Muscles to know Lab 21 Muscles of the Pelvis, Leg and Foot psoas major iliacus gluteus maximus gluteus medius sartorius quadriceps femoris (4) gracilus adductor longus biceps femoris semitendinosis semimembranosus tibialis anterior ext hallucis longus ext digitorum longus fibularis (peroneus) longus gastrocnemius soleus flexor hallucis longus flexor digitorum longus Muscles of the Pelvis and Lower Limbs Pelvic girdleis tightly bound to axial skeleton: permits little movement has few muscles Muscles that Position the Lower Limbs 1. Muscles that move the thigh 2. Muscles that move the leg 3. Muscles that move the foot and toes Generally Muscles that are lateral are abductors Muscles that are medial are adductors flexors are on inner surface of joint extensors are on outer surface of joint the Thigh Gluteal muscles Lateral rotators Adductors Iliopsoas group Note: in legs and feet, look at each joint individually (cf. arms) 1
Muscles of hip and thigh psoas major iliacus gluteus maximus gluteus medius adductor longus Gluteal Muscles (1 of 2) Cover lateral surfaces of ilia Gluteus maximus: largest, most posterior gluteal muscle produces extension and lateral rotation at hip Originates on illiac crest, etc., inserts on illiotibial tract and femur Gluteal Muscles (2 of 2) the Thigh Gluteus medius and [gluteus minimus]: originate anterior to gluteus maximus insert on trochanter of femur Figure 11 19a, b the Thigh Adductors Adductor longus: hip flexion and adduction Gracilis (UPPER LEG): hip flexion and adduction Figure 11 19c, d 2
Iliopsoas group 2 hip flexors insert on the same tendon: psoas major originates on lumbar vetebrae, inserts on femur iliacus originates on illium/fossa Move the Thigh Table 11 16 (1 of 2) Move the Thigh the Leg Flexorsof the knee: originate on the pelvic girdle generally: hamstrings Extensors of the knee: originate on the femoral surface insert on the patella generally: quads Table 11 16 (2 of 2) Flexors of the Knee Biceps femoris Semimembranosus Semitendinosus Sartorius: originates superior to the acetabulum long, ribbon-like muscle traverses the quads and wraps around to the back of the knee Hamstrings Made up of: biceps femoris (long and short heads) semimembranosus semitendinosus All are knee flexors 3
the Leg Extensors of the Knee 4 muscles of the quadriceps femoris: 3 vastus muscles: vastus lateralis vastus medialis vastus intermedius rectus femoris muscle Figure 11 20a the Leg Move the Leg Figure 11 20b, c Table 11 17 (1 of 2) Move the Leg Extrinsic muscles that move the foot and toes include: muscles that produce extension at the ankle (Plantar flexion) muscles that produce flexion at the ankle muscles that produce extension at the toes muscles that produce flexion at the toes Table 11 17 (2 of 2) 4
Muscles that Produce Extension at the Ankle (Plantar flexion) Calf muscles Large posterior calf muscles, both insert on Achilles): Gastrocnemius Soleus Fibularis longus Figure 11 21a, b The Achilles Tendon The calcaneal tendon (Achilles tendon): shared by the gastrocnemius and soleus Figure 11 21c, d Muscles that Produce Flexion at the Ankle Tibialis anterior: opposes the gastrocnemius Figure 11 21a, b 5
Muscles that Produce Extension at the Toes Extensor digitorum longus Extensor hallucis longus Toe extensors are on top of foot Note: there are no muscles in toes themselves (only tendons) Figure 11 21c, d The Intrinsic Muscles of the Foot Muscles that Produce Flexion at the Toes Flexor digitorum longus Flexor hallucis longus: oppose the extensors Toe flexors are on bottom of foot Figure 11 22a The Intrinsic Muscles of the Foot Move Figure 11 22b, c Table 11 18 6
Today Lab 21 Ignore muscles that are not on the list Due Next Week 7