Fig. 12. 15 b • Muscles deep to gluteal muscles laterally rotate thigh and hip joint • • Piriformis Superior gemellus Obturator internus Inferior gemellus Iliac crest Sacrum Gluteus maximus (cut) Piriformis Superior gemellus Obturator internus Inferior gemellus Ischial tuberosity Gracilis Adductor magnus Gluteus medius (cut) Gluteus minimus Gluteus medius (cut) Gluteus maximus (cut) Quadratus femoris Iliotibial tract

Iliac crest Fig. 12. 18 Gluteus medius Gluteus maximus Adductor magnus Gracilis Iliotibial tract Semitendinosus Biceps femoris, long head Biceps femoris, short head (a) Right thigh, posterior view • Hamstrings are on back of thigh • Extend thigh and flex knee • Have common origin on ischial tuberosity; insert separately on leg • Biceps femoris inserts on head of fibula • Semitendinosus inserts on proximal medial tibia • Semimembranosus (deep to biceps femoris) inserts on posterior surface of medial condyle of tibia

Fig. 12. 18 (b) Thigh extensors Ischial tuberosity Linea aspera Semitendinosus Biceps femoris, long head Semimembranosus Adductor magnus Biceps femoris, short head Head of fibula

Quadriceps group • Located on front of thigh • Extends the knee joint

Fig. 12. 17 Greater trochanter Rectus femoris Vastus lateralis Vastus intermedius (deep to rectus femoris) Sartorius Patellar ligament Tibia (b) Anterior thigh muscles Vastus medialis

Fig. 12. 19 Anterior leg muscles dorsiflex the foot and/or extend the toes. View of cross section Posterior leg muscles flex the leg, plantar flex the foot, and/or flex the toes. Lateral leg muscles plantar flex and evert the foot. Posterior

(a) Right leg, anterior view Fig. 12. 20 • Crural muscles move ankle, foot, and toes (some also help flex leg) Gastrocnemius Fibularis longus Fibularis brevis Extensor digitorum longus Fibularis tertius tendon Extensor digitorum brevis Tibialis anterior Extensor hallucis longus Extensor retinaculum Extensor hallucis longus tendon Extensor digitorum longus tendons Extensor hallucis brevis

• Extensor digitorum longus flexes foot and extends toes (a) Right leg, anterior view Fig. 12. 20 • Fibularis tertius tendon extends from muscle to evert foot • Extensor hallucis longus dorsiflexes foot and extends big toe • Tibialis anterior is primary Fibularis dorsiflexor of foot, also inverts brevis Extensor foot • inserts on medial plantar side of foot digitorum longus • Tendons of these muscles pass through extensor retinaculum at ankle Fibularis tertius tendon Tibialis anterior Extensor hallucis longus Extensor retinaculum Extensor hallucis longus tendon Extensor digitorum longus tendons

(a) Right leg, anterior view Fig. 12. 20 • Crural muscles move ankle, foot, and toes (some also help flex leg) Gastrocnemius Fibularis longus Fibularis brevis Extensor digitorum longus Fibularis tertius tendon Extensor digitorum brevis Tibialis anterior Extensor hallucis longus Extensor retinaculum Extensor hallucis longus tendon Extensor digitorum longus tendons Extensor hallucis brevis

(b) Anterior leg muscles Fig. 12. 20 Tibialis anterior Extensor digitorum longus Fibularis tertius tendon Extensor hallucis longus

(b) Lateral leg muscles Fig. 12. 21 Gastrocnemius Tibialis anterior Fibularis longus Fibularis brevis Fibularis longus tendon 5 th metatarsal

Fig. 12. 21 Patella Head of fibula Gastrocnemius Soleus Fibularis longus Fibularis brevis Fibularis tertius Calcaneal tendon Extensor digitorum brevis Tibialis anterior Extensor digitorum longus Extensor hallucis longus Extensor retinaculum Extensor hallucis brevis Extensor hallucis longus tendon Fibular retinaculum Fibularis tertius tendon (a) Right leg, lateral view Extensor digitorum longus tendons 5 th metatarsal

• Posterior compartment muscles plantar flex foot • Gastrocnemius has two bellies Fig. 12. 22 Plantaris • flexes leg and plantar flexes foot • Soleus is deep to gastrocnemius, resembles flat fish • plantar flexes foot • Gastrocnemius and soleus have common tendon, calcaneal tendon or Achilles tendon • Plantaris (absent in some people) is weak leg flexor Gastrocnemius Lateral head Medial head Soleus Calcaneal tendon (a) Right leg, superficial poster

(b) Deep posterior view Fig. 12. 22 Plantaris (cut) Gastrocnemius (cut) Popliteus Tibialis posterior Fibularis longus Flexor digitorum longus Flexor hallucis longus Fibularis brevis Calcaneal tendon (cut) • Popliteus rotates tibia slightly to unlock fully extended knee • Tibialis posterior is deep to soleus • plantar flexes and inverts foot • Flexor digitorum longus attaches to distal phalanges of toes 2 -5 • plantar flexes foot, flexes MP, PIP, and DIP joints of toes 2 -5 • Flexor hallucis longus attaches to distal phalanx of big toe • plantar flexes foot and flexes big toe

Fig. 12. 22 Tibia Popliteus Tibialis posterior Fibula Flexor digitorum longus Interosseous membrane Tarsal and metatarsal bones Distal phalanges of toes 2– 5 (c) Deep posterior leg muscles Flexor hallucis longus Distal phalanx of hallux

Fig. 12. 23 • Lumbricals flex MP joints and extend DIP and PIP joints Flexor digitorum brevis Abductor hallucis Abductor digiti minimi Adductor hallucis Lumbricals Flexor hallucis brevis Flexor digiti minimi brevis Tendon of flexor hallucis longus Tendons of flexor digitorum longus Quadratus plantae Abductor digiti minimi (cut) Abductor hallucis (cut) Calcaneus (a) Layer 1 (superficial) (b) Layer 2 (deep) (c) Layer 3 (deeper)

(e) Layer 4 (deepest), dorsal view Fig. 12. 23 (d) Layer 4 (deepest), plantar view Plantar interossei Dorsal interossei • Dorsal interossei abduct toes • Plantar interossei adduct toes