Gross Anatomy- Anterior Thigh Muscles Flashcards
Decsribe the Anterior Thigh Muscles
- Generally innervated by femoral n.
- Contains flexors of hip and extensors of knee
- Includes pectineus, iliopsoas, sartorius and quadriceps femoris mm.
Describe the Pectineus m.
- Flat quadrangular muscle
- Composed of two layers, innervated by different nerves
- Transitional muscle between anterior and medial compartments
• O: Superior pubic ramus
* *I:** Pectineal line of femur, inferior to lesser trochanter * *A:** ADD and flexion of thigh; assists with MR * *N:** Femoral n. (L2, L3); may receive a branch from obturator n. * *B:** Anterior branch obturator a.
Describe the Iliopsoas m.
- Chief flexor of thigh
- Composed of iliacus and psoas major mm.
• O: Iliacus – Iliac crest and fossa, ala of sacrum, anterior sacroiliac ll.
* *Psoas major** – Sides of T12-L5 vertebrae and IVD; TPs of all lumbar vertebrae * *I:** **Iliacus** – Tendon of psoas major, lesser trochanter and femur distal to it * *Psoas major** – Lesser trochanter * *A:** Flexion of thigh or trunk; stabilize hip joint * *N:** **Iliacus** – Femoral n. (L2, L3) * *Psoas major** – Ventral rami of L1, L2 * *B:** Femoral and medial femoral circumflex aa.
• Capable of moving trunk if thigh is fixed
o Bilateral contraction initiates flexion of trunk
• Postural muscle
o Active during standing in maintaining lumbar lordosis
o Resists hyperextension of hip
Describe the Sartorius m.
- “Tailors muscle”
- Long and ribbon-like
- Longest muscle in body
- Passes from lateral to medial
- Is a pes anserinus m.
- Superficial in anterior compartment
- Acts on two joints
• O: ASIS and superior part of notch inferior to it
- I:** Superior part medial surface of tibia (pes anserinus)
- *A:** Flexion, ABD, and LR of thigh; flexion of leg; MR leg when knee is flexed
- *N:** Femoral n. (L2, L3)
- *B:** Femoral a.
- Actions bring lower limb into cross-legged sitting position
- Mainly a synergist
Describe the Quadriceps Femoris m.
• Forms main bulk of anterior compartment
• Composed of:
o Rectus femoris
”Kicking muscle”
Crosses hip and knee joints
Ability to extend knee, limited when in flexion
O: AIIS and ilium superior to acetabulum
I: Tibial tuberosity via patellar tendon
A: Extension of leg; flexion of thigh; steadies hip joint
** N:** Femoral n. (L2, L3, L4)
B: Femoral a.
o Vastus lateralis
O: Greater trochanter and lateral lip linea aspera
** I:** Tibial tuberosity via patellar tendon
A: Extension of leg
N: Femoral n. (L2, L3, L4)
B: Femoral and profunda femoris aa.
o Vastus intermedius
O: Anterior and lateral surfaces of shaft of femur
** I:** Tibial tuberosity via patellar tendon
A: Extension of leg
N: Femoral n. (L2, L3, L4)
B: Femoral and profunda femoris aa.
o Vastus medialis
O: Intertrochanteric line and medial lip of linea aspera
I: Tibial tuberosity via patellar tendon
** A:** Extension of leg
N: Femoral n. (L2, L3, L4)
** B:** Femoral and profunda femoris aa.
• Vastus lateralis and medialis mm. attach independently to patella
• Form aponeuroses, medial and lateral patellar retinacula
o Reinforce joint capsule of knee joint on each side of patella
o Play a role in keeping patella aligned over patellar surface of femur
Describe a test for the Quadriceps Femoris m.
• To test the quadriceps femoris m.:
o Person is supine with knee partly flexed
o Extends knee against resistance
o Normally, muscle should be observable and palpable
o Tests integrity of femoral n.
Describe the Medial Thigh Muscles
- Comprises the adductor group
- Includes adductor longus, adductor brevis, adductor magnus, gracilis and obturator externus mm.
- All supplied by obturator n., except hamstring part of adductor magnus m.
Describe the Adducttor Longus m.
- Large, fan-shaped muscle
- Most anteriorly placed
- Covers anterior aspect of adductor brevis and adductor magnus mm.
• O: Body of pubis inferior to pubic crest
* *I:** Middle 1/3 of linea aspera * *A:** ADD thigh * *N:** Anterior division, obturator n. (L2, **L3**, L4) * *B:** Anterior branch obturator a.
