Anatomy 2: Gluteal Region and Posterior Thigh Flashcards
Identify and draw, on a skeletal drawing, the gluteal muscles. Describe and identify the attachments and main actions of these muscles.
*Gluteus maximus
Origin: Ilium to posterior gluteal line and from dorsal surface of sacrum, coccyx, and sacrotuberous ligament
Insertion: distal to IT tract and gluteal tuberosity of femur Extension and lateral rotation of thigh
*Gluteus medius AND Gluteus minimus
Medius is most superior.
Medius - ilium and aponeurosis to greater trochanter
Minimus - ilium to greater trochanter
Abduct femur and medial rotation of thigh.
*Tensor Fascia Lata
Arises from ASIS and anterior iliac crest.
Inserts: anterior of lateral condyle of tibia thru IT tract
Flexion of thigh, abduction and medial rotation of thigh, tensing of IT band
*Piriformis
Arises from pelvic surface of sacrum, inserts on greater trochanter Lateral rotation and abduction of flexed thigh
*Obturator internus
Arises from margin of obturator foramen and inner surface of obturator membrane.
Inserts into medial surface of greater trochanter
Lateral rotation and abduction of flexed thigh
*Gemelli
-Superior: ischial spine to obturator internus tendon.
-Inferior: ischial tuberosity to obturator internus tendon
Lateral rotation and abduction of flexed thigh
*Quadratus Femoris
Origin: ischial tuberosity
Inserts: quadrate tubercle on intertrochanteric crest
Lateral rotation. Hip stabilization.
*Obturator externus
Attaches to trochanteric fossa deep to quadratus femoris
Lateral rotator and stabilizer
Identify and draw, on a skeletal drawing, the posterior thigh muscles. Describe and identify the attachments and main actions of these muscles
*Semitendinosus
Ischial tuberosity to posterior tibia
Extensor of thigh, leg flexor, internal rotation of leg
*Semimenbranosus
Lateral ischial tuberosity to posteriormedial side of medial tibial condyle Same ^
*Biceps femoris
Origin: Long head - ischial tuberosity.
Short head - linea aspera and lateral intermuscular septum.
Inserts - head of fibula
Extensor of thigh (long head, short head NOT hamstring), flexor of leg (short head), external rotator.
d. Identify and describe the origin, course, and distribution of nerves that innervate the gluteal and posterior thigh muscles.
a. Sacral plexus
i. Part of L4 to part of S4
ii. Cutaneous innervation (N470, N528)
b. Superior gluteal nerve
i. Dorsal branches L4-S1
ii. Innervates: Gluteus medius, gluteus minimus and tensor fascia lata
iii. Injuries result in abnormal gait (Trendelenburg test positive)
c. Inferior gluteal nerve
i. Dorsal branches L5-S2
ii. Innervates gluteus maximus
d. Nerve to piriformis
i. Dorsal S1-S2
e. Nerve of obturator internus
i. Ventral L5-S2
ii. Innervates: Superior gemellus and obturator internus
f. Nerve to quadratus femoris
i. Ventral L4-S1
g. Pudendal nerve
i. Vental S2-S4
ii. No innervation in gluteal region
h. Sciatic Nerve
i. Dorsal and ventral divisions of L4-S3 (Ventral = tibial, dorsal = fibular)
ii. Tibial portion innervates true hamstrings, fibular innervates short head of biceps femoris
Identify and describe the origin, course, branches, and distribution of the following arteries: femoral, profunda femoris, medial circumflex femoral, lateral circumflex femoral, popliteal, obturator, superior gluteal, and inferior gluteal arteries.
a. Superior gluteal
i. Largest branch of internal iliac
ii. Gluteal muscles and overlying skin.
b. Inferior gluteal
i. One of terminal branches of anterior internal iliac
ii. Gluteal muscles, upper hamstring, skin over coccyx, sciatic, and hip joint. Typically anastamoses with superior gluteal
c. Femoral - covered in anterior/medial thigh
d. Profunda femoris - Also covered in A/M thigh
e. Popliteal
i. Continuation of femoral as it passes through adductor hiatus
ii. Muscular branches to lower portion of adductor magnus and hamstring to proximal gastrocnemius, soleus and plantaris. Cutaneous branches to posterior leg. Genicular arteries.
Discuss the origin, course and tributaries of the femoral vein.
a.Forms as continuation of popliteal vein as it passes through adductor canal. Becomes external iliac at inguinal ligament.
b. Tributaries:
i. Profunda femoris
ii. Medial and lateral femoral circumflex
iii. Great saphenous
Identify, draw, and describe the borders and contents of the popliteal fossa.
a. Borders
i. Superolateral - biceps femoris
ii. Superomedial - semiteninosus and membranosus
iii. Inferolateral - lateral head of gastrocnemius
iv. Inferomedial - medial head “
v. Posteriorly - popliteal fossa and skin
vi. Anteriorly - popliteal surface of femur, knee joint capsule, proximal tibia
b. Contents
i. Popliteal artery (deepest)
ii. Popliteal vein (superior to artery)
iii. Tibial nerve (most superficial)
iv. Common fibular nerve (closest to biceps femoris tendon)
v. Plantaris and popliteus
vi. Popliteal lymph nodes
Obturator Nerve; origins, if damaged what are the consequences.
L2-L4 - lumbar plexus
Damage results in weakness of adduction and a lateral swinging of the limb due to unopposed abductors.
Femoral Nerve; origins, if damaged what are the consequences.
L2-L4 - lumbar plexus
Damage results impaired flexion of the hip and impaired extension of the leg from paralysis of the quadriceps femoris.
Superior gluteal nerve; origins, if damaged what are the consequences
L4-S1 - sacral plexus
If damaged results in weakened abduction of thigh by gluteus medius, disabling glut. medius limp, and gluteal gait.
Inferior gluteal nerve; origins; location
L5-S2 - sacral plexus
enters buttock through greater sciatic foramen below the piriformus and above the superior gemeli.
Posterior femoral cutaneous nerve of thigh; origins, location
S1-S3, sacral plexus
Enters buttock through greater sciatic foramen below the piriformus
Sciatic Nerve (not real); origins, divisions
L4-S3 - sacral plexus
Tibial nerve division & Common femoral nerve division
Tibial division innervates the hamstrings except the short head of biceps femoris, this is innervated by the common fibular nerve.
Damage to sciatic nerve results impaired extension at hip and flexion at knee. Also, loss of dorsi and plantar flexion at ankle, eversion and inversion of foot, and a peculiar gait to lift the foot off the ground.
Common Fibular (perineal) Nerve; origins, location, consequences of damage
L4-S2
Arises at popliteal fossa but fibers are traceable up into sciatic plexus.
Vulnerable to injury as it passes around the lateral head of the fibula.
Damage results in foot drop (loss of dorsiflexion) and loss of sensation over the dorsum of the foot and lateral aspects of the leg. Paralysis of all muscles in the anterior and lateral compartments of the leg (dorsiflexors and evertor muscles of foot).
Superficial Fibular Nerve; origins, location, consequences of injury
Arises from common fibular nerve (L4-S2) along the lateral side of the neck of fibula.
Descends in the lateral compartment of the leg to innervate skin on lateral side of lower leg and dorsum of foot.
Damage causes loss of eversion.
Deep Fibular Nerve; origins, location, consequence of injury
Arises from common fibular nerve (L4-S2) along lateral side of leg.
Enters anterior compartment of leg and descends on the interossious membrane.
Innervates anterior muscles of the leg and splits into lateral and medial beaches.
Injury results in foot drop (loss of dorsiflexion), hence, characteristic high-step gait.
