1. Muscular System Part D Prepared by Alexander Cheroske and W. Rose.
HESC310
11/15/2018
Muscular System
Part D
Prepared by Alexander Cheroske and W. Rose.
Some figures from Martini et al., Visual A&P,
and Marieb & Hoehn, Human Anat. & Physiol..
Muscles labelled in light gray are not on “Muscles_to_know.html”
and will not be on test.
Portions copyright Pearson Education
Axial Skeleton

2. Muscles that move the thigh
Originate on pelvis & associated ligaments & fascia
Iliac crest
Sacrum
Gluteus medius
(cut)
Gluteal Group
Gluteus medius
Gluteus maximus
(cut)
Gluteus maximus
Gluteus minimus
Tensor fasciae latae
Iliotibial tract
Figure The muscles that move the thigh originate on the pelvis and associated ligaments and fasciae
Gluteal muscles, posterior view
Lateral view of the gluteal region
Figure – 2 2

4. Muscles that move the thigh
Originate on pelvis & associated ligaments & fascia
Gluteal Group
Iliopsoas Group
An anterior view showing the
isolated iliopsoas muscle
group and the adductor group
Gluteus
maximus
(cut)
Gluteus
medius
(cut)
Gluteus
minimus
Tensor
fasciae
latae
Psoas major
Iliacus L5
Lateral Rotator
Group
Inguinal ligament
Piriformis
Adductor Group
Superior gemellus
Obturator internus
Pectineus
Obturator externus
Adductor brevis
Inferior gemellus
Adductor longus
Quadratus femoris
Adductor magnus
Figure The muscles that move the thigh originate on the pelvis and associated ligaments and fasciae
Gracilis
Ischial tuberosity
Iliotibial tract
A lateral view of a dissection of the gluteal region
Figure – 4 4

5. Knee flexors: hamstrings Knee extensors: quadriceps femoris
Muscles that move the leg
Anterior superior
iliac spine
Originate on pelvis & femur
Iliac crest
Inguinal ligament
Gluteus medius
Iliacus
Tensor fasciae
latae
Iliopsoas
Psoas major
Pubic tubercle
Tensor fasciae
latae
Gluteus maximus
Pectineus
Adductor longus
Gracilis
Adductor magnus
Sartorius
Gracilis
Extensors of the Knee
(Quadriceps muscles)
Iliotibial tract
Rectus femoris
Vastus intermedius
(lies deep to the
rectus femoris and
vastus lateralis) SM BF
Flexors of the Knee ST
Biceps femoris
Vastus lateralis
SM+ ST+BF=hamstrings. SM+ST=med ham.
BF=lat ham.
ST, SM, & BF long head originate on post ischium.
BF short head from post femur. Longer distal tendon on ST compared to SM, hence the name. Distally, belly of SM medial to belly of ST.
Figure The muscles that move the leg originate on the pelvis and femur
Semitendinosus
Vastus medialis
Quadriceps tendon
Semimembranosus
Sartorius
Patella
Popliteus
Patellar ligament
Knee flexors: hamstrings
& popliteus
Knee extensors: quadriceps femoris
Figure – 2 5

6. [Right thigh posterior views.]
HESC310
11/15/2018
Figure 1.  Drawings illustrate the three muscles in the posterior compartment of the thigh that together constitute the hamstring muscle complex. The short head of the biceps femoris muscle is deep to the long head. The tendinous nature of the semitendinosus muscle inferiorly is appreciated, as is its raphe. The origin of the semimembranosus muscle is noted to be superolateral to the conjoint tendon.
[Right thigh posterior views.]
Hamstring Muscle Complex: An Imaging Review. Koulouris G, Connell D. RadioGraphics 25: , 2005.
Good review of normal hamstring anatomy and function in gait, followed by review of injuries and imaging – mostly MRI with some ultrasound.
Axial Skeleton

8. Muscles that move the leg
Thigh cross section
POSTERIOR
Semitendinosus
Semimembranosus
Sciatic nerve
Adductor magnus
Biceps femoris
Gracilis
MEDIAL
Adductor longus
Vastus lateralis
Great saphenous vein
Vastus intermedius
Sartorius
Femur
Vastus medialis
Rectus femoris
Figure The muscles that move the leg originate on the pelvis and femur
ANTERIOR
Figure 8

9. Tendon of flexor digitorum
Muscles that move foot and toes
Multiple muscle layers in posterior leg
Superficial Dissection
Deep Dissection
Ankle Extensors
Plantaris
Head of fibula
Gastrocnemius
Popliteus
Ankle Extensors
(Deep)
Soleus
Tibialis posterior
Fibularis longus
Fibularis brevis
Digital Flexors
Gastrocnemius
(cut and removed)
Flexor digitorum
longus
Figure The extrinsic muscles that move the foot and toes originate on the tibia and fibula
Flexor hallucis
longus
Tendon of flexor digitorum
longus
Calcaneal
tendon
Tendon of fibularis brevis
Calcaneus
Tendon of fibularis
longus
Figure 9

10. Muscles that move foot and toes
Lateral View
Medial View
Iliotibial tract
Patella
Medial surface
of tibial shaft
Head of fibula
Patellar
ligament
Ankle Extensors
Gastrocnemius
Ankle Flexors
Ankle Extensors
Fibularis longus
Tibialis anterior
Gastrocnemius
Soleus
Soleus
Fibularis brevis
Digital Extensors
Tibialis posterior
Extensor digitorum
longus
Superior extensor
retinaculum
Superior extensor
retinaculum
Figure The extrinsic muscles that move the foot and toes originate on the tibia and fibula
Tendon of extensor
hallucis longus
Calcaneal tendon
Calcaneal tendon
Inferior extensor
retinaculum
Inferior extensor
retinaculum
Tendon of
tibialis anterior
Figure – 3 10

11. Superior view of foot showing muscles of foot and toes
Superior extensor
retinaculum
Medial malleolus
of tibia
Lateral malleolus
of fibula
Tendon of
tibialis anterior
Inferior extensor
retinaculum
Intrinsic Muscles
of the Foot, Great Toe
Tendons of extensor
digitorum longus
Extensor hallucis
brevis
Intrinsic Muscles
of the Foot, Toes 2–5
Abductor hallucis
Dorsal interossei
Figure The intrinsic muscles of the foot originate on the tarsal and metatarsal bones and associated tendons and ligaments
Tendon of extensor
hallucis longus
Tendons of extensor
digitorum brevis
Figure 11

12. Clinical Example: 69 y.o. male at E.R.
Sx: Stabbing pain & swelling in R leg commenced suddenly, upon standing from sitting position. Hx: At age 13, R Achilles tendon was partially severed. Repair was attempted. R gastrox smaller than L since then, but no pain or loss of mobility until now. Physical exam: Ruptured Achilles tendon suspected. Diagnostic studies: Plain radiographs shows ruptured calcified Achilles tendon. Dx: Ruptured calcified Achilles tendon
Wick and Rieger (2008) NEJM 358: 2618

13. Muscle Actions of the Leg: Summary
Leg muscles:
Plantar flex and evert the foot (lateral compartment)
Plantar flex the foot and flex the toes (posterior compartment)
Dorsiflex the foot and extend the toes (anterior compartment)

14. Muscle Actions of the Leg: Summary
Figure 10.24b