Describe the Adductor Brevis m.
- Lies deep to pectineus and adductor longus mm.
- Two divisions of obturator n. pass anterior and posterior to muscle
• O: Body and inferior ramus of pubis
* *I:** Pectineal line and proximal part of linea aspera * *A**: ADD and limited flexion of thigh * * N:** Anterior division, obturator n. (L2, **L3**, L4) * *B:** Anterior branch, obturator a.
Describe the Adductor Magnus m.
- Largest, most powerful and most posterior of adductor group
- Triangular muscle
- Has adductor part and hamstring part
• O: Adductor part – Inferior ramus of pubis, ramus of ischium
Hamstring part – Ischial tuberosity
I: Adductor part – Gluteal tuberosity, linea aspera, medial supracondylar line
Hamstring part – Adductor tubercle
A: ADD thigh; Adductor part – flexes thigh; Hamstring part extends thigh
N: Adductor part – Posterior division, obturator n. (L2, L3, L4)
Hamstring part – Tibial division of sciatic n. (L4)
B: Anterior branch obturator and perforating aa.
What is the Adductor hiatus?
o Opening between distal attachments of two adductor magnus parts
Located just lateral and superior to adductor tubercle
o Transmits femoral a. and v. to/from adductor canal to/from popliteal fossa
Does not contain saphenous n.
Describe the Gracilis m.
- Long, strap-like muscle
- Most medial of adductor group
- Weakest member
- Crosses hip and knee joints
• Joins with two other two-joint muscles from two different compartments:
o Semitendinosus and sartorius mm.
o Have common tendinous insertion the pes anserinus (goose’s foot)
On superior part of medial surface of tibia
• O: Body and inferior ramus of pubis
- I:** Superior part of medial surface of tibia (pes anserinus)
- *A:** ADD thigh, flexes leg; MR of leg
- *N:** Anterior division, obturator n. (L2, L3)
- *B:** Anterior branch obturator a.
- Synergist in ADD of thigh, flexing knee and rotating leg medially
- With two other pes anserinus muscles, it adds stability to extended knee
Describe the Obturator Externus m.
• Flat, small fan-shaped muscle
• Obturator canal exits superior to muscle
• Deep in superomedial part of thigh
o Deep to adductor longus and pectineus mm.
• Tendon passes directly under acetabulum and neck of femur
• O: Margins of obturator foramen and obturator membrane
* *I:** Trochanteric fossa of femur * *A**: LR of thigh; steadies femoral head * *N:** Posterior division, obturator n. (L3, **L4**) * *B:** Anterior branch obturator a.
Describe how to test the Medial Thigh m.
• To test medial thigh muscles:
o Person lies supine with knee extended and thigh is ADD against resistance o Normally, proximal ends of gracilis and adductor longus are easily palpated o Tests integrity of obturator n.
Desribe the Vasculature of the Anterior and Medial Thigh
• Arteries –
o Femoral a. – direct continuation of external iliac a. distal to inguinal l.
Primary a. of lower limb
One of the four places to take a pulse
Passes through femoral triangle lateral to femoral v.
Superficial circumflex iliac a. –
• Parallels inguinal l. towards ASIS
Superficial epigastric a. –
• Runs subcutaneously towards umbilicus
Superficial and deep external pudendal aa. –
• To skin of scrotum/labia majora
Profunda femoris a. (deep a. of thigh) –
• Chief a. of thigh
• From lateral or posterior side of femoral a.
• Gives off 3 perforating aa., terminating in a 4th
o Supply all 3 compartments of thigh
o 1st participates in cruciate anastomosis
• Medial femoral circumflex a. –
o Supplies most blood to head and neck of femur
Via cruciate anastomosis
• Lateral femoral circumflex a. –
o Mainly supplies lateral thigh muscles
o Divides into the following branches:
Anterior – cruciate anastomosis
Transverse – cruciate anastomosis
Descending – genicular anastomosis
Traverses adductor canal
• Descending genicular a. –
o Branches off just before femoral a. passes through adductor hiatus
o Participates in genicular anastomosis
Terminates as it traverses adductor hiatus
• Becomes popliteal a.
o Obturator a. – from internal iliac a. (usually)
20% branch from inferior epigastric a.
• Accessory or replacement obturator aa.
Divides into:
• Anterior branch of obturator a.
• Posterior branch of obturator a.
o Acetabular branch –
Supplies head of femur
Found in ligament to head of femur